Would you replace this flywheel?

[Maxhouse97]

Would you replace this flywheel, machine it, or use as is? 123k miles, clutch being replaced for the second time. Its on its way to Patrick Motorsports for the final say, but wanted your opinion.

[porsche930dude]

with a new clutch you should really machine it to smoth it out and take off the glaze. at the very least rough it up with a sander. only need to replace if it has been machined before and too worn and screwed up to do it again

[Chuck.H]

I replaced my flywheel at 300k miles - others may disagree, but I've never had good results from machining flywheels - they always seem to chatter afterward. Maybe I'm not finding the right shop to do this, grinding vs turning, regular grinding vs blanchard?, is it flat or sligtly concave, etc. so I stopped doing it.

I'm very happy with the new one, starts now are silky smooth. I kept my old one in case I find the definitive place to resurface it.

Chuck.H
'89 TurboLookTarga, 370k miles

[sc_rufctr]

For a street car it's fine. Clean it up and use it.

But does it have any surface cracks?

[chris_seven]

Old worn flywheels may have some residual stress built up and it may be an idea to stress relive before re-grinding otherwise they may never be flat.

[RWebb]

how do you stress relieve them?

BTW - did anyone mention you need to check the runout?

[Bob Kontak]

Long established shop in Akron did mine for $45. Given Cincinnati has a bit of commerce, you may have to pay $55.

No cracks are the key. Get it surfaced.

[geoz]

Originally Posted by RWebb

how do you stress relieve them?

a couple of cold drinks??

[Dodge Man]

There is a spec on min thickness after surfacing. I have a small surface(new Sachs large ID) friction disc & light weight pressure plate. I got the resurfacing at a local auto machine shop that deals a lot with short track cars. However, I got the dreaded chatter when trying to slip the clutch in the driveway. New cable helped. Guide tube is next when I go for internal trans parts. Its always something.

[Ferrino]

I would try to get it resurfaced first. I'm having mine done hopefully later this week and found some excellent scans with machining specs from a previous thread: HERE.

[Maxhouse97]

I'm sure Patrick MS will check for cracks and run out. Just wanted to see what everyone thought. A lot of "while you are in there" crap has run up the price so I am looking to save money where I can.

[Maxhouse97]

Good to hear someone hot 300k out of one - was wondering what's normal amount of miles was.

[Flat6pac]

Its a G50 flywheel, theyre not suposed to be cut, just replace.
Bruce

[shinrai]

^ this. OP just replace if it's on your '87.

FYI part number on the flywheel is probably 930 102 233 3R. New part you receive may have 964 102 239 0R. Not to worry, they're both the same part. I don't know why they changed the number because it does cause some confusion.

[spuggy]

Originally Posted by Flat6pac

Its a G50 flywheel, theyre not suposed to be cut, just replace.
Bruce

Pretty sure you can machine a G50 flywheel if you use a spring-centered clutch like the early 930-style instead of the factory rubber-centered type.

[Maxhouse97]

Agreed.

[RichardNew]

You'll never regret and aluminum flywheels purchase. I love mine. The good part is they usually have a replaceable face.


Here's an article I wrote for Vintage Motorsport about flywheels.

Richard Newton

[aquazulu2]

Nice article, now I understand why the engine on my son's car would stall on me when I engaged his racing clutch, it was grabbing so aggressively that it demanded more throttle. I am about to purchase a replacement flywheel for a 1986 Carrera, I like the idea of a replacement face, how is price, and do you use a reference sensor pin.

[RichardNew]

Prices vary depending who is selling it and how light it actually is. I'm not sure about the sensor pin. Anyone else know how this works.

btw - People are always amused when I back out the garage at Homestead Speedway. Some figure I just don't know how to drive and others are impressed because they know what's going on.

Richard Newton

[Dodge Man]

If you are not racing then a stock type set-up should be seriously be considered. I did my AL pressure plate but a stock flywheel & OEM type pp are much more manageable in traffic. Make yourself happy. To race or not to race is the question?