datsun-roadsters
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RE: CC'ing a head

To: "'Gordon Glasgow'" <gsglasgow@comcast.net>,
Subject: RE: CC'ing a head
From: "Daniel Neuman" <neuman@radonc17.ucsf.edu>
Date: Thu, 10 Nov 2005 16:35:27 -0800
Gordon, Ronnie,
        I think that the less stuff I remove from the head the less there is
a chance of me screwing something up.  I just have to decide if I'm less
likely to screw up if I just remove the rocker arms or if I turn the crank
by hand.
        I do want to actually CC the head because I am curious what the CR
is and if its different for each cylinder and I really want to try to get my
CR down to about 8-1.
        Irene has 'authorized' some funds for the roadster fix up so I want
to get on it before she spends everything we have on the wedding......

        Daniel Neuman
        Oakland CA

$Subject: RE: CC'ing a head
$
$Just take the rocker arms out before you do anything else and all the
valves
$will be closed.
$
$The likelihood that the head has had some machine work done in the chamber
$is pretty small unless you bought the head from a racer. Measuring the
$thickness with a micrometer or a very good caliper will give you a
$reasonable baseline. A stock 2000 head is 4.528-4,530" thick.
$
$If you do actually CC the head, you will most likely see variation from
$chamber to chamber. This is because the valves can be sunk different
amounts
$due to valve seat grinding.
$
$As far as the cam-center-to-crank-center distance goes, shimming the head
if
$it has been milled will restore that distance, as long as the cam towers
$haven't been shimmed. The wipe problem occurs when you shim the cam towers,
$because that increases the distance between the cam and the rockers. With a
$milled head, you can shim on the bottom of the head or on the top of the
$head, but you shouldn't do both.
$
$Gordon Glasgow
$Renton, WA




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