V6 Midget Bill Young Kansas City, MO (1337 posts) Registered: 10/23/2007 09:23AM Main British Car: '73 MG Midget V6 , '59 MGA I6 2.8 GM, 4.0 Jeep |
Re: MGB Roadmaster
Jim, I would have been more than happy to donate the welder, but after I thought about it for a while I realized that the assets of the organization will eventually have to be disbursed when the project is complete and any physical assets other than the car could be a problem. Better to let you purchase it and continue my cash donations which can be applied to the car for parts or services. I think I've already found another small MIG machine, so no problems there.
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BlownMGB-V8 Jim Blackwood 9406 Gunpowder Rd., Florence, KY 41042 (6499 posts) Registered: 10/23/2007 12:59PM Main British Car: 1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS |
Re: MGB Roadmaster
Thanks Bill.
We're now officially cutting metal on the IRS! Here you see the original half shaft alongside one that is rough turned. The diameter is 1.215" and will be turned to finished size after the tubing is purchased for making up the finished part. These stock half-shafts are not balanced, are in the rough forged condition and as such are not round and not especially straight either. The turning was done on a small 7" bench lathe with a cemented carbide tool at 850 rpm and there was a fair bit of bouncing going on which eased up noticeably as the shafts were turned round and straight. There are still variations in the ends but the balance overall should be much better when we are done Here we have both shafts rough turned. The dark streak is all that remains of the original forged surface. Since the original width was 66" we need to remove 7" from each shaft to reach the MGB's 52" track width and could consider taking another 1/2" or so to fit wider tires. This would be the marks on the unturned shaft above, showing how much shaft will be left to insert into the tube as a pilot. Simple mild steel tubing should suffice, but with a wall thickness of around 1/4". I have on hand some 2" x 1" hollowbar but that would be overkill and add more weight than we need, as well as requiring a good bit more turning. These shafts need to be able to stand up to about 2200 ft/lbs of torque so a thinwall tube just won't do. CWI uses a 2-1/2" .156" wall tube for their driveshaft style half-shafts, our OD will be about 1-5/8 to 1-3/4" so a thicker wall is needed. Jim |
Phillip G Phillip Leonard Kansas City (395 posts) Registered: 02/03/2008 04:12PM Main British Car: 1992 MG RV8 Rover 3.5 |
Re: MGB Roadmaster
Guys,
Great project ! I see a lot of brake/hub/ work. Has anyone got a good supplier for upgraded MG B lite weight O/E disc rotors - ones vented, slotted and much drilled for SCCA road racing ? Phillip G |
accobraman50 Arthur Mitchell Chicago (43 posts) Registered: 01/27/2008 08:14PM Main British Car: 1965 Butler Racing AC Cobra replica 350 SBC |
Re: MGB Roadmaster
Jim,
Great job on the turning of the half-shafts. Will these be a press fit into the tubes? After reading about the vibration you encountered while turning them, I'm concerned that I never once considered having the half-shafts on my Jag rear end balanced. I don't know why the thought never crossed my mind, Duh! Had the engine balanced, and flywheel, clutch, driveshaft too. Never considered the half-shafts. I'll be dismantling the Cobra to get it ready for paint in about three weeks. At that time, should I consider pulling the shafts & U-joints to have them balanced? Would appreciate all comments . Arthur |
BlownMGB-V8 Jim Blackwood 9406 Gunpowder Rd., Florence, KY 41042 (6499 posts) Registered: 10/23/2007 12:59PM Main British Car: 1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS |
Re: MGB Roadmaster
Arthur, I don't think I'd tear a car down to balance the shafts, but if I was in there anyway I'd plan on having the balance checked. Chances are good you'd never notice it, but if everything else is running nice and smooth you might. At highway speeds depending on tire size you would be in about that range. Your machinist should be able to balance one without drilling holes in it I would think, grind a little off the high spots. I'm guessing you have XKE half shafts. Being shorter they should be a little better balanced to start with. The probable reason most people don't bother with them is that the half shaft rotates 1/3 to 1/4 as fast as the driveshaft. I could have run these up to over 3000 rpm but wasn't comfortable with doing that. I'm sure they would have shaken rather badly at that speed. As far as the brakes go, the rotors should be pretty well balanced to begin with. I can't say I know but I'd think the manufacturer takes care of that for you. Still it would be interesting to check just to see how close they are out of the box. Should be really close. The half shafts have a center hole drilled in each end so they are mounted up between centers for machining. A driveshaft shop should have fixtures for attaching them by either the flange or u-joint to their balancing machine. Sometimes U-joints come center drilled also.
Once I have the tubing the shafts will be turned for a light to medium press fit in the tubing ID. Although a heavy press fit might sound better, in practice it requires an absolutely straight setup in the press to avoid deforming the tube and with the rounded ends of the yokes that is difficult to achieve. I'll probably use a .002" interference fit, leaning towards the tight side and then weld the ends with the shaft between centers on an old scrap lathe bed, then pop it back in the lathe for final cleanup and to make sure it runs smooth. I've had lots of practice on driveshafts and have no doubt that this will give us the right part for the job. A tubular driveshaft such as those sold by CWI would be a lot lighter, something worth looking into if there is clearance. In our case I'm not sure if it would be an option, but this is a low bucks project so we're going the low bucks route. Something else worth thinking about if you build an IRS with a top link (UCA), Spicer sells various sizes and lengths of splined couplers. By proper selection it may be possible to combine a male and female spline with the proper u-joints and flanges to get the needed half-shaft length. Since these are fully machined parts no balancing is needed and this gives a viable alternative to CV shafts. In fact it is probably the simplest route to converting a Jag IRS to full control arms and floating half shafts. Jim |
accobraman50 Arthur Mitchell Chicago (43 posts) Registered: 01/27/2008 08:14PM Main British Car: 1965 Butler Racing AC Cobra replica 350 SBC |
Re: MGB Roadmaster
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 Jim Blackwood 9406 Gunpowder Rd., Florence, KY 41042 (6499 posts) Registered: 10/23/2007 12:59PM Main British Car: 1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS |
Re: MGB Roadmaster
Arthur, check out this thread:
[www.clubcobra.com] 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 |
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BlownMGB-V8 Jim Blackwood 9406 Gunpowder Rd., Florence, KY 41042 (6499 posts) Registered: 10/23/2007 12:59PM Main British Car: 1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS |
Re: MGB Roadmaster
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 Rob Ficalora Willis, TX (2764 posts) Registered: 10/24/2007 02:46PM Main British Car: '76 MGB w/CB front, Sebring rear, early metal dash Ford 302 |
Re: MGB Roadmaster
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 Rick Ingram Central Illinois (1523 posts) Registered: 10/17/2007 09:36PM Main British Car: 1974.5 MGB/GT 3.9l Rover |
Re: MGB Roadmaster
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 Edited 1 time(s). Last edit at 02/24/2008 10:06PM by mowog1. |
BlownMGB-V8 Jim Blackwood 9406 Gunpowder Rd., Florence, KY 41042 (6499 posts) Registered: 10/23/2007 12:59PM Main British Car: 1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS |
Re: MGB Roadmaster
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 Arthur Mitchell Chicago (43 posts) Registered: 01/27/2008 08:14PM Main British Car: 1965 Butler Racing AC Cobra replica 350 SBC |
Re: MGB Roadmaster
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 Jim Blackwood 9406 Gunpowder Rd., Florence, KY 41042 (6499 posts) Registered: 10/23/2007 12:59PM Main British Car: 1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS |
Re: MGB Roadmaster
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 Rob Ficalora Willis, TX (2764 posts) Registered: 10/24/2007 02:46PM Main British Car: '76 MGB w/CB front, Sebring rear, early metal dash Ford 302 |
Re: MGB Roadmaster
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 Carl Floyd Kingsport, TN (4556 posts) Registered: 10/23/2007 11:32PM Main British Car: 1979 MGB Buick 215 |
Re: MGB Roadmaster
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. [www.weldracing.com] |
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rficalora Rob Ficalora Willis, TX (2764 posts) Registered: 10/24/2007 02:46PM Main British Car: '76 MGB w/CB front, Sebring rear, early metal dash Ford 302 |
Re: MGB Roadmaster
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BlownMGB-V8 Jim Blackwood 9406 Gunpowder Rd., Florence, KY 41042 (6499 posts) Registered: 10/23/2007 12:59PM Main British Car: 1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS |
Re: MGB Roadmaster
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 Rob Ficalora Willis, TX (2764 posts) Registered: 10/24/2007 02:46PM Main British Car: '76 MGB w/CB front, Sebring rear, early metal dash Ford 302 |
Re: MGB Roadmaster
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).
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MGBV8 Carl Floyd Kingsport, TN (4556 posts) Registered: 10/23/2007 11:32PM Main British Car: 1979 MGB Buick 215 |
Re: MGB Roadmaster
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 Rob Ficalora Willis, TX (2764 posts) Registered: 10/24/2007 02:46PM Main British Car: '76 MGB w/CB front, Sebring rear, early metal dash Ford 302 |
Re: MGB Roadmaster
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.
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