> Daniel Neuman
> In my quest to reduce my compression ratio and to return my
> crank-to-cam distance back to normal I am liking the idea of a thicker head
> gasket to make up the difference. With a thicker head gasket I won't have
> to shim the cam towers and worry about the wipe pattern on the followers or
> worry about having to align bore the cam journals.
> Does anybody have any experience with this? I thought that maybe it
> was possible to get thicker copper head gaskets? Mike was telling me he
> thought he heard it was possible to take two stock head gaskets and glue
> them together somehow but he did not have any first hand experience with it.
> Mike also has a metal plate in the shape of a head gasket that he got from
> Stan a long while ago. Supposedly this plate can be used with a stock head
> gasket to lower your CR and return your valve timing. He was not sure how
> to implement this. Has anyone had any experience with doing something like
> this? I am of course concerned about sealing the head under boosted
> conditions. Any (helpful) thoughts on any of this stuff?
> Also, man I am feeling really special here, but I don't understand
> why a too thin head messes with the valve timing? If the timing chain is
> not overly slack I don't see how the valve timing is disturbed? Anyone
> wanna set me straight??
Okay, I'll give this a shot. To get a good understanding of the complexities
of Datsun OHC set up read Racer Brown's cam chapter from the original "How
to Modify 510,...etc", posted at
<http://www.datsport.com/Racer_Brown_Menu.html>. I'd suggest saving the
whole thing for future reference and study, not just for you, Daniel, but
for anyone who wants a through understanding of how the cam geometry works.
Yes, it focuses on the L-Motors, but unless I missed something, everything
applies to the U-20. too. IMO, it's pretty simple in theory, but getting
everything set up right is a real PITA unless you have the experience and
the tools to do it right.
Regarding the thicker head gaskets, the head on my U-20 had been cut from
.100 to .120 and I thought about that option. Several folks on this list,
the opinions of whom I highly respect, suggested that it would be a short
lived band aid at best. If I ever get the head off the car I'm sending it to
one of the vendors who's digging up a good used head.
Is this the absolutely cheapest fix for my problem? No, but I feel that it's
the least expensive fix that will last more than just a few miles or a few
weeks of driving. And, yes, I do think this will be far easier, less time
consuming and cheaper than swapping in the SR20 that I already have.
HTH,
Ron
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