MG Sports Cars

Radius arm is now nearly impossible to reattach since the toe was corrected. (It was easier when the car was first assembled-- it was 5deg toe OUT! (Steve info here).)




Edited 1 time(s). Last edit at 02/25/2013 09:10AM by madmax.

Last one for now... overfilling the tranny (Carl's suggestion).

What the hay, two More. :-)

Going back together:

The stress cracked rear subframe mount....

Thanks to Max and the crew for all this work, the car should be much better now. Anyone want to take it from here for some of the early spring events? It needs to find a home for a while as Max doesn't have the facilities to store it long term. I'm sure that most of you are not thinking about car shows now and are looking at a white world outside as we are here in Kansas, but spring is not far away. Our first local event isn't on the calendar until April 20, just before the winter meet. Send me an e-mail if you want the car for a while, mgmidgetbill@gmail.com

Good job guys! Max, I'll have to get with you or one of the other guys first chance we get to get a better understanding of the issues you discovered with the IRS. Obviously the attachment points are the most serious but don't sound too severe. Probably not quite enough give in the rear mounts isolators, that sounds like a redesign somewhere down the road might be a good idea. I'm not sure what you meant about the porosity in the carrier/bushings but am curious for more details. I know what you mean about the wiring, maybe a wiring channel in the top crossmember would be a good idea.

Incidentally, I am in the market for a spare Jag IRS assembly in good condition, good brakes and Power-Lok preferred, if you happen to run across something at a great price.

The brake M/C was selected by Bill Guzman. It seems to work OK once it is bled but I agree, what a pain it is. Entirely too resistant to bleeding, and it does seem excessively large and heavy. It's possible there is something wrong in the internal clearances. I like the stock single cylinders very well as they can gravity bleed overnight, but they require a balance bar. There is no reason we couldn't use something else if someone has a good suggestion. The car is fitted with the late pedal box, but I believe we still have an early one we could use if we need to.

Can't wait to hear what you guys thought of the car with the new rear gears.

Jim

Jim:

(Quick response. Home fer lunch).

a) There was just a little ovalling of the front spring mount (drivs) and then the break at the rear pass mount upper. So maybe just a little misalignment? I think the rebound mounts just need some better side bracketry and possibly thicker metal? The whole subframe, however, is fairly easy to remove so we were impressed by that. :-) If you do another one, maybe doing some final welding when you are actually on a frame machine? The radius arm issue was a near panic getting it reconnected. :-(

b) One of the other Techs thought the BMC pushrod might be adjusted too much and this is prohibiting the reservoir from drawing back in. (However, in a TR6, this would make the brakes slowly lock on!) I'm curious if the PDWA is still working correctly (they often get gummed up when old. We rebuild frequently.) That might be worth looking into.

c) The carrier housing was just some "nubs" of aluminum that stuck out past the bushings. So, the bolts would clamp down onto them (shiny marks). We ground them away and now it flops around smoothly (until the coil over is installed.)

d) So far, axle seems quiet. I'll do a highway stint tomorrow. I'm more worried about the pinging and running on, but Steve says this will go away with some Hi-Test. I'll fill up tomorrow. I'm hoping (fingers crossed) for maybe 20 mpg cruising with the new ratio, but Carl thought it might now rev too low, off the power band (I never saw dyno graph to know..) and thus the motor won't be that happy. I'll see how it feels tomorrow at speed.

Cheers,

M

I see, thanks Max.
The trouble with that forward (diagonal) link arm, whatever it's proper name is somehow I can never remember. Anyway it could be affecting the mounting points when it is bound up that tightly to bring in the alignment. Don't know why it was out that far to begin with, but as we know MGB bodies aren't exactly straight so maybe it's necessary to account for that by offsetting the soft mounting points a little. I'll know a little more when I get my RD aligned. I'm sure we could compensate for that but it would mean a lot of new mounting pieces. If I need them for mine I'll make extras for the RM. Also, curiously enough, the binding of the upright's lower pivot would have increased the loading on the mounting points on that side and may have caused the other problems or at least contributed to it. It's good that you guys had it out so we could see how the body was handling the torque loading. Not too bad, everything considered.

The next version of this is going to get one piece LCA assemblies welded up out of aluminum and the long pivot rods will be a thing of the past. Instead they will have a pivotable, adjustable front and rear attachment, and an as yet undetermined intermediate point, possibly a cam follower. (necessary to control pinion rise using LCA counter-torque) They will very likely get a new hub and bearing carrier assembly as well. I think with the right parts and the right wheels there is a very good chance that I can get the whole package inside the stock bodywork and still have the long wheel travel.

How is the acceleration with those gears?

Jim

Excellent work, Max.

Driving report:

Well, the highway stint was disappointing-- Vibration is atrocious! Thought a wheel was going to fly off.. I think others have made comments about this but I didn't think it was this bad. I found the car undriveable at ~70 mph. (However, down around 60, it seems fine!)

WELL.... pretty sure we know what this is! (Steve found it.)

The LUGNUTS we are using are shanked @ .680". But the WHEELS (Jag wheels) are .700! Thus, we slop around the hubs!

We ran the car on the lift and found the wheel NOT concentric with the hub. (We'd also noticed the fronts seemed "out of round", but we thought that was tire not wheel mount).

I've scrounged some Jag lugs and installed them on the rear-- PERFECT!

The bitch is going to be getting the FRONTS! From research done today,they don't make a 7/16-20 lugnut with anything bigger than a .687" shank.

(JIM:-- what is that hub? Is there a way to get the 1/2-20 lugs up front?)

So, my first attempt tomorrow will be to do a thread insert in the old Jag lugnuts to downsize them from the 1/2-20 to the 7/16-20. (With SAME thread pitch, this shouldn't be too much of a cluster F...)

Anyway, that's tomorrow as it just didn't seem driveable to the BMTA as it was. Hopefully this cures it (and if so, i'll make a spare lugnut or two to keep with the spare.)


The "shutdown" issue has gone away with the Premium gas. However, I'm still not happy with the overall tune. Twice it fell on it's nose when given the beans and there is noticeable hesitation at mid-throttle. (This seems transitional between Primary and Secondary?) It was Rainy today, though, so we might still be ingesting too much moisture for smooth running? I'll see how it does on a "nice" day. :-)


RE: overall driveability. I like it! The rear end feels very compliant, it doesn't seem to "push" (someone else's complaint. Perhaps this went away with freeing up the binding in the right rear suspension?). The gear ratio seems fine-- very tractable and versatile. Found myself doing city driving in 2nd gear, but could shift up to 3rd and still pull fine. The acceleration is strong, but maybe not blistering? (SEe above "stumble" issue.) It still puts you in the back of the seats.

Given the stiffness of the steering, it's not a great autocrossing car. And, with how it was used last year (Power Tour), I think a "Grand Tourer" is a good goal for it.

I'm hoping to be able to report gas mileage of 20mpg with the new axle. (Which IS quiet, BTW!) We'll see after the Conference.

Cheers,

M

(JIM:-- what is that hub? Is there a way to get the 1/2-20 lugs up front?)


you can drill the hub, by hand if necessary.

a mill machine would be best to be certain that you were maintaining concentricity.

Max,
The hubs are late '60s Chevelle or Camaro. I believe, around '69, whatever was the first years they had disc brakes. I'm positive the holes for the studs are going to be somewhere in the range of 5/8" down to around .575" so it will be possible to find studs in a 1/2" - 20 size that will fit the existing holes, at which point the stock Jag lug nuts will fit. The studs also attach the rotors to the back of the hub so the shank will be about 3/4" long with the knurl towards the threads. I think this is going to be a pretty common stud, and because Ford, Mopar, International Harvester and many others used 1/2" those should be the ones that will work. You can bang them out one at a time and pull the new ones in with an impact wrench if you get the right size. Variations in the knurl is not an issue, and a few thousandths difference in the shank size and step for the rotor can usually be tolerated.

Now that the gearing is taller any shortcoming in the tune is going to be more apparent. With the oil consumption cured we can now take steps to dial it in correctly, and anything that you do which results in the car running better will certainly be an improvement.

But mostly, I'm just thrilled that you like it.

Jim

From page 6 of this very long MG Roadmaster thread:

Quote:

The brake rotors are 11" diameter 1968 Camaro. I have notes that also show that these may be the same as: 1968 to 1972 Nova. 1969-1972 Oldsmobile Cutlass and F85. A GM parts supplier should be able to make sense of it. I knew a guy at NAPA that gave me some of this info. I also noted that I found that these rotor-hubs were available from from a performance supplier as a two piece hub-rotor combination. I did not keep part numbers, as I saw something (Fast Cars) in the future, although I did'nt know of Ted at the time. The two piece combo would be ideal for anyone wanting to do this mod today, as the hubs require some machining.
There are no places to read the specs about the Butler brakes. The inner and outer bearings on the Camaro have the same inner diameter dimension as the MGB stub axle/bearings. So the Camaro bearings would fit right on to the MGB. However the the distance between the inside and outside of the Camaro bearing as installed in the rotor are about roughly *3/16" wider then the MGB. (* will find out and confirm this exact dimension.) Butler's cure was to machine the rotor hub inner bearing recess deeper by the roughly *3/16". to align the plane for proper bearing/seal fit.

The rotors on mine (yours) are different. I did not machine the inner recess of the Camaro hub. I worked a couple of doors down from Berry Bearing (now known as Motion Industries) and found a bearing set that was thinner. However, I ended up having to machine the outer bearing recess roughly 1/8" deeper so that the castelled nut would be deep enough for the cotter pin to fit the hole in the axle. Thinking about this now it may have been easier to change the outer bearing to a thinner one too and eliminate the machining. I don't know why I did'nt take this approach. It may be worth looking into now, as there are so many bearing combinations available from bearing suppliers.

The caliper/bracket is not a modification I would consider doing today even though the caliper is still available for about $75.00 from NAPA. Have other MGB guys created brackets to fit multi-piston calipers to the Bee? The bracket for the caliper was modified by Butler Racing. Caliper and bracket were 1974 Dodge Dart 400.

Edited 2 time(s). Last edit at 02/26/2013 10:08PM by MGBV8.

The correct studs should be fairly easy to find, Max.

--->The correct studs should be fairly easy to find, Max.

O-kay... So, why didn't we? The car has smaller studs front then rear. I assumed (first mistake!) this must have been from some PITA factor... ?

There IS one stripped stud in the LF already. (Found this trying to take the wheel off. Must have been from airbag issues....) So, we'll have to do this at some point.

Alas, I have little time to make this right before the Conference TOMORROW. IF the lugnuts don't go well, this will force my hand... :-/ (I already had to overnight the thread inserts as it was. :-( )

Thanks for the info on Hubs. I'll take a look tonight, see about making a plan for the future.

FYI, new Jag lugnuts are $6/each, so another $60 to get nice ones when we swap lugs.

Why didn't we?...

Mainly a manpower shortage. There are any number of things on the car that could have been done to make it better and were not for that reason or because of a money shortage, both of which were constant problems. In the end I felt we struck a pretty good balance on what we got done and how quickly we did it but we missed the mark on perfection by a pretty wide margin, and the whole project set work back on my car by about two years because of time I spent on it working here alone. I'm not making excuses or complaining, that's just the way it was. It was quicker and cheaper to go to the local tire discounters and buy lug nuts than it was to change out the studs, and at the time we were in a crunch, maybe for Townsend. Almost like what you are dealing with now except that we didn't fully appreciate the misfit issue. If we had, I would have fixed it. I'm not sure we even considered changing the studs in fact, but I had already bought out the local store and hadn't found another source for studs so it might not have mattered anyway. That's the only thing I see as a possible issue, parts stores have stopped stocking wheel studs.

Jim

VIBRATION IS GONE! :-)

Took the car from a (presumed) 60 mph all the way up to what must have been 90 mph (zooming past traffic..) and there was no steering wheel shake!

The inserts (installed with red loctite so as not to get stuck on the stud!) were a doggle-- all I had to do was lightly countersink the top for the flange of the insert. (Otherwise, they threaded right in by themselves! Thus just wouldn't lock in place unless I get the flange tight.) Took me about 30 minutes to put inserts in 11 lugnuts (one spare, rem.) and then to swap them onto the front of the car. Took it for the lunch run and it was fine in that regard.

HOWEVER... ooh, it still pings. (Nice day, here, too. Sunny. 60F.) And it stumbles on the transition and does NOT like the Full WOT all at once. Once cleared out it pulls great, but it's an inglorious moment. (Engine really shakes). Also, the violent shut-down was back and it made restarting a little difficult.

Car is a comfortable cruiser, though, and for tomorrow that should suffice. :-)

Jimmy Browne came by (REM: British V8 2009) and gave the outside a wash and wax and mild detail. (He spent two hours on it.) It looks good for the drive tomorrow. Just needed a little luv... :-)

I'll report next (hopefully) on some improved gas mileage. Then we need to see a) who wants it next and b) how much we should worry about this tuning issue. It's a driveable car, but not as much of a "pleasurable" car as I think we would all like? Just my opinion here..

But the Vibration is gone. Yay! :)

M

PS: Splurged and got the Moss replacement mirror for the pasenger side-- what crap! Gooseneck is bent so poorly all you see is the wheel arch! (Won't adjust up). This is going back. I really like having a pass side mirror. Anyone else missed this? I can easily put on a later style (flat) mirror on the pass side (much cheaper, too!) but it won't match the OE on the drivs side. I was hoping this would be a nice, barely noticeable addition, but I'm not paying $100 (yep!) for a piece that looks great but doesn't WORK!

Inserted lugnuts are top/OE Jag is bottom (one extra of each in back with Spare)





Edited 2 time(s). Last edit at 02/28/2013 12:27AM by madmax.

I'm interested in hearing a report of comments from the BMTA boys.

No steering wheel shake? Man! I want to drive that car again! Way to go MAX! You da MAN! WOOHOO!!

Jim

:-)

Now... last minute problem. Brake Fluid leak.

WE suspected, because STeve showed up with nearly NO fluid in the rear of the reservoir (which, BTW, is the FRONT brakes!). Well, we had some clear fluid leaks on the floor in the clutch slave/below the BMC sort of area.

CMC was nice and full. BUT... rear of master was low again! (Like, halfway already and we'd just bled it Sunday morning!)

I found a drip on the lower line from the PDWA and was able to tighten that fitting almost 1/2 turn. We stomped on the pedal (still rock hard!) and did not immediately see any drips.

However, we'll be travelling with a bottle of Dot 4... :-)

Cheers,

M