Resurfacing flywheel and pressure plate

[jkh2cpu]

Does anyone know of a shop in the midwest (Michigan) that can resurface flywheels and pressure plates. I just dropped the engine and transmission for some routine maintenance, and find the clutch disk glazed but with 7 mm thickness. I'd keep it, but it has the rubber center, which I don't want to experiment with. The flywheel and pressure plate are fairly smooth, but there are high and low spots that I can feel with my fingers. These variations are minimal as a straight edge on the pressure plate does not pass light light from my led flashlight.

Thoughts? I'm thinking that maybe I should just install the new disk and go with the pressure plate and flywheel as they are and let things take their course.

John.

[Oh Haha]

Hey John,
Where are you located in MI?

If close to Midland, talk to the guys at Rallye Import. They could tell you a good machine shop for the resurfacing.

Otherwise, check the phonebook for a race shop. Even if they are circle track or .25 mile guys, they know what to do.

[gregwils]

You may was to send cgarr a PM. He lives in Kentwood, not sure how far you are away. If he can't do it, for sure he knows who can.

[jaybird840]

+1 for contacting CGarr. Craig will set you straight.

[James Brown]

can you, should you resurface the pressure plate? or just get a new one?

[jkh2cpu]

Hi, Guys. I followed up on Oh Haha's comment because I'm in Mt Pleasant, which is about 25 miles away from Midland. From Rallye, I was directed to a machine shop in Midland who does their machining. He only does flywheels, as the pressure plate is not given to easy resurfacing. I'll reuse the current pressure plate (dated 10/72) as it is smooth and flat. It will need deglazing as it is well-polished. As a side note, I went to press the pilot bearing out, and it would not budge. Oh s--t... I was pressing from the wrong side, but I don't think I broke or warped anything. I'm guessing that casting would break first.. I'll know tomorrow.

[James Brown]

ouch**** when l did my clutch overhaul l found one of the rubber dampner clutch disks in there from new! 150k and 28 years and was still good! and l did reuse the old pressure plate, it looked good, no stress crackes. Yeah l couldn't figure out how to resurface it (do you need a specal jig?)
any ideas? thanks

[jkh2cpu]

Porsche says that the flywheel may be reconditioned with a lathe, but it can be no thinner that 8.5 MM, with a runout of 0.1 MM. I'm guessing that the only reconditioning of the pressure plate is by use of a crocus cloth. Porsche also says that the pressure plate must be flat with a 'permissible lateral runout of 0.6 MM.'

HTH.

[dentist90]

I've never considered resurfacing the pressure plate. I always buy a clutch kit: pressure plate, friction disc and throw out bearing (also the pilot bearing). These are all wear items IMHO. You can make the pressure plate smoother and flatter by machining, but you can't make the finger springs younger. I would think you would also start to lose the accumulated thickness of grinding the material from the pressure plate disc and get less clamping force on the friction disc.
The flywheel you can repeatedly machine until you reach the minimum thickness where warping and overheating become a concern.

JMHO, and YMMV.

[911pcars]

The wear rate of the pressure plate may have some bearing on the residual strength of the diaphragm spring. In that respect, I'm surprised when some sellers offer a used pressure plate for almost the same price as new or rebuilt.

Assuming, it's "rebuildable", I would insist on grinding to resurface the pressure plate (or flywheel) surface rather than turning on a lathe.

Hard spots that develop on the cast iron friction surface will cause a regular carbide lathe cutting tool to skip over the affected area. Same goes with refinishing brake rotors. A grinder will produce a better, more uniform finish.

Sherwood

[jkh2cpu]

In my case, the pressure plate face was not damaged by scoring or warping. All that I need to do it rough it up with crocus cloth. I'm not worried about the strength of the clamping force as it's in a 140 HP motor with not a whole lot of torque, and I've never had slippage. I'm going to replace the current TO bearing with the original... 34 years ago a deal wrench put 8 pints of oil in the transmission which was 2 pints too many. The excess oil came out the mainshaft blowing that seal and wrecking the clutch disk. I replaced the original TO bearing as standard practice, not that it was bad. The current one is a little noisy, so I'll put the original back in ;-) If I was paying 120 an hour to have the work done, I'd get the package and rest easy. I'm retired and love to wrench, so I don't mind dropping the engine and putzing around. Oh... the pilot bearing... to change that, one needs to remove the flywheel, so the stretch bolts need to be renewed. It's always something which is why I love this beastie ;-)