M758

I have seen the ball joint pins on Fabcar arms break.

dmoffitt bought Chris Cervelli's old 951 race chassis. He drove it on the street after installing a street motor and broke the ball joint pin. This was on a car with Fabcar arms. I know the Charly arms have a pin that is 2mm thicker. The pics of the failure looked just like a the binding falure. I believe the Fabcar arms have rebuildable ball joints.

Do remember that Chris's Car was pushing 450 to 500 rwhp, had something like 10" wide wheels in front with slicks, was lowred as much as possible and was driven hard.

Sam Lin

So what exactly is different with the aluminum arm?

Sam

Al P.

The billet arm uses an entirely different type of "ball joint" technicaly not a ball joint at all but rather a bearing into which the pin that attaches to the spindle is secured. This design eliminates the binding failure that occures when lowering a 944 with aluminum arms. The secondary issue is that the ball joints on the aluminum arms were not ment to be replaceable or serviced, they have no provision for greasing. When they wear this necesitates purchasing a new OE arm at an unbelivably high price, rebuilding the non-rebuildable arm or switching to a stronger serviceable arm.

Al P.

I need to learn to type faster three replies before I sent mine

M758

Here is a picture of the Fabcar arms.

These are made of 4130 chromoly steel so quite strong

Ball joints look like stock ones.

Here are the Charly Arms

RedlineMan

Sam -

The issue of ball joints breaking can get mudied a bit. The only way the ball joint itself fails is from over lowering, binding, and having the shaft snap at the keyway or the ball/shaft intersection.

When a ball joint pulls out of an alloy arm, that is the ARM failing, not the ball joint.

Here's the bottom line on all this, guys. Whatever arm you run, it needs to be inspected. Alloys, a lot, and make sure you rebuild those joints! Steels, not so much, and the ball joint is "bulletproof." Steel reinforced, much less yet.

It's a matter of degrees of use, and the responsibility you should take upon yourself to do what is necessary.

Bill L Seifert

Mainly to Geo

This thread is getting kinda full, but I wanted to answer a couple of things. PCA let people use the FABCAR arms, or modified steel, because there was a real problem. AS IN CRASH. Look at Grassroots motorsports mag this month. There is a race at Putnam park where 2 944's had ball joints break. To say we cant use not stock parts is BS. We do it all the time. If I want to put a fuel cell in my car I can, BECAUSE IT IS SAFER, not because it enhances performance. The a arms fall under the same area. My shocks are made by Koni, I have Weltmeister sway bars, etc etc etc. Saying I made a decision to run a substandard car, and should have to live with it is WRONG. Lots of things are changed on lots of cars. Look at fast track in Sports Car every month. The steel arms weigh MORE, so they are a performance disadvantage, not advantage. I have no idea if you are reasonable or not, but I know if this rule is not changed it is because of stubbornness on the part of the SCCA, not common sense.

One other thing, you said that the AC delete is illegal. Do you mean to tell me that I have to run the AC compressor on my car? I know that is not true.

Because I hate email, Geo or anyone else who wants to discuss this topic, please call me at 615-512-9899. If you want me to pay for the call email me at BillLSeifert@aol.com and give me your phone number.

Bill Seifert

You know what car I have

Sam Lin

Bill, try reading.

Sam

Sam Lin

There's been zero proof of an alloy arm failing due to pull-through or cracking UNLESS it has been damaged from the aforementioned lowering and binding. Within the stock demands, there's no difference between steel and alu arms. Outside of stock demands, both are going to fail from the same reason.

Sam

Oddjob

To stray a little bit....

If I recall, the Charlie Arm ball joint post is 19mm and the stock is 17mm. The steering knuckle pinch mount needs to be bored out to fit the larger post, correct?

Has anyone seen the steering knuckle fail where it is bored/drilled out to fit the larger diameter ball joint post?

I did see one 944T (with Charlie Arms) that crashed hard at a track event, where the steering knuckle broke at the ball joint/pinch bolt mount. It was a severe impact with an earth wall and roll over, so not a good example to cause any legitimate suspicion of the bored steering knuckle.

In comparison, however, I saw another totaled turbo (with stock arms) from a street accident where the strut rod actually broke and the control arm cracked through, but the ball joint/steering knuckle were still connected (not that it really mattered at that point…).

Obviously, there are way too many variables and differences in the type and magnitude of these impacts to compare them. But it seems like the Charlie Arm arrangement may be strengthening one component at the expense of another.

Also, it seems unusual to me that the factory was well aware of the ball joint failure and upgraded the control arms on the motorsport cars (Turbo Cup cars and S2 Club Sports). But they never updated the ball joint for the street cars, even through the 968 production. On the motorsport arms, the ball joint post does not have the grove for the pinch bolt machined all the way around the post, it just has one single slot. So even though the post is the same diameter, it has a lot more material at the weak point. The cost or effort it would have taken to put that style ball joint post in the production control arm seems minimal.

Bill L Seifert

To Sam and Geo

Yeah, I guess I read the thing too fast. SORRY!!!!!!

To Geo

I was talking to friend this afternoon about this (He runs a 944 also) I mentioned that you were on the comp board. He asked if Chris Camadella was also on the board. I seem to remember you saying he was. This friend reminded me that Chris's car at the ARRC in 2002 had the FABCAR A arms. I had forgotten.

Bill Seifert

Geo

You can delete the AC on any car in IT. You can run the 944 AC delete kit only because it was offered from the factory this way. Otherwise all that could be done is to remove the AC components.

AC delete IS legal in IT and the 944 AC delete kit IS legal in IT.

Geo

Sam, excellent point.

There is zero need IMHO for an alternate control arm. If excessive lowering causes failures, don't lower it to the legal limit. We have to do this with our SE-R. Lowering to the legal limit cause CV joint failures so we cannot lower to the legal limit. Simple matter.

Geo

Actually, I'm not on the Club Racing Board (nee Comp Board). I am on the Improved Touring Advisory Committe, an ad hoc committee that reports to the Club Racing Board. Chris Camadella is indeed on the committee as well.

As for him racing with FABCAR A arms, if he did then he raced with them illegally.

RedlineMan

Sam -

I must respectfully dissagree with what you said, at least to the literal extent that you offered it.

First, let me restate the first part of what you say as I read it. You are saying that the stock alloy ball joint does not fail by pulling out of the socket in any way but through over-lowering of the vehicle?

I must give you the benefit of the doubt and qualify that statement for you by saying that you are refering only to alloy joints that are not worn and have tight tolerances.

It is of course utterly false to state that these ball joints do not fail ALL THE TIME if they are allowed to wear to the point that the ball pops out of the arm. This is EXTREMELY common. I just wanted to make sure that everyone understood that, or did not missunderstand what you were saying.

I will state here that I have never seen an early 944 ball joint get to the sorry state that it will come apart, and in this regard I utterly dissagree with the second and third assertions you make.

The early joint is a "classic design" that is time tested on millions of vehicles. Further, it is my feeling that if an alloy joint can fail in this manner in any event or circumstance, then it is "possible" for it to happen in instances where "everything was checked, and failure was not anticipated."

In my mind, this gives the clear advantage to the early arrangement. I think it is obvious that the percentages are with me in this regard.

Respectfully offered!