MGB Roadmaster

[accobraman50]

Jim,

I'm tearing the car down to paint it and the frame will go out for powder coating.  So the Jag rear end will be out if it.  I may consider having it balanced at that time.

It would be interesting to hear if other Jag rear end owners did a balance job or not, and what the results were.

Regards,

Arthur

[BlownMGB-V8]

Arthur, check out this thread:
http://www.clubcobra.com/forums/shop-talk/16600-help-builders-mechanics-do-halfshafts-require-balancing.html
It should answer your questions. Looks to me like the only issue is the difficulty of removing the stub shaft from the hub flange. The right puller should handle that.

Dale Spooner called me this morning about the engine. Turns out we have about .006" of cylinder wear. I didn't think it was that much, but then he has better instruments for measuring that sort of thing. The good news is that he has a possible line on a decent set of pistons which are .040 over, so if he's able to get those he'll go ahead and finish the bores to match. Meantime I have to get back to work on seeing if I can get us a set of aluminum heads. Just a little paperwork to finish up and I can get back on the phone calls. I've been putting that off but I think the time has come to see how my best effort reads. More soon.

Jim

[BlownMGB-V8]

The "Vendor Presentation" is now completed. It includes Photos and hyperlinks and I have sent it to Curtis to see if we can post it somewhere on this site. I also want to send it to our officers for their final approval and will do that later today. Hopefully by the first of the week I can start prospecting for heads, painting and other parts that we will need to finish the project. Who knows, I may even be able to get us some tires. Wouldn't that be grand?

Jim

[rficalora]

Jim, the shafts look great.  this is probably stuff you know, but I couldn't help but think of Larry Shimp's snapped 1/2 shafts...  I don't recall the details of the Hoyle IRS, but the donor car 1/2 shafts are bigger diameter than the hubs so they're turned down & resplined at one end to fit (to be fair to Hoyle, I don't know if that's their design or based on donor parts Larry was able to find in the US).  Anyway they broke right at the edge where the smaller diameter met the bigger diameter.

If the tube that'll reconnect the shafts on the Jag parts will be welded to the yokes, there's probably no issue.  If it's going to be welded to the shafts, it might be a good idea to radius where the turned shafts meet the yokes.

[mowog1]

This is a great project...and the organizational skills of Jim is certainly helping to keep all of us well focused.

Jim...I'll help out more by contributing to the fund needed for our IRS donation mentioned in your post of February 18th.

I have your address....how would you want the check made out?

rick ingram
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[BlownMGB-V8]

Thanks for the compliments guys, I do appreciate it. Rick the check can be made out to BADASS, NLC if you like. Wouldn't hurt to put something like "Fees" in the memo field or after the "who to" entry. I'll make sure it's earmarked for that... have to make sure Steve knows.

Rob, the welds will indeed be on the yoke. There was a question somewhere about using tubular units. That's an excellent idea but two things argue against it. First I don't know yet if we have enough room, basically every inch increase in the diameter is a 1/2" decrease in potential suspension travel so I'm not too eager to go bigger until we look at tire clearance in the wheelwell. The second reason is cost. The Spicer yokes will cost around $15-20 each so it adds about a buck in costs. Tubing cost will be close either way. I'd rather put that money on tires or coil-over shocks.

Weekend Report:
Not a whole lot happened this Roadmaster Weekend, but that wasn't a big surprise. So there really isn't anything to report. Dale missed out on the pistons he was trying to get, so we need another line on a deal. We'd like to get .030 or .040 over and around 9 or 10 to one compression. Maybe the boys on the V8 Buick site know of some. Everything else that's been going on I've pretty well kept up on the reporting. Let's try to plan for something next month, it should be warming up enough to get out and do some work. In the meantime hopefully there will be some nice days so I can clean up the Lab.

Jim

[accobraman50]

Jim,  

When you weld the halfshafts at the yoke are you planning on inserting a solid fitted shaft through the eyes of the yoke to hold the alignment and prevent the weld from distorting the yoke?  

Arthur

[BlownMGB-V8]

Arthur I hadn't considered doing that. It isn't a bad idea, but would require a very precisely made piece (x2) in order to be able to mount it between centers. Perhaps a good alternative would be to measure the spread and recheck after welding to see if they had opened up any. I expect we'll be OK on that though, it doesn't seem much of a problem on tubular driveshafts which have a less massive yoke.

We may have our pistons. One of the guys on the Buick board has a set, he's going to measure them for wear. Looks like $50 plus shipping, .040" over but an undetermined CR, maybe 8.5, maybe 10. I'll ask if he's willing to donate them but even if not I think we should buy them if they check out.

Jim

[rficalora]

Looks like I have two extra Omni flares that I can donate to the project so that'll get the rear done.  The ones I have are from the rear of the car.  They have parts of the inner fenders still attached.  I'll cut off the excess so I can get them in a smaller box & get them out to you next week.

Worst case if we can't come up with two more for the front, we could make fiberglass ones using one of the Omni ones as a mold.  I'm probably going to make molds out of mine anyway since they're getting harder to find & I may want an extra inch or two on the back (drawback to IRS is once made it's even harder to further narrow than regular axle & I had Todd make mine about 1-1.5" wider than I should have!!)  I'm thinking making fiberglass Omni flares a bit wider than stock ones is easier/cheaper than narrowing the IRS!  -- Learn from my mistake & get the width right Jim, which means you have to know the wheel width & offset & even have a good idea of your tire section width -- ideally have them on hand & mock it up, then measure between them for the IRS width.  Err on the narrower side since you can get wider wheels, bigger tires, &/or use spacers way easier than you can deal with a rear end that's too wide.  Sorry for the preaching... I just get frustrated with my screw up every time I think about it.

Rob

[MGBV8]

Rob,

Time for different wheels? The Weld Prostars that Jim picked out have a choice of 3 backspacings for the 15X7s. 3.5, 4.5 & 5.5.  That could make all the difference.

http://www.weldracing.com/wheels/details.asp?wheelid=36&name=Prostar&style=96&desc=1-Piece%20Forged%20Alloy%20Polished

[rficalora]

Yeah, but I like my wheels...
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I think I'd rather adjust the flares than sell these & replace... althought i do also like the Weld Prostars.  Maybe i'll look for some of those when i tire of these.

[BlownMGB-V8]

Those are very pretty wheels. Couldn't make out the name but they look vaguely familiar.

Another issue is lug-centric vs hub centric. We'd be better off if we can get wheels that use tapered lug nuts. Of course I suppose tapered seats can be installed... if you can get them. I noticed the centers on mine are definitely thick enough to do that.

Jim

[rficalora]

Hi Jim, they're American Racing 427's -- American Racing's version of the Mustang Eleanor wheels.  These do use tapered lug nuts (e.g., lug centric).  By the way, i'm not sure I still have your address... i'll look in the earlier pages, but if it's not in there somewhere, email it to me so I can send you the flares (assuming you want the two I have).

[MGBV8]

They look like the original Halibrands.

The Welds won't have tapered seats. I have Weld Dragstars on my Camaro. They use long shouldered lug nuts. And no, you can't have 'em. They're 15X10 & 15X6, anyway.

[rficalora]

Yea, very similar to Halibrands, but aluminum instead of Magnesium.  Pretty sure the halibrands were magnesium... they're way more expensive these days than reproductions like these anyway & magnesium has a tendency to crack.

[MGBV8]

"Pretty sure the halibrands were magnesium."

Yep. They are making them again for the Cobras. $700+/wheel.

[BlownMGB-V8]

The Jag hubs don't have a centering boss so if we use untapered wheels we'll have to put in seat inserts. I need to do this with mine also so I'll probably set up to machine some seats. That'd be about 40 pieces so it'll take a little time but not too bad all at once. I'll have to come up with the right sized counterbore tool though. Carl, do those 15 x 10's have a 4-1/2" backspacing by any chance?

Jim

[Bill Young]

Jim, if the wheels use a shouldered lug nut lilke most older style alloy wheels as long as the shank of the lugs is a good snug fit in the wheel bores I've never had any problem with centering the wheels. Either way you're relying on the accuracy of the lug studs to locate the wheel. The 113X7 Americans I run on the Midget don't index on the Midget hubs or rear axles and I've had no problems with any balance issues or vibration. I'd use caution machining any wheels in the lug area not to remove any of the design strength in this area to fit tapered inserts.

[mgb260]

Jim, Checkout this site on Jag IRS in a early Mustang. Dazecars.com early Mustang IRS. Also did you notice the Toyota 4X4 Jag set up on CWI site. It uses the leaf spring mounts as does the newer Mustang Cobra IRS.
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[mgb260]

Here is another idea. The shock prevents wheelhop. I was thinking that you could make a bracket like that only facing the frame for your upper A arm idea. 1/4" strap twice as long sandwiching in the hub carrier.
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[BlownMGB-V8]

Nice find on the upright brackets Jim N, and the diagonal anti-torque braces on the back are a nice touch as well. That one is clearly a top end system as evidenced by the custom uprights. Looks like they were attempting to use the shocks as a replacement for the radius rods but it seems that solution would be less than ideal.

I did some more checking this morning and first things first, the Jag hub does have a pilot boss for the wheel. At 2.900" it is larger than the Chevy boss at 2.781" but could easily be turned to match, meaning that we should be able to use just about any GM hub-centric or lug centric wheel. The Jag uprights raise a whole new issue in terms of backspacing though which came to light when I looked at Jim N's brackets.

Also, Bill you are absolutely right about machining the wheel centers. On the Weld wheels IIRC they have two 1/2" sections mated together which if so might not allow the necessary machining. My Centerlines may be the same. As for the discussion of whether hub centric wheels can be run on lug centric hubs, I can only say that is the setup on my car and I've never gotten rid of the wobbles entirely. 'Course it could be the tires. There have been complaints about them.

The issue with the uprights is twofold. First, a top link is going to be difficult to design due to the need to go inside the frame rail to allow maximum space for rubber in the wheelwell. Otherwise the link will take up at least 1" of tire space with a conventional design and materials, and attaching it inside the frame rail is likely to severely limit wheel travel and lowering of the body. So we need to make a decision here: Do we move the wheels out and flare the fenders similar to the flares on my car to get the needed tire space? Or do we forgo the suspension top link, beef up the LCA, go back to timken LCA bearings instead of Delrin and hope for the best?

I had some light outside wheel rub with 1" spacers and maximum lowering and with the spacers gone have about 1-1/2" averaged clearance to the shock bolt heads on the inside, so possibly 2" of clearance that I am not using with these tires. (10.37" section width, 8.35" tread) so the potential is at least there for 12" wide x 27" tall tires maximum, or 11" wide with a top suspension link.

Adding compexity to this decision is the configuration of the uprights themselves. If we use a conventional backspacing of 3 to 5 inches the bell of the upright is the limiting factor in upward suspension travel. It may be possible to trim it to get more upwards movement. But there's another possibility.

I have some old Probe GT wheels which are 16 x 7 with about a 5" backspace. I set a hub and upright in the wheel to see how that works out:
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As you can see, a careful construction of the LCA could allow use of a deep backspacing, moving the upright further inside the wheel and thus moving the bell closer to clearing the frame rail. From this it looks like the new FWD wheels could be very useful. Something like a 17 x 10 with a 7" backspacing would probably let us clear the frame and leave room for a robust LCA attachment.

Obviously the fronts would have to be different. But since it's generally easier to find wheels in pairs this may not be a bad thing. We could stagger the diameter and width and use the Omni flares on the front. Neutral handling can be restored with a stiffer front bar and staggered tire pressure so I'm not that concerned about the handling changes this would cause.

Guys, it looks like we are moving ever closer to the drawing that we need for our club logo! Wonder if there's a way to run open headers out through a set of ventiports?

Jim

[BlownMGB-V8]

Anybody think we should try to buy these?

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=110226743947&ssPageName=STRK:MEWA:IT&ih=001

Jim

[MGBV8]

Are you wanting the tires or the rims?

Zoom that last pic. That rim is cracked pretty bad.

[BlownMGB-V8]

I missed it anyway, oh well. Cast wheels obviously huh? That's what I meant about the wheels sticking out past the tires. I'm seeing a lot of damaged rims.

Looks like the 255/40-17's are real common, and 265 and 275's are not exactly scarce. Apparently the 50 series 14's and 15's were dropped in favor of them. Go figure.

Of all the 50 series tires that used to be made, there's nothing much anymore bigger than a 225 that I can find, with one notable exception: the 295/50-15 (LR50-15). Now why is that? A Corvette tire perhaps? That'd be my bet. And probably after tires are no longer used those tires for old Corvettes will still be available. I found the page for calculating tire dimensions, and that size works out to a 26.6" diameter and 11.6" overall width. My handy dandy chart for BFG TA's (who still make them) shows a rim of 9-11" and a design rim of 8" wide, overall dia of 26.21" and a tread width of 9.4" meaning that they could probably be fit into the rear wheelwells of my roadster, or if we made similar flares on the Roadmaster they could work there also. Interestingly enough, the 295/35-18 tires for the Z06 Vette work out to very nearly the same dimensions and the front tires are 265/40-17's which might work on the front. The modern Vette wheels also have some serious backspacing, which could be real helpful on the rear, but only if we went to the 17 or 18" wheels.

Which gets us back to 35 or 40 series tires and rims wider than the tread, and curb damage. But, a typical offset for these wheels may be the 57mm I saw on a 9.5" wide rim (rear). That works out to a 2-1/4" offset, or a 7" backspacing which is pretty ideal for our Jag IRS. If this is typical for Corvette then it gives us a ready source of wheels and rubber provided we can stuff it under the car. It also matches the rim to the tread width and gives us a 1" sidewall bulge to protect the rim. Although I wasn't really planning to do another set of rear flares I can see where this would be a real advantage.

On the front things are a bit different. We need a wheel with a 3 to 3-1/2" backspacing in order to clear the inside and we are more limited on the diameter. We may be able to use as large a diameter as we can in the rear but even with the Omni flares we can't go all that much wider, and  as we increase the diameter the offset to the inside has to decrease to keep from rubbing the footwell (going from memory here, corrections encouraged.) This all means the wheels are likely to not match if we go this route, unless we make up a pair of big honkin' billet spacers about 3" thick. Can be done, theoretically no worse loading on the spindle. Any fans of that approach here?

So you see, all of this stuff just gets to running around inside my head to the point where I have difficulty doing anything at all. Much easier for me if someone just says, "Here, this is what you have to work with. See if you can find a way to make it happen."

Anybody got an old set of Corvette wheels lying about the place? Bill Guzman are you out there?

Well, it's a thought anyway.

Jim

[BlownMGB-V8]

What about these wheels?
http://cgi.ebay.ca/ws/eBayISAPI.dll?ViewItem&rd=1&item=200203206735&ssPageName=STRK:MEWA:IT&ih=010

A little wide for the back maybe. Any comments?

Jim

Maybe we ought to just put N50 wrinklewalls on it ;-)