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JFairman JFairman is offline
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Join Date: Jul 2006
Location: S. Florida
Posts: 7,274
Originally Posted by AFM744 View Post
There's a LOT of things you *can* do with the heads still on the engine, heck, with the engine still in the car. Point is, if you booger something up trying to cut that corner it'll be a LOT more work than just pulling and reinstalling the heads.
I know people have successfully removed the retainers and changed springs by pressurizing the cylinder to hold the valve shut. But DAMN, if that seal breaks while you're trying to compress the valve spring the valve will go slamming into the piston. A decent valve spring compressor was the best $60 I ever spent when I had to reassemble my heads. It turned a sweaty, wobbling, cursing tool-through-finger job into a relaxing experience shared with my son.
I have this head off the engine large, sturdy C - clamp type valve spring compressor from Sears and it works great... and it's only $20. I'm sure they would let you return it if you were inclined too.
I called and they had them at the local sears.

The valve spring compressors that do it with the head on the car can easily overcompress the spring.
Some are like a lever that hooks onto something solid on the head like a camshaft, and some designs grab the spring coils with claws and should be avoided on a porsche. They grab and squeeze the spring unevenly and afterwards the spring is bent, crooked, and only good for a low reving tractor or lawnmower engine after that.

Filling the combustion chamber with compressed air keeps the valve from sliding in from gravity after you remove the keepers. The valve won't go "slamming" in and hit the piston when you remove the keepers if the air pressure seal holding the valve seated and closed is breached.
The exhaust valve won't go anywhere because it's pointed downward obviously, only the intake would possibly slide in because of gravity.
Old 01-23-2009, 11:38 AM
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