Resurfacing head for metal head gasket

Wayne Cox wmc_sr20@bellsouth.net
Tue, 10 Dec 2002 18:45:30 -0600


At 06:09 PM 12/10/2002 -0500, you wrote:
> >If the cam gear is about 4" diameter, then its circumference

>Actually, it's not that easy. The chain doesn't follow a straight line
>between the crank and the cams.

Well, I was offering it as a simplified explanation of what was going
on.  I hadn't considered the angle issue.  Don't think it makes much
difference on an SR20, but something like the GA16 with the idler gear and
2nd chain it might.

Hmm, lessee...  A^2 + B^2 = C^2   is still a little over-simplified, since
it's working from the cam & crank center-line and not the chain's tangent
points, but should be close.  If it's 8.3" from the crank center to the
block deck (FSM) and another 5.5 (tape measure) to the cam center, and the
cams are 2.5" off center, then Sqrt(13.8^2 + 2.5^2) = 14.0246 chain
length.  Knocking 0.010 off the height would increase the chain length to
14.0148 (delta = 0.0098)  That's no significant difference, due to the
angle;  BUT it is the opposite of what I was thinking a few minutes
ago.  The SMALLER the included angle, the larger the difference.

>I have seen some big name brands that were as much as 12 degrees off. (No
>comment on who.)

Aww, com'on.  If there's bad product out there let us know!

>Hint # 2: Buy JWT cams for your Sr20de, they know cams.

Got a set of S3s I've had for 3 or 4 years and never put in :(

    -Wayne    '91 NX2k - '93 NK2k - '92 SE-R parts car