crank balancing / clutch ?
 

repost from the tech forum:
i'm doing my 72 e rebuild, a driver no tracking planned.
its time to balance my crank.
my pressure plate "looks" good no scoring.
the body is aluminum, the plate is steel.
questions:
should i buy a clutch kit and replace all components?
can i reuse my pressure plate instead and replace the throwout bearing only?
is the aluminum body something special or standard to that type clutch?
its starting to get expensive!
all opinions welcome.
thanks

The aluminum pressure plate is still an option but the fingers will show wear under the TOB. if you need a clutch disc, just replace the disc. Remember,if you cut the flywheel, youre actually cutting clutch life.
Why spend money on balancing a crank that has a factory balance? Any part that you bolt to it afterward has a zero balance built in.

Bruce

How do you know?

The aluminum pp is expensive and not standard in the kits. I would use your old one. I would replace the throw out bearing and the disc.

-Andy

Article in UPFIXIN DE PORSCHE, Porsche Club condensing of tech articles circa 1972 basically stated all replacement rotational items for Porsche are zero balanced.

I am playing devil's advocate; Porsche has a spec. of course and if it meets that, then fine. However, the spec. on rods is 9g delta, and depending on the balance machine, I have seen Porsche cranks that need a little tweaking. It's most likely "good enough" but is it zero? ;)

I'm with Scott on this.

How do you get rid of a throw out bearing?

Throw out bearing finds it own center.... not part of a balancing scheme..Think that the t/o bearing and clutch disk start and stop at a different point on the clock every time you actuate them.. the flywheel, crank, and pressure plate are indexed together, in time.

t/o bearing and clutch disk are not included in balancing procedures.

Also when zero balanced is mentioned.. that is to Porsche specs... When you balance the assembly to better than Porsche specs..You need to match mark the crank/flywheel/pressure plate.

"....You need to match mark the crank/flywheel/pressure plate...."

So as not to confuse:
During an engine build, while the flywheel and pressure plate masses can be included when balancing the engine parts (crank, rods, pistons, pins, rings, crank pulley, etc.), for practical purposes, the flywheel and pressure plate (and even clutch disk) should also be balanced independently of the crank. These are so-called replacement parts. The engine shouldn't rely on these parts to achieve basic balance.

Sherwood