I was very sad last night when I felt the clutch slip while accelerating hard on the highway. The clutch, a stock-replacement Sachs kit, only has about 7,000 miles on it.
I'm not sure if the clutch kit was 1) poor quality or 2) just not suitable for the extra 50-ft lbs of torque, but either way, I need something a bit heavier duty.
Any recommendations? I want the car to be easy to drive as much as possible. The motor is stock LX9 (200 hp, 220 ft-lbs torque) mated to a stock 282 Getrag with the stock flywheel.
I thought Luk (or is it Luc) was the OEM clutch... 9 1/4", make sure you didn't get a 4 cyl clutch which is smaller diameter.
I've never had a problem with the 9 5/8" HD Ram clutch (it's been behind my 3.4's and my 4.9) but other people haven't been so lucky... I'm using a Spec 3+ on my 6 speed 3.400 motor. It's heavier than stock but takes a licking and keeps on kicking. Costs a pretty penny though.
Thx for the info. I clutch I used was a Sachs kit K005901 which shows as 9 1/8", however, I remember it came with the wrong throwout bearing, so I wonder if the kit may have been incorrect. I had to call them and get another bearing special ordered. Sucks
The throwout bearing I got looks like the ones in these kits, for the 4-speed Muncie:
Spec stage 3+ is much heavier that stock. Engagement is not as smooth, but man does it hold the torque... HD Ram clutch from Fiero Store always felt like stock to me or close to it.
The 9 11/16" disk will be slower to shift than the 9 1/8" disk. This is because it's hard for the synchronizers inside the transmission to spin the larger diameter heavier disk up and down when shifting.
There are 9 1/8" clutches that are more than capable of handling a 3500. I would have guessed a SPEC Stage II would be good, but I don't have direct experience with that clutch. SPEC has had problems with wear on the hub spring retention tabs on their disks. If going with a SPEC, I'd get a solid hub. The hub springs can also contribute to clutch chatter. ClutchNet has a much better design for their hub spring retention, but I've heard that they've started to be difficult to order from recently.
I have a SPEC Stage III on my Northstar. It holds torque very well and can take abuse, but chatters. Since it's a puck type disk, it's lighter than stock and shifts faster.
I have the heavy duty Ram clutch on my 4.9. Haven't made it slip since it was installed, several thousand miles ago. I had a Spec 2 on my built up 3.4. It, in a word, sucked. Never owned the 3+.
Honestly I thought that a stock V6 replacement clutch would be just fine for the 3500 - that's why I am somewhat suspicious that I installed the wrong kit.
I have a hard time believing that after 7,000 of easy driving, ANY clutch would be worn out.
Honestly I thought that a stock V6 replacement clutch would be just fine for the 3500 - that's why I am somewhat suspicious that I installed the wrong kit.
I have a hard time believing that after 7,000 of easy driving, ANY clutch would be worn out.
I've got a bully stage 4 in my turbo 3500, I haven't driven it yet, but the pedal doesn't feel excessive to me.
------------------ "I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."
Check with a local clutch builder if you have one, they can give you info not readily available at retailers. The stock OE pressure plate is not as strong as the modern equipment however, it's hard to know what you're getting when descriptions are more play on words than they are hard numbers.
I started with a stock heavy duty pressure plate which according to the shop documentation had more than 200 lbs clamping pressure than the stock Fiero plate was rated at, then I had it modified to apply even more pressure. The stock plate from what I recall is under 1700 lbs clamping pressure. The shop was also able to measure the clamping pressure of my stock F40 plate as well at 2000 lbs.
I recall debating with someone here a few years back regarding their recommendation for a pricey high performance pressure plate kit one of their connections offered that was pretty much the same pressure as the ~$50 HD plate I started with and ended up wtih over 2200 lbs of clamping pressure after it was modified.
Having to drop the cradle in a Fiero repeatedly over something like this is no fun. Buy a setup and take it to a shop and get some numbers you can use before installing it.
Check with a local clutch builder if you have one, they can give you info not readily available at retailers. The stock OE pressure plate is not as strong as the modern equipment however, it's hard to know what you're getting when descriptions are more play on words than they are hard numbers.
I started with a stock heavy duty pressure plate which according to the shop documentation had more than 200 lbs clamping pressure than the stock Fiero plate was rated at, then I had it modified to apply even more pressure. The stock plate from what I recall is under 1700 lbs clamping pressure. The shop was also able to measure the clamping pressure of my stock F40 plate as well at 2000 lbs.
I recall debating with someone here a few years back regarding their recommendation for a pricey high performance pressure plate kit one of their connections offered that was pretty much the same pressure as the ~$50 HD plate I started with and ended up wtih over 2200 lbs of clamping pressure after it was modified.
Having to drop the cradle in a Fiero repeatedly over something like this is no fun. Buy a setup and take it to a shop and get some numbers you can use before installing it.
Yeah, I was honestly hoping I wouldn't have to drop the cradle again (or at least for a while), this is a real bummer. I can't find any local clutch builders in Charlotte though.
It seems to me that its torque, not horsepower, that would cause the clutch to slip. I have about 30% more peak torque than the original 2.8. Is it safe to say that 30% more capacity will be sufficient for a long and healthy clutch life?
According to RAM, their clutch can hold 40% more power than stock (~238 ft-lbs). According to SPEC, their stage 1 kit will hold 344 ft-lbs of torque, sounds a bit generous. Clutchnet's stage 1 shows 250 ft-lbs.
So any should be sufficient - I would rather not sacrifice more driveability than I need to. Any opinions between these three options? Price point is similar ($270-300).
Yeah, I was honestly hoping I wouldn't have to drop the cradle again (or at least for a while), this is a real bummer. I can't find any local clutch builders in Charlotte though.
It seems to me that its torque, not horsepower, that would cause the clutch to slip. I have about 30% more peak torque than the original 2.8. Is it safe to say that 30% more capacity will be sufficient for a long and healthy clutch life?
According to RAM, their clutch can hold 40% more power than stock (~238 ft-lbs). According to SPEC, their stage 1 kit will hold 344 ft-lbs of torque, sounds a bit generous. Clutchnet's stage 1 shows 250 ft-lbs.
So any should be sufficient - I would rather not sacrifice more driveability than I need to. Any opinions between these three options? Price point is similar ($270-300).
That's is correct, torque is the main deciding factor in clutch performance handling. I found my receipt and confirmed that my finishing pressure after modification was 2357 lbs, and 1957 lbs before modification. Although it's nice to have the manufacturers torque rating, the actual clamping force makes it much easier to compare "apples" and "oranges" fairly, as the type of friction material plays a role also and their ratings may be only with their specified clutch disc.
I checked a moment ago and the unmodified HD pressure plate costs $55, modified it's $219. The part # is NCA1914-HD, you have to ask for the unmodified version to reference the $55 part. Tampa Clutch Supply Inc. 813-623-1416.
I believe this is a 4 speed pressure plate so you'll need to check compatibility, or an optional equivalent. The builder and shop owner is Jim and he can build pretty much whatever you want.
As for a clutch disc, look for longevity and couple that with a high pressure plate. No one told me that dual friction plates didn't last long, fortunately for me I discovered this during a swap when I realized mine was nearly worn out with only ~30,000 miles on it. Dual friction can also be brutal on flywheels which I also noticed.
[This message has been edited by Joseph Upson (edited 01-13-2015).]
That's is correct, torque is the main deciding factor in clutch performance handling. I found my receipt and confirmed that my finishing pressure after modification was 2357 lbs, and 1957 lbs before modification. Although it's nice to have the manufacturers torque rating, the actual clamping force makes it much easier to compare "apples" and "oranges" fairly, as the type of friction material plays a role also and their ratings may be only with their specified clutch disc.
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As for a clutch disc, look for longevity and couple that with a high pressure plate. No one told me that dual friction plates didn't last long, fortunately for me I discovered this during a swap when I realized mine was nearly worn out with only ~30,000 miles on it. Dual friction can also be brutal on flywheels which I also noticed.
This would be a major factor in my case.
Would a "stage 1" type clutch with an organic friction material last longer than a dual-friction clutch for my application?
Originally posted by masospaghetti: This would be a major factor in my case.
Would a "stage 1" type clutch with an organic friction material last longer than a dual-friction clutch for my application?
I'd expect the stock style disc to have a typical life span with a higher pressure plate. Dual friction grabbed and held very well but the metal in the disc wore faster and left it's mark on the flywheel behind a turbo 3.1 L. It would help if you knew what the clamping pressure is of your current pressure plate but of course like in all sales, the less the customer knows about what they are buying, the more likely they are to buy it in error. Good luck trying to get that info out of the vendor.
I called Tampa Clutch Supply, they were very helpful. The lady recommended a steel-backed disc (dual-friction, I assume?) using a unmodified pressure plate, and thought that a heavier pressure plate would be overkill for it.
She even suggested reusing my current pressure plate as long as it isn't damaged. The advantage is that I would only need the friction disc, which is about $100.
I called Tampa Clutch Supply, they were very helpful. The lady recommended a steel-backed disc (dual-friction, I assume?) using a unmodified pressure plate, and thought that a heavier pressure plate would be overkill for it.
She even suggested reusing my current pressure plate as long as it isn't damaged. The advantage is that I would only need the friction disc, which is about $100.
Thoughts or comments?
I've dealt with them many times and have indeed reused a stock pressure plate (with my dual friction clutch) which they resurfaced. They've never steered me wrong. I would however inquire about the longevity of the disc being recommended as I was steered towards the dual friction clutch disc for holding capacity, no mention of mileage was made because I just assumed I could expect the same service as one normally would with a stock application that was not abused. I have a Kevlar disc which is stated as high performance with longevity. The only complaint I have with it is the noise due to my use of the stock G6 disc frame which has tiny springs in it that some times make noise in the plate when the clutch is engaged. Make sure you use a sprung hub. I know many delete that but I believe for the purpose it serves no daily driver should be without it.
They are also very familiar with H.O. hubs losing springs and showed me a few examples and explained that the springs actually screw out due to clutch disc wobble.
Tampa Clutch is saying that their dual friction is organic and steel backed, not organic and kevlar.
Joseph, the clutch you had with short life was a organic-kevlar clutch, correct?
Sorry, different time frames here. The discs are independent of each other. The dual friction was in use initially and was replaced with a Kevlar disc which has the same lining on both sides..
I just spoke with Jim and he thought that a stock clutch should do just fine for my setup for at least 60,000 miles. My conclusion here is that either
1 - the stock clutch was the wrong 4-cyl size (kit put together wrong) 2 - oil contamination (no evidence of leaks), or 3 - One of my friends that I let drive the car let the clutch slip like crazy and glazed the disc.
Number 3 is the most likely.
Regardless, he recommended the kevlar disc with a stock pressure plate and insisted that the longevity is even better than stock, as long as the flywheel is resurfaced. So that's what I'm going to try. I'll let ya'll know what happens.
Originally posted by masospaghetti: I just spoke with Jim and he thought that a stock clutch should do just fine for my setup for at least 60,000 miles. My conclusion here is that either
1 - the stock clutch was the wrong 4-cyl size (kit put together wrong) 2 - oil contamination (no evidence of leaks), or 3 - One of my friends that I let drive the car let the clutch slip like crazy and glazed the disc.
Number 3 is the most likely.
Regardless, he recommended the kevlar disc with a stock pressure plate and insisted that the longevity is even better than stock, as long as the flywheel is resurfaced. So that's what I'm going to try. I'll let ya'll know what happens.
With a 3.4/3.5 behind a stock clutch, it's easy to burn. My 2.8 Formula just turned 98k miles on stock hardware...however, it's my daily driver so I have been babying it since I bought it with 53k miles.
So here's what I found out after I got everything apart. The clutch disc isn't worn excessively. It has some light glazing, but that's all. No oil contamination. The pressure plate, however, is noticeably "flattened" compared to the new one. The fingers that ride on the throwout bearing have been pushed in. I'm almost positive this was the root cause of my problem, not enough pressure, also would explain the rising clutch pedal.
Since i already had this special-ordered clutch from Tampa Clutch Supply, I went ahead and put in the new friction disc along with a new pressure plate and resurfaced flywheel.
