Razor---Others have covered the head and the probable C.R. as the result
of the milling, so I'll
take a stab at what's left.
You may have to use shorter pushrods to get the rocker geometry
correct, and also to where the adjustment screws (to set the lash) is
back to about the middle of the threads.
Others have found it sufficient to just shim up the rocker pedestals to
get the adjustment back. (About .090 per pedestal in your case?)
I'd further suggest that a lot depends on the diameter of the camshaft
base circle as to how this will all shake out. If you are going to use a
cam that's been reground (again I will assume that you are also going to
change to a performance cam) sometimes a "smaller" cam will let the cam
followers drop down enough. In some such cases you may not need shorter
pushrods. I would put it all together to see where the lash adjustment
comes out. It's easy enough to install shorter pushrods, if you then
find it to be necessary. Check with TSI.
High compression can break piston rings, IF the engine is allowed to
detonate. You'll definitely want to listen closely to avoid this. If
high octane gas and retarded ignition timing doesn't stop the
knock/rattle when the engine is under load, you'll need a decompression
plate, which was also suggested in another post.
Dick
>From Razor Bob:
RazorBobSr@aol.com Date: Tue, Feb 22, 2005, 3:50pm (PST+3) To:
6pack@autox.team.net Subject: Are u kidding me???
I have a head just about to come out of the shop,this was a stock head,I
had is milled to give 35 CC combustion chambers and from stock that
meens 135 tho off the head.My plan was to up CR to 10.1 or so,WILL I
need shortened pushrods??? IF SO how much shortened? I was also told
that 10.1 will/could/perhapts/ couse the top ring to fail of the
pistons?
ADVICE from all welcomed.Bob
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