This seems hard to believe, but the British web site, V8 owners forum, has an interesting thread in the drivetrain section. Someone has found that Ford 9 inch spider gears will fit in an MGB differential cage once 10 mm is machined off the backs of the gears. This allows the use of Ford 9 inch axle shafts (though with a custom length) in the MGB axle housing. Further experimentation with a Ford 9 inch spool showed that the spool fits perfectly in the MGB housing using stock MGB bearings. Machining a little off the crown wheel mounting faces on both the crown wheel and the spool gives a perfect mesh of the MGB gears once the usual shimming procedures are followed (new crown wheel bolt holes have to be drilled as well). The next step is to see if an actual Ford 9 inch differential cage assembly will fit...
Larry, Probably the small 9"/8" 28 spline. It would be much easier to use a 4X4 locker in the MGB case with no machining (may need a custom cross pin)and do away with the spider gears entirely. You can get cut to fit long spline axles and make it any width you like. With the Moser 8.8 small 9" bearing ends, Mustang disc brakes bolt up too.
Interesting. I wonder if it would be possible to fit a 9 inch lunch box locker with the same modification?
Scott, that is what I suggest. I looked at the article on V8 owners forum that Larry refered to. It's our friend Perry Stephenson's drag car and he machined the spool to fit and is using the larger 31 spline axles. My idea is to use the Powertrax No-spin, more streetable than the clunkier 4x4 ones but, about $100 more.
http://www.v8forum.co.uk/forum/viewtopic.php?t=12520&postdays=0&postorder=asc&start=0
I have lurked on the V8 Owners Forum for many years, It's a great resource.
Jim's Powertrax suggestion would make much more sense in an MG than a regular locker. The on/off nature of a locker is not very sports car friendly.
WOW, who would ever have thought that?
This is phenomenal news because the axle housing can be retained and still have an axle as strong as any available with that diameter of ring gear. No more weak spiders or axles!
So I have to ask. How about the banjo axle? It uses the same carrier and gears right? So you can do the internal stiffening mods and have a very stout but super light axle, right?
I expect that's the way I'd go if I didn't already have IRS.
However... I must say one thing here. I *have* destroyed an MGB Salisbury ring gear by putting too much torque through it. (But I also have broken spiders, and have broken a transmission case. Have never twisted an axle shaft though, surprisingly. I imagine the 28 spline Ford axles are plenty strong enough. YMMV)
Jim
QuoteHow about the banjo axle? It uses the same carrier and gears right?
No, different carrier and gears.
Also on the Salisbury I think another weak link is the pinion crush sleeve. When the crush sleeve gets hammered with drag race starts you increase clearance and slop. A solid spacer with shims such as Ratech makes for the American axles would fix that.
FWIW, I would like to meet the very skilled machinist, who can actually machine the backsides of spyder and ring gears,AND drill/ tap new mounting holes, at 62rc. hardness ? Soo, the late MGB has very close, to a 9" ring gear dia ? roverman.
No Art, The inner axle bearings are close between the two. Perrry cut the spool way down to fit the MGB ring gear. I've never measured the MGB ring gear but heard it was 7 7/8". I think he is going to redrill the spool or case not the ring gear. The spider gears and ring gear can be milled, but is damn hard on the tool bits and slow going.Or they can be ground down. You would need to reheat treat though I would think.
Just the spider gears, the back side is flat and you should be able to cut those with a carbide bit. May or may not be through hardened but it probably doesn't matter there. The pinion flange could be pinned and re-drilled as well as faced down thinner. May not have to touch the ring gear, it depends on how much meat is there but from Perry's photos it looked like there was plenty. Also it makes a difference which carrier you use. Normally there will be 3 or 4 with different flange offsets for different ranges of gear sizes. If he's using a carrier for a 3.31 it might be possible to switch to the 4.10 or even 5.13 carrier and not even have to machine the flange at all.
I measured the MGB ring gear and got 7-7/8" at the mounting flange but ring gears typically are larger at the teeth so where you measure it determines the spec. At the teeth I believe it would be 8" or possibly a bit larger. But it's been awhile since I measured it. Dana44's are often referred to as a 8-1/2" gear but at the flange they are 8.4" I'm sure Basil could answer that question though. Is the 8" Ford 8" at the flange or at the teeth? I don't know. The MGB gear could be the exact same size as the 8".
Jim
I know the 7.5 ring gear is actually bigger than the 8" because of the angle of the ring gear so I assume it's flange measurement. here is a picture , big hunk of steel.
photo21.JPG
With perhaps less machining ?
As I understand it the intent was to build a stronger axle for drag racing but keep a stock appearing axle. The first approach was to try to put Ford 9 inch spider gears in an MGB differential carrier to allow the use of Ford 31 spline axles. Measurements showed this would work if about 10 mm were taken off the backs of the spider gears. But then a Ford 9 inch spool was acquired and it was found to fit with no modifications except to the crown wheel mounting surface. This is apparently where the original project is going to stop. The unanswered question is if a Ford 9 inch carrier complete with spider gears will fit in the MGB axle housing. If it will, probably the only machining needed would be to the crown wheel mounting area. However this needs to be checked by someone in this forum...
The 9" has 2 different carriers, one large one with 4 pinion and 31 spline side gears. A smaller one with 1 pinion and 28 spline side gears that is practically the same as the 8" except ring gear bolt pattern. I think the smaller one would fit better in the MGB housing. Like Jim B said there is a carrier break for lower or higher gears also that would affect the width same as MGB/MGC. I still think the Powertrax Locker would be easier. It already has the side gears for the Ford axles and would fit in the MGB carrier with modification to the pin and maybe shimming or machining depending on width. I agree with Larry one of us would have to lay out the parts and compare.
I wonder how the 7.5 or 8.8 spider gears would fit into the MGB carrier? It would be great to find a locker that would fit into the stock axle with minimal machine work. One of these days I'll try to get some spider gears out of a junk 7.5 axle at the local pick n pull.....when I can find the time. :)
That might work Scott. I didn't realize the ring gear was bigger than 7.5" on those axles. Wouldn't hurt to get an accurate measurement. Pinions tend to fall within a fairly narrow range of diameters but the spread from large (like 3.08) to small (like 4.10) is much more than you might expect, and this is the determining factor in whether the gears will mesh properly. So the mesh interface for a 7.5 (or 8" - different helix angle though) should fall very close to the mesh interface for the OEM axle with the same gearset, but the mesh interface for a 9" 4.10 might be about where a 3,54 or a 3.08 is for the stock gears, meaning that is some cases you might have to put 3.31 gears on a 200 series carrier for instance. But it's worth looking into, and if the journals don't match up there are a LOT of Timken bearings in different sizes. You also may have to play with spacing the pinion in or out some. In is easy. Out, not so much. Obviously the helix angle, or offset from centerline has to match exactly.
Jim
I think the 8.8 carrier is too big also.The Ford 7.5 spider gears are usually what break under high horsepower, second most failures are the thin main caps(Girdle type cover helps). I would just try to adapt the carrier to fit for the 28 spline Ford axle in the MGB housing. Track-Loc with spider gears for lower than 300HP any more either go Tru-Trac(like Quaife) or Powertrax No-Spin for higher HP. Or just use the Powertrax No-spin for the 7.5 in the MGB carrier with Ford 28 spline axles.
QuoteThe Ford 7.5 spider gears are usually what break under high horsepower, second most failures are the thin main caps(Girdle type cover helps).Or just use the Powertrax No-spin for the 7.5 in the MGB carrier with Ford 28 spline axles.
Jim,
Not sure your last post was in response to mine or not but I wasn't suggesting that I would use the 7.5 spider gears in the MGB carrier. I'd be using them to test fitment for a lunch box locker like the Powertrax.
It still isn't clear, in my mind at least, if it there is an advantage to modifying the stock rear end over just swapping in a narrowed axle. I'm guessing it will cost a bit more to modify the stock axle. Maybe this will be one of those things that some of us will do just to see if it can be done.
Scott, Yes, I did think you wanted to fit the spider gears to fit Ford axles. The main advantage is you already have the axle and there are better ratios now. The MGB axle is pretty tough if you eliminate the spider gears and use a solid pinion spacer instead of the crush sleeve. The one piece cut to fit Ford axles are much better than the 2 piece also. So everything you would do to beef up the 7.5 can be done to the MGB axle. Cost difference for 3.31 gears in MGB axle vs paying someone to narrow the Ford axle. Doing it yourself the Ford would be a little cheaper. For your HP I'd go with the 8.8 instead of the 7.5. I only recommend that for under about 350HP.
Hey, Perry got his 31 spline axles in! Check the V8 forum link above.
I'd say the 300-350 range is going to be a little iffy myself but it's a judgement call. If the helix angle matches the 7.5 it is just possible those and the carrier could be used in the MGB housing, eliminating the machine work and making the swap to new gears, a cheaper posi, and stronger axles a distinct advantage. It's worth looking into.
Jim
Hi Folks!
There seems to be a little confusion on this thread but its mostly on the right lines.
I'll try to be brief: But anyone that knows me already knows that this wont be brief :)
The crown wheel is 7.5" O/D. This is the same for the V8 diff and the 1800cc diff. Both crown wheels have 43 teeth. But the angle of the teeth on the V8 version is steeper to accomodate the angle on the bigger V8 pinion which has 14 teeth as opposed to 11 teeth on the 1800cc pinion.
My first thought was to fit 31 spline side gears into the original diff cage. As I use a welded diff this was going to be done by cutting some metal off the sides to make two flats so the gear would slide into the cage. This was not a bad idea, but the messing around involved in boring out the side bores of the cage were going to mean making some tools for the lathe. While I was playing with a spare axle in the garage I remebered that a friend had given me a 9" spool last year as something to play with. That was easy to fit. The axle tubes are more than big enough to take the thicker shafts. My man at the shop has reduced the raised section of the spool so the MGB crown wheel / ring gear will fit. In order to get the mesh right he is skimming 5mm off the face of the spool. And grinding 3mm off the mating face of the crown wheel. He said the spool was very hard material. And the crown wheel is harder, hence the surface grinding required.
The Shaft bearings for the Ford 9" shafts are a stock item where I work so they are free. The bearing size is what Moser call "Big Ford" ? The O/D of the ford bearings is 1mm bigger that the stock MGB shaft bearings. So my friend at the machine shop has made up a mount so the bearings can go on his paralell grinder / tube grinder to trim them down.
The bearings on the 9" spool are smaller in O/D than the MGB bearings. The bore on the MGB diff bearings is just a few thou smaller than the Ford. So I cleaned up the ends of the spool after cutting off the Ford bearings and heated the MGB bearings in the oven to 220C. They dropped on easily with just a light tap from a hammer with a block of wood.
I dropped the spool in and only needed to trim 25thou off one of the side shims (which were 132thou) to make it sit nice and snug.
The shafts I have are multi drilled. I'm going to use the 5x4.5" holes.
I need to trim the O/D of the wheel flanges down to fit into the recess on the brake drums so I can get them fitted flush.
The shafts are 30" with 8" of splines cut into them so I can trim them to length as required.
I'm going to re drill the brake drums to 5x4.5" and then find some 5 stud steel rims that I can get banded to the backspace and width I want to fit the slicks.
This weekend I'm going to clean up the casing and weld the tubes onto the diff housing.
The brake assemblies will be re fitted as the wheel flanges will sit in just like the originals.
So its just wheels I need to look for now.
Regarding the MGB axle and its strength!!
This is the original MGB V8 axle from 1975. It had 90,000 miles on it when I bought the car back in 1999 and used it as a show car.
The car has been drag raced since 2004 when it was a 3500 with stock tranny and nitrous. In 2006 I fitted the TH350 gearbox and a 4.6 engine with nitrous. We ran like this for 5 years until I started snapping the stock shafts. I then had the MGB shafts copied by Moser and they were very strong. However, they were machined down to 1" at the drive end to fit the stock diff. They lasted really well I think. Up to the point before I fitted the blower I was running the engine with a 600DP carb and a 250 shot of gas which made 390hp on the dyno with 602 ft/lbs of torque. To be honest, the stock MGB shafts would have held this on the dyno as the power build is quite gentle to stop the slicks overheating. But they would have broken on the launch in the strip.
So I now had the 4/71 fitted and the Moser copy shafts. And I kept adding boost and nitrous until I got down to 10.1's on the drag strip. No problems with the shafts or the diff. But con rods were now an issue.
So I scrapped the 4.6 and found a 3.9 to work with. I wont go into too much detail about the engine. But suiffice to say it has a lot more grunt than the old 4.6 did.
When we took the new engine for shakedowns it ran 9.8's on the strip. Then I did a few tweaks and got it on the rollers. With 12psi and a 175 shot she made 525hp with 545 ft/lbs on the dyno with AFR rich and timing knocked back around 10 degree's from where I think it will end up. This again was with a gentle power build on the dyno. The Moser copies were holding up fine with months of 9.6's on the strip while I was testing and data logging.
The car was so predictable that almost anyone could jump in and run a 9.6 second pass with ease.
The car was put away last November and was then hauled out for some use on 19th Jan this year. First pass was a 9.6 as usual. Then I decided to add 2.5 degree's of timing and try again. This time the engine came to life and broke a shaft and twisted the other within 2 feet of leaving the line. So the Moser copies had now been tested to their limit.
After some talks with folk in the USA it seems that the difference in thickness between my old Mosers and the Ford 31 spline (at the drive end) would yield around 89% more strength on paper.
So the obvious thought was to buy a Ford 9" axle and have it shortened to suit my car and have all the brackets welded on etc so it would drop in. And I would want a gear set as close to 3:1 as I could get. This would run out to at least $5000.00 over here.
But $250 for shafts with $290 for shipping I have what I need to work with for a lot less than a full axle.
Which is why I'm doing what I'm doing now. :)
I'm under no illusions regarding the diff. I know that improving the shafts will now just go backwards through the drive train to find the next weak link. That may be the diff gears, the prop shaft or the gearbox which has now been dragged for 8 years ??
If I add on the $400 that I will pay my friend at the machine shop for doing all the work I'm still under $1000 for the whole job.
Track info to date is:
60 foot = 1.37 seconds
The rest you can see here:
https://www.youtube.com/watch?v=N_yCCMlQ7ME&list=FLqIlXfSAoiZ--GyG4tfRrjw&index=16
And the first test run this year with the new exhaust sytem fitted:
https://www.youtube.com/watch?v=119ozwyIVbU&list=FLqIlXfSAoiZ--GyG4tfRrjw&index=9
And what happened when i added 2.5 degee's of timing :)
If you look closely you will see that the new Hoosiers dead hooked and the front left wheel was off the ground immediately. As you can see I backed off the pedal within a few feet. I coasted over the 60 foot beam in 1.40 seconds :) I normally only run high 1.3's with full power in the 60 foot. So hopefully the new shafts will help me go sub 9.5 this year ?
https://www.youtube.com/watch?v=dSKYSH6vmRg&list=UUqIlXfSAoiZ--GyG4tfRrjw
Hey Perry, Thanks for keeping us posted! I just signed on the V8 board and I find you over here!
No problem Jim
I've been quite busy and not had much time to come on here to update :)
Perry
Small update from today!
I welded the axle tubes onto the diff casing and straightened out the bent leaf spring mounts. Tomorrow I will weld in some fillets to make the spring mounts stronger as they seem to be suffering from the leverage effect from the slapper bars on the launch ? Hell ! I may even clean and paint the axle case :)
The axle case is now ready for sand blasting and powder coating :)
The time and effort involved for me to clean the 40 year old casing good enough for me to paint it and get a nice finish just gives me a headache. My friend will do all the work for around $50 all in !!
(http://i205.photobucket.com/albums/bb270/mgbv8_photo/DSCN3937_zpsc2ff491e.jpg) (http://s205.photobucket.com/user/mgbv8_photo/media/DSCN3937_zpsc2ff491e.jpg.html)
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Perry, Welding the tubes to the housing is always a good idea. The small rosette welds holding the tubes in place aren't strong enough for high HP where you get traction. Thanks again for keeping us posted.
I'm now looking into trimming the wheel flanges down to fit the recess in the MGB drums. But as the stud holes in the flanges are 15mm that only leaves about 2mm of metal around the edge if I use the 5 x 4.5" holes.
The MGB studs are obviously smaller, but I havent measured yet !
I'm not too concerned about the lack of metal outside the holes, but I'm wondering if the studs when pressed in will mis shape the thin outer wall and stop the brake drum dropping on?
If this does happen I can weld the studs onto the flange and then turn any extra metal off the outer edge of the flange. I would like to keep my original MGB rear brakes if I can without compromising the strength of the wheel flanges. OR! I could see if I can find some brake drums with 5 x 4.5" bolt pattern that are 10" x 2" which is what I think the MGB brakes are ? Time for some research methinks ?? :)
Perry, Ford Ranger pickups over here have 9" and 10" brake drums with 5x4.5 lug pattern.
Thanks Jim!!
Thats good info mate :)
My friend has an old Ranger in his yard ready to break ?
Perry
Dag nabbit!! He sold the Ranger :(
I'm going to find some cheap wheels to get me by for the near future now. Because I have a dream of seeing Cragars on the MGB now :)
I've loved the look of these wheels since I was a kid. And as my 60th Birthday is only 5 years away I feel I owe it to myself to have Cragars on the car in 2015 or sooner ;)
8-9" Cragars on the rear with Hoosier slicks and maybe skinny Cragars on the front or some centreline front runners with 4" tyres would look so cool I think .. That would make one hell of a track picture at launch with wheels in the air ??
So now I have a plan for the final look of the wheels. but first I need to get some rims so I can go racing when the axle is finished.
Perry, you might want to reconsider those Cragars. They rust, and there's not much you can do to stop it. Matter of fact, despite their popularity (or maybe the cause of it) they really are some pretty cheap wheels. I put a set of brand new ones on my MG way back when and within a year they were going bad. By the time I could replace them they had turned brown and flaky. The joint between the rim and center looked none too solid too.
Now for a really GOOD drag wheel you might look at the polished Centerline Classics. Forged, around 11 lbs each (light as you can get) and strong. Keep 'em shined up and they'll look good forever. Only flaw is the silicon center seal but that can be removed and re-sealed if it starts to leak.
Jim
Cragars have an aluminum center. That's the part that the chrome flakes off of first. Been known to break.
Personally, I like Weld Superlite II or Pro Stars for a good looking drag wheel.
http://ba5ff4f7910368ced8d0-fdac4e44cc35e2759af294e7b095ba3d.r33.cf1.rackcdn.com/weld-draglite-mustang-drag-wheels_7850.jpg
http://ba5ff4f7910368ced8d0-fdac4e44cc35e2759af294e7b095ba3d.r33.cf1.rackcdn.com/5-lug-weld-pro-star-mustang-drag-wheels_5368.jpg
Thanks Jim and Carl.....
Possible disaster averted eh??
Now I have more possible wheels to look at :)
I'm out for a days bracket racing tomorrow with a normal car. But when I get back I'll do some pics of the axle case in powder coat and the next alteration that is required to the 31 spline shafts ??
Regards
Pel
Welds are heavier.
Jim
Perry, Check out these wheels: http://www.team3wheels.com/production_wheels.html
Thanks Jim!
I like the look of some of those :)
Yesterdays bracket racing was a real blast. I did this last year in the tow truck because the MGB does not hot lap. But the truck is in the garge broken so I used the hire car instead. A compact Skoda automatic :)
46 entrants, 3 rounds of qualifying and eliminations. I got knocked out in the 1st final. Won the 2nd final and got knocked out in the 3rd semifinal. I came 3rd overall which was cool. Overall winner was my friends wife inher Jag XK8 auto. And this was only her secnond time on track. She did a RWYB 3 weeks ago and liked it. And although the car is slow she is a demon on the lights and the car is consistent.
Right!
Back to the axle....
Only just in from Mothers days visits so I have not had any the in the garage this weekend. But I did trial fit one shaft by measuring the distance from the mating face of the wheel flange to the rear face of the shaft bearing so I had a measurment to work with. The spool is not fitted so the shaft is not sitting perfectly level.
I slid the brake plate and bearing cap on and got it to sit in place. I slid the shaft in to the required distance (+/- 1-2mm) as it was by eye. And it all looks good so far.
The wheel flange is trimmed on the O/D by 6mm and the recess in the brake drum will be opened out by around 4-5mm so it will sit on flush. I'm using the 5 bolt holes nearest the flange centre. This has left as much meat on the flange as possible while allowing clearance for the brakes and the metal taken out of the brak drum recess still leaves a raised face to locate over the wheel flange so it all lines up on centre.
Next job will be to pull a complete brake assembly off the car as I'm using spare backplates for the mock up. Then I can see if there will be any interference issues with the brakes themselves. So far it looks like this may not be a problem. Then I need to find some studs to fit into the wheel flanges to see if the back of the studs foul anything behind. I cant see this being an issue either.
In order to fit the bearings in the right position I will have to remove about 7mm of the raised section between the back of the wheel flanges where it meets the section of the shaft that is machined down to fit the bearings. Then the bearing shoyuld push on to a defined face and stop there in the right position. This has cheered me up somewhat as I was expecting to have to press the bearings on to a specific marked point and get it spot on.
Now I have another question about C clip eliminators ??
I'm assuming that the bearings will need around 3+ tons of pressure to press into place. These will be clamped into the housing with the existing brearing plate which has an oil seal fitted which pretty much mounts snug onto the thicker portion of the shaft just behined the wheel flange. The car only turns corners at low speed when in the pits. Do I need to worry about a C clip eliminator that would be pressed onto the shaft? I'm using the correct bearings to match the shafts so I assume they will not be a loose fit? I dont think I will have enough room to fit a C clip eliminator kit. So for safety's sake should I add some chemical metal to bond the bearings onto the shafts or should I add some small tack welds on the diff side of the bearings to fix them to the shafts? I can do this by cleaning the coating off the bearing hubs and pressing the bearings into place. Then add some tacks with the big Mig at work while coating the bearings in heat sink Gel and wet rags to prevent any damage to the inner oil seal on the bearings? This is all prototype stuff this time round so I'm not bothered about trying new things :)
From what I can see the C clip eliminator is just another clamp that is pressed onto the shaft like the bearing? Does this clamp need more pressure to press onto the shaft than the bearings? If it does not need more pressure to press it on then 3 good tack welds will suffice I think??
Sorry for the long ramble guys... I'm just thinking out loud at this time.
Here is a shaft and back plate mounted very close to where it should be..
Regards
Perry
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Perry, C clip eliminator doesn't apply to the 9" or MGB pressed on bearings. It is for the 7.5/8.8 to eliminate the C clips on those axles. For the dragstrip on those axles are OK, but leak if doing corners. Best to convert those axles to 9" press on bearing axle retention. No welding necessary, .003 interference press fit and 4 bolt flange keep the axle in. What outside axle bearing did you find that is MGB OD and large 9" ID(.003 smaller than shaft).The spacing of axle flange has to be right for whatever brakes you are using. Might want to copy MGB stock flange to backing plate.
Thanks Jim
The bearings I have are the ones specified for the shafts which are SKF 6307-2RS-3C.
These are a stock item at work so they are free to me. This bearing is 1mm larger in O/D than the MGB stock bearings and 1mm thinner. My mate is going to grind the 1mm off the O/D and make a pair of 1mm shims this week. To get the mating face of the wheel flange in the right place he will remove 9mm of the raised shaft section just behind the wheel flange to extend the section where the bearing will press on.
Thats good that the press fit will do the job :)
The existing seal in the MGB bearing retainer plate fits quite well over the thicker section of the shaft as well. I may get some new ones or even take the shaft and retainer to a local bearing and seals place to see if they have anything that will fit a little better.
I've just ordered 10 wheel studs from a local supplier. The holes in the wheel flange are 0.590" which he says is a stock item at the race shop :)
So things are moving on nice and steady now!! I have to work all next weekend but I'm hoping to have the machine work done middle of next week so I can start assembly and maybe have it together over the Easter holidays. Fingers crossed :)
Regards
Perry
Perry, COOL! Lots of pictures for others to follow.
Tonight was the first proper trial fit.
I wasnt far off with my guesstimate about where the shaft would end up as per the previous pictures.
I had both shafts trimmed back to extend the area where the bearings will press on. I used a spare bearing and took the O/D down by 1.1mm on the belt sander so it was a slip fit in the casing. Then took about 4thou out of the bore of the bearing so it was a slide fit onto the shaft with just light pressure required to push it on by hand.
Then I fitted the bearing and brake back plate onto the axle case and slid the shaft in until it hit the stop up against the bearing.
It looks pretty darn good I must say :)
At least 5/8th" clearance for the back of the wheel studs, but I just need to trim a chamfer onto the back of the wheel flange to clear the bottom brake spring. Cant really see it in the pics but there is about 10thou clearance. I'm just worried about the spring vibrating and touching the flange. I fitted the brake assembly with temp bolts and nuts. When the brakes etc are fitted and the bearings pushed on I will have to fit the bearing retainer plate bolts from the rear and use a modified spanner to hold the nuts while I do it all up.
And you can see the shaft will need to be trimmed to size when the final fit is done. I cant do this until I have the spool back from the machine shop though. The splines in the spool are not central, so I'll need to measure and mark the outside of the spool to show where the splines are and then strike two marks onto the diff case so I can fit the shafts without the spool and mark the pints where I need to cut. This will be done on the loose fit bearings. When the shafts are cut (long on drivers side and short on passenger side for my UK car) I can then assemble the brakes etc and press the bearings into place on the shafts in my mates hydraulic press.
So far so good I think ??
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Brake drums are now being re drilled for the 5 x 4.5" pcd and I hope to have those in a few days. The only issue at the moment is the width of the bearings. They are 1.2mm thinner than the MGB bearings so I nedd some shims. Luckily, the shims for the diff are just about the right size for the job. And I had one at 1.5mm thick and fitted that inside the beraing retainer cap for the tril fit this evening :)
I'll get my chap at the machine shop to trim two spare shims down to 1.2 mm on the surface grinder this week.
More to follow when I can get some time off work
Regards
Perry
Re drilled drums fit perfectly :)
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I should have the spool back on Friday this week :)
I've decided to use cap head bolts so I dont have to take so much metal out of the spool flange for hex head bolts and a socket. Not sure what the old bolts are regarding strength. I assume 8.8 or similar. The cap head allen bolts are 12.9 rated so should be ok?
I'm still waiting for my wheel studs, but a friend dropped round a set of used studs from his Ford axle in his MG Magnette tonight so I can drop them in loose for lining up the drums on the drive flanges so I can drill and tap for drum retaining screws :)
This weekend I will be fitting the spool and crown wheel / ring gear so I can do the checks to make sure the gear mesh is still as it should be. If all the machine work is correct the sshould mesh within a few thou of where they were originally. It wont be long before I have to take the cutting wheel to the shafts to make them the right length. Having looked inside the spool I can see that it was splined all the way through, and then the splines have been trimmed back to give a lenght of splining in the spool which sits with even splining either side of the spool flange. I guess this is done so each shaft (despite being odd lengths) has the same amount of spline contact at the same point from the area central to where the power is transferred into the spool ??
As you can see in the last picture, the axle case has been sandblasted and powder coated to tidy it up a little.
Moved on a bit today!
Got the spool dialled in on the mill and drilled the new bolt circle. As the existing holes are where they are it was always going to have some holes close to each other. But I'm happy with the result so far. I still have to counter bore so 6 of the bolt heads will sit low down at the same level as the existing bolt surfaces. But the two bolts in the thicker section will stay as they are. The bolts are 12.9 strength cap heads and will be fine for the job. I wonder if I could buy a spool that is not pre drilled? This would be great for me.
I sat back in the sun today while my Son in Law and my mate Mike got to checking gear mesh. After 2 hours and lots of measuring we concluded that I need to move the crown wheel away from the pinion by 10 thou. I made a mistake when surface grinding the side shims DOH!!
To save the aggro of re grinding shims it will be easier to take the spool back to the machine shop and have 10 thou taken off the spool face :)
I think it looks quite nice in Silver Sparkle powder coat.
So I'm another step closer to getting the axle back in now !
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Perry, I know you are not done but, the thick part of the spool should be spot faced to have a flat surface under the allen head. The ones that intrude on the holes should have a countersunk hole and spacer under the heads.
Thanks Jim!
Thats on the menu for this week. I'll drop the spool back to the machine shop after work tomorrow and hopefully he will get it done in a couple of days.
I have also decided to drop the idea of making shims to go inside the shaft bearing retainer caps to make up the difference in thickness between the Ford bearings and the MG bearings. I'm just going to trim 1.25mm off the mating faces of the bearing retainers so they will bolt up with no shims inside.
I'm going to use ARP washers under the allen bolts I think. I have spares on the shelf from old ARP head stud kits that I only used 20 bolts from. So I sohuld have at least 16 spare washers in the stock somewhere?
Wheel studs should be at the shop on Wed so by Thursday I may be able to start getting the brake ends fitted and the bearings pressed into place.
I'm in no rush at the moment. I still have 6 weeks in hand too make sure all this prototype kit goes together as best it can so I can be ready for testing in early June.
I have learnt so much in the last 2 months while I have been playing with the rear end, and its been a lot of fun for me to be honest. I cant believe how calm I am about having missed so much racing since the 19th Jan when I broke it again. Normally I would be getting quite twitchy, but as the end result should be a sub 9.5 pass after shakedowns I'm happy to wait. An dif that goes ok I'm going to start looking at adding some power and then start aiming for the 9.4's :)
Regards to all from a lovely warm and sunny UK today 67 degrees and no wind.. Hell, I even cut the grass today.....
Perry
Perry, When you get ready to bolt up the Allen's for the last time, you should use blue Locktite on the threads and torque in back and forth pattern in 3 stages.
Perry,
Your determination and unyielding drive to complete this project is an inspiration.
I particularly enjoy your problem solving and "oh that won't work, we'll just do this instead" attitude.
I can hardly wait to see it run.
Well done.
Cheers
Fred
Thanks Guys!!
A little more progress today. We trimmed another 10 thou off the spool face and got it pretty darn flat. I blued the face of the ring gear and spun it on the spool to see good contact marks all over :)
We bored and paired the washers on the lathe from EN40 steel stock so I now have nice hard washers !!
We re milled the bolt holes as well. But now my bolts are too short Ha Ha!!
No problem as I can call my nut and bolt guy in the morning and he will post me some 3/8 unf 12.9 grade bolts in 3/4" length to replace the 1" I have now.
I have mounted the spool and ring gear on the table and with a dial gauge all I can find is 1 thou of error all around the mating face. And the ring gear has been checked with a feeler gauge all round to make sure there is no gap evident with the bolts just nipped up gently in sequence. So I think I'm going in the right direction ?
Its holiday weekend coming up so on Friday I will clean everything with carb cleaner and make sure all the surfaces and holes are clean and dry. I will then bolt the items together as per Jims comments with loctite and ensure I reach the final setting of 65 ft/lbs in sequence. On Saturday I will drop the spool in and start checking mesh on the gears so I can figure out the final figure I need for the spool bearing shims.
I have had the 1.25mm ground off the bearing retainer caps so they are now ready to install when I have re ground the wheel bearings.
I hope to have a call from Webster Racing tomorrow to say my wheel studs are in the UK as well.
And if all goes ok this weekend I may be ready for final marking and cutting the drive shafts to length? But I do also need to tidy the garden and take lots of junk to the rubbish tip as promised to my long suffering wife.
I can now see a small glimmer of light at the end of this tunnel now. And I'm looking forward to shakedown runs by the end of May :) I am hoping to get back out and drop straight back into mid 9's on the 1/4 for shakedowns in the near future. And then I will be gunning for a sub 9.5 pass as my starting point on the way to that elusive 8 with the MGB.
In the meantime I have to crew for my friends Methanol slingshot on 26th as well as another friend who is rolling out his Ford Capri avec 598ci big block !!! Should be a hoot.
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"...my friends Methanol slingshot"
Would that be the front engine Digger in one of the pics? Any action video of it? Looks like a fun ride!
Hi Carl
Yes, thats it in the picture :)
I have some vids I'll dig out soon. We havent made a full clean pass in it yet as we are still learning how to drive the thing. The best run was a sloppy launch on the transbrake at 1800 rpm which put the front wheels in the air. He then backed off and tickled the pedal to get it running straight. But each time he hit the power the rears just ballooned and let go. He pedalled it 4-5 times and backed off each time. It still ran a low 10 though.
I'm sure when we have it dialled in and working ok it will run high 7's with no issues. The next 6 or 7 months should see the car running ok, and I will be driving it again for some shakedown passes. The methanol engine has been a long and interesting learning process for the last 2 years. I thought my carb system was basic. But the mechanical injection setup on the Slingshot makes my fuel system look positively cutting edge :) So many pipes and by pass valves !!!
My wheel studs and nuts have now arrived from Summit. When I opened the box I thought they hade made a mistake as there were 4 bags of nuts, with 4 nuts in each bag?? Then I remembered that I now have 5 nuts per wheel. I then thought how odd it was that there are only 4 nuts per bag. The wheel studs come in packs of 5 but the nuts in packs of 4?
I'm not sure how expensive these items are in the USA. But the 10 studs and 12 nuts were delivered today for the sum of $147.96 inc of all taxes etc.
I'll be back in the Slingshots garage tomorrow for more trial fitting of my spool....
Dagnabbit!!!
The wheel studs where wrong GRR!!!
So Friday was not going well. I rang several Drag Race buddies and by Saturday 10am we had found a new set of studs just 70 miles from my house. By Saturday afternoon the studs were fitted :)
So the weekends work was now back on track.
I ground the wheel bearings down to fit the axle case and continued with the trial fitting.
I found another problem with the wheel bearing retainer caps. After trial fitting I found they need 10 thou trimming off the mating faces to ensure correct clamping off the wheel bearings.
I'm happy though, because tomorrow I will drop the caps through the letterbox at the machine shop with a note to say I need the done TODAY.... As soon as I collect the bearing caps I will go a my friends workshop and press the bearings onto the shafts.
So on Wednesday I will have the last parts I need to assemble the axle to hopefully have it ready to run next weekend?
The last job for final fitting will be to double check my measurements and attack the drive shafts with a cutter to trim them to the correct length :)
Tomorrow (Monday) I will be collecting my Ebay Slot Mags which are 5 x 4.5" pcd. The back space on these rims is 3.5" and my old ones are 4" so they will fit just fine I hope.
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Today was the last leg of the job I think. Shafts cut to length. The final fit was as expected with 4mm of space between the shaft ends in the spool.
I'm so close now. When the bearing caps are milled down by 10 thou I'm ready to fit the brakes and bearing caps so I can press the bearings on. Then bolt it all together one night this week. My new problem is the wheels. I collected them today, but one of them has some damage in the stud holes. They were used on a fuel altered and obviously one of them had wheel nuts come loose to the point that the holes are now slightly ovel with thread marks inside. I'm taking the wheel to the machine shop tomorrow to see if my friend can over bore the holes and make some top hat liners in ally to slip in. Then I can weld them in place. Or make them from stainless steel to a tight fit so I can bond them in with epoxy or my favourite JB weld. Or maybe even re bore the holes and thread them, and have the liners threaded so they can be screwed in with loctite. I have a lot of options on repairing the holes. Because of the damage I got the seller to let me have them for next to nothing, so I have money in the budget for repairs now. Check out the cuts on the shafts ? I may be old, but damn I'm good with a disk cutter :) I put the chamfer back on with a scurfing disk.
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The rear axle is now fitted :)
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Perry, Stealth look! Looks a lot like the stock rear axle. I like the steelie rims also.
Hi Jim
Apart from the missing handbrake cable and brackets the exterior of the axle is as stock :)
Its just the wheel studs that tell a tale eh ;)
My Grand Daughter likes the steel smoothies !
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Did some shakedown runs today and the axle conversion seems to work ok ??
Long story short!
Several test runs on boost only gave me a string of 10.8's.
Turned the gas back on with real gentle launch setting and long build time got me back in the 9's with no drama. I have added 3 degree's of ign timing as the engine has run safely retarded for nearly a year now.
The result is slower 60 foot times of 1.5's instead of my usual 1.3's. But the added timing makes the engine pick up and rev better. Even with the 1.5 60 foot times I ran just a tenth slower with a 9.7 on my quickest run, BUT I ran faster with 141mph as opposed to my old 137-138mph 9.6 second passes.
I will drain the axle and open it up this week to check it out. If it looks ok I can get the car ready for next weekend which is two days of RWYB when i will think about adding more power for the launch ??
Pic shows less air with the gentle launch, and the vid of the slower 9 shows just how soft the launches were today, even with the better MPH !!
Sorry!! the vid is a silent slo mo. But the launch shows good info. The rest is slow and boring.
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https://www.youtube.com/watch?v=35k7ePfdrjw&list=UUqIlXfSAoiZ--GyG4tfRrjw
I drained the diff oil and saw nothing in it. I took the back cover off and scooped out what oil was left laying inside on my finger. I found some microscopic shiny particles on my finger. This does not worry me to be honest :) The moving parts are all 39 years old and I have upset them from their old resting place, so I guess they need to settle back into the new resting place now?
The wear marks on the ring gear are all central on the teeth which I'm happy with.
The slop between ring and pinion can be felt when I try to rotate the propshaft back and forth, but it cant really be seen. I can just feel a little something when I wiggle the propshaft. ?
I have to say that I'm a litte concerned with the amount of slop between the drive shafts and spool when I try to turn the wheels. But my mate with the Slingshot says this is the amount of play he has on his new setup so I should not worry ??
The diff now has new oil and is ready for next weekend. After 3 months of no racing I now have two whole days of track time coming up. And I am hoping to come home with a 9.59 second ticket on Sunday :)
Perry, Sounds like you eliminated a weak link with the rear axle swap! Good luck and keep us posted.
Darn it!!!
I was hoping to do good stuff last weekend. But I had a weepy head gasket which I changed at the track. During the course of stripping to replace the gasket I found I had a broken adjuster stud on one of the Kenne Bell roller tip rockers GGRRRR!!!
So I made got some Loctite permanent stud lock and glued the sucker back in place after deep cleaning with carb cleaner. I didnt want to go mad so I set the shift light down at 4800rpm and decided to use that as my rev limit while testing the head gasket repair. When I reached the shift light in top gear I backed off the pedal a little to cut the nitrous just before the finish line. I hot lapped two 9.7 passes and called it a day.
I have now removed the broken stud (which had not moved) and I am re tapping the rocker to take a Chevy Pro Comp adjuster which is slightly larger in diameter. So I can run next Sunday while I have some used rockers coming in the post.
The axle seems fine as I did my usual burnouts and then let it drift out of the bleaches box while under power until it hooked just before the start line so it would give the axle a shock load. All seems fine so far :)
Perry, Sounds like the rear axle will be fine. Are you using the 3.91 ratio ring gear?
Hi Jim
I'm still using the factory V8 3.07:1 diff gears which now have over 110,000 miles on them ;)
The car had 110,000 miles on it when I bought it back around 2000. I think i put around 2000 miles per year on it until 2007 when it came off the road for track use only. So it may be closer to 115,000 miles now. :)
Perry
Perry, Most over here use 4.10 or lower. Basil on the Mgexperience board has new 3.31 ratio also. You might have quicker times with the 3.91 gears but a lot harder launch. I was the pit crew on my brothers Pro Gas/Bracket Chevy Vega. SBC 400,Power Glide, 4.10 9" Ford rear. Just a gutted shell for the body with Art Morrison Suspension front and 4 bar rear. He was in the high 9s without Nitrous or blower.
Wow Perry, a 3.07 really? That's amazingly quick with that gear. A 3.54 or 3.73 might also be good choices.
Jim
Ok, so it all makes sense now.
I think a lot of Perry's longevity is due to his gear choice.
His car just runs hard all the time and doesn't tear things up very often.
That gear ratio is very easy on everything.
He doesn't have to RPM to make the car move. Which keeps his fragile engine together.
Launching is softer so the chassis stays together.
And the 3.07 ratio means that the pinion gear is larger so it has a much better chance at staying together.
He might ET a little better with a higher ratio but the mph will drop and the breakage will increase.
Such a light car with a blower and nitrous won't be as sensitive to a gear change as you would think.
I would keep that ratio as long as you can Perry, and find the speed in the rest of the car.
But most of all, enjoy the heck out of it. That's why we do this isn't it?
Cheers
Fred
Good point Fred.
I would think more gear, as well. Hard to argue with a 1.37 60' time, though.
Perry, what is your trap RPM & MPH?
""But most of all, enjoy the heck out of it. That's why we do this isn't it ""
Thats my intention Fred ;)
Regards
Perry
""I would think more gear, as well. Hard to argue with a 1.37 60' time, though.
Perry, what is your trap RPM & MPH?""
Hi Carl
She has been running around 5200rpm across the line with 138mph.
But recently since I started adding timing she has run 5500rpm with 141mph.
But I think I am now driving through the torque converter or the gearbox is slipping as after a few runs with added timing giving me the better mph she is now slowing down to just under 140mph with the same rpm?
I cant complain as the gearbox and coverter have been dragged now for 8 years solid. I have a new transbrake gearbox waiting to go in later this year. And I'm going to talk to Coan about a new converter. Some of my friends have pointed me to this company as they have had their converters done by them. Apparently I need to fill in a form to tell them about engine power and max rpm + gear ratios and tyres sizes etc. And they will come back to me with some details on the converter I should be using from now on.
The converter I have fitted is a TCI nitrous holeshot unit that locks up around 2800-3000 rpm. But I make peak torque at 4000rpm now.
""Perry, Most over here use 4.10 or lower. Basil on the Mgexperience board has new 3.31 ratio also. You might have quicker times with the 3.91 gears but a lot harder launch. I was the pit crew on my brothers Pro Gas/Bracket Chevy Vega. SBC 400,Power Glide, 4.10 9" Ford rear. Just a gutted shell for the body with Art Morrison Suspension front and 4 bar rear. He was in the high 9s without Nitrous or blower""
I can see that a 6.5 litre (400 ci) engine which possibly revs to 7000 in a light body would hit the 9's.
Mine is a small Rover 3.9 Litre maxxed out to 4.8 litres (293 ci) in a 2600 lb car. which isnt that heavy, but its no lightweight either compared to the tube framed MGB's with composite bodies that race the circuits.
The reason for keeping the original factory MGB gear set is the same reason I still run a Rover V8. I need to be able to make the numbers with a Rover V8 engine as that is what my car came from the factory with. I have fitted better drive shafts but I have retained the original factory diff gear set and ratio. And changing the gear set = money I dont have.. ;)
Perry
Perry, Can't knock success! Keep us posted. It is amazing what you've done so far.
Thanks for the support Jim!
I am very happy with what the car has done so far with the Rover V8. Sadly, a lot of folk over here who run bigger cube American engines in their UK cars are not so happy for me when I beat them on the 1/4 mile?
There does seem to be a trend over here where folk fit big ci engines in their UK cars, but then run them with a mild tune so they run reasonably quick without wanting to stress the motors. But they are not very quick on the 1/4 mile? I spoke to one guy who runs a small block chevy in his UK classic and he said it was tricked out to the max. But it only runs high 11's. When I asked him about using nitrous he said that he could not do that because SBC's are notoriously weak and would split in two if he used nitrous?? Who the hell told him that??
I forgot you were using an automatic. Is it the BW-35 or something else? That changes your choice of axle ratio of course and the 3.07 sounds a lot more reasonable with the small diameter tires you can fit under the MGB.
Jim
Jim!
I run a Chevy TH350 3 speed gearbox with a B&M ratchet shifter. This is a stock gearbox that I bought new back in 2006. I nade the Rover to Chevy adaprtor plate at home in 2006.
I dont use stock sized tyres. I run Hoosier 28 x 9 x 15 slicks on the rear end. A sopposed to the 24" tall stock MGB tyres :)
My problem has been running out of gearing over the years so I have countered that by increasing rear tyre size to compensate. I just cut out the steel arches / wheel wells so the tyres would fit and then covered the carnage with Sebring fibre glass covers to keep it looking slightly pretty. The engine is not a screamer. Its a torque monster up to 6000rpm with the sweet spot being around 5500rpm.
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If you are now crossing the line at 5500, sounds like you have the gearing & tires figured out.
Hang on & have fun!
Hi Carl !
I'm crossing the line at 5500 but the mph is dropping off. I'm now talking to Craig a Coan about a new converter. My B&M converter is only rated for 350hp. And I think its slipping now. I need to make sure that the converter and gearbox are working ok to make sure I can have a stab at an 8 second run this year.
Perry
Perry, you and the GT are "BAD TO THE BONE"
Thanks Kelly!
That made me laugh :) It could be a name for the car?? I've been thinking about giving the old girl an identity.
I'm very happy with the axle modification so far.
I took it out last Sunday to run on an old airfield. I ran a 10.6 and then a 10.4 which is very good for a concrete surface. The 10.4 came from me launching at half pedal and then going flat out after a couple of seconds. So I had an idea to programme in a nitrous delay of 1 second and then launch flat out on boost only. I have to say that this was not one of my better ideas on track :)
The tyres let go on the launch and then the nitrous dropped in and the tyres got to skipping and gripping and bouncing me all over inside the cabin. I leaned forward in the car as my helmet was banging on the roof and kept my foot in as long as I could. But I had to shut off a good way before the finish as the car was quite unstable. She still pulled a flat 11 with no power for the last 100 feet or so which was fantastic :)
So I put her on the trailer and did something that I dont normally get to do at the track. I watched some racing for a couple of hours and also got dragged off to help some guys with BBC and SBC motors in their classic Fords who were having ignition timing troubles. Sadly one of the guys who had fitted the SBC into his old Ford Pop clearly had a bob weight spring broken. This news really upset him as he has to remove the engine and tranny to remove his distributor ???
Anyway!
Here is a vid of how not to do it on concrete :)
Regards
Perry
https://www.youtube.com/watch?v=vEMFQgDulT0&index=2&list=FLqIlXfSAoiZ--GyG4tfRrjw
The rear axle is working very well now. I can hit it with all i have off the line. But as I add more power from the Rover V8 I get lower ET's on the strip.
I hit it as hard as I could oiff the line last weekend and it hooked ok and carried the front wheels for around 60 feet off the line. But as soon as the engine gets a hold the rpm's climb above normal and I run 9.8's instead of 9.6's or better :(
So I'm now backing off around 100hp to reduce the slip on the converter for the rest of this seasn while I save up for more stuff !!
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Perry, great job ! What is your estimated hp ? What crankshaft is surviving this torture ? Rods ? Cheers, roverman.
Hi Art!
Sorry for the delay in replying. Work has been hectic and then I had my holiday and I'm just back in the UK now.
Dyno HP was 525 with 12psi and a 150 shot of gas. But the run was cut short as the slicks pretty much caught fire on the rollers with full power. So I guess its 525hp+ ? Since that time I have added another 25 shot of gas. My ESTIMATE is 600hp with 600 ft/lbs at this time.
The crankshaft is a stock Rover 3.9 that has been offset ground. The rods are stock Chevy 5700's.
The torque converter is only rated for "up to" 350hp so I'm not surprised thats its slipping a little now.
I spoke to Caon Racing and gave them all my specs and they said I need a converter that will handle over 800hp with a stall sped of 4200-4500 rpm. My present converter is a 3000 rpm stall item from B&M. So i know I wont get any better on the track until I swap out the converter and start testing again. I can see that this extra half a second on the track is going to be expensive now :)
Even tohugh the MG is suffering with tranny issues I took it out for a weekend at the Mopar Nats here in the UK. The MGB was given a warm welcome by the Mopar Muscle guys and I had a great weekend.
I was trying to make some adjustments with the nitrous and boost so as not to over power the converter and the results were good and not so good overall. On the Saturday she ran reasonably well but she struggled to get below 9.8 on the strip. And on one of my runs i got it all wrong and had the most odd launch which my friend caught in slo mo. I hit the pedal and she backfired and died for a split second. So I backed off and got back on the pedal again. By this time the car was all over the place. But I kept my foot in for a real funny launch as you can see in the vid. The run wasnt very good but the slo mo makes me laugh everytime I see it :) I even felt a litte tyre shake ??
https://www.youtube.com/watch?v=wJw3Be2xpVs&list=UUqIlXfSAoiZ--GyG4tfRrjw
Then I got back on Sunday morning and ran a 9.62 straight off the trailer with no drama which made me smile and also set the tone for the day ahead. As the air temps rose the car got slower as usual and for 2 runs I was on my own as nobody in the queue wanted to race me ? WHAT!! I was in the RWYB queue and two times in a row the guys next to me in the queue held back when we were called forward? The first guy was in a really cool Dodge Dart that looked like it was pretty well tricked out. I had been talking to him for an hour in the queue. But when we got called forward he held back so I had a solo run. The next run was going to be with a Plymouth superbird. He did the same and let me go on my own. On my next run I got to the front to be called forward and the guy in the other lane held back as well ? I called to the guy who was running the queue and asked why I had to run on my own. So he called on one of the super street class cars forward and asked him if he would race me. And he obliged. So we had a really good side by side race for my last run of the day.
https://www.youtube.com/watch?v=yZiAcxWUrr8
I also did a side by side with the other car I have been working on for the last 3 years while he did some shakedown passes just before hte Mopars :)
https://www.youtube.com/watch?v=z0TnF551c-0
Perry, Cool videos! I have a question on your rear axle. Did you use the crush sleeve or solid spacer?
I'm still using the original 1975 crown wheel and pinion gears Jim. The car had 110,000 miles on when I bought it 16 years ago. So it has a few more miles now. The old crown wheel was re used on the spool as you know. The only work the diff has had was new pinion oil seal when I had it apart for the mods early this year.
Perry, I thought maybe you did a custom solid spacer as the crush sleeve will take a pounding and start to loosen up.
Hi Jim
I decided to leave the diff as is. Mainly to see what it will take in stock form. I had the prop shaft off last weekend to do a box and converter swap and could not feel any play in the pinion when I heaved on the diff flange? The pinion does try to push towards the front of the car when under acceleration. But this force is held in check by the very large inner pinion bearing. So i dont think the crush sleeve will suffer much even with 700hp being put into the diff :)
I will however keep checking the pinion play as the bearing will no doubt start to suffer in the future. The inner pinion bearing is a huge item which is why I am not worried about the potential crush sleeve issue. I've seen this discussed on forums and have wondered why folk think that the crush sleeve would be affected ?
My understandng is that the crush sleeve is there to set the pre load between the inner and outer bearings during assembly.
Regards
Perry
Perry, With your auto trans you probably won't have issues. Probably the racers with manual trans dumping the clutch is what hammers the crush sleeve in some rear ends. Keep us posted!
That should be interesting Jim!
I've just swapped out the stock TH350 for a race version with transbrake fitted. And a new 4500 stall converter to replace the old 3000 stall converter so I can give it some more power on the launch :)
I'm going to take it easy while I learn how to use the transbrake though. I do not have a launch rev limiter setup yet. So it will have to be "seat of my pants" launches for the time being !
So in anticiaption of the harder hits off the line I'm going to wind up the slapper bars so they are pretty tight on the rear springs to make the rear end a bit more solid to improve the 60 foot times if I can. I have a wheelie bar kit ready to fit if required, but I would love to run 9.5 or quicker without wheelie bars if I can. ??
Perry
Well !!
I went out last weekend and did some testing. And what a fool I am :)
I did 5 test passes and 4 of those test passed saw me shifting from 1st to N ?? I had real problems teaching myself to pull the stick backwards on the new gearbox after the launch. At least i know that my rev limiter works I guess :)
On the one pass where I actually got the gear shift right, the tyres let go in 2nd gear so the run was quite slow.
As I tried each pass on the T Brake I increased the launch rpm. On runs 4 and 5 I held 4000 on the T brake and made 1.4 and 1.5 in the 60 foot (these were non nitrous passes) and still hit 10.9's with the missed gear shifts. It was 1st gear off the line, and then neutral, and then hear the limiter popping and pull back twice to 2nd and then again to 3rd gear. I'm hoping that when I go out again I will get it right and run a 10.7 on boost only. When I do that I will turn the gas back on ??
Perry, Thanks for keeping us posted!
I forgot to post a video :)
This is me missing 2nd gear again !
http://www.youtube.com/watch?v=8BXRnsAeeR8&list=UUqIlXfSAoiZ--GyG4tfRrjw
Its nearly time to go racing again :)
I have been practicing my gear shifts and if all goes well I will find my 10.7 with no gas on Saturday.
If i can do a couple of pulls and get my shifts right I will turn the gas back on. Then i will be wanting to come home with a 9.5 timing ticket in my pocket !
Wow, Perry. A nine second quarter in a Rover powered MGB! Wouldn't that be spectacular.
Jim
Can't wait to watch the video!
Jim!!
I've been running mid 9's for a year now. The norm is a 9.6 when all goes ok. I've done around fifteen 9.6 passes now :)
https://www.youtube.com/watch?v=Xs-elD0eyDk&list=UUqIlXfSAoiZ--GyG4tfRrjw
I'm acutally hunting an 8 second pass from now on !
The new torque converter may be the key to having my Rover V8 engine power matched to the transmission now. I did a test pass last weekend with the new converter and the same old nitrous settings. The launch was, well ! quite exciting to say the least :)
https://www.youtube.com/watch?v=nVscbPHgue0&list=UUqIlXfSAoiZ--GyG4tfRrjw
https://www.youtube.com/watch?v=eg3avnsNKrc&index=1&list=FLqIlXfSAoiZ--GyG4tfRrjw
Perry, Looks like it is time for wheelie bars!
Looked like you peddled it a bit. The crowd always loves it when the front end reaches for the sky. :) Don't beak anything, though.
You Big Game hunter, you!
All I can say Perry is WOW!
Your little MGB has got it "goin on"
I know it goes against everything proper and right. But have you thought about moving the driver to the left side?
On every launch that I have seen, your car is really light on the left. To the point that the right rear tire is having trouble carrying the entire weight of the launch.
This can be tuned out of course, but at a detriment to high speed stability and reaction time, generally.
Moving the driver over is cheap, and costs nothing in power.
Just a thought.
And again "go get em man" I'm thoroughly impressed!
Live like you mean it.
Fred
Thanks for the comments guys!
That launch took me by surprise I must say. I backed right off until the car had got back on 4 wheels and then put my foot back in again. Bit I had been off the pedal for 1-2 seconds I think. I'm more than happy that this would no doubt have been my sub 9.5 pass for sure :)
I'm going to take a little time out to re think things now. I have wheelie bar parts in the garage. I know that I now need to back off the nitrous onnthe launch as well.
I do need to do some checks on the suspension and the landing was quite hard and I can see some slight damage underneath. But thats drag racing eh?
I'll figure out all the problems I have now developed with this new found power and then I'll be back out gunning for my 9.0 pass :)
Perry
He really means 8s. :)
Imagine that, an 8 second Rover powered MG!
Who would have ever thought it would happen?
Jim
""He really means 8s. :)""
Are you a mind reader Carl ?? ;)
I have been at this so long now it would seem rude not to secretly hope for an 8 :)
Back in the day we were gunning for sub 12 seconds. Then got stuck a whole season on low 11's right down to many passes with an 11.0? The 10 eventually came and we enjoyed a whole year of doing them. We then kicked it up a notch and found the 9's. Then the regular mid 9's for a year. Then came the axle mods and the new torque converter, and thats where we are now with the car. And I must say its great to feel like I'm on the verge of another improvement now. I'm not rushing though. I want to take some time to give the whole car a good going over and do some refurbishment of the cylinder heads and refresh fluids etc. I may take her out at the end of the month for some demo runs at a show. But I'm not going mad. I would like to start next season ready to learn how to drive it again.
Regards to all
Perry
Mind reading not needed. As much as you would enjoy telling someone that your MG did the quarter in 9 flat, in your head you would know that you only needed one more thousandth and you could tell the world you put it in the 8s!
It'll happen. No doubters here.
Thanks Carl.
I do think that there could be an 8 in the car for next year. It makes me shudder a little when I mention the number 8 though !!
But then I shuddered a while back when I spoke about a 10 :) Then we found the 9.6's time and time again. So I guess the 8 may be possible for next season. I think I have done all I can to this old Rover V8 so I hope it will hold together for a new PB next year ? I still run normal pump gas + boost + nitrous on this home modified Rover 3.9 engine in a car that weighs in at 2800 lbs with me in it on the 1/4 mile. What ever happens from now on I will be happy. If I can beat my 9.62 PB I will be one happy camper :)