83na944

I've read recommendations that you should send the flywheel to a machine shop for resurfacing when doing a clutch replacement. Since this pretty much adds at least a day to the process, I would like to skip this step.

So my questions is this: does everyone resurface the flywheel during clutch replacement or have youe skipped the resurfacing?

TIA,
Steve

nj924s

depends on what it looks like i guess, its a good idea to get it done and worthwhile while its out. i would think if a shop isnt too busy they could do it in a very quick turn around time as they are only facing it.call a local shop and ask how long itll take

83na944

Sounds like a good idea. I was going to try to finish this over a long weekend. But if I run into issues with removal, I'll be in pushed to get it to a shop in time for resurfacing.

abduln

Some people and some shops will tell you only do so if your flywheel friction surface is extremely damaged. Some shops will tell you it's not required for lightly cracked surfaces.

At a minimum, you should clean the surface well and verify that it's smooth. Then take a straight edge and test the surface in multiple places, making sure it's flat.

Some info I have run across recommends that if the friction surface is glazed, you can use a block and sand the surface fresh, but clean up everything very well before putting it back together.

As I said, some shops would tell you that minor cracking is not a problem. I personally would have a flywheel with any cracking surfaced. Cracks are stress risers and will only lead to bigger cracks, and eventually failure.

Also, flywheels should be ground, not faced on a lathe; if you take it in, ask the shop how they surface it.

A little hot-rod trick:

If you take your flywheel out to have it gound, you can also have the area of the flywheel that the pressure plate bolts to cut down on a lathe; do not have the friction area cut on a lathe, just the surrounding circular area that receives the pressure plate bolts. This effectively increases the clamping force of the stock pressure plate, without having to buy an aftermarket pressure plate. The amount of extra clamping force is determined by how much you cut down, and how much you can cut down.

Just keep in mind that stiffer clutches have their downsides, and this is not the same as buying a high performance clutch set; it's just a poor man's tweak. I wouldn't actually do this unless I really needed to, it's more of an FYI.

83na944

Thanks for the advice. I planned to clean it well. But I would never have expected to see any cracks. I've heard horror stories about flywheels breaking, but I doubt I get it spinning that fast anyway.

'88-924S

I just got my clutch replaced, and they did NOT resurface. It only has 62k orig. on it. The shop cleaned it well though. After almost two weeks with the clutch, no problems other than a much lighter wallet.

BruceWard

I changed the clutch on my 968 recently. I could not find anyone local to resurface the dual mass flywheel so a friend came by and broke the glaze using steel wool. We cleaned it well with acetone to remove and impurities. I have not had any problem in the 800 miles since.

Stan944

From experience on Jeep Cherokee - I would say: have the flywheel resurfaced. A brief delay and a few $$ are well worth it. Afterall, it takes lots of work to do it again if needed.

I did my first clutch job without resurfacing the disk, and regreted it a lot. There were severe vibrations upon releasing the clutch pedal, and it was very hard to launch the truck from a dead stop. The vibrations didn't go away within half a year. On the contrary, it got worse, and eventually a new loud noise developed. Upon dissassembly, I found out the pilot bearing seized. I believe due to the vibrations.
So I took the flywheel for resurfacing, and it works fine now.
I also put a more expensive clutch package, so maybe this helped?

The moral is, the amount of labor involved in a clutch job makes it worh paying extra $$, and waiting for a shop to resurface the flywheel.

Jay W

I second Stan944's comments. My 944 had a new clutch put in by the PO and I guarantee they didnt resurface the flywheel because it vibrates on startup from a dead stop and when downshifting. Very annoying. My brother put a new clutch into his 924S and skipped the resurfacing, and he had chatter too. Alot more time and effort than the 1 day turn around if you have to do the clutch again. And its probably less than $40 to get the flywheel turned anyway.

83na944

Well, it looks like the parts won't be here until Monday, but the tools will be here this weekend. If I can get it apart this weekend, I won't have the parts to button it back up. So if all goes as planned, I'll at least look at it very carefully and probably take it in to a shop Monday.

Can just about any shop do this? Is there anything special I need to know when I talk to them?

iloveporsches

I didn't resurface mine when I replaced my clutch. It looked pretty good, so I just cleaned it off really nice. No complaints a year and maybe 5000 miles later.

83na944

One of my concerns about resurfacing is flywheel thickness. This will be the third clutch in this car. The first had a premature death caused by rubber failure about 10 years ago. I had a dealer replace the clutch at that time.

They didn't mention resurfacing the flywheel at the time and I don't remember seeing anything on the bill about it. My feeling is that didn't.

But if they did, and I have it cut again, it may be too thin to use. I sure don't want to replace it if it's serviceable.

scular

Just some more points to bring up:

The flywheel is much like the brake rotors, it will be annealed from heating by use. Unevensurfaces are not easy to see.

It is a good idea to have it machined to remove the heat treated surface if nothing else.

If the clutch surface is machined, the outer ring must be turned down, I have had a number of clutches burnt up from not having the proper work done. Now I have my own machinary.

The proper way is to have the flywheel resurfaced with a surfacer; however, with care and a good machinist a flywheel can be turned on a lathe with excellent results.

The machining takes at most 1 hour. Think about how long it takes to get to that flywheel... Do you want to even risk the possibility of having to do the work again within a short period of time?


SCular

Matt Romanowski

I would recomend having the flywheel surfaced too. You should be able to find someone locally to do it. I would insist on having it ground though. Non-directional finishes are much better for friction material wear.

Matt

83na944

Good point, Matt, I'll ask about grinding instead of milling or turning.

SCular, are you talking about reducing the thickness of the ring gear? That fits to the clutch plate, right? Since I'm replaceing the clutch, I won't need to have the ring gear thickness reduced, coorect?