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MG MGB Technical - Front end Alignment

OK guys i need to do something with the alignment of my '73 B. the camber is quite bad. I have upgraded to the V8 lower control arm bushings already.

I have wiggled the front end and the King pins seem fine.

What and where is the adjustment for this?? I do plan on doing this myself. I am commited to do all of the work to the Car myself.

Thanks for the Help guys

Joel H
JH Joel

Toe-in is the only thing adjustable, it is done by screwing the tie rod ends in or out as needed.
Ken Lessig

When you say the camber is bad, what exactly are you referring to?
Mike Howlett

Joel,
The only way to (significantly) alter the camber (the amount of "lean" the tire has in and out when looking at the tread straight on from the front of the car) is with different A-arms (aka control arms). Negative camber A-arms are sold that significantly improve handling, or so I'm told. I think that they provide about 3-5 degrees of neg camber (which is when the top of the tire leans toward the middle of the car as opposed to positive camber when the top of the tire leans toward the outside of the car.)

Ben
Ben Pender

OK I get you Ben. So really there is no adjustment, (Oops I ment camber) except for getting new control arms which vary in length depending if they are positive camber or negative camber arms.

From what I can gather then I have the Negative camber arms.

So the toe is about the only real adjustable point. That will be done easily.

thanks for the info guys. I have only had My B for about 3 Months now and I have been fixing regular maintenace items the the PO never even considered doing. In doing so i noticed that the front tires are feathering a bit on the inner edges and that they looked tilted a bit too much for my liking but if it is normal for the 3 degree then I am cool with it.

Thanks again

Joel H
Joel H

Joel

3 deg neg is really for racing, for road use a max of 1.5deg.

Feathering could be a sign of incorrect toe which can be set to zero or slight toe in.

Paul
Paul

Joel,
One thing to wonder about is whether the PO lowered the front end with shorter springs or if the springs are quite worn out. When looking under the car, are the lower control arms fairly parallel with the ground? They should be. If the springs have been shortened (or are extremely saggy) the control arms will point upwards at the outer ends. This would create excessive negative camber (and not in a good way).

I have the longer "extra negative camber" arms on my MGB race car. For racing purposes they are great for cornering. I'm sure that with more normal driving use they would cause premature inner edge tire wear like you have. In road racing, slowing down as little as possible for the corners is the goal. Tire longevity, rather than being measured in "thousands of miles" is instead measured in "weekends".
Kelvin Palmer

Kelvin they are pretty much horizontal to the ground.

BTW how are the springs suposed to look?? Do they look simetrical top to bottom or does it end abruptly on the top??

I did notice this when I had them out when changing the lower control arm bushes.

How long are the negative camber arms suposed to be, then I can measure mine and see what there is there. Give me the measurement between the center line of the 2 bushes if possible. Within an 1/8th of and inch will tell me right away.

Thanks guys

Joel H
Joel H

Joel,
The measurement from bushing center to bushing center along the front side of the lower arms on my car is close to 13" even. Realize this is with a tape measure just held across the pivot nuts.

My quick, crude measurements on the camber suggest that I have about 2.5 degrees negative.

Assuming that a "normal" arm has zero camber (I don't really know this) and that the spindle height from pivot to pivot is about 8.5", I calculate that the length of a "normal" arm would only be about 3/8" shorter, or around 12-5/8" between bushings. I don't have any normal ones lying about to measure. Maybe somebody wants to measure their stock arms and tell us what they get.

By the way, when you first set the car back on the ground after the front end has been up on a jack it will appear to have a higher front end and LESS camber. Until you roll the car back and forth or twist the steering back and forth it won't settle to a normal stance.

I've seen springs with flat, finished looking ends and springs that seem to have just been cut-off mid coil. I don't know what way they're supposed to look.

Kelvin Palmer

Joe, I just measured a stock A frame, center to center and it measures 12 3/4". It is a spare and not on a car so my measurement should be close. Good luck, Clifton
Clifton Gordon

Well I measured my A-frame arm last night and it is about 13" even also. I cvalculated the toe to be about 2 deg out on each hub, I was able to get it somewhat straight now. Seems to track better, but seems to wander to the right and sometimes to the left. I think it just needs some fine tuning. I'll check it again in a fiew days.

Thanks for the help guys

later
Joel H
Joel H

Kevin or Clifton, Can you give me the way you are measuring this, and if it with the car flat on the ground or on a jackstand? My car pulls slightly to the right on hard braking so I am thinking some camber adjustment may be needed.
john

John, I measured a bare front wishbone arm from the center of the bushing eye to the center of the hole for the bottom king pin through bolt. Clifton
Clifton Gordon

Joel, I assume you mean the camber is about 2 degrees on each hub, toe is usually measured in inches. I use an 18" I beam type aluminum level to check camber. I drilled holes in the aluminum beam to match 13", 14" and 15" rim flanges. The holes were tapped with a 1/4" coarse thread tap. Two 1/4" bolts with lock nuts are threaded into the holes for the size rim you wish to check. The bolts must be adjusted to the same length. They can be measured with a dial caliper. Or find a level floor using the horizontal vial, turn the level over and verify the the bolts are equal with the level vial. To check camber place the heads of the two bolts on the rim and see how close to vertical the wheel is. The car should be on a level floor with tire pressure set to normal. If the bubble is center there is some camber in the wheels. If the bubble is off center toward the car you have positive camber, off center away from the car the camber is negative. This will give a quick rough check of the camber. Of course if your rims are not straight the check will not be valid. The easy way would be to go to a wheel alignment shop with a computer alignment machine and have them give a complete 4 wheel alignment printout. Other than toe in/out there are no alignment adjustments you can make on the MGB other than replacing worn parts.

When you remove tie rod ends and replace them the replacement tie rod ends should be turned an equal number of turns on each side to insure equal length tie rods. This is important for two reasons. The car was designed so that equal length tie rods will cause very little or no bump steer. Also unequal tie rod lengths will cause the steering to be off center and the turn radius will not be equal in each direction. To verify the the steering is centered turn the steering wheel from lock to lock and position the wheel exacttly half way between the two. If the steering wheel is not centered or very close to center it should be removed and centered. The car is now ready for toe in setting.

The toe in will need to be adjusted so that you keep the equal length tie rods. If you have toe out you will need to turn each tie rod an equal distance, (example 1/4 turn on each side), so it's wheel moves toward the center of the car. To measure toe in you can buy a simple toe gauge from places like JC Whitney or you can fabricate one. One simple accurate method is to use a carpenters plumb bob. Scribe a line around the tire tread, hang the plumb bob from the scribe mark at front and rear of the tire. place some masking tape under the plumb bob, lower the plumb bob to the tape and make an x mark with a fine pen. When you have done both wheels roll the car back and measure the distance between the rear marks and record the reading. Measure between the front marks. If you have a front measurement 1/8" shorter than the rear that is your toe in. Keep checking and adjusting until you get the desired toe in/out.

Good luck, Clifton



Clifton Gordon

Clifton, thanks for this input. This will be a Saturnday project. There is no way I can do this with Hockey tonight and BBall the rest of the week. I'll start with the plumb bob method. Thanks again.
john

This thread was discussed between 02/06/2003 and 10/06/2003

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