careful1

I am doing the flex plate tension release and I am not sure if I am supposed to let it rest where it released to or pry it back a little and tighten it. I moved it back and forth and then pryed it towards the rear of the car . I only ask because of reading about pre-loading it and I am not sure if that means to hold it back and then tighten. Thanks , Doug.

docmirror

Pry the flywheel/flex plate all the way to the rear. make sure the pinch bolt is really loose, and insure there's no strain on the flex plate at the yoke where it has the splines. Now tighten the pinch bolt to spec, or get the later model P-klamp and tighten that. Put a dab of white paint across the hub and spline to detect if there is migration later. and closer er up.

GregBBRD

Put a small straightedge on it and make it flat.

Sometimes the plate will get deformed from being flexed forward, for so many years and require some "backward prying" to make it flat. Sometimes they get flat, when you loosen the pinch bolt only.

Tails

If you wish to fully understand how your thrust bearing is, loosen the clamp and pry the flywheel aft and set up a magnetic dial indicator and set the dial indicator to zero on the flywheel vertical surface. Pry the flywheel forward and take a reading and then compare this reading to the specification end play for the thrust bearing. In doing this you will bear the "bump" as the crankshaft collar hits the thrust bearing.

After the reading has been taken pry the flywheel aft, check the flex plate is flat and tighten the clamp allen headed set screw to 10% over the specified torque. As a safety measure use a new set bolt, they are relatively cheap.

Mark the clamp end of the flex plate spline muff and the spline on the drive shaft with some white paint.

If you wish to be be really particular, measure the distance of the flex plate clamp vertical surface to a flat surface on the bell housing and record this reading. When you next check the flex plate prior to releasing the clamp, you can get a good reading to get the migration of the clamp.

As recommend also fit an PKlamp and you should not get any migration.

MainePorsche

The Pklamp is, I think, quite impressive as an auxiliary clamp that is not costly and easily installed/applied. It works. I have not had ANY migration in 2 years and many miles. I remove the four bolts about quarterly (or every other oil change) to have a look. I'm already under there and it takes 10 minutes. Measure at my marking on the spline and straight edge check the flexplate.

GregBBRD

The really interesting thing about this entire flexplate thing is that this doesn't happen until the vehicles get considerable mileage on them. Very rare to find one of these that has pre-load on it in a vehicle with less than 60,000 miles.

My "current" thinking is that this starts to occur as the driveshaft begins to get weaker and "twists/yields" more......but the shaft doesn't twist/yield as much, when it is "newer".

Anyone have any thoughts about this?

careful1

Thanks everyone .After loosening the bolt and moving it back and forth, It does appear to still have a little bow to it. I am going to get the pklamp for the added safety and piece of mind.

MainePorsche

Are you saying that after releasing the tension there is still a forward concavity on the flexplate when you put a straight edge on it ? After releasing the forward force on the flexplate it should 'rebound' to straight edge. Hmmm..

The pKlamp is a very good and practical choice. When you go back under to do the install see Dwayne's tutorial on the flexplate business. You can see what to measure and mark, and this will be helpful down the line. Good your are mindful of this matter, and this will keep the demon away.

http://dwaynesgarage.norcal928.org/

depami

How far back and forth does the crank shaft move?

This is important and should be measured before you tighten things back up.

MainePorsche

Denny,
Almost sounds like he just moved the clamp back and forth on the sleeve.
Oh careful 1, have a look at the Dwayne's write up and this should clarify things up.

careful1

It did mostly flatten out. Just a very little bow. It doesn't seem like the flywheel moves at all. I did get the Flexplate to move on the spline. I didn't ,although, ream on it because every time I get carried away bad things happen.

MainePorsche

That is prudent.
As in Dwayne's pictorial gently lever the flywheel back (toward the rear) and then button her up.
When you receive the pKlamp and go back in, I know you will have a micrometer by then so you can follow Dwayne's guide to measure the endplay. It sounds like you'll be OK in that you perceived no real movement. Torque clamp bolt to 65 ft lbs. Replace 4 of the 6 belhousing bolts (the 4 most aft) for easy access. Torque these to 15 ft lbs.

careful1

Thanks MainePorsche, I will