951and944S

Not possible.

The bore for the current ball joint in stock configuration is not cylindrical.

If a reliable solution could be done with non-modified parts I would have done it long ago.

We have suffered probably 5-6 DNFs from P1 leading position and repaired body damage at each event occurrence.

Let's get on the record...., that I am highly motivated to resolve this economically once and for all.

There's a lot going on behind the scenes that I can't discuss right now even willing to be as open as possible on this.

Several RL'ers, top respected posters/racers here are in daily contact with me over this.

When something is able to be shared, I'll share it.

T

951and944S

We went the 19mm route on one set.

If you don't continually check torque on the factory 17mm spindle (or any bore size), the stress will elongated and misshape the bore to the point that stock 17mm spindles are no longer usable.
Having the option of the 19mm pin allowed us to put previously scrapped spindle back into service.
Other than that reason, I would never have gone the 19mm route to uselessly weaken the spindle.

Having said that, the evidence that others, pushing the reliability of the bored spindle past limits that any street car will ever see, have not had any failures at the pinch bolt area that I am aware of, is testament enough for me that the spindle (not counting it's other shortcoming re more robust wheel bearings) in the factory 17mm bore configuration, is not an issue at all.

T

Cloud9...68

Thanks, but I'm a little confused by this statement. At the beginning of the sentence, you say that many people have tested the reliability of the bored (by this I assume you mean bored to accept a 19 mm pin, but I could be misinterpreting) spindle under very severe track conditions without any known issues, but at the end of the sentence, you say that this applies to the factory 17 mm configuration. Maybe I'm just being dense or not understanding something that might clear to everyone else, but could you please clarify whether you're referring to a stock spindle, or one that's been bored to accept a 19 mm diameter pin? Thanks.

951and944S

Hah hah, no, it does seem to be conflicting...., I thought about it a little while typing.

We tried that avenue once, to recover usage of what would have otherwise been scrap parts (wallowed out 17mm factory size)

We broke 19mm pin.

Went back to 17mm since the +2mm didn't seem to resolve the issue so I saw no reason to machine future spindles.

We never broke a 19mm bored version, but neither had we ever broken a 17mm version, only had the receiving hole elongated.

T

951and944S

BTW, that comment was addressing a point made in another post about not "addressing the reliance on the factory pinch bolt" by 'Droops' who sourced pins and welded his to the spindle itself.

T

Cloud9...68

Thanks - so you broke a 19 mm pin (wow!) that was used in a spindle whose 17 mm pinch point had been enlarged through heavy track use? Well, as one of the dummies who forked over the $1600 for a set of RE A-Arms that look like they could hold up the Brooklyn Bridge, I'm hoping the fact that this arm has a high quality spherical bearing to support the bottom end of the pin will take some strain off the spindle pinch point and not fail on me.

951and944S

Well, not me personally, my son.

I just build and work on the cars these days so I am only responsible for the good stuff and none of the bad....

And yes, to be even more clear, when we discovered that the rate of breaking the pins increased in frequency, we investigated further and found that the factory pin bore in the spindle had become worn and no longer cylindrical.
To repurpose those spindles, we tried the 19mm pins and had the out of spec spindles bored to 19mm.

When you really think about it, $1600 is not much more than a set of tires that we ball up and toss after a weekend...., it's the principal of the matter for me.
I fabricate one-off parts all the time and I know material costs.
It was another person here that described it as "the a-arm cartel".
I'm the perfect candidate to pay the mafia...., fed up, paid the damage piper one too many times, but I know I can fix this and can't bring myself to fork over.

T

Cloud9...68

Do you think the spindle bores are wearing out under track use because of the lack on a spherical bearing on their bottom end? I'm no expert on the topic, but common sense indicates that keeping the pin bound at the connection point to the A-Arm will put more strain on the upper connection point at the spindle.

Droops83

The combination high lateral forces from track use and the increased leverage exerted by a longer pin put strain on the pinch sleeve, and the nut slowly loosens, which leads to wear of the bore due to the now-loose pin hogging it out.

After confirming that the pinch bore is in good shape and the new pins fit snugly , I would install a new factory bolt and nut and re-check the torque after every event---very quick and easy to do.

Or do the modification I did and forget about it .

Cloud9...68

Makes sense - unfortunately I don't have the resources to easily perform your modification.

What is the torque spec for the pinch bolt? Also, what is the torque spec for the nut that holds the pin to the control arm?

At my current ride height, my control arms are angled to the tune of the outer attachment points at the spindles being 28 mm higher than the inner attachment points, so I just ordered a set of 1" longer-than-stock pins from RE. He also supplies 1.5" longer-than-stock pins, but they are on long term backorder. Anybody use pins or other forms of extensions that arre grater than 1" longer than the stock pins?

Droops83

Good question. The OE 10MM pinch bolt is Grade 12.9, so its torque spec of 37 ft-lbs is higher than that of the typical Grade 8 bolts used elsewhere in the car. If this has ever been replaced with Grade 8 hardware, the bolt will stretch and come loose (grade is stamped on the bolt head). The OE bolt also has a long shoulder and short threaded section to ensure a tight fit in the bore and within the channel on the ball joint pin. If a fully-threaded bolt is ever used, it will act as a low-speed file if it ever comes loose and will ream out the pinch bolt holes.

The bolt is Porsche part # 900 074 372 02, locknut is N 021 130 2.

Sorry, can't help with the Racer's Edge stuff, you should contact them for torque specs and other maintenance recommendations.

Cloud9...68

Thanks - this has been a very useful discussion that has pointed out a number of items that should be checked that I wan't aware even existed. I can't remember if I replaced the pinch bolt when I installed the RE control arm - I want to say I did, but I'm not sure. I'll check the torque when I rotate my tires tonight. Thanks for the part number - I'll definitely install a new one when I install the longer pins. And I should have RE's instructions for installing the heavy-duty arm with the 19 mm pins, which will have the torque spec for the lower nut. If not, I'll contact them.

Cloud9...68

Chris,

How much longer are the ball joint pins you used for your mod than the stock ones? According to the roll center calculator I'm using, increasing the length of the pin by one inch will raise the roll center by about 2". Thanks.

Droops83

Hi Andy,

My car is lowered just shy of 2" lower than factory height in the front, so I went with the standard SCCH 2" drop pin and it got the control arms just about parallel with the ground as pictured in the first post of this thread-----not as scientific as a roll center calculator, but the end result works quite well!

In the end, it all depends on what your actual ride height is . . . .

Cloud9...68

Hi Chris,

Thanks for the info. Yes, this stuff definitely depends on where your ride height is. Measured using the method prescribed in the manual, my caster block bolt heads are an average of 188 mm below my wheel front centers, and my torsion bar centers are 78 mm below my rear wheel centers. Somewhere I found that stock ride height is 147/37 mm front/rear for these metrics, which places my front and rear ride height 1.6" lower than stock, which sounds like it's pretty close to yours. I measured a 4.3 degree inclination on my front control arms, which translates to the outer attachment points (at the ball joints) being 28 mm higher than the inner attachment points (using a 14.5" measured length for the control arm - sorry about mixing metric and SAE units!). I was planning to use your method, in that I was going to order ball joint pins that are 1.5" longer than stock, and adjusting the ride height until the control arms are parallel to the ground. Unfortunately, 1.5" longer-than-stock pins for my Racers Edge heavy duty control arms are currently unobtanium, so I went ahead and ordered and recieved the readily availibe 1" longer-than-stock pins. So, I think I will keep the ride height where it is, and live with control arms that are inclined (at least in theory) abut 3 mm, which strikes me as pretty insignificant.

I think I misunderstood what you said when I first read your latest post, When you say you have SCCH 2" drop pins, I though you meant pins that are 2" longer than stock, which at your ride height would leave your control arms inclined with their inner attachment points higher than the outer. But the 2" length probably includes the length of the standard pin, which would make your pins about 1" longer than stock, just like mine, correct? Thanks.