rithsleeper

1989 ZF6 - Well I didn't have the money for a expensive clutch and I guess I'm paying. I got a stage 2+ and its slipping in first. So annoying.

So question is, I read that it is the disk that is unreliable, can I just get a high quality disc from another company and reuse my new single mass flywheel and pressure plate?

What would you guys recommend?

I think I burn it up taking my steep driveway and huge bump at the bottom so I need something that can hold up against this. I've changed my driving habits but I guess it was too late. Still makes me mad this thing couldn't hold up for even 5K miles.

Repzard

Spec stage 2 clutches are really good.
Did you break that sucker in correct ?

mgroshong

I'm not trying to be "that guy" but 99% of the time there is 2 reasons a clutch goes out way to fast. Your making tons of power and tried to use a clutch that was in no way up for the job, or you can't drive and like to slip, slip, slip that clutch to death.

Repzard

Clutches also have a break in.If you don't break it in correct that will cause clutch disc to burn up fast or glaze.Causing slipping.

96GS#007

mtwoolford

I can't say yeah or nay, but my experience is that metallic clutch discs hold up way longer than any alternative. That would be a stage 3 disc which is a puck type disc. a stage three plus is a full face disc with additional friction material; this is what I run and I am very pleased with it. My past experience (in other vehicles) is with RAM full metallic clutches (very similiar) and I can say without qualification that they last forever; they are impervious to oil; and the hotter they get, the greater their coefficient of friction. Back in the day, in El Dorado County, California, stop and go driving in the mountainous terrain was tearing up school bus cutches; as an experiment, the organic clutch discs were replaced with metallic discs. At three times the average service life of an organic disc, the clutches were pulled and the metallic discs found to be completely serviceable.

on another note, did you reuse a flywheel ? was it resurfaced by grinding, not being cut in a lathe ? when the flywheel was installed was the surface checked for run out ? even a small burr on the mounting surface can really throw a flywheel out of whack.

did you check the pressure plate to see if its surface was adsolutely flat; it doesn't take a lot to put a warp in it.

and finally, is the clutch disc releasing fully ? to a certain extent hydraulic clutches are self adjusting, but with the short service life of your clutch, I'd overlook nothing.

78pacer

Proficient break in or not, it's tough to kill a clutch in only 5k miles. Ask me how I know? I'm a father that put three kids thru driver training on a stick. As the OP stated, you's have to be slipping the snot out of it to burn it up so fast.
Mike

rithsleeper

Ok, well I totally agree that it would seem I was just a crappy driver that rides the clutch but I assure you I'm not. Only time I ride it is going up the huge sidewalk hump and steep driveway but I always try to keep the rpms below 1K. I've been driving stick for about 3 years now and have never had a problem with clutches going out till now. (motorcycle, vw, small 4 banger saturn.)

I drove the thing (I'll be honest) about 400 miles city, to and from work before I layed on it.

My car is pretty much stock except exhaust, chip, and few other odds and ends.

I bought the entire package as one deal, new flywheel, new pressure plate, and the disk.

Could I re-use the pressure plate and change to a stage 3 puck style SPEC clutch or another brand clutch disk? or do I need to get another pressure plate to match the new clutch disk?

rithsleeper

The Spec tech guy seems to think it is a contaminant more than I have burnt it up this fast. So I guess I'm just going to have to pull it and inspect it and then order a stage 3 or something if it is contaminated.

Thanks for the help, still would like some recomendations for another company if you have any.

Thanks all

davenbocafl

pacers right, i dought its the clutch although you might have fryed it now, maybe the wrong throw out bearing or slave cyl. holding to much pressure or just a bad pressure plate, but even a cheap clutch would last longer then that. Look elsewhere or you might do it again

mtwoolford

You can certainly reuse the flywheel; at the worst, a machine shop might have to kiss it with a surface grinder, but probably not, cleaning with emery cloth would probably suffice.

The pressure plate, if the plate hasn't been warped and is still flat, or excessively heat checked, can be cleaned up and reused.

The disc ? is probably toast. I'd recommend a full faced stage 3 plus disc. And don't be scared off by it's (or any metallic disc) reputation for aggressive engagement. They do hook up fast, and require a little more attention from the driver, but once you get used to them, are very easy to drive. Other clutches begin to feel slow and uncertain in comparison.

There's only two places contamination can occur, from the rear crankshaft seal, available anywhere, which is accessible and easy to replace once the flywheel is out. Or the transmission input shaft (front) seal. ZF doc can help you there, although he told me those seals often go 300K miles without leaking.

One overlooked aspect in the subject of clutches, is the end play on the crankshaft. The clutch will not work properly if the flywheel is moving in and out an excessive amount. The rear main bearing contains the thrust surfaces and these do wear over time.

How sensitive are organic discs to oil? Written accounts about shelby mustangs reported that the clutch installers wore plastic or rubber gloves to prevent skin oil from contaminating the discs. Urban myth ? Maybe / maybe not.

mtwoolford

And don't forget the pilot bearing.

Gale Banks 80'

Something dosn't sound right. It should slip the worst in 6th Gear not 1st. 1st gear has the most mechanical advantage. When my Stock Clutch went on my 96 GS I could punch it in 5-6and get it to slip but in the lower gears it would still hold.

rithsleeper

I've had it slip in 1st, 2nd, 4th, and 5th. The first slip it ever did I was at 120 with the foot to the floor and I thought something was wrong with the engine when I felt it go. Then another time I was crusing at 80 on the highway and down shifted to 4th and hammered it once it engaged and it slipped. I guess I just notice it more in 1st because I use it the most on hard acceleration.

I take it since no one has given another company just to go with a stage 3+ from SPEC instead of trying another brand if it is indeed burnt and not contaminated...

87 vette 81 big girl

When you have your flywheel resurfaced......
Make sure that is done on a Blanchard Style flywheel resurfacer.

Winona Van Norman flywheel resurfacer is my choice of machine to use for the job.

If it is equipped a Diamond Dust Coated grinding wheel,
You will excellent surface finish results with a RA of 5 or less with a skilled operator.

A friend runs an Auto & Diesel engine machine shop.
He builds Drag and dirt track engines also.

He has the Winona Van Norman flwheel resurfacer and Diamond grinding wheel. Wet coolant flow equipped.

After I have a stick flywheel cut or resurfaced by him,
The Surface shines like a mirror.
Especially a Billet steel Flywheel Like a McCloude.
I can see my own reflection- face in the diamond cut surface.
Dead on True when checked bolted to the crankshaft and engine rotated by hand checking Lateral Run-out with a Dial indicator.
Dial indicator reads "0" always.
Not even 5 ten thousandths out.
More like .0002" run-out.

Proper break in is important for a new clutch set.

But so is the Flywheel RA surface.
Smoother, the better.
Makes for quick break in of the clutch set and flywheel with Good preparation.

Aluminum Flywheels are not resurfaced.
Steel insert is replaced when worn or damaged.

Brian

tpi 421 vette

I have had good luck with Spec clutches. Clutch wear can happen by customer driving habits. I am not saying the OP did anything wrong, but you can ruin a new clutch in no time if abused.

A clutch would be something that would be hard to stand behind because of peoples driving habits.

I put a McLeod dual disc that was properly broke in a 97 Camaro with a 396 I built with Nos. The owner ruined it the first time at the track. The clutch was rated to 1200hp, and the customer had just around 750hp. I run the same clutch, and they last years.

87 vette 81 big girl

If your engine makes over 600Ft/lbs of torque & 700 + HP,
I would consider using a Daul Disc clutch.
What manufacturer is entirely up to you and your preference.

McCloude is my 1st choice.
Old school but very reliable under severe abuse by the engine and the driver.

Light rotating mass is ok and nice to have.
But I prefer a proven clutch setup that can withstand hundreds of 7,000 - 8,000 RPM launches in 1st gear and sticky rear tires.
And severe abuse driving on the street.

Once a clutch set slips under full torque load - power, its done for.
It will continue to gradually slip more till ultimate failure.

Unless you have Crower Glide Clutch.

BR

mtwoolford

my friend, you need to upgrade your clutch

mtwoolford

there are a ton of good high performance clutches; ....however almost all, except SPEC, require converting from the oem pull type clutch ( with the slave cylinder mounted outside the bellhousing), to the more common push type, which on a ZF requires the slave cylinder to be combined with the throw out bearing and mounted inside the bellhousing...which at this point would represent a substantial expense over the stock slave cylinder and throw out bearing.

a final thought...when assembling your clutch, make certain that the stud supporting the throwout bearing fork is installed correctly; it has a shoulder that seats on the inside surface of the bellhousing. If it isn't fully seated, it may keep the throwout bearing partially engaged and prevent the pressure plate from developing its full clamping pressure.

grantar2

I can say after 6K miles my Spec 2 is toast. Slips terribly especially in 1st and 2nd. Really bad when hot. Yes I auto cross the car, but really.