resurface flywheel

[Packy]

Do any of you know who resurfaces/rebalances 915 flywheels? Someone close to SoCal would be nice.

[DRACO A5OG]

Engine Machine Service, Inglewood near LAX, Dan or Bill

[Packy]

Soooooo, I bought a used lightweight flywheel that I think is causing some shuddering when I go into first. Would you guys re-surface it or just buy another?

[Flojo]

counterquestion: do you seriously envisage using doubtful parts?
rather not.

[dalboa]

Just had mine done at Napa they have a machinist. He's done work for me before, cost me 48.00

[schumicat]

i would resurface unless it has been done before. I did some research before having mine resurfaced and many people advised not doing it more than once. any competent machine shop should be able to do it, the one who did mine did a great job and I picked it just because it was close. $40, I think.

[911pcars]

Originally Posted by Packy

Soooooo, I bought a used lightweight flywheel that I think is causing some shuddering when I go into first. Would you guys re-surface it or just buy another?

Would that symptom occur while engaging the clutch in first or while fully engaged? Makes a difference.

Resurfaced correctly? Some flywheels have two surfaces to remove material, the friction area and the pressure plate mounting area. Material removed should be equal.

In addition, the preferred method of resurfacing is to grind it rather than machining with a lathe. Grinding will remove hard spots while a lathe tool is more apt to skip over hardened areas leaving high spots that may cause the symptoms you have.

MHO,
Sherwood

[Marc Bixen]

+1 For Engine Machine Service

[Packy]

Originally Posted by 911pcars

Would that symptom occur while engaging the clutch in first or while fully engaged? Makes a difference.

Resurfaced correctly? Some flywheels have two surfaces to remove material, the friction area and the pressure plate mounting area. Material removed should be equal.

In addition, the preferred method of resurfacing is to grind it rather than machining with a lathe. Grinding will remove hard spots while a lathe tool is more apt to skip over hardened areas leaving high spots that may cause the symptoms you have.

MHO,
Sherwood

It happens during engagement. When engaged, it drives fine.

[911pcars]

Originally Posted by Packy

It happens during engagement. When engaged, it drives fine.

Diagnosis is pretty much a guesstimate from long distance, but the situation I suggested (uneven friction surface due to uncut hard spots) can produce the chattering symptom you're experiencing. Could also result from a lubricant leak onto the friction areas (faulty trans. input shaft seal or rear main seal).

To confirm, remove the starter motor assy. and inspect the clutch/flywheel area and trans. clutch housing for signs of centrifuged oil stains. Gearbox oil has a unique odor as well. If the shaft shaft seal is good, you shouldn't smell any in that area. The absence of gear oil doesn't preclude a leak in the rear crank seal.

If any of the friction areas were previously soaked with lube, then "cleaned", the oil could resurface and cause the friction components to grab rather than smoothly engage with each other.

Perform your diagnosis in the order of easy-to-do first, before moving on to the more involved/difficult/costly strategies. In the end, you may have to drop the drivetrain and separate the gearbox and trans and take a closer look at all the related pieces. It doesn't sound like the end of the world, but merely an inconvenient glitch to make it drivable again.

Sherwood

[Packy]

Originally Posted by 911pcars

Diagnosis is pretty much a guesstimate from long distance, but the situation I suggested (uneven friction surface due to uncut hard spots) can produce the chattering symptom you're experiencing. Could also result from a lubricant leak onto the friction areas (faulty trans. input shaft seal or rear main seal).

Sherwood

Thanks Sherwood. This is what I figured as well. I'm planning on dropping the motor and tranny. There is a big transmission oil leak dripping in my garage. It's easy to tell because it's the blue swepco stuff. I'm planning on changing the seals and anything else (I still need a list and my info and I'm reading up here), but was wondering if I could salvage my lightweight flywheel. I have the original flywheel if I need it.

-P