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MGB Kingpin conversion: anyone have camber problems?

Posted by Duncan 
barneymg Avatar
Barney Gaylord
Naperville, Illinois, USA   usa
1958 MG MGA "MGA With An Attitude"

A and B lower A-arms are same parts. A and B shock arms are same length. A and B shock bodies are both symmetrical so the body can be turned around without changing camber. Offset distance from kingpin to top trunnion bolt is different, positioning the top of the kingpin farther inboard on the MGB. But the MGB wheel still stands straight up with zero camber. Does that mean there is greater kingpin angle with the MGB knuckle (in the standard MGB)? Or is the shock mounted farther outboard on the MGB?



Barney Gaylord - 1958 MGA with an attitude - http://MGAguru.com
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colynf Avatar
Colyn Firth
South Yorkshire, United Kingdom   gbr

Duncan

Dont go for negative camber if you intend to do any really high speed cornering (especially if you have the suspension lowered a little like mine is)
The negative camber makes the steering amazingly sharp on the slower very tight bends and it is great fun BUT at high speeds on the longer curves the rear wheels may easily break away from you.
The problem is that the steering becomes so sensitive that when you try to correct the slide the car just snaps the other way.
Even driving on the freeways was difficult as the car would need constant steering to keep it in a straight line.
I have been very very close to losing the car at speeds over 60 -70 mph on fast corners and have just taken the neg camber lower suspension arms off and replaced them with standard ones.

The car has been transformed and is now a delight to drive at all speeds.

I wish I had done it years ago.

Colyn
bills Avatar
Bill Spohn
W. Vancouver, BC, Canada   can

In reply to # 2301742 by colynf Duncan

Dont go for negative camber if you intend to do any really high speed cornering (especially if you have the suspension lowered a little like mine is)

Colyn, I have to think that at least some of your issues come from enhanced bump steer from lowering as my street coupe is neither twitchy nor has it any problem holding a line in a high speed corner and is easy to catch if it starts to lose adhesion. Same with the Jamaican, although I don't recall submitting it to really hard cornering above maybe 80 mph. Both cars track stright - you can take your hands off the wheel and no veering due to road surface - that really sounds like severe bump steer to me.



Bill Spohn www.rhodo.citymax.com/carstuff.html
1958 MGA Twincam (race car (170 bhp)),1962 MGA Deluxe Coupe (98 bhp)
1969 MGC roadster (175 bhp), 1957 Jamaican MGA (200 bhp)
1965 Jensen CV8 (375 bhp), 1971 Jensen Interceptor (350 bhp)
1969 Lamborghini Islero S (350 bhp), 1988 Fiero GT turbo (300 bhp)
2009 Pontiac Solstice GXP Coupe (350 bhp)
West Vancouver BC

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colynf Avatar
Colyn Firth
South Yorkshire, United Kingdom   gbr

Thanks Bill

I think you are correct about the lowered suspension issue when combined with negative camber, the bump steer was vicious and nearly had me off the road on many occasions.

I put up with how the car handled for many years as the turn-in on tight country lanes was just sensational. But on a recent MGA Register tour I had the car sideways almost from lock to lock when I hit a bump on a long bend at about 70mph. My wife wasn`t very impressed!

So I ditched the negative camber lower arms and fitted standard ones and the car was transformed even though I still retained the lowered springs.

It now tracks straight and corners beautifully and I no longer have to take a deep breath and take a step into the unknown each time I drive into a fast bend!

The benefits from the lowered suspension are few:- slightly better cornering due to reduced body roll and it looks great (to me anyway!)

The disadvantages:- a much harder ride and reduced ground clearance.

I have found that the improved cornering can only be used on a very smooth road surface, a race track for instance. On bumpier road surfaces, the car and the driver get rattled about a fair bit and I find it hard to keep up with MGAs with standard suspension whose cars ride the bumps much easier. So I may well fit standard springs sometime in the future

So to me, the conclusion seems to be:- Dont fit lowered suspension and negative camber lower arms at the same time, just chose one or the other!

Colyn
bills Avatar
Bill Spohn
W. Vancouver, BC, Canada   can

I agree with your conclusion,. Colyn!

It is annoying that Moss doesn't offer proper stiffer front springs (something that works well on the MGs). They went the cheap way - chop a coil off the stock springs, have their manufacturer make them shorter so they can claim they are stiffer (which si true, of course) but using the same wire diameter, instead of just winding them from a different diameter of wire. They are essentially making the height decision for you - want stiff springs, you have to lower the car.

I have used their springs as it is cheaper than having custom wound springs made, and then I machined up some spacers for the top of them to get back to stock ride height.



Bill Spohn www.rhodo.citymax.com/carstuff.html
1958 MGA Twincam (race car (170 bhp)),1962 MGA Deluxe Coupe (98 bhp)
1969 MGC roadster (175 bhp), 1957 Jamaican MGA (200 bhp)
1965 Jensen CV8 (375 bhp), 1971 Jensen Interceptor (350 bhp)
1969 Lamborghini Islero S (350 bhp), 1988 Fiero GT turbo (300 bhp)
2009 Pontiac Solstice GXP Coupe (350 bhp)
West Vancouver BC

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front-springs-comp.jpg (68.6 KB) –
front-springs-comp.jpg

dipstick Avatar
Kenny Snyder
La Center, Washington, USA   usa

Our ex Steve Beckham MGB E/P racecar (Rainbow), destroyed at Willow Springs, had adjustable spring pans. The spring depression had been cut out and fitted with a male threaded ring, and the pan fitted with a female threaded ring. From under the assembly in the center was a bar with a 1/2" square hole for fitting a breaker bar. I can't find a picture of that setup.



Be safe out there.
Kenny
bills Avatar
Bill Spohn
W. Vancouver, BC, Canada   can

I've seen that too, Kenny, but it has always struck me as being something you'd fit, set up for the tracks you run and then never adjust again. Might as well just set the suspension at an average height and forget about it. Seems over complicated.



Bill Spohn www.rhodo.citymax.com/carstuff.html
1958 MGA Twincam (race car (170 bhp)),1962 MGA Deluxe Coupe (98 bhp)
1969 MGC roadster (175 bhp), 1957 Jamaican MGA (200 bhp)
1965 Jensen CV8 (375 bhp), 1971 Jensen Interceptor (350 bhp)
1969 Lamborghini Islero S (350 bhp), 1988 Fiero GT turbo (300 bhp)
2009 Pontiac Solstice GXP Coupe (350 bhp)
West Vancouver BC

. You can hide this ad & support this site by upgrading to a Gold Membership ~ click here for more info
dipstick Avatar
Kenny Snyder
La Center, Washington, USA   usa

Bill,

Oh yeah, way overkill and heavier, plus the threads got full of grit. The setup did serve in a couple of ways: Patricia was/is considerably lighter so we could quickly drop and equalize the ride height for her, and for those long rainy weekends with the dog-bone rains on the entire time the front could be lowered to compensate for the increased tire height.



Be safe out there.
Kenny
bills Avatar
Bill Spohn
W. Vancouver, BC, Canada   can

In reply to # 2302887 by dipstick Bill,

Oh yeah, way overkill and heavier, plus the threads got full of grit. The setup did serve in a couple of ways: Patricia was/is considerably lighter so we could quickly drop and equalize the ride height for her,

Ah - I always wondered why she was often faster - that must have been it! devil smiley



(Just kidding, although I do recall her sometimes being faster, which I always attributed to her being a smoother driver than us guys usually are.)



Bill Spohn www.rhodo.citymax.com/carstuff.html
1958 MGA Twincam (race car (170 bhp)),1962 MGA Deluxe Coupe (98 bhp)
1969 MGC roadster (175 bhp), 1957 Jamaican MGA (200 bhp)
1965 Jensen CV8 (375 bhp), 1971 Jensen Interceptor (350 bhp)
1969 Lamborghini Islero S (350 bhp), 1988 Fiero GT turbo (300 bhp)
2009 Pontiac Solstice GXP Coupe (350 bhp)
West Vancouver BC

Duncan Avatar
Duncan Cowen
Delta, Vancouver, Canada   can

In reply to # 2301000 by PeterC ..there IS a difference of roughly half a bolt diameter where the MGA is farther outboard than the B.

As I said to Duncan, I think a set of offset camber adjusting bushings such as Moss sells (282-308) would be sufficient to adjust the camber to either dimension you would want.

Peter C

I had a look at the pic Moss provides of these bushings.



Reading the directions for installation clearly indicates that they replace "3d" in the image below, the rubber between the MGB shock arm and the top of the kingpin.



Interestingly, Moss gives camber suggestions in the text below that exploded view.

From a purely aesthetic point of view, I'm glad they're used at the top, because I think MGA front wheels "look" like they tuck into the wheelwells more than the rears do. Also, my lovely new wide tires rub on the swaybar as I approach full lock, so I'd prefer to pull the top of the kingpin out, rather than move the A-Arm in.

Can anyone comment on UHMW Polyethylene as a long term bushing material, as opposed to rubber or Polyurethane?
bills Avatar
Bill Spohn
W. Vancouver, BC, Canada   can

Duncan, those bushes are the answer for you if you don't like the negative camber you have (I must look at your car to see if it is excessive or not, but you could get the camber checked and post numbers for us!).

No solid bush is as forgiving as a rubber one that flexes instead of presenting a wear surface to an unyielding pin (which is why I always use V8 Metalastic lower bushes on my street cars), but having said that I doubt you'll see fast wear and they are the easiest of all to replace if you had to - without totally disassembling the suspension.

Just make sure you assemble them correctly - they are eccentric and both have to be in the same orientation, plus you have a choice of how much posistive effect to dial in - hard to tell by eye and ideally you'd have this done on an alignment rig, but it is possible using the right technique to use a magnetic level and a couple of greased steel plates. If you can, let us know the before and after camber measurements for posterity.



Bill Spohn www.rhodo.citymax.com/carstuff.html
1958 MGA Twincam (race car (170 bhp)),1962 MGA Deluxe Coupe (98 bhp)
1969 MGC roadster (175 bhp), 1957 Jamaican MGA (200 bhp)
1965 Jensen CV8 (375 bhp), 1971 Jensen Interceptor (350 bhp)
1969 Lamborghini Islero S (350 bhp), 1988 Fiero GT turbo (300 bhp)
2009 Pontiac Solstice GXP Coupe (350 bhp)
West Vancouver BC

RJBrown Avatar
Randy Brown
Queen Creek, Arizona, USA   usa

Pictures of a 58 MGA with MGB front suspension. Shocks are MGB swapped left to right with arms reversed. MGB kingpin. MGB lower control arms with sway bar reenforcement. No apparent camber issues. Inner tier rod ends were shortened as needed.

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Duncan Avatar
Duncan Cowen
Delta, Vancouver, Canada   can

I thought I'd post to let everyone know that I haven't given up on this thread!

I've cleaned, repaired, and painted everything regarding the front suspension, and I received 2 stock MGB shocks to mount on the front (and two stock MGAs for the rear - thanks for being so quick Peter!), so I'll get them in and post pics soon.
Duncan Avatar
Duncan Cowen
Delta, Vancouver, Canada   can

As another update to this thread, I've finished the front suspension and rolled the car back and forth, although I haven't driven it. But I have not tried to adjust the camber at all, and when I put an angle finer on the front wheels, they are apparently only one or two degrees off vertical!

So this makes me wonder, what remaining parameter is different between the MGA and MGB shocks that we have not discussed?? Using MGB kingpins with MGA shocks seemed to change the camber enough that the car chewed through tires (after an alignment by BC Shock and Strut). On the other hand, MGB kingpins with bone-stock MGB shocks has resulted in very little camber. I can't figure it out!

I still haven't driven it to see what it's like, but the steering wheel is easy enough to turn in the driveway, even with my wider tires. I can't wait to check it out with the lovely rebuilt shocks all around!!
Duncan Avatar
Duncan Cowen
Delta, Vancouver, Canada   can

Well, as an update to this thread, I've now done two long runs in it. The first long run was... eye opening. As Colyn foresaw, the car was terrifying when cornering at even moderate speeds. I've owned this car since 1992, and the handling has never been unsettling - until now. As long as I held even a small amount of throttle, it was fairly sure-footed. But if I felt a bit fast in the corner and let up at all, the pucker factor was awful, as the car turned tighter! I was really worried a number of times that I would end up backwards in a ditch (or worse) just keeping up with traffic! Kept me on my toes, that's for sure, and it chewed up the inside of my brand new tires pretty bad in only 1500kms.

In addition, the steering was very stiff near center, and the wheel would not return on it's own. The car was tiring to drive after a few hours of horsing the wheel around just to drive on the highway!

After that run, I corrected the camber as much as possible by moving the shocks outboard. What an improvement on Gary's Run! The car is much more predictable in the corners, the steering is lighter, and it returns to centre much better now. I still can't get the camber equal on both sides though, as I cannot remove the negative camber on the right side. But it still has a bit of turn-in when I let up on the throttle in a corner, more than I remember with the old shocks and tires.

I wonder what the heck is different between the two sides? I can't imagine the kingpin would be bent, because surely the steering would be more difficult? At any rate, I'm still looking for more adjustment, so I may have to get the bushings from Moss. In the meantime though, at least the car is not as terrifying to drive corners!



Edited 2 time(s). Last edit at 06/21/2013 10:15AM by Duncan.
bills Avatar
Bill Spohn
W. Vancouver, BC, Canada   can

In reply to # 2308466 by RJBrown Pictures of a 58 MGA with MGB front suspension. Shocks are MGB swapped left to right with arms reversed. MGB kingpin. MGB lower control arms with sway bar reenforcement. No apparent camber issues. Inner tier rod ends were shortened as needed.

Randy, switching the shocks like that results in reversed valving and screws up the rebound/bounce settings. Might be able to solve it by using MGA valving.



Bill Spohn www.rhodo.citymax.com/carstuff.html
1958 MGA Twincam (race car (170 bhp)),1962 MGA Deluxe Coupe (98 bhp)
1969 MGC roadster (175 bhp), 1957 Jamaican MGA (200 bhp)
1965 Jensen CV8 (375 bhp), 1971 Jensen Interceptor (350 bhp)
1969 Lamborghini Islero S (350 bhp), 1988 Fiero GT turbo (300 bhp)
2009 Pontiac Solstice GXP Coupe (350 bhp)
West Vancouver BC




Edited 1 time(s). Last edit at 06/21/2013 08:00AM by bills.
bills Avatar
Bill Spohn
W. Vancouver, BC, Canada   can

Duncan, perplexing problem. Probably time to have the car set up on a proper laser alignment rack and find out exactly what is happening side to side. Accident damage, or assembly issues pretty much have to be involved. I know a guy with race set up experience that works at a shop in North Van you might want to talk to.



Bill Spohn www.rhodo.citymax.com/carstuff.html
1958 MGA Twincam (race car (170 bhp)),1962 MGA Deluxe Coupe (98 bhp)
1969 MGC roadster (175 bhp), 1957 Jamaican MGA (200 bhp)
1965 Jensen CV8 (375 bhp), 1971 Jensen Interceptor (350 bhp)
1969 Lamborghini Islero S (350 bhp), 1988 Fiero GT turbo (300 bhp)
2009 Pontiac Solstice GXP Coupe (350 bhp)
West Vancouver BC

PeterC Avatar
Peter Caldwell
Madison Wisconsin, USA   usa

Duncan,
I was hoping you'd update this post. The symptom you describe can be ascribed to loose rear spring u-bolts. The rear axle shifts. Might be worth a look, and snug the nuts.

I'm still surprised that there was that much camber difference.

Bill S. when we make the shocks as Duncan has, we do use MGA valves instead of MGB valves.

Peter C

Member Services:
Supplier of New Old Stock parts for all imports. Rebuilder of lever action shock absorbers for British cars. Call (800)362-1025 M-F 8-5 Central or parts@nosimport.com
bills Avatar
Bill Spohn
W. Vancouver, BC, Canada   can

In reply to # 2398886 by PeterC
Bill S. when we make the shocks as Duncan has, we do use MGA valves instead of MGB valves.

Peter C

Peter - didn't realize you'd supplied Randy. I'd have assumed you'd have the correct valves if I had. winking smiley

Duncan - interesting suggestion from Peter. We are concentrating on your front end (still think there is no reason you'd have much different camber side to side, absent owner error or damage to frame/suspension) but it could be rear end.

I run a 3 link set up on the rear of the race car that has the springs sliding between fixed plates, so the only thing locating the axle are the lower traction/locating arms and an upper arm. I once forgot that I'd removed the lower arms for service once, and went out on the track for practice. Decidedly interesting handling with the rear end floating about. Loose/stretched U bolts can emulate that behavior. Have you checked them?



Bill Spohn www.rhodo.citymax.com/carstuff.html
1958 MGA Twincam (race car (170 bhp)),1962 MGA Deluxe Coupe (98 bhp)
1969 MGC roadster (175 bhp), 1957 Jamaican MGA (200 bhp)
1965 Jensen CV8 (375 bhp), 1971 Jensen Interceptor (350 bhp)
1969 Lamborghini Islero S (350 bhp), 1988 Fiero GT turbo (300 bhp)
2009 Pontiac Solstice GXP Coupe (350 bhp)
West Vancouver BC

Duncan Avatar
Duncan Cowen
Delta, Vancouver, Canada   can

Yes Peter, I've experienced loose u-bolts on the spring before, and that certainly causes a lot of throttle steer. So during the Spring Thaw I popped underneath and snugged up the u-bolts for the rear springs. None of them were loose at the time. I've also considered the bushings in the spring eyes, but I understand they rarely fail so I haven't dropped the front of the springs to check yet.

Changing the camber made a big difference, so I think I'm on the right track working at the front of the car! And yes, "owner error or damage to frame/suspension" are strong possibilities on this poor old car! winking smiley But can that massive boxed cross member really bend?? Or, can kingpins bend and still be functional?


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