MGB Roadmaster

[BlownMGB-V8]

We will immediately be moving to this forum as the Official site of the MGB Roadmaster group project under legal authority of the non-profit organization, British American Deviant Automotive Sports-car Society, LLC or BADASS, NLC for short. I will put notices on all three existing forums to that effect.

This upcoming weekend is the October Roadmaster weekend (Oct 27th-28th) and participants are invited.
The address is 9406 Gunpowder Rd., Florence, KY 41042

I may be reached at: Jim (at) BlackwoodLabs (dot) com or at: (859) 816-2187.

Jim



It all began with the ravings of a madman/genius:

"It'll work, I swear to God! I just was eyeballing and measuring a 430 Buick engine and comparing it to my 215 install, and there is room!"

"Think about it, the MGB-V8 started with the smallest Buick V8 engine ever made. It just won't be complete until it has been done with the largest Buick V8 engine, now will it? We simply have to do this, and by all rights it should be a group effort for the benefit of MG posterity. Let's show the world that we CAN hang with the big dogs, and do it with style, flair, AND a small budget!"

Then gasoline was poured on this spurious/deviant/harebrained idea:

"I think you have a great idea, Jim. I would love to see this concept car happen.
To get the ball rolling, I have a spare T-5 to donate for this project."


This is the original thread where it all began:

https://www.mgexp.com/forum/mg-engine-swaps-forum.40/big-block-mgb.538455/



Donations to the Roadmaster Project can be made to:

Rick Ingram, Treasurer
1372 County Rd 2275 East
P.O. Box 588
St. Joseph, IL 61873

mowog1 (at) aol (dot) com

Checks should be made out to:

"British American Deviant Automotive Sportscar Society" or "BADASS"

[Bill Young]

I didn't think it would take Jim long to get moved over here. At last a permant home for BADASS. Feels good to be home Jim.
Curtis, since BADASS is building a MG but will be supported by a lot of other owners of British V8s can we get a link off the other boards as well? Thanks.

[BlownMGB-V8]

Didn't take long at all Bill. If you'll recall, Curtis was one of the earliest supporters, assuring us that we would have a place at the British V8 Newsletter. Well, he's made good on his promise and so are we. Personally I'm 100% in support of the newsletter. I know what it was like before there was one. Things are now so much better that it's impossible to make a comparison and it's getting better still. There's a lot we can do working together that will have the synergistic effect of helping this project and helping the newsletter at the same time and Curtis understands that as well as I do. Better probably. So onward we go.

I have some photos from the Roadmaster Weekend. There's still one day to go but I probably won't get all of the news in this post anyway and there are more than 4 photos.

Friday evening, Dan Masters brought the Jag IRS. He had been up to Ted's place and sorry to say he was behind schedule getting home so he couldn't stay even long enough to come in for a bowl of chili, in fact in the rush I may not have even remembered to offer it. Apologies if not Dan. Anyway we went out to the lab and unloaded all the parts and Dan even managed to explain some of it for me, and then he was on his way. I had gotten him to help me lift the center unit up onto the upside down GT and position it. That's one heavy piece. Anyway today I got to spend some time unpacking all of the parts. To Dan's credit, he did not just give us a junkyard takeout. The suspension had been disassembled and inspected, and many new parts purchased including bearings, seals, bushings, 4 new u-joints, stub shafts, yokes, and a pair of brand new Brembo brake rotors. You cannot view this attachment.
In fact, as far as I could tell by looking the only part we still need for it is one hub flange as one of those appears to have been damaged in disassembly. It might be usable but should probably be replaced so if anyone can get us one.... It's just the flange that the wheel bolts to. We will be needing a set of brake calipers for it and I'll have to have those before I can mount the housing to the car as I need to check clearances, but I will contact Bill Guzman to see if there is anything he can do to help on that.
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The fit of the center unit is nothing short of amazing. It's almost like the MG engineers had planned for it. I have a Ford 8.8" unit from a T-bird and set it up on the mule and it didn't fit at all. The front mount eyes hit the battery boxes with the ring gear in the space needed by the tank. Just no practical way to use that and keep the boxes. The Jag unit is near perfect. With a 1/4" plate between the shelf and the housing the brake rotors have good clearance all around and the mounts for the lower pivot brackets line up very well with the corners of the battery boxes. In fact they are exactly the same width. A top bolt-in mount will be quite easy to build and with minimal reinforcing the battery boxes will make perfect anchor points for the pivot brackets. Remember, those battery boxes are structural. They do provide a significant amount of bracing where the transmission tunnel ties in. People have removed them without ill effect it's true, but that is just a testament to the strength of the body shell itself. Until the brake calipers are on hand I won't be able to say for certain, but it looks like the battery boxes will stay, largely unmodified.
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The plan is to replace the lower control arms with welded up tubular units similar to those offered by several aftermarket suppliers, along with redesigned welded up pivot brackets. Measurements show that there is room to go to tubular half shafts as well, and these two changes will eliminate a great deal of weight from the assembly, half of which is unsprung weight. The tubular half shafts are also dead simple to make up to any custom length.
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We will have to come up with a pair of coil-over units of course. I hope someone can donate a set.

Jim

[danmas]

Jim,

I apologize for being so rushed, but it took me about two hours to get through Cincinatti, after encountering a lot of road construction all along the way, so I was running way late. I got home right around 11, after leaving Ted's around 8.

If there were no brake calipers in the box I left, I most likely have them here at home. I'll look and see and let your know. I'm pretty sure I didn't toss them out.

[Jacmo]

Jim--OK--In regard to the alum. 300 heads (and associated pieces)--I would be happy to ship these items truck freight (and absorb the cost as a donation).  But my main concern is damage and whether or not I'll be able to adequately protect from damage without running up outrageous freight costs.  So...........I live in Chattanooga.  I'll be willing to drive 3 or 4 hours in any direction from here to deliver to someone headed your way.

Anyone headed toward Jim's within the next month or so--that lives within 3-4 hours of Chattanooga?
Let me know.  I'm at jackmorris99@comcast.net.  
Thanks!

[BlownMGB-V8]

Thanks Jack. Steve DeGroat is bringing the engine up the first weekend of December. He lives near Columbia, SC. That's 5 hours from you but I'm guessing that he can route his trip up through Knoxville which brings him within less than 2 hours of you. Perhaps you could arrange to meet there and make the transfer. Alternatively, since Dan M. lives at Alcoa, TN that might make a good drop-off point, or a better alternative might be our VP, Carl Floyd near Johnson City. That'd be just a hair over 3 hours but might be a better route for Steve.

Hey Carl, is that Kingsport or Kingston? I think I may have it wrong in the spreadsheet. Incidentally I put the aerosol supplies in the spreadsheet as donations also. Which reminds me, Steve when you are here we'll talk about getting receipts to our contributors so that they will have documentation of their donations for taxes. I think we can make that a fairly simple task. We do need everyone who has made a donation and has not already done it to send us their address, phone number and email address. We are missing that info for a lot of you. Also lest I forget to mention it Steve, you and Margaret are more than welcome to the guest bedroom that weekend and we'd love to have you stay here and save the motel costs.

We have accomplished quite a lot at this point. I'm guessing that Dan will probably find the calipers, (Incidentally I totally understand about the rush. As you said, we'll have time to socialize at Ted's winter party.) someone else will come up with a set of coil-overs for us, and a good hub flange will materialize, clearing the way for assembling the IRS. I still can't believe how well that fits in there. I can purchase four U-joint yokes and some tubing to make up the stub shafts and as short as they are they may not even need to be balanced if I use seamless tubing. I will also need to buy tubing for the lower arms, probably 1-1/8 or 1-1/4" diameter, some 1 x 1-3/4" rectangular tubing for the upper brace and a small piece of 1/4" plate, but I will talk to Victory Tubing about making a donation and see what it gets us. Come to think of it, maybe Dayton Clutch and U-joint will contribute the shafts, at least I can ask.

Finally, Jim Stuart, if you've caught this post, could you let me know what the rim width and backspacing is on that set of wheels? I may have asked you that already but it would be buried in the old threads somewhere and I'll need that info before I can determine the control arm length. Even better would be if we can find a way to get the rims here, but I'm thinking maybe we can coordinate that with the trip to transport the engine to Dale Spooner's shop. Thanks everyone!

Jim

[danmas]

Jim,

I found the brake calipers, and I also have the emergency brake assemblies as well.

According to Mapquest, the route from Steve's home in Columbia, SC passes through Knoxville, about 20 miles from my house. Steve could drop by and pick them up without going a long way out of his way. I could give him a tour of my TR6 V8 project while he's here.

[Jacmo]

Dan--could I drop my items off at your place--assuming Steve will actually go thru Knoxville?

Thanks!

[danmas]

Jacmo Wrote:
-------------------------------------------------------
> Dan--could I drop my items off at your
> place--assuming Steve will actually go thru
> Knoxville?


Jack,

That would be fine. We should be hearing from Steve or Jim soon as to Steve's route.

[danmas]

Jacmo Wrote:
-------------------------------------------------------
> Dan--could I drop my items off at your
> place--assuming Steve will actually go thru
> Knoxville?


Jack,

That would be fine. We should be hearing from Steve or Jim soon as to Steve's route.

[Citron]

everyone,
We will be coming up through Knoxville on Thursday, 12/29.  We can come by Dan's and pick up whatever is there.  Don't know what time we will get there.  We will leave Columbia about 9:00 to avoid the morning traffic here.  I will try to get an aprrox. time of arrival in Knox.
Jim- thanks for the offer of the spare room, but we will probably stay at the same motel, it is cheap and easy.
Anybody that has stuff to donate that can get it to Dan's, we can pick it up.

Hope all this works out.
Steve

[BlownMGB-V8]

Unless anyone has an objection, we will move the November Roadmaster Weekend to the 1st and 2nd of December to accommodate Thanksgiving and coincide with Steve's visit.

I've gotten a four part article from Dan M. about the Jag IRS that looks pretty complete. In looking at it I can see where Dan has already done a lot of work on this IRS and spent a fair amount of money on parts. Thank you Dan, that is a very significant contribution. We have the upgraded UHMW control arm bushings as well as new bearings and u-joints. I've come up with a design for the differential support and I'm working on the details of the mounting cushions. I also want to make it adjustable for pinion angle. A range of 0-6 degrees would be more than anyone would need, but I won't know what angle the BBB will take until it's test fitted the next time and it would be good to be able to match the engine angle within 1/2 degree or less. The best I recall the engine angle is 2 or 3 degrees, so really if we have a range from 1 to 4 that should be plenty. I think I can find a way to build that into the mount.

The lower control arms are the next issue but they don't have to be completed until the car is ready to set on it's wheels. Still the sooner the better. It might be possible to use the stock arms, but space by the battery box corner is tight and they have to be shortened as well. A built up set should work fine and could be made adjustable so they can be set parallel with the ground. I'll give that some thought as well.

Jim

[Citron]

Just reread my post.  We will be going to Jim's on 11/29 not 12/29.  So we will pick up whatever at Dan's on 11/29 if that suits Dan.

Steve

[danmas]

That suits me fine.

[danmas]

The December issue of Hot Rod magazine has an interesting article on IRS setups that might be worth a look.

[BlownMGB-V8]

I went out and bought the magazine, figured I might as well subsidize those 4 old articles even though by now I think I've seen most of it on the web anyway. It is interesting what guys are doing with IRS these days, and apparently some of them are spending a lot of money doing it, up to twelve grand in some cases. I don't think such overkill is necessary for our car though. I see a lot of what looks suspiciously like Jaguar geometry on those conversions and that is probably because the Jag geometry is very simple. I have yet to see a good explanation of the principles of anti-squat and rear wheel steering in terms of how the forces are applied to the different suspension components, where and how the pivot points can be located to control it and which direction does what. That would be handy. I used to have Fred Puhn's book around here somewhere but I can't find it anymore, might have gotten some pointers out of that, but I don't recall him going into any great detail on the IRS either. If someone would send me that excerpt I'd add it to the Jag IRS binder though. We could probably make fairly minor changes to the Jag geometry as we go if it would be helpful, particularly in terms of anti-squat and traction control. I'm not sure the Jag has much of a problem with anti-squat just looking at the layout, but anything we can do to control wheel hop would help.

I get the idea that anti-squat is more of a problem with cars that have the lower control arm (LCA) mounted at an angle to the long axis of the car, and I suspect this is done to control wheel movement fore and aft. The use of a radius rod for this purpose means compliant bushings are needed somewhere. The only other alternative is widely triangulated inner pivot points, but this can also be accomplished with radius rods that have their inner pivot on the axis of the LCA inner pivot and this can be either forward or behind the axle. With that arrangement it is still possible that there could be some reactionary forces that tend to compress the suspension, but I don't know.

Wheel hop to my mind is largely the result of flex in the driveline and suspension and this is greatly aggravated by the way the Jag unit is made. Starting with the half shafts, a solid axle will twist somewhat under heavy load so going to tube axles will help, if only incrementally. We can do little about flex in the tires but going back the other way the upright (hub bearing carrier) is only supported at the bottom at two points. And as much as the UHMW bushings are a good idea for replacement of the stock timken bearings, they do have more give to them and will contribute to the problem. The stock LCA uses a large heavy tube and this is extremely resistant to twist, much more so than a built up LCA would be, but it is at the disadvantage of having the load applied through a lever arm (the upright) which is several inches long and this is the basic problem with the design. Jaguar did a fine job of designing around this problem by using rigid components and zero clearance bearings but the source of the problem is at the upright. Finally there is the connection from the LCA to the body of the car which includes the isolator mounts for the IRS cage. Other components that can contribute are the spring hub on the clutch and the motor mounts.

So knowing that twist at the upright is the biggest problem how do we fix that? Clearly if there was a way to tie the top of the upright to the body so it couldn't move fore and aft but could still move up, down, and sideways that would take care of it. A radius rod to the LCA doesn't do that, it would require an attachment of some sort at the top above the spindle. I suspect that Jaguar experimented with something along this line at some point but I've never seen anything on it. Two possibilities come to mind right away, the ubiquitous radius rod which in this case would need to be a little contorted or tie into the body in a higher location and this might work well with the UHMW bushings, and a strut of some sort similar to a McPhearson but shorter. A Watts linkage also should work just fine, provided there is room for it.

Now for anyone who has made it this far and wants to know why the half shaft is not enough for the upper control arm (UCA), although the half shaft is fine for controlling lateral movement of the upright it can do nothing to control fore and aft or rotational motion because of the u-joints and because it rotates, leaving every bit of the reactionary forces to be carried by the LCA. This explains why the LCA is so beefy on the Jag, and also should be a cautionary note to anyone considering built up LCA's, as they will not resist torque as well as the original arms do. Basically, that tube has to resist all of the torque output of the engine, multiplied by first gear and the ring and pinion, so if the engine produces 300 ft/lbs of torque which is multiplied by a factor of about 10 and the diff has a posi that's 3000 ft/lbs of torque that the LCA has to resist, applied through about a 6 inch lever. If it is correct then to say that we have 3000 x 1-1/2ft/lbs that converts to 4500 ft/lbs, or about the equivalent of me jumping up and down on a 20 foot lever and I guarantee something in that suspension is going to give. So there's your wheel hop. Not such a mystery anymore, is it?

Jim

[Moderator]

Fred Puhn's book is excellent... but when you're thinking about engineering your own IRS you've moved on to other territory. I'd recommend "Tune to Win" by Carroll Smith. It has long, detailed, extensively illustrated suspension chapters. That were written primarily for people designing their own open-wheel race car suspensions (e.g. "Formula Fords"), but all the same physics will apply to your IRS. All the Carroll Smith books are outstanding, by the way.

Have you ever spoken with Tom Hoagland? He has recently retired from doing MGB V8 conversions (he formerly operated a shop in Michigan under the name "Richland Motor Cars"), but while he was in the game he built up several Jag IRS MGBs. I don't remember too much of our discussion about them, but one thing I remember was he stressed his preference for working with the E-type IRS vs. the later components.

I don't know if this contact info will still work for Tom:

P.O. Box 311
Palmyra, MI 93010
telephone: (517) 410-7628
e-mail: Tom_Hoagland@hotmail.com

[Citron]

Wow!  You people have lost me.  If it helps any, I plan to bring my Jag when I come up with the 455.  We can look at a working model.

Steve

[Bob in Vancouver]

Hi Jim, I've been following this project with interest - it should be one torquey beast when complete!  Reading what you wrote about the Jaguar IRS and the torque loads on the control arms and the uprights got me thinking about the design of that system.
    It strikes me that the torque reaction to the rotating drive shaft - which is transmitted to the body structure of a beam axle car through leaf springs and spring shackles or by ams attaching the axle to the body is quite a different scenario to an IRS set-up where the differential is bolted solidly to the body structure.
In this case the torque reaction would be transmitted to the body by the differential mounts and the suspension from there on out would not be subject to those loads. This should mean that the outboard suspension would not need to be that strong in a rotationally resistant sense and this is probably the reason for the inboard discs with their mounting points being part of the differential assembly as then the braking torque loads are also not placed on the uprights or the control arm - only the drive shafts
     The suspension still has the job of locating the rear wheels vertically, fore and aft and laterally and of absorbing full braking and acceleration loads in a fore and aft sense. So hopefully the only new control arm needed would be the lower trailing arm, similar to the Jaguar item, to provide fore and aft stability for the wheels. I look forward to seeing how this conversion runs as I have been thinking of a Jaguar IRS for my car for some time. Its great to see a cooperative effort like this and I wish it every success. Bob Elwin

[BlownMGB-V8]

I believe you are right Bob, that does make perfect sense. However, the arm still needs to resist the force of the tire gripping the ground and acting as a lever against the anchor point, which is the upright pivot. So with a 24" diameter tire (for simplicity) transmitting 3000 ft/lbs of torque to the pavement that means 3000 lbs of acceleration force is being applied ( 3000 X half the tire diameter or 1 ft.) to the pivot which is halfway between the contact patch and the stub shaft or the center of the wheel. That (roughly) 6" distance means that at least half of that torque will indeed be transmitted through the torque arm simply because there is no other member to resist twist on the arm developed as a result of the acceleration force from the contact patch, even if there is a radius arm attached at the pivot to absorb linear acceleration forces.  Does that sound right? I still think it is this twisting force that generates the wheel hop and it makes sense to me that an upper link could control it quite easily. What you just pointed out though is that the link only needs to be about a third as strong as I had originally thought, a great advantage.

I will try to contact Tom Hoagland later today. I haven't gotten much done on the car in the last week other than theorizing. Jim Stuart is going to send one of the wheels so we can set the hub to hub distance and shorten the arms and shafts, but we need one hub. I can machine the new stud pattern but I don't want to set up the mill for that until I have both parts since it involves removing the vise and dialing in the index table. I'd much rather not have to do that twice. The stud pattern has to be machined before the hubs can be assembled into the uprights, and the uprights have to be assembled before the half-shaft length can be determined. So I really need someone to find us a hub and send it to me. That's the flange that the wheel bolts to. One is good but the other one is broken under the inner bearing race. We might be able to get by with using it that way, but it's risky since the bearing wouldn't be supported properly. I don't think that is the sort of risk we should be taking on this car.

Jim
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[Bob in Vancouver]

Hi Jim, Your quite right about the lower radius arm mainly taking lateral and vertical loads as the base isn't very wide for all the fore and aft loads. That is where the trailing arm comes in to maintain the rear wheels in the correct fore and aft location against acceleration and braking forces. I think the tractive effort as the tires turn will still be taken by the differential mounts with the hub carrier and its lower arm acting purely as a bearing and a means of maintaining the wheel in the correct position. The reason for this is I'm hoping you can get away with the lower trailing control arm alone as there may not be enough room for an upper one as well.
      I remember driving a very tired E-type many years ago which would change direction left or right depending on whether you accelerated or braked accompanied by strange clonking sounds from underneath - perhaps the trailing arm had rusted away from the body!! Cheers, Bob.

[BlownMGB-V8]

Well, here's what I'm thinking Bob,  as the thrust of acceleration is applied to the trailing arm the point at which it attaches (the upright pivot pin) acts as a fulcrum or pivot for the load that is applied because the force is applied at the tire contact patch, rather than 6 inches higher where the trailing arm is. In other words, there is a 6 inch long lever arm applying the load to the trailing arm pivot. This creates a torque load on the lower control arm equal to the axle torque divided by the radius of the wheel/tire and multiplied by the distance of the pivot above the road. In our example, resulting in 1500 ft/lbs of torque applied to the lower control arm. Attachment of the differential is irrelevant in this case because we are dealing strictly with a linear acceleration load at the trailing arm which is then translated into torque by the offset between the point where the load is applied and the point of rotation. My numbers could be off but the transmission of forces is accurate I believe. Your idea of dual trailing arms is a good one as that would control the torque thus created, in effect moving the rotation axis back to the center of the hub or depending on the geometry of the trailing arms allowing it to be located where it would do the most good. I think that is the basis of a good four link system on a live axle, though in that case it has to deal with rotational loads on the housing also. I don't claim to really have a handle on this, it's been a long time since I studied force vector loads and I'm plenty rusty. Plus there's a lot going on back there, much more than just rotation and counter rotation.  However, just taking the basic geometry as a good starting point I think if we do no more than transmit the rotational force created by acceleration to the body of the car we should be able to just about eliminate wheel hop. But the next question is where it gets tricky. If we do that with an additional linkage will it cause the body to go up or down under acceleration? I think that depends on how and where it is attached.

Jim

[jimbb88]

I found boxes for 2 wheels & will try to get them to the UPS guy this week.

[BlownMGB-V8]

Thanks Jim, that will help a lot.

Guys, somebody needs to step up and find us a wheel flange (photo in above post) as soon as possible. I can buy one but it'll deplete our funds by probably about $75 after tax and shipping. Doesn't anybody know some Jag people who might have a spare lying around?

Roadmaster weekend is coming up in another couple of weeks (Dec. 1 and 2). There well be several people here that weekend. Steve and Margaret are bringing up the 455 engine, Pete Mantell mentioned that he'll try to contact Rick and Dave and see if the three of them can run over, Dan B is coming in, and several local club members are planning on coming to the BCC-S meet Sunday afternoon which hopefully will be a good opportunity to make introductions. A few more weekends like that and we may be able to achieve critical mass.

New shop equipment is on-line.
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The new buffer is now operational, it is a 15hp 3 phase large frame motor with a 16" diameter 2-1/2" face buffing wheel. I've tested it out on some stainless I'm using for the control set on my motorcycle and it works well, though I'm not sure I have the right compound for it yet. Very stable and vibration free though and impossible to bog it down. I've nearly completed the foot pedal for the TIG as well and hope to finish it by next month.
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Still have a small bracket, the cord and a protective cover to do and then attach the cylinder holder to the welder and wire in the solenoid, pedal and hook up the torch, but with luck that'll be ready for the weekend. We still have some trimming and straightening to do before we need it. Incidentally for those of you who show up, all of the shop equipment is available for your use while you are here so if there's something you need to take care of on your car you can do that. Just another added incentive, courtesy of Blackwood Labs, LLC.

[Bill Young]

That's some buffer Jim, you could buff a brick to a high gloss with that thing. I like the TIG pedal too, nice idea to use a bass foot pedal, shoud give very good control with a good switch/rheostat attached. I know I promised another contribution to the funds. It will come, but I got bogged down a bit with the purchase of another driver last month and the associated license and title fees. Definitely by this time next month you'll have it, that should make the hub problem easier to overcome.
You mentioned redrilling the hubs, what bolt pattern are you going to use? I thought the Jag sedan bolt on pattern was the same as Chevy and you've already figured out how to do the front hubs on your car. I'd think you'd just use that pattern with the much larger wheel selection it brings.