Ball Joints and Racing?
05-04-2006, 02:19 PM
#32
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Jerome951- I plan on racing the car both drift, time attack and the occasional Auto-X. Total id say (when in running order) the car will be on the track every other weekend. So the more I look into I realize im gonna need something heavy duty.
But for now till I can afford them I will prolly hit some events w/ the stock arms. Hopefully they hold up.
Oh and the car is a 87'.
But for now till I can afford them I will prolly hit some events w/ the stock arms. Hopefully they hold up.
Oh and the car is a 87'.
05-04-2006, 02:50 PM
#33
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I know quite a few guys running stock arms with no problems, as everybody knows the arms are fine it's the ball-joint that's the weak link. If some one is using a ball-joint, thats X number of years old what do you expect, it's going to fail.
Last edited by pk951; 05-04-2006 at 03:45 PM.
05-04-2006, 03:34 PM
#35
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Yeah Brett, thats what I was curious about? Anybody know bout those balljoint kits? If I seam weld the the arms (Dont know if they are stampped steel or not) and get the bestest Rennbay Ball joint kit would I still run into all said problems?
For now Im just looking for the cheapest option so I can run the car on the track sooner than later.
I know a lot of sanctioning bodies require the upgraded arms. But since there are no such regulations in drift or time attack then they might not be NECCESSARY (still good to have tho)
And say if I did go the Rennbay route, and they still failed, how much OTHER damage would I be looking at?
For now Im just looking for the cheapest option so I can run the car on the track sooner than later.
I know a lot of sanctioning bodies require the upgraded arms. But since there are no such regulations in drift or time attack then they might not be NECCESSARY (still good to have tho)
And say if I did go the Rennbay route, and they still failed, how much OTHER damage would I be looking at?
05-04-2006, 03:50 PM
#36
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If you break a ball joint, youre going to damage the fender, the strut, and the tie rod for sure. Depending on the speed of the car, losing 1 of the 4 corners could get you into a catastrophic accident.
But running stock/factory control arms on the track, isn’t juggling hand grenades – as some would lead you to believe.
The 85.5 and 86 aluminum arms are of questionable strength when running them hard on track with heavy sway bars (especially the weltmeister front bar). But the 87 and later control arms are plenty strong and wont break (unless you hit something).
But the ball joint is still a (the) problem. General rule of thumb when using stock arms, don’t lower the car too far (which increases the potential for binding the ball joint within the control arm socket at full upward suspension travel – can bend and break the ball joint post). And you need to make sure that you check the joints for play. Once the bushings start to wear out and there is some slop in the joint, the arm needs to be replaced.
Mileage and rough/abuse will wear out and damage the ball joint bushings. The more pot holes, rumble strips you hit, the faster the wear will be. Some severe impacts will destroy a ball joint bushing in one incident (something that would also probably bend or damage the wheel). If you ever get a popping in the front suspension when turning, or when changing momentum (accelerating from a stop or accelerating to braking), check the ball joints. A very bad ball joint will pop and feel like someone is hitting the control arm with a ballpeen hammer. Definitely do not track a car in that condition, and shouldnt even drive it on the street.
Two checks: jack the car up in front so both sides of the front suspension is hanging freely.
1) Use a large pry bar (2x4, hockey stick, etc) to pry/push up on the bottom of the brake rotor ( putting the ball joint in tension). The suspension will move and the strut and spring will slightly compress (a ¼” or so is enough). Watch the ball joint and control arm. If you see any perceivable movement in the joint, where the knuckle is lifting the ball joint out of the control arm, indicates a problem beginning (even a 1/16”).
2) Take a big channel lock pliers and try to pinch/squeeze the ball joint down into the control arm socket. The channel lock jaws will be on top of the ball joint pin and on the bottom of the control arm below the ball joint. Squeeze and check for movement (joint in compression). If you have big enough channel locks and can get good linear leverage, you should not see any movement. If there is some movement, around a 1/16” or more – you need to keep an eye on the joint and be prepared to replace it. If you have small channel locks and you end up catching just the edge of the bottom of the control arm, you cause some rocking/pivoting of the joint, so just be careful that you don’t confuse this motion with actual play in the internal bushings.
But running stock/factory control arms on the track, isn’t juggling hand grenades – as some would lead you to believe.
The 85.5 and 86 aluminum arms are of questionable strength when running them hard on track with heavy sway bars (especially the weltmeister front bar). But the 87 and later control arms are plenty strong and wont break (unless you hit something).
But the ball joint is still a (the) problem. General rule of thumb when using stock arms, don’t lower the car too far (which increases the potential for binding the ball joint within the control arm socket at full upward suspension travel – can bend and break the ball joint post). And you need to make sure that you check the joints for play. Once the bushings start to wear out and there is some slop in the joint, the arm needs to be replaced.
Mileage and rough/abuse will wear out and damage the ball joint bushings. The more pot holes, rumble strips you hit, the faster the wear will be. Some severe impacts will destroy a ball joint bushing in one incident (something that would also probably bend or damage the wheel). If you ever get a popping in the front suspension when turning, or when changing momentum (accelerating from a stop or accelerating to braking), check the ball joints. A very bad ball joint will pop and feel like someone is hitting the control arm with a ballpeen hammer. Definitely do not track a car in that condition, and shouldnt even drive it on the street.
Two checks: jack the car up in front so both sides of the front suspension is hanging freely.
1) Use a large pry bar (2x4, hockey stick, etc) to pry/push up on the bottom of the brake rotor ( putting the ball joint in tension). The suspension will move and the strut and spring will slightly compress (a ¼” or so is enough). Watch the ball joint and control arm. If you see any perceivable movement in the joint, where the knuckle is lifting the ball joint out of the control arm, indicates a problem beginning (even a 1/16”).
2) Take a big channel lock pliers and try to pinch/squeeze the ball joint down into the control arm socket. The channel lock jaws will be on top of the ball joint pin and on the bottom of the control arm below the ball joint. Squeeze and check for movement (joint in compression). If you have big enough channel locks and can get good linear leverage, you should not see any movement. If there is some movement, around a 1/16” or more – you need to keep an eye on the joint and be prepared to replace it. If you have small channel locks and you end up catching just the edge of the bottom of the control arm, you cause some rocking/pivoting of the joint, so just be careful that you don’t confuse this motion with actual play in the internal bushings.
05-04-2006, 05:33 PM
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Thanks Oddjob thats some good information. I think from all ive heard what im gonna do is first check the condition of the ball joints, then depending on what I find get the Rennbay Kit, Look into seam welding the arms, install spring/shock combo (not lowering the car more than 1"-1.5"... still researching as well), Swaybars (Weltmeister mostlikely) and possibly some torsion bars.
As long as I dont lower the car too much the upgraded balljoints should last. Then, with how drifting is, when I eventually crash
ill take that opportunity to go for the race arms.
As long as I dont lower the car too much the upgraded balljoints should last. Then, with how drifting is, when I eventually crash
ill take that opportunity to go for the race arms.
05-04-2006, 06:56 PM
#38
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Just to pop in here real quick...
If you guys are worried about ball joint pin failures we do have a line of 19mm pin kits. These are the same diameter pins that the Charlie arms use. Spindles do need to be machined to use these kits but we do have a machine & ream service for the spindles. $100 gets both of them done with about a 2 day turnaround. The down side is you have to ship them both ways so it takes a little over a week total depending on where your at.
Here is the link to them.
http://www.rennbay.com/ball-joint-re...4-c-30_51.html
If you have any questions on materials, specs, etc.. on any of the Rennbay kits just let me know.
If you guys are worried about ball joint pin failures we do have a line of 19mm pin kits. These are the same diameter pins that the Charlie arms use. Spindles do need to be machined to use these kits but we do have a machine & ream service for the spindles. $100 gets both of them done with about a 2 day turnaround. The down side is you have to ship them both ways so it takes a little over a week total depending on where your at.
Here is the link to them.
http://www.rennbay.com/ball-joint-re...4-c-30_51.html
If you have any questions on materials, specs, etc.. on any of the Rennbay kits just let me know.
05-04-2006, 07:41 PM
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Hey there Travis, Seeing as how you are the manufacturer of the Ball Joint kits would you mind giving us a run down of the product and how you feel it compares in durability to a full arm upgrade w/ 19mm pins (at least in my case with the stronger 87+ suspension).
And do you think for my purposes that product would be sufficient?
Thanks!!!
And do you think for my purposes that product would be sufficient?
Thanks!!!
05-04-2006, 08:18 PM
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Interesting. I see now why I couldn't find the thread - I searched using the correct spelling of "Blaszak" 
A few points:
- FABCAR's - which I have sitting somewhere - also have (had?) a design flaw - they don't clear the Aluminium crossmember, so you get a divot in them. Not a huge deal, but kinda annoying ... I like bumpstops to limit suspension travel, not the a-arm hitting the crossmember.
- the old thread's primary criticism isn't applicable to Markus' arms. The Blaszak arm does not have a threaded rod on the ball-joint end of the arm, which is what the posters were up in arms about.
- I understand that the rod end criticism also applies to the mounting side, but to a much lesser extent - there are two rod ends, not one, the loads are very different in magnitude due to geometry, and the rod end diameter and a greater length of thread engagement can overcome these points to make it moot. In addition, using rod ends overcomes the binding inherent in the stock arms.
- many of the arms are race parts. They don't have protection on the rotating surfaces that street parts have. Using them without regular inspection is not intelligent.
- if you re-build stock arms, Zyglo them, and somehow ensure that the "hole" that the ball joint goes into hasn't been expanded / made out-of-round / etc. by excessive movement of the old ball in the bore. AFAIK, this is why Porsche does not offer re-built arms. Mind you, that is what I remember from a discussion of this and many other issues (like timing belts) after many (Canadian) beers around a campsite at Mosport when the turbo cup first came to Canada - Porsche sent over a couple of race engineers to give us the ins and outs of prepping the turbo cup cars - which reminds me, I have to put up on my website the turbo cup build sheets - I scanned them in months ago (from Markus, BTW), and forgot all about them until, ah, this instant.
- it could be worse - we could be talking about E30 M3 arms - which were so disposable that teams kept spare arms in the pits during endurance races back in the day.
A few points:
- FABCAR's - which I have sitting somewhere - also have (had?) a design flaw - they don't clear the Aluminium crossmember, so you get a divot in them. Not a huge deal, but kinda annoying ... I like bumpstops to limit suspension travel, not the a-arm hitting the crossmember.
- the old thread's primary criticism isn't applicable to Markus' arms. The Blaszak arm does not have a threaded rod on the ball-joint end of the arm, which is what the posters were up in arms about.
- I understand that the rod end criticism also applies to the mounting side, but to a much lesser extent - there are two rod ends, not one, the loads are very different in magnitude due to geometry, and the rod end diameter and a greater length of thread engagement can overcome these points to make it moot. In addition, using rod ends overcomes the binding inherent in the stock arms.
- many of the arms are race parts. They don't have protection on the rotating surfaces that street parts have. Using them without regular inspection is not intelligent.
- if you re-build stock arms, Zyglo them, and somehow ensure that the "hole" that the ball joint goes into hasn't been expanded / made out-of-round / etc. by excessive movement of the old ball in the bore. AFAIK, this is why Porsche does not offer re-built arms. Mind you, that is what I remember from a discussion of this and many other issues (like timing belts) after many (Canadian) beers around a campsite at Mosport when the turbo cup first came to Canada - Porsche sent over a couple of race engineers to give us the ins and outs of prepping the turbo cup cars - which reminds me, I have to put up on my website the turbo cup build sheets - I scanned them in months ago (from Markus, BTW), and forgot all about them until, ah, this instant.
- it could be worse - we could be talking about E30 M3 arms - which were so disposable that teams kept spare arms in the pits during endurance races back in the day.
05-04-2006, 10:56 PM
#41
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Busta,
Check out the SSI ball joint kit at http://www.ssiauto.com/cgi-bin/sales/00018.html
I rebuilt the ball joints on my turbo S two years ago with this kit and was most impressed with the quality. The SSI kit uses brass cups based on the 944 Cup cars, while they are a bit more expensive than some of the other rebuild kits out there they are a good product. I plan on running a few more DE seasons with these before upgrading to billet arms and have no reason to believe they will not continue to hold up. Remember one of the leading causes for failure is a lowered suspension, I have resisted lowering my car until I can do it properly, and would recommend against it. Good luck.
Check out the SSI ball joint kit at http://www.ssiauto.com/cgi-bin/sales/00018.html
I rebuilt the ball joints on my turbo S two years ago with this kit and was most impressed with the quality. The SSI kit uses brass cups based on the 944 Cup cars, while they are a bit more expensive than some of the other rebuild kits out there they are a good product. I plan on running a few more DE seasons with these before upgrading to billet arms and have no reason to believe they will not continue to hold up. Remember one of the leading causes for failure is a lowered suspension, I have resisted lowering my car until I can do it properly, and would recommend against it. Good luck.
05-04-2006, 11:29 PM
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Well what is concidered "Lowered" Cuz some ppl call 4 inches lower when id be happy with 1 inch. Would that still cause BJ failure (haha that was worth a chuckle)
And can I find springs in a rock solid spring rate that wont lower the car that much?
And can I find springs in a rock solid spring rate that wont lower the car that much?
05-05-2006, 12:33 AM
#43
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Nice...
Can't comment on spring rates, haven't gone there yet.
While 1" would not seem excessive it does change the geometry of the ball joint pin in relation to the socket on the control arm and reduces the travel distance available before binding issues. I'm sure many on here have lowered their suspension and have had no problems with bj failure, it has more to do with what you're willing to risk. It will take me many more years of track time to learn to handle the car as it is currently set up and while I have a long list of improvements to make, I also have a budget.
What did you think of the SSI kit?
BTW, I have a new Rennbay kit sitting around minus the ball joints, if you decide to go this route and are interested let me know.
Can't comment on spring rates, haven't gone there yet.
While 1" would not seem excessive it does change the geometry of the ball joint pin in relation to the socket on the control arm and reduces the travel distance available before binding issues. I'm sure many on here have lowered their suspension and have had no problems with bj failure, it has more to do with what you're willing to risk. It will take me many more years of track time to learn to handle the car as it is currently set up and while I have a long list of improvements to make, I also have a budget.
What did you think of the SSI kit?
BTW, I have a new Rennbay kit sitting around minus the ball joints, if you decide to go this route and are interested let me know.
05-05-2006, 10:17 AM
#44
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Originally Posted by mj951
Busta,
Check out the SSI ball joint kit at http://www.ssiauto.com/cgi-bin/sales/00018.html
The SSI kit uses brass cups based on the 944 Cup cars...
Check out the SSI ball joint kit at http://www.ssiauto.com/cgi-bin/sales/00018.html
The SSI kit uses brass cups based on the 944 Cup cars...
The Club Sport/Cup ball joint pin does not have the full groove all the way around it (for the pinch bolt), it is only slotted on one side. So in effect, the pin is stronger than the stock pin.
The picture in the ad, shows what looks to be the standard fully grooved pin, not the Cup/Club sport part.
Never heard that the Club Sport arms used brass bushings either, but I will check that. I have a spare arm off a Club Sport/Firehawk S2 that I can pull the boot off to check (should be able to see the upper cup from the top with the boot off -?)
05-05-2006, 10:34 AM
#45
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Originally Posted by shiners780
Is this the thread you refer to?
https://rennlist.com/forums/showthre...r+control+arms
200 posts debating the structural integrity of various control arms, yet no mention of Blaszak failures. Proof is in the numbers, show me the numbers.
If the ball joints used were a joke, they would be failing, yet we hear no mention of this. The majority if these arms are being used on track cars with proven success.
You want to ask a competing fabricator about a considerably less expensive product available elsewhere? Please. What do you think he's going to say?
You're entitled to your opinion, and I respect that. But you're publicly bashing a product with absolutely no hard data to support your statements.
My apologies to Bustadouglass for the tangent.
https://rennlist.com/forums/showthre...r+control+arms
200 posts debating the structural integrity of various control arms, yet no mention of Blaszak failures. Proof is in the numbers, show me the numbers.
If the ball joints used were a joke, they would be failing, yet we hear no mention of this. The majority if these arms are being used on track cars with proven success.
You want to ask a competing fabricator about a considerably less expensive product available elsewhere? Please. What do you think he's going to say?
You're entitled to your opinion, and I respect that. But you're publicly bashing a product with absolutely no hard data to support your statements.
My apologies to Bustadouglass for the tangent.
#29
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>>>Yep,
As mechanical engineeer myself I agree with Mumzer & Cervelli.
The loading of rod end is completly wrong and will result in failure. I could draw diagam of the loading on these control arms underbraking and that would show this clearly. There is also an agrument about the stiffness resulting from the bend near the caster block. The loading will tend to undo the existing bend. This will also probably cause a crack to develop at weld there. Also there is no buckling support for the center of the angled bar. This will not cause failure (probably) but mean less stiffness underbraking.
Even these Blazek arms don't use the rod ends right.
Here the load is taken ok at the ball joint (still and issue with neckdown to square tube & a welded joint), but the inner fwd rod end will also be loading bending although to a much lesser degree.
The rear rod end is fine since the caster block is not designed to take a thrust load there will be miniumal to no bending there.
Here too how ever there will be bending about both welds for the angled part. They can be strenghtened greatly with additon of large web fillets.
Remember also that a weld joint is typically a weak spot due the basic nature of welds. Always try to put peak stress points away from welds and especially keep fatigue type cyclic loading away from them.
As they stand however I'd still rather stay with stock <<<
Quote-Joe P.