21 replies to this topic

[gkiing]

Hey all,
A while back I came across a CRX with an integra swap, where the guy had reduced the pressure plate mounting surface by 0.015 or 0.020 in order to cinch the pressure plate closer to the flywheel. Right now I have a 89 civic with a D16Y7 I am thinking of doing the same to... is this reccomended and does it increase the holding power much? Cheers!

[jsgprod]

... is this reccomended and does it increase the holding power much? Cheers!

Yes, and yes.

It doesn't increase the clamping ability a tremendous amount but it's definitely an improvement over stock.

[Rampage]

I've done an extra half-millimeter with great success.

[badpenny]

just to clarify, where does one take the meat off the flywheel? I was under the impression it would have been the back side to lighten it.

[firstgencrx]

They're not talking about lightning the flywheel. They're talking about reducing the depth of the inner surface, relative to the outer surface machined on the face. The flywheel face is machined with two elevations. The outer ring elevation (which is higher) is what the pressure plate bolts to, and the inner recessed face is where the clutch plate grips. By reducing that elevation a tiny bit, the pressure plate will clamp down a little harder on the clutch plate, theoretically increasing the clutch pressure.

Did I get that right Jay?

[gkiing]

They're not talking about lightning the flywheel. They're talking about reducing the depth of the inner surface, relative to the outer surface machined on the face. The flywheel face is machined with two elevations. The outer ring elevation (which is higher) is what the pressure plate bolts to, and the inner recessed face is where the clutch plate grips. By reducing that elevation a tiny bit, the pressure plate will clamp down a little harder on the clutch plate, theoretically increasing the clutch pressure.

Did I get that right Jay?

So how much have you guys reduced the pressure plate mounting surface from stock? I don't know what the stock "step" between the flywheel surface and the pressure plate is. I thought about reducing it 20 thousandths, which isin't much, but 0.5mm works too with no clutch release problems?

edit: 0.5mm is 20/1000ths. So no problems releasing the clutch with this mod?

Edited by gkiing, 05 September 2010 - 02:17 AM.

[gkiing]

On this topic does anyone know where I can find the step size for an 88 CRX si flywheel (21 splines, 200mm)?

[A-Man]

i honestly didnt think about that its a good idea

[jsgprod]

They're not talking about lightning the flywheel. They're talking about reducing the depth of the inner surface, relative to the outer surface machined on the face. The flywheel face is machined with two elevations. The outer ring elevation (which is higher) is what the pressure plate bolts to, and the inner recessed face is where the clutch plate grips. By reducing that elevation a tiny bit, the pressure plate will clamp down a little harder on the clutch plate, theoretically increasing the clutch pressure.

Did I get that right Jay?

You got it right but the way you described it could be confusing if you just glance over it quickly. I even thought you had it backwards until I re-read it and noticed you said, 'relative to the outer surface'.

If someone were to miss that (as I did initially ) they might think that they needed to reduce the depth of the inner surface, which would DEFINITELY be the wrong way to go!

Just to be clear, it is the outer ring that the pressure plate bolts to that would need the material removed. And 0.5mm would be all I would remove. You could take more if you want to experiment but just remember, if you take too much...you can't put it back.

Jay

[Buford]

I have it written down somewhere. I'll try to find it.

[Old School REX]

+1^ I had some removed the last time I did my clutch job and it worked great. About .5mm sounds about right as to how much my machine man told me he would take. Felt great!

[Rampage]

No release problems, but the side effect is slightly higher pedal effort and a little bit reduced pedal feel. Well worth the improved grip, if you ask me!

[firstgencrx]

You got it right but the way you described it could be confusing if you just glance over it quickly. I even thought you had it backwards until I re-read it and noticed you said, 'relative to the outer surface'.

I know, I suck at explaining things.

It's an interesting thread all the same.

[gkiing]

So I did the flywheel, had the step machined off the flywheel so it was flat, this was 0.025 inches or just over half a mm. Now with it installed, the clutch wont release.. the cable has to be adjusted at the tyranny so its almost tightened to the limit. Its like the release bearing doesn't have eneough travel to disengage the clutch. Any ideas? I was thinking I could put a washer behind the release bearing so it could travel further. Btw the stock step on an 88 crx is 0.025in. Any ideas?

[gkiing]

Did some more research, I don't think the problem is loss of the flywheel step, it may actually be the pressure plate. I may have used a hydro pressure plate and this is a cable trans. Still not clear if hydro/cable pressure plates are different. But if the pressure plate is 200mm diameter, then it HAS to be an 88, right?