Positive camber

Trevor Jessie

Yoda

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• Aug 31, 2008

• #1

OK, I need to sort out my suspension. After a complete rebuild the right side has almost 2 degrees of positive camber and the left has about 1 degree. What is going on here? The A-arms are from two different cars, but I can not imagine that they are that different. The frame showed no signs of tweaking. So is this just poor quality control from 50 years ago?

 

jlaird

Great Pumpkin

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• Aug 31, 2008

• #2

Could very well be, I think it is supose to be 3 degrees.

 

OP

Trevor Jessie

Yoda

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• Aug 31, 2008

• #3

Three degrees positive? I thought they were supposed to be 0 degrees.

 

H

highhilleer

Guest

Guest

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• Aug 31, 2008

• #4

I just checked the BL workshop manual for the 1500 series
Toe 0 to 1/8"
Camber 3/4 degree
Castor 3 degrees

I don't have a reference for the earlier cars. From what I can see in the Moss parts books it looks like all front suspension parts are the same for all disk brake cars so I would suspect the alignment specs would be the same.

 

jlaird

Great Pumpkin

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• Aug 31, 2008

• #5

Bad me, senior moment, sorry. Above is correct of course.

Guess I need to research more and quit relying on my old memory.

 

tosoutherncars

Jedi Knight

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• Aug 31, 2008

• #6

Any looseness? How does it drive?

 

JPSmit

Moderator

Staff member

Silver

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• Aug 31, 2008

• #7

you didn't install the trunnion backwards the way the rest of us did, did you?

 

OP

Trevor Jessie

Yoda

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• Sep 1, 2008

• #8

Nope, a backwards trunnion gives about 20 degrees of positive camber.

It drives OK, but the steering is twitchy going to the left. I'm in the process of getting my ride height set and I want to have about 1.5 degrees of negative camber on the front. But I do not want to start off making changes if there is a larger fundamental problem.

 

bill_young

Jedi Warrior

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• Sep 2, 2008

• #9

Trevor, what type of upper trunion bushings do you have? There are urethane and nylatron upper bushings on the market that have an offset hole to adjust the camber. If you got these by accident and didn't notice that might explain the difference from side to side. The only other thing I can think of is the possibility that the shock arm is a different length. I'm probably wrong but I seem to remember that the shock from a Morris looks almost the same as the Midget but has a slightly different arm. Peter C. could tell you for sure.

 

OP

Trevor Jessie

Yoda

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• Sep 2, 2008

• #10

The shocks are from Peter, and I did not notice anything unusual about them. The bushings are rubber (from Peter as well). I suspect the shock tower was not well located when the car was welded together (this is a fairly early car). I need to figure out how to do some proper measurements. I'm almost 100% positive that the car has not been in any collisions, but I'm also aware that a few jumps of a curb can tweak a unibody and leave little visible evidence.

 

Glen_B

Jedi Trainee

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• Sep 2, 2008

• #11

A front Morris Minor shock is TOTALLY different from a Sprite or Midget front shock. Side by side they cannot be mistaken for one another or traded between the two cars.

To correct the tweaked geometry, the offset bushes can be used (if you like cussing, screaming and re-setting them every other month after they turn themselves out of adjustment) or you can add and subtract (grade 5 or 8) whashers from beneath the appropriate front shock. I didn't like the handling or the tire wear on my bugeye, so I added one washer under each shock bolt and it adjusted the camber a small amount. I then drove the car 4080 miles on fresh tires. The wear pattern in the front was excellent and the handling was very good.

Glen Byrns

 

OP

Trevor Jessie

Yoda

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• Sep 2, 2008

• #12

Thanks,

I need to figure out a good way to measure from the lower inner A-arm mount up to the pivot on the shock. I think there is some discrepancy from one side to the other.

 

Hap Waldrop

Yoda

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• Sep 4, 2008

• #13

Trevor Jessie said:

Nope, a backwards trunnion gives about 20 degrees of positive camber.

It drives OK, but the steering is twitchy going to the left. I'm in the process of getting my ride height set and I want to have about 1.5 degrees of negative camber on the front. But I do not want to start off making changes if there is a larger fundamental problem.

Click to expand...

Winners Circle, www.spridget.com makes a offset trunnion bushing that will net you about 1.25" max of negative camber, which is plenty for a street car, you can turn it to net less negative camber by placing the offset in a different location. They are made of a dleron or nyln type of material. I used them for years on the SCCA race cars.

Negative camber will indeed make your car corner better, but the cost will be a bit of inside tire wear. I would think it possible to get the offset trunnion to net you less negative camber based on wwhere you put the offset. If tire wear is a bigger concern then you could postion the offset to net you a more modest .5" of negative camber.

 

OP

Trevor Jessie

Yoda

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• Sep 4, 2008

• #14

Thanks Hap.
I'm aware of offset bushings, and extended trunnions. I was wondering if I had missed something that was causing the excessive positive camber. After I get my ride height sorted, then I'll take a look at getting the .5 or 1 degree of negative camber I want. Then I'll see where that leaves my tie rod angle/arc. I've been through this on my midget, but it was more "square" to start with. (Ironic since it was involved it a hard rt/front shunt)

 

aeronca65t

Great Pumpkin

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• Sep 4, 2008

• #15

Yeah, I'll second the offset bushings as a good fix.

But note Glen's point too: You can put spacers under the shocks and this will increase negative camber too. Most people use large washers for this purpose.
This can be used as a pretty simple and easily reversible experiment to see if more negative camber will improve handling.
Don't space the shocks up too much.....not more than 3/16" I would think.

 

GeeBee1

Jedi Knight

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• Sep 4, 2008

• #16

I have seen the spacers done, and they really do not do that much, due to the very inward location (years ago they were the way to go :wink: ). IMHO, for a street car the trunnion offset bushings are the way to go. You get the most stability, bang for the buck and they are very simple to change.

I have them with almost a 1" squat and am running 1' negative camber.

Nial, this brings back the old memories for me of slotting MGA A-frame mounts (ahh they good ole days).

 

aeronca65t

Great Pumpkin

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• Sep 4, 2008

• #17

GeeBee1 said:

Nial, this brings back the old memories for me of slotting MGA A-frame mounts (ahh they good ole days).

Click to expand...

Ha ha!

What do you mean, the good old days? :laugh:

The shocks in my race-Spridget has slotted holes to adjust camber (but I wouldn't recommend this method...it's lots of work to get right).

 

Glen_B

Jedi Trainee

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• Sep 4, 2008

• #18

The problem I had with the offset trunnion bushings is that they tend to rotate on their own. Their fit into the upper trunnion is not tight enough to lock them into place. You dial them carefully to get what you want and after a rough road or two, they are turned to a different, WRONG, position. I guess they could be glued into the correct position, but I just tossed them in a box and bought a few washers. Can you say pragmatism?

Glen

 

GeeBee1

Jedi Knight

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• Sep 4, 2008

• #19

Glen, I didn't have that problem.

Nial, years ago I bored them out with a bigger bit, but didn't get much on emm.

 

Hap Waldrop

Yoda

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• Sep 5, 2008

• #20

Trevor Jessie said:

Thanks Hap.
Then I'll see where that leaves my tie rod angle/arc.

Click to expand...

If you running the late model rack, then call me and I tell you how to space the rack up for bump steer. The later model sterring rack allow you to modify the steel rack mounting brakets, with the early race you cn still do it just require more thought and aluminum welding, with the stell mounts it's a 5 minute mod. Of course hiem joint will coure this even quicker, but alot of guys don't like to run the on street cars.