Ford 9 inch components in an MGB axle?

[MGBV8]

"...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!

[perrymgbv8]

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....

[perrymgbv8]

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.

[perrymgbv8]

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.

[perrymgbv8]

The rear axle is now fitted

[mgb260]

Perry, Stealth look! Looks a lot like the stock rear axle. I like the steelie rims also.

[perrymgbv8]

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 !

[perrymgbv8]

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.



https://www.youtube.com/watch?v=35k7ePfdrjw&list=UUqIlXfSAoiZ--GyG4tfRrjw

[perrymgbv8]

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

[mgb260]

Perry, Sounds like you eliminated a weak link  with the rear axle swap!  Good luck and keep us posted.

[perrymgbv8]

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

[mgb260]

Perry, Sounds like the rear axle will be fine. Are you using the 3.91 ratio ring gear?

[perrymgbv8]

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

[mgb260]

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.

[BlownMGB-V8]

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

[DiDueColpi]

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

[BlownMGB-V8]

Good point Fred.

[MGBV8]

I would think more gear, as well.  Hard to argue with a 1.37 60' time, though.

Perry, what is your trap RPM & MPH?

[perrymgbv8]

""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

[perrymgbv8]

""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.

[perrymgbv8]

""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

[mgb260]

Perry, Can't knock success! Keep us posted. It is amazing what you've done so far.

[perrymgbv8]

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??

[BlownMGB-V8]

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

[perrymgbv8]

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.