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Posted by: Joseph Mills Jun 23 2004, 07:16 AM

My heads are being flycut to remove just enough material to dress up the face that meets the top of the cylinders. What else is required for a good seal?

Posted by: redshift Jun 23 2004, 07:18 AM

Seals need lots of good, clean water, a steady food supply, and love..

they like beachballs too.. ARP! ARP! ARP!



M

Posted by: James Adams Jun 23 2004, 07:27 AM

You can use some valve lapping compound and lap the top of the cylinder into the head. It is an abraisive paste you are using to true the two surfaces to each other.

You can probably use all the compression you can get in your case, so the bump in compression from deleting the gaskets is fine. If you did need to lower the compression, you would install shims between the case and cylinders.

Posted by: balljoint Jun 23 2004, 07:51 AM

Yes M. but don't forget fish for treats and a small-breasted girl in a shorty dive-suit to hand them out to crowd applause. No..................
...wait............... , nevermind, that is Sea Lions.

Posted by: rhodyguy Jun 23 2004, 07:57 AM

does the elimination of the gaskets require establishing and confirming the deck heigth? one would think the depth of the fly cut would have to be a known value.

kevin

Posted by: James Adams Jun 23 2004, 08:03 AM

I think Joseph is reusing the original pistons and cylinders (correct?). Therefore the compression is pretty low, and it will not even be up to stock Euro ratio with a clean-up flycut.

It would not hurt to check the deck height, but I think it will be just fine with these parts.

Posted by: Joseph Mills Jun 23 2004, 01:31 PM

James, that is correct, I am using the existing pistons & cylinders (but new rings). Actually my engine has a Mahle Euro P/C set. The pistons have a flat top. Purportedly, it has an Isky valve train and mild cam.

Does the deck height establish the clearance between the valve and piston top? This sounds like something I may need to resolve.

Also, I have been told of several methods of cleaning up the top of the cylinders:

1. Using some 400 grit wet sandpaper taped to a piece of plate glass and pulling the cylinders across it.

2. Using abrasive compound and rotating the cylinders in the head (as James mentioned).

3. A combination of both.

Are one of these methods preferable over the other two?

As always, thanks for the feedback. And special thanks for all the good info on sea mammals.

Posted by: James Adams Jun 23 2004, 01:37 PM

You won't have any valve to piston clearance problems with your combo.

Check the deck height for the heck of it - you want at least 0.045 or so minimum distace from the piston touching a head surface. I bet you will be way beyond it with your parts.

Lapping will work better and takes care of both surfaces at once - no chance of bad technique giving you a non-flat surface.

Posted by: vsg914 Jun 23 2004, 02:19 PM

When I have lapped valves, I've used the suction cup on a dowel rod, going both directions. Same with clyinders, or only one direction?