Hoping someone can help me think though this...

I purchased a 13lb fly wheel for my 88 NA.. My very slow NA... The flywheel was used, and looked pretty rough.. But i went ahead and tried it out with a mildly used clutch and P plate, and a new to me tranny that i wanted to "test" out.. .. in this order

Flywheel ( un-resurfaced ) used clutch and new to me tranny:
SLIPPAGE
Flywheel ( got it resurfaced !) used clutch and new to me tranny:
Slippage, MASSIVE amounts.. ( no torque at all)
Flywheel, still looking good, brand new clutch "heavy duty oem" and P plate:
STILL slipping with added machine gun fire noise which went a away when....
Tried with my old, proven tranny and STILL slipping

So, so far, the only truly unchanged variable is the flywheel. Ive tried 2 dif trannys, 2 diff clutches and a brand new one..

The flywheel is of unknown brand, it weighs 13lb without the counter weight. Instead of raised areas on the outer ridge ( like a the stock wheel) it comes with individual spacers that sit between the p plate and fly..

I have had my tranny out a total of 4 times in the last week, and the only thing improving is my transmission pulling speed! At this point im faster then the car! and im pulling my hair out. The car makes very little power, so im sure its not slipping to do HP.

 

Are you sure you still have the Key in place between your flywheel and Eccentric shaft, and that your flywheel bolt is properly torqued? If so, then I would check to make sure your clutch pedal is adjusted properly. If your not sure, then try twisting the rod connecting the clutch pedal to the clutch master cylinder counter clockwise about 3 or 4 full turns.

 

^ Good point.

Also, when you mate the clutch pressure plate to the flywheel, do you feel the pressure plate force against the bolts as you tighten them. In other words, with the clutch engaged, is it holding the friction plate? Sometimes, flywheels are machined wrong and/or spacers are the wrong depth.

 

HH... yes the key is in place.. good idea tho.. regarding the rod you spoke of.. i assume you mean the "linkage" under the dash? are you thinking that the clutch might be slightly engaged 100% of the time.. causing the slip?

PFsantos... YES.. theres a big gap when i put the p plate on with finger tightened bolts.. then when i torque them down, i see the gap squeeze tighter.

The seller has confirmed that it " worked when pulled" but suggested that his after market clutch was of a thinner spec.. ( perhaps causing the flywheel to wear too much, and then be too wide of a gap by the time i got it machined, leaving the gap too wide) anyone know the OEM spec on what that gap should be?

At this point it seems like i could do a few things...

...........pull my tranny for time #5.....

1) replace the spacers with stacked washers, to create a thinner gap

2) have it re- machined and have the mounting face taken down further than before.. To create a thinner gap

3) re-install my stock flywheel... to say f*ck it all.


in the mean time, i will look at that rod, but i wonder, would bleeding the slave cyl have the same effect? because i did that too, to make sure it wasnt accidentally engaging the clutch all the time.

 

Sadly, adjustment of the above mentioned adjustment rod had zero effect.

To give an example of the slippage... say im driving 30 mph in 3rd gear and i punch it WOT. The revs skyrocket for second then it catches, but has no real acceleration.. its like a BIG slip, then one long drawn out slip.

 

Nooo maaaaan (jamaican accent here), you shouldn't be able to finger tighten the PP bolts (unless you can finger tighten to 13-20 ft-lb) and get the clutch PP mounting flange against the flywheel. Once you tighten the bolts to spec. there should be no gap between the flywheel, friction disk and pressure plate. They should be under a lot of *Pressure*, don't remember the spec., which depends on what PP you're using.

Also, don't use stacked washers, it could throw the balance off, since there may be a gap between the PP bolts and the I.D. of the washers.

I'll say use the stock flywheel (machine it again if it's not perfect, unless you want clutch chatter). I wouldn't trust the other flywheel or clutch assembly at this point. A stock flywheel can be better for a street car, depending on driving style anyways. Spend the money on a new OEM style clutch assy, use a turbo throwout bearing, and then see what tranny is in better shape. GL.

edit to throw in: Some aftermarket PP need too much force, which sometimes break the ball screwed on the tranny case where the fork pivots.

 

Just re-read your post. Your clutch assy is new., so if it's still in excellent shape, loose the a/m flywheel.

 

Hm.. I guess when i wrote "finger tighten" i meant, well, you gotta get those bolts started somehow right? so they thread in using the finger, then get to a point where you need a wrench. Then the wrench does the actually tightening... when i mentioned the gap, i meant it started with a large gap, and ended with the appropriate gap...

Regarding the "gap" and washer/ spacer scenario.. the stock flywheel has a "peak and valley " feature on the outer surface ( the surface that mates to the p plate) The A/m flywheel have no such features, its just all one level surface. This is where the spacers come in ( they came with the flywheel) They create the space that the stock flywheels "peaks" make.

so.. that said, if i machined the spacers smaller ( or used the washers as temp test only) to create a smaller gap aka, more pressure on the clutch.. i wonder if this would solve the issue.

Im 99% in agreement with you on just reverting to the stock fly, but theres 1% of me that wants to give this one LAST try. I spent $160 on the wheel, $30 machining it, $100 on a new clutch and at least 20 man hours so far.. its hard for me to count it all as loss

 

If you can afford it, just buy an upgraded pressure plate and be done with it. I've had lots of issues with my clutch slipping over the years. If you buy a good pressure plate it will never slip again, the pp makes ten times more difference in preventing slippage than does the clutch disc. Racing beats pp gripped really well but for the non turbo it was unsprung which puts extra strain on your tranny and diff. But it never slipped again after that.

If you don't mind the possibly having to take the tranny down again I say try using the washers. If I were you I would try to find a couple of thicker washers so you don't have to stack them.

 

OK, you're gonna have to explain or take a pic. of the gap you're talking about.

All I can tell you is there should be no gaps I can think of. Remember that once you tighten the clutch PP to flywheel bolts, the clutch PP will be applying pressure, sandwiching the friction plate in between (you're using a clutch centering tool on the friction disk, btw?). No gap there, and remember, nothing is pressing on the outside of the PP (as when you step on the clutch), so the clutch is engaged.

It's only when you step on the clutch that the hydraulic pressure acts on the (few parts skipped) fork, then release bearing which presses on the PP fingers which pivot against spring pressure in the PP assy, which release the force holding the friction plate between the PP and the flywheel. Basically, you only have a (small)gap when you press in the clutch.

And yes, the stock NA flywheel has the machined surface below the PP mounting area. You want to make sure the difference is similar to the aftermarket flywheel spacer depth.

 

Stock wheel.... see on the outer surface, there are natural raised areas? this creates low areas, which are the "gap" im referring to.

On this A/M wheel.. the outer surface is just one flat surface ( minus the 3 little gaps, unimportant) The spacers that came with the wheel are supposed to be used in between the pp and the wheel, to re-create the specific amount of space that the raised areas on the stock wheel make. AKA gap.

ill also add that im not using the above wheel as you see it.. it was resurfaced. Not covered in rust. LOL.


HH.. thanks for the ides.. i may end up going that route.. but not unsprung.. im not that intense yet. ( gah! also, just dropped the cash on THIS P plate setup! ) Oh i love the money-pit that is my fc.
either way, lesson learned.. used **** ends up costing just as much as new, in the long run.. and is a pain in my ****.

 

"first owner" of the flywheel here.

This is odd. I had no problems with this setup on my car.

Like I had told endneu, I baught a rx7 that was an auto, with a manual swap, and this is the flywheel that was on it. I switched over to a turbo trans, so i no longer needed this.

As you can see from the pic, the flywheel, disk, and pressure plate sat together and had gotten wet a few times, thanks to a leaky garage.

The stock style, full face disk is what was used with this flywheel. I noticed that even being worn out, the stock friction material was thicker then the friction material on my current puck styl disk.

That was my reason for thinking maybe the spacers for the pressureplate are to thick for the disk he is using now.

Don't take this the wrong way, but im not sure how trustworthy a $100 clutsh is, unless you just got a good deal on a nice brand kit.

 

I see now what you meant by gap.

When you add the spacers to the aftermarket flywheel to re-create the distance between pp mounting plane and friction plane, keep in mind that the aftermarket flywheel friction surface is also recessed a bit. If you don't take that into consideration, you'll end up with too much gap.

 

thanks for jumping on here Oinesra!....
Well.. the box said Exedy all over it... LOL... no worries.. im sure its a decent clutch.. Got it from an outfit down in socal.. "gripforce"

Santos.... YES.. one poll i wanted to take was.. as i "remove gap" via washers or spacers.. where would be a good place to start? 5 or 10% less.. 20% less... probably not TOO much... If you image how much resurfacing takes off.... its a very small amount.

 

endneu - yes, I think that may be your whole problem. If I was in your shoes, I'd grab my digital vernier, and measure the difference between the friction surface and the mounting surface on the stock flywheel. Then I'l measure this dimension on the aftermarket flywheel, which is obviously less, but still there, judging from the pictures. I'd add enough spacer(s) to account for the difference.

Now on to uncharted territory....at least for me. You'll have to judge whether the clutch will be grabbing hard enough, when you tighten the pressure plate to flywheel bolts. If it seems O.K. then put in the tranny. You won't know for sure until you do. Good luck!

 

or should we say.. "remove" space.. to create enough pinch? LOL..

Thats one of the frustrating parts.. its hard to say "how much is enough" ....for instance.. im sure at some point during wrestling the tranny in... the weight of the tranny was held by just the disc alone ( meaning, the disc was never forced out of place by the weight of the tranny resting on it) so obviously, its impossible to just it till you drive it! Weeech is ahh paayne in mee ahhhhs donttcha know! ( jamican backatcha)

 

Ive pulled the tranny once again..... And compared the stock fly and a/m fly side by side.. and used some very rudimentary measurement techniques to find out that the "depths" are somewhat different.. a full centimeter on a measuring tool. ( this was just for preliminary measurements, tomorrow I will take to the machine shop for accurate measurements) I used a straightedge across the face of the fly, with a cross-sectioned ruler. I also measured another stock flywheel that was laying around my garage.. it was "identical" to the other stock fly.

This shows clutch mounted to fly, still on engine ( just to finally show the spacers infulleffect)

Here is how i measured as accurately as possible without digital tools

Heres 2 photos of the AM fly AS-IS.. should i resurface this.. AGAIN? the light swirly scratches are from my hitting it with some sandpaper after it slipped on try #3.. ( it was driven perhaps 10 miles on 2 different test drives.. Slipping merrily along the whole time)



So heres the poll... Would 1cm cause this much slippage?

 

EDIT above.. when i said 1cm.. i meant 1mm....

also.. went to the auto parts store. he measured my stock fly gap step and the a/m step..

stock: .6500 of an inch
a/m : .6750 of an inch

difference: .0250 which looks to be about .653 mm. so lets call it .5mm

Now.. to make this even funner.. anyone know where a stock fly gap starts brand new? that would give me an even better idea of how much space to remove.

 

..... and the verdict is.... .DONE! yay.

i removed about 1.5 mm from the gap.. works like a new clutch should now... seems perfect!

 

...... i take that back.. it works great, save the horrible vibrations when accelerating! the engine itself sounds fine... but the inside of the car vibrates like crazy! i know a/m flywheels are supposed to cause a bit of vibes at idle.. but is this normal? i assume the counter weight was s4.

 

I would have to say that I'm 99% sure it is a s4 counter weight. But like I said before. I bought the car with this installed, and dont really see why they would use a different counterweight, sence it already had one.

When I was still driving with it, it did seem to vibrate, but i had not driven the same car/motor setup with a dtock flywheel, so I cant really compair the two.

 

Only automatic cars came with the rear counterweight. On manual cars it's cast into the stock flywheel.

 

^ yes this is true... thank you

in this situation, a stock ( auto ) counterweight must be used when using a lighter flywheel to compensate for the stock flywheels offset weight.

 

Good to hear your clutch is now grabbing fine...

As for the vibration...you only get it while accellerating, clutch fully engaged? No vibration before you started this clutch ordeal?

A vibration due to imbalance should always be there, whether accelerating, coasting or holding RPM/Speed, I think. I was thinking clutch chatter, but you machined the flywheel and didn't say it was doing this when engaging the clutch, so I'll rule that out.

 

i get the vibration while accelerating.. clutch "engaged" it starts at like 2-3k.. then gets worse up around 4-5k... around 6k i suspect my car might explode. LOL.... but it seems to just be vibrations as a consequence.. not like the engine itself is making new vibes and noises.

No, no vibes before this poorly executed ordeal. : (