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Clutch Suggestions/Help? Grenaded Disk and trashed DS (PICS ADDED - CARNAGE)
Hey all!
Been a while since I hung around in these parts, I've been busy recovering from a motorcycle accident in July and had some other issues.
On to the crux of the issue: I have a 1986 951 with a 89 951S engine, MBC, Test Pipe, Chipped with 3Bar FPR. You know, the basic stuff. Well when I bought it (in boxes) last year it came with a lightweight flywheel, Cup/930 disk, and KEP pressure plate (not sure which stage, need to double check when I pull it out of the bellhousing later.
It also came with a ruined torque tube (driveshaft was trashed) which I replaced with a pretty good, low miles one supplied by a local friend (thanks Doug!)
I drove the car for only about 3,000 miles (clutch and all associated was lightly used, had only a couple thousand documented miles, should have known something was wrong...but i did replace all the bearings!) before the clutch fork snapped while driving this spring.
Because of my accident I wasn't able to start pulling the car apart until a couple weeks ago. Once I dropped the trans and the exhaust system I had a buddy help me unbolt and pull the torque tube back (the old rotate 180 and yank method). It was stuck in there pretty good, and when I pulled it out I saw why...the clutch disk (don't have PN or specifics off the top of my head) must have been a sharp splined design, as opposed to the squared style of the 944 torque tube splines, as the clutch disk ate the splines on the TT down to points, creating a lot of slop between disk and shaft, and basically filling in the valleys in between the splines on either side of a ~2 inch section of driveshaft.
Since I have a broken clutch fork and a destroyed driveshaft I'm going to need to purchase some parts:
- What clutch would you guys recommend? I'm not running huge power (obviously) but I would like something stout as I will inevitably end up modifying the car in the future and I don't want to be under-prepared. I'm not afraid of a little chatter or continuing to run my lightweight flywheel etc. But I don't want an extremely heavy pedal bla bla bla.
- Money is not a huge issue, since this car was (and will be again) my daily driver I would like to put something in it that will be less likely to create additional issues in the future...for this reason I have been looking at the Spec Mini Twin that Lindsey Racing offers for the 951 that uses a hydraulic T/O bearing. It is expensive, but since I don't have a usable clutch fork I'm considering this as an alternative to grinding down a N/A fork, but I would like to know if anyone is using it and what their impressions of its feel and longevity are.
- What is the final cost of a rebuilt torque tube from Constantine (Black Sea R&D) with 3 bearings? With 4? Does anyone have one of these on the East Coast they would be willing to part with? Anyone done the bearing replacement themselves or had a local machine shop do it? Looking for suggestions on what to do with whatever TT I end up with, as I'm going to want to put high quality stuff back in this car and don't want to be re-doing everything in a couple years.
I'll post up pics of the carnage later...for now I thank you all for reading and for your help.
Ethan
Last edited by lovemyp-car; 10-28-2014 at 12:30 AM.
I have the cup clutch disk with a KEP pressure plate. I works well and has a good reputation. I would stick with what you had.
As for the clutch fork, I also broke mine this year, on the track. The KEP pressure plate is a heavier pressure plate and the old clutch fork just couldn't cope. I replaced it with a N/A clutch fork which I gently trimmed to fit, whereas the factory turbo clutch fork is a crudely ground NA fork. Check the threads I've started to see what I did. Let me know if you need any info.
I was also looking at the LR mini twin, but it's overkill for what I'm using the car for. Also for the money you save you can buy some other go fast goodies, like beer.
Torque tube from Constantine he built for me was 600.00 a few years ago.
Thanks for the reply! Where are you located? I'm trying to get an decent ballpark figure on what it will cost for one by the time it is sitting on my doorstep.
Originally Posted by 944Phil
I have the cup clutch disk with a KEP pressure plate. I works well and has a good reputation. I would stick with what you had.
As for the clutch fork, I also broke mine this year, on the track. The KEP pressure plate is a heavier pressure plate and the old clutch fork just couldn't cope. I replaced it with a N/A clutch fork which I gently trimmed to fit, whereas the factory turbo clutch fork is a crudely ground NA fork. Check the threads I've started to see what I did. Let me know if you need any info.
I was also looking at the LR mini twin, but it's overkill for what I'm using the car for. Also for the money you save you can buy some other go fast goodies, like beer.
Hi Phil,
Thank you for the suggestion, but the Cup disk is what destroyed my torque tube (re-read above if you didn't catch that part). Whatever disk is in this car is what created a significantly larger amount of work and cost for me, so I will not be putting the same type back in. I'm considering either going to a stock (Sachs type) setup (keeping my lightened flywheel as it's nice and I like it a lot) or something made by Spec (most likely the twin disk).
I don't really care if it's overkill, I know most people will say there's no point in spending that kind of change on an almost stock car, but my reasoning is simply that I want to take as few chances on this type of catastrophic failure in my future setup as possible. Whatever I can do to minimize my future down time because of clutch related issues and maximize my amount of driving time and money I can spend on gas and other fun little mods is worth the time and money to figure it out and buy the right stuff now.
A lot of people are running cup disks and 930 disks without any issue. I feel that there must've been something else that lead to the issue.
I can understand wanting to put something bullet proof in there because the clutch is such a pain in the *** and it means a couple lost nights under the car and not driving it. I've done the clutch 3 times; once because I had the stock disk with the springs that had fallen out, the second time because my TO bearing failed and the thing time because of the clutch fork that broke. I seriously considered the LR mini twin this year when my clutch fork broke, but I had already spent too much on the car. If you put a clutch in with a fork I recommend using the NA fork and grinding it down.
If you out the LR mini twin in I am very curious about how it feels, please let us know.
A lot of people are running cup disks and 930 disks without any issue. I feel that there must've been something else that lead to the issue.
I can understand wanting to put something bullet proof in there because the clutch is such a pain in the *** and it means a couple lost nights under the car and not driving it. I've done the clutch 3 times; once because I had the stock disk with the springs that had fallen out, the second time because my TO bearing failed and the thing time because of the clutch fork that broke. I seriously considered the LR mini twin this year when my clutch fork broke, but I had already spent too much on the car. If you put a clutch in with a fork I recommend using the NA fork and grinding it down.
If you out the LR mini twin in I am very curious about how it feels, please let us know.
Cheers,
Phil
Hi Phil,
Definitely appreciate the insight...and I'm starting to think that the disk that I had in this car may have been a knockoff or I was misled as to what exactly it was.
Please have a look at the carnage, my assumptions of what had failed were WAY off:
As you can see it was not the clutch fork (it is intact) but rather the clutch disk that completely grenaded, either because of the damage it had caused to the torque tube, or doing that damage after failing (since I continued to drive it without a clutch for a couple miles to get off the main road).
So I've got some different parts I'll be looking at...but I might still consider the mini-twin as an option.
Let me know what you all think.
Also looks like Constantine is moving his shop and may not be up and running for a bit, I'll have to get in contact with him tomorrow if I can and see if he's got anything to help me out over here...
Thank you for the suggestion, but the Cup disk is what destroyed my torque tube. Whatever disk is in this car is what created a significantly larger amount of work and cost for me, so I will not be putting the same type back in.
Ethan, just because the PO said your car had a "cup" disc in it doesn't mean it had a Cup disc in it. By the way, the Sachs Cup disc and Sachs 930 disc are not one and the same. Either can be fit, but neither will/should cause the damage seen on your driveshaft. And if the PO said your car had a "cup/930 disc", he/she doesn't know what they're talking about.
In any case, if you decide to run a factory 951 disc with your KEP pressure plate, let me know. I keep a couple spares [one with ~16k and one with ~74k] in the bin for just such an occasion.
Thanks for the input, greatly appreciated! That was the last time I believed anything that this particular previous owner told me about this car... :-/
Because of the lack of visible part numbers on the disk, and the fact that I can't seem to find anything that looks quite like it, I'm going to hazard a guess that it is a knockoff or something like that.
I'll be looking into clutches a lot in the next couple days...I will report back with questions, comments and findings.
Can you take a closer picture of spline inside of that disk.
It appears that the splines were not a proper match and only engaged about 50%. If splines in disk are not missing half, then somebody used disk with splines that only engaged drive shaft as much as it now ground off.
Probably splines started to turn which caused high speed eccentric movement and engagement of disk which in turn caused disk to fall apart.
Voith...very very good info! Thank you for bringing that up.
The splines are definitely not of the correct shape or type...and the clutch itself does look very similar to the Bronco type.
Clicking on the pictures I posted above will allow you to go to my photobucket page and all of the pictures are extremely hi-res...so if you click on the last picture I posted here, and click on the zoom button when it takes you to my photobucket it will blow up to full screen and you can sort of see the splines. When I get home from work today I will clean it up a bit and take some more pics (hopefully not on my kitchen floor this time LMAO)
It is probably better to buy used OE clutch (with good springs) and have it relined with new friction material than to use some knockoff or ford clutch. New OE is expensive, but relined old one should work just fine if not better.
Local clutch/brake relining company uses some high tech carbon lining material that lasts much longer and is almost completely burn-proof, suitable for heavy abuses.
10-27-2014, 02:38 PM
Clutch Suggestions/Help? Grenaded Disk and trashed DS (PICS ADDED - CARNAGE)
