HELP Monoball front suspension points. POST Your pics please.

[Vintage911Racer]

I am a little concerned that my new alignemnt may be a bit off. I took my race car to get corner balanced and aligned after I had new monoball front upper mounts installed. I know since this is a race car you want as much positive Caster as you can get. With my old mounts, the top of the strut was pushed all the way back towards the fire wall (max adjustment). Now with my new monoball mounts, the top of the struts are pushed all the way to the front (using all the adjustment in that direction, away from the fire wall). Is it possible a mistake was made or do these new monoball goodies change the dimensions that much?

Before alignment


After Alignment


The new spec sheet shows I have +7 degrees caster.
Very close to the old sheet that was +7.25 caster.

If you have any pictures of yours please post them.

Over all specs are as follows.

Front Camber -2.25 (bothe sides)
Caster +7.0 degrees.
Toe in .06 inches

Rear Camber -3.25 (both sides)
Toe in .08 inches.

Total weight. 1950 with out me.
With me 2130.

[Chuck Moreland]

Mark, can you show the big hole that the strut passes through? This is the one that is square with rounded corners, about 2.5 inches across.

The bolt holes you've shown allow a range of adjustment, so the picture as-is doesn't really tell the story.

[Vintage911Racer]

I new that would be the probelm.

Chuck. The adjustment was all the way back (towards fire wall before) for max caster before I installed the monoballs using stock rubber bushed mounts.

Now the adjustment is all the way forward for max caster adjustment.

Why would you gain caster by moving the adjustment backwards with the old mounts and forwards with the monoballs?

You would think it would be the same adjustment no matter what. Am I wrong?

And let me correct myself, the shock stays centered in the monoball mount so it is not the shock itself but the whole assembly that is being adjusted to gain the caster.

[Chuck Moreland]

Originally posted by Vintage911Racer

Why would you gain caster by moving the adjustment backwards with the old mounts and forwards with the monoballs?

You would think it would be the same adjustment no matter what. Am I wrong?

No you are not wrong.

The big center round part of aftermarket camber plates (as shown in your picture) is smaller in diameter than the factory round center. Because of this, identical caster settings make the aftermarmet part appear to be spaced further forward than the factory part. Could this be what you are seeing?

What brand is the camberplate?

If you saying the new camberplates are pushed forward to the limit of their travel, then it sounds like something is wrong. Likely the alignment is incorrect. A symptom would be a very light feel to the steering. Caster makes steering feel heavier.

[Vintage911Racer]

Chuck,

They are from Tarett Engineering. Fit from 65-89 911/912/914/930.

So they should be the same as what I had as far as fit goes.

I talked to the place that did it. (VERY reputable place here is So cal) and they said there was an optimal postition for gaining the max - (negative) camber up front. That positon is not all the way back. SO in order to gain more camber they had to utilize the the different setting. I went from -1.75 camber to -2.25 camber.

To get that setting I was giving up a bit of caster. It used to be 7.50 degrees, now I am at 7.0 degrees.

So I think I am OK... I hope...

As far as the light or heavy steering goes. Is that rolling or parked or both?

[Vintage911Racer]

If in fact the setting is wrong, how will this effect handling?

[Tyson Schmidt]

The camber will make about a 4-to-1 ration larger difference in handling than the caster. Steering feel aside.

That's a good trade-off. You'll never feel .5 degrees of caster difference.

[Vintage911Racer]

Thanks Tyson...

I appreciate the input from both you and Chuck. Just got my new 2.5 back together and it sounds great. Testing and breaking it in some time ni the next 3-4 weeks. How is your motor/car coming along?

[Vintage911Racer]

Chuck,

Here is a better image of my situation. I think I am going to be OK.. The red indicates the adjustment range or area.

Old setting


New setting

[Chuck Moreland]

The explaination by your mechanic makes perfect sense, but that doesn't fit with the last sketches.

The pink area is actually a bit more squared off, and the top of shock could be slide further towards the back of the car without compromising the camber. But as your mechanic says, camber will be maximized by giving up a little caster.

[Dixie]

The numbers do not lie. You are fine. All the caster you really need is enough to self-center the wheel at speed. Camber and toe matter more.

[Vintage911Racer]

Thanks for the input.