MGB Roadmaster

[Bill Young]

Looks good Jim. Good to have Willy's input on the rear end, experience is always appreciated. Remind me again why we're using a big block Buick instead of something more exotic? I see you have the Florence anti gravity machine working again, so some power source using dilithium crystals should be easy! ;-)
I think we need to leave the body width alone, I don't think I can find any flares wide enough to cover those meats unless the rear axle is narrowed, we were just lucky with the Omni flares showing up at the right time, don't press our luck.
Looks like I'll be able to make the trip to Port Washington after all, so seats will be delivered for the car there. Anything else I can bring up from KC?

[Citron]

Jim,
I was in Mauldin yesterday.  I can not get the seal washer.
Had scare here over the weekend.  I was loading the wheels and tires in the trailer and something in my right arm popped.  Lots of pain, many phrases used that I learned in the Navy.  Sore all weekend.  DR. says I have a ruptured bisept tendon.  They don't usually fix that sort of thing.  Just leave it alone.  Arm now feels fine.  I may not be able to leap tall building anymore.

Steve

[MGBV8]

"I think we need to leave the body width alone, I don't think I can find any flares wide enough to cover those meats unless the rear axle is narrowed"

I wasn't talking about bigger flares. Split the whole thing right down the middle.  Hand me a chop saw!  ;-D

[BlownMGB-V8]

It's OK about the washer Steve, it turns out it can go in later by unbolting and removing the spline. I can maybe find something for a temporary spacer. It'll be late tonight before I can look at it. Sorry to hear about your arm. Won't that make driving painful? I wouldn't expect you to make the trip in your somewhat weakened condition.

I'd respond to Carl but that might only encourage him. Bill, I'm sure glad you can come, and not just because of the seats either!

Jim

[Citron]

Jim,
Arm does not hurt, but is not strong yet.  I will be albe to drive with no problems.  I will leave in the morning, not sure what time.  
Should reach you by late afternoon or early evening.
Can't wait to see the progress.  Really want to see it on it's wheels.

Steve

[BlownMGB-V8]

Steve, we'll do it if we can.

I put the one good hub assembly together and installed it on the car with the vette wheel and 315/35-17 tire. Now bear in mind that we're planning to use 275/35-17 tires on the car, so that means we have an extra 40mm to play with, or about 3/4" per side, inside and outside. With that in mind I've taken measurements on the long side (right, or passenger-US spec) at various points in the suspension travel. Droop is limited by LCA interference with the brake rotor and beyond a certain point has no bearing on track width, but at a point somewhere in the neighborhood of 3" below nominal ride height it does limit track by interference with the inner shock mount bolt head and with the frame section lower seam. This seam can be folded inward somewhat but clearance to both it and the bolt head with these tires is almost exactly 2", measured on an axis roughly parallel with the half shaft.





The other limiting factor is in compression, at the point where the tire would contact the inner fenderwell. Because we have not yet cut the fenders for clearance we cannot take a direct measurement of this so it must be measured indirectly with the tire removed. Luckily I can do this. You will recall there was a single vette front wheel that came with the two rears which was not used. This wheel is the same diameter but is 1" narrower and has 1/2" less backspacing. Taking the 5/8" that the tire protrudes beyond the rim, adding that 1/2", plus our 2'' dimension for narrowing gives us 3-1/8" for our dimension from the rim to the inner fender at full compression.

Maximum compression is limited by u-joint interference with the LCA which occurs just beyond 6-1/2" of compression from our nominal point where the tire is resting on the existing fender lip. However, at this point even including our 3/4" of extra clearance we are into the inner fender some 1/2". At 5" of compression though the picture is much rosier and we have exactly 3-1/8" which is our target dimension.

This tells me that we can compress the suspension 5" and allow considerable droop as well, for a potential total suspension travel of around 10-12 inches! Too bad we can't hope to match that on the front. It also tells me that a 2" narrowing of that side of the car is appropriate. The other side should come in about 1-1/4" more for a total of about 3-1/4". Not bad, and mostly made possible by the deeply offset wheels.

More photos coming.

Jim

[BlownMGB-V8]

Here is a side view of our compressed distance of 5". Looks to me like that should be adequate upward travel, I have yet to see if the differential clears the ground at that point, but it looks as if it would.

Here is our nominal ride height.

And here is maximum droop.


Now I know what you're thinking, this isn't an off road machine. And you are right of course. We will plan to set the ride height 1-2" lower than nominal which will cut our jounce to 3-4 inches, a very workable range, and then allow another 3-4 inches of droop for a total travel of 6-8 inches, very very respectable in a car of this type.

Jim

[BlownMGB-V8]

The other side checks out. In fact the 3-1/4" dimension is right on the money. Now the question must be asked, do we wish to "cheat" by stealing some of the 20mm clearance we will have on the inside with 275 tires? The question is a very valid one because at nominal ride the tire sticks out past the fender about 2-1/2 inches. Even subtracting the 20mm there (3/4") that's 1-3/4" that we're asking the Omni flares to cover, plus they don't do a whole lot for us as we move on up into the well. So things could get real tight on the outside.

The counter arguments would be that first off, what if we go to a 285 tire due to availability problems? Now we just have 15mm. Plus, how much is the tire going to deflect under hard cornering? 5mm? 10mm? 15mm? 20 even? (Personally I doubt that last one but I certainly do not know.) Some of you guys with tight tire clearance should weigh in here, especially if you run a panhard. Tell us if you've had tires rub and at what clearance distance. If we have to go 20, we'll go 20. But it may impact our tire choices.

Jim

Oh, and I did get to thinking about what Carl said. You know, that would give us a little more room in the driveshaft tunnel so that we could keep both sides the same length... and we could have enough room in the engine compartment for conventional headers... and wider seats... But Nah!! Just the windshield alone would be problem enough to say faggidaboutit. But maybe someday...

J

[BlownMGB-V8]

One more thing before I call it a night. Is it just me, or do you guys think those tires just don't look right from the side? Tomorrow I'll look to see how much clearance we have inside the rims and shoot a photo or two of it. We may be able to get by with 16" rims. I doubt we could go 15 but won't know until then. Of course that will make tire choices more of a challenge and we've been through this already, but we may as well make it look as good as we can, within reason.

Jim

[Bill Young]

I agree Jim, something doesn't look right with those 17s. We should be able to use a 15" rim, that's what Jag used with those rear uprights. I realize that the sill is missing and that would add a bit of depth to the body, but the photo of the car at nominal ride height looks pretty high with those tires and wheels. We probably need to find something a little smaller that would tuck up in the wheel wells better. I realize the limitation is with finding tires these days in a 15" rim with any width, but I think we could get by with a lot less width if we want and still have a car that hooks up pretty well. Of course from the onset of the project I've leaned towards the "sleeper" look so smaller tires fit right in there.

[MGBV8]

"...for a potential total suspension travel of around 10-12 inches! "

Whoa! I raced motocross with less travel than that. My MG may have 3" of working travel.

Outer fender clearance: When I sit on the quarter panel, I can barely get my index finger between the fender lip & the tire. No rubbing with 205/55-14s since installing the panhard rod.  The amount of deflection will change with the aspect ratio.

Jim, don't forget more elbow room with the wider MG.  ;-)

Bill,

Hook up? With 500 ft/lbs of torque? Not without wrinkle walls.

[BlownMGB-V8]

OK, the first photo shows clearly why we can't use 15" wheels. Those are 1" gage blocks sitting on the pivot and they obviously will not fit between the pivot and the rim. Jag did not use a deep backspacing on their wheels, so it wasn't an issue for them. For us, it keeps the upright away from the bodywork and allows the use of longer suspension arms for better geometry and more tire clearance.

The second photo shows a section of bar stock sitting on the floor for a visual reference.

 It is even with the bottom of the cross braces and forward rails but would be slightly below the sill and roughly even with the jack tube. I measured 9" to the contact patch area. On my car the rear of the sill is 8-1/2" above the floor, you might check your own car. considering that we'll pick up 1/4 to 1/2" on sidewall bulge and that we plan to move the tire upwards into the well 1-2" I believe this puts us right where we should be on ride height, so the visual is somewhat misleading. But my car isn't the best reference as the new springs make it sit a little high in the back so a second opinion would be good.

Anyone care to look for a 16 inch tire with a 275 width and a fatter aspect ratio? We could get by with going perhaps as much as 1" larger on the diameter than what the 315/35-17's are but no more.

Jim

[BlownMGB-V8]

Steve got here about mid afternoon, and after the usual pleasantries we got down to business, catching up on changes and such and deciding on our plan of attack. First we did some work on the hub he brought from Jim Thompson, removed a seized bearing race and the other old bearing and spacer, then turned the hub pilot down to match the other side and cleaned up the bearing journal. Incidentally for those of you who haven't had the pleasure of removing a seized bearing, what we did was to slot opposite sides of the race almost down to the shaft, and then used a heavy chisel and a hammer to break the remaining part and split the race off. The trick is to do it without nicking the shaft. We did get a small nick but dressed that out with a very small chainsaw file to remove any stress risers. The journal had picked up metal from the bearing race and was close to .010 larger on the diameter than it was supposed to be. Without a lathe and an accurate setup this part would be scrap, but we were able to dial it in and turn it back down to the correct size. We then assembled the second upright with new bearings and seals and matched them up with a pair of spline yokes. Good enough for the uprights, at least for now, we next turned our attention to the half shafts. First we rough turned the shafts  to 1.020" and then set up for finish turning and polishing, cutting both shafts to 11-7/8" x .997", which gave us.0005 to .001" of clearance with the tube.We precisely cut the tubes to length, squared and chamfered the ends, and cut the shafts to exactly fit the length of the tubes. On assembly the fit was dead on, so close in fact that the parts slid together easily but snugly, trapping the air inside and bouncing  before being shoved home. They snugged up just right as they seated, but still could be rotated. I don't think we could have gotten a more perfect fit for this application. Once welded the internal shaft will provide full support for the tube to help resist wrinkling under torque, and the slip fit will allow the torque to be absorbed by the full length of the tube rather than a short section between the ends. Given the weight of the car I think they will hold up well.

Tomorrow we weld. Also cut down the LCA's and prep them for welding. I think we'll have this car back on it's wheels soon, maybe by tomorrow evening.

Jim

[rficalora]

I agree they don't look right in the pics.  Not sure it's the overall diameter though as 24.6 isn't that different than the ~24" a lot of MG's are running.  I think it's a combination of the diameter & small side wall.  Look at Evan Amaya's car http://www.britishv8.org/MG/EvanAmaya/EvanAmaya.htm.  He has 205/45/17's which I calculated as just .3" less diameter & it looks fine.  Now, at the risk of opening a can of worms... I still like the look of 15" or 16" & even more side wall.  There are a few companies making 275/50/15's although those would be about an inch bigger diameter - not sure how that'd look.  There are also a few doing 245/50/15 which would be the same diameter as the 17s you have now, just more side wall (and depending on wheel offset might make the IRS work w/o narrowing it at least on the side that only needs 1 1/2" narrowed).  I think that's what Joe Shaeffer is running & they fit with the omni flares.  Of course, that'd mean a little over an inch less width in the contact patch.  Something to think about maybe.  Pretty sure both those sizes are staples in the Cobra kit market so they're noy likely to go away any time soon.

[Bill Young]

Thanks for the last couple of photos Jim. I see the clearance problem, it's close but no cigar for the 15" rim. I don't know what it is but the second photo now looks like the ride height will be ok. I guess it's just turning off the anti gravity machine that makes all the difference to my eyes. As to the wheels looking big, maybe it's just the flash of the chrome and the style that makes them appear all flash and no tire. I agree with Rob, on Evan's car the 17s look fine. I'm like him though, still old school and like a little more sidewall showing and less rim, but with those sizes getting harder to come by we need to look at something that will be replaceable in the future at a reasonable price. I don't doubt that with 500+ foot pounds of torque tire life will be significantly shortened if we're not careful.

[BlownMGB-V8]

You guys have been missing all the fun! We finished all the cutting, welding and painting by lunchtime.

So nothing would do but that we had to start putting things together.

Pretty soon we had this:

And then we just had to flip it over.

By then it was after supper but we really felt like we had to go one step farther...

Jim

[BlownMGB-V8]

So we did this:

and then we played,

played some more,

and sat around a bit and dreamed about how we are going to play when it's finished!

Jim

[BlownMGB-V8]

Then we put the cars to bed,

tucked them in for the night,

and called it a good day's work. I will probably try to give more details later about the work we did but for right now a shower's in order and something cold to drink.

Jim

[MGBV8]

That sure is one awesome toy box!

[Moderator]

This photo qualifies for entry in the photo contest!

[MGBV8]

Steve,

Hold your hands closer together. I don't think we need a 20" steering wheel.  ;-)

[castlesid]

Jim,

Just been having a re read of what you were saying about the narrowing of the drive shafts, and noticed that you are suggesting that one side is going to be 1"+ narrower than the other.

I'm probably throwing the proverbial spanner in the works, but I do have concerns as to having effectively shorter upper and lower wishbones on one side of the car and what that will do to the geometry, and the effect on camber change, ie the camber gain will be different on each side of the car and the handling strange to say the least.

The other point is ride height, for the geometry of the Jag suspension to work correctly the lower arm needs to slope down towards it's outer pivot point by 1 1/2" - 2" with the car on the ground.

 I would be looking at a ride height of approx 14 1/2"  measured centre of hub to underside of the chrome strip position and then check the angle of the lower arms to see if it's in the right ball park,

Hope you don't think I'm interfering but thought it important for you to consider these issue before you get to far advanced.

Regards,

Kevin Jackson.

[BlownMGB-V8]

Thanks for the suggestions guys. Curtis, I'll send that photo in. I was looking for a link of some sort for photo contest submissions but didn't find anything.

Kevin, I don't think the camber change will be enough to tell the difference, one side to the other. No street car is perfectly symmetrical anyway. They can't possibly turn right exactly the same as they turn left, yet nobody seems to notice. The difference in the arm length is minor given the overall length. The total is 1-1/4" due to the pinion gear being 5/8" off center in the differential housing. In order for the driveshaft to be centered in the transmission tunnel and not offset from the engine centerline the only way to do it was with a small difference in the length of the control arms. Anyway we only removed 2" from one side and 3-1/4 from the other so our control arms are still much longer than in the typical MGB installation, therefore our rate of camber change is much less to start with. This gives us a more forgiving geometry. I'll measure our present dimension to the beltline. It may be a bit over that spec but I'll try to find out tomorrow. We can easily vary the ride height by a couple inches and still keep the axle shafts near horizontal so I think we'll be in good shape on the drop of the LCA's.

So moving right along, here's our first photo of the day.

I'm sorta proud of that shot, put up a backdrop and everything. But as you can see we got the 455 and T5 ready to put in the car. Here's another view.

We really made far more progress this weekend than I expected. I would have been really happy with getting the car on it's wheels. (and I was!) But Steve was so apathetic about what we did or didn't do to the car that every time I mentioned what would be the next thing that would have to be done we ended up just doing it. By the end of the weekend we had this.

It's all Steve's fault really, once we had it shiny side up I just couldn't keep him out of it.


Jim

[BlownMGB-V8]

I have some more photos, several of the engine in the car.

Rear view

clearances

and with the hood in place


From this point I don't expect to have much trouble getting the car to the show, but if anyone would like to help, there is still time to do that.

Jim

[castlesid]

Jim,

Fantastic progress, the engine and box look great and sit in the bay nicely. When I posted, I missed that you had already done the narrowing of the rear end, and what a nice job you've made of it.

Kevin.