[xk] Update; shrunken timing chains

XK
1

Finally got back to the Xk120, had to get away from it for a while
to calm down, plus a trip to Chicago area to visit daughter and son-
in-law. Removed the head and measured the composite gasket,
measured from .075 to.080 at various spots, compared to .017 for
the stock gasket. Then I put on an old 120 head that had been
surfaced at least once, with the composite gasket and had no
trouble hooking up the timing chains. Called the supplier to find
out if they carry the composite in different thicknesses only to
find out they have but one size(thickness). Not sure of my next
step, will probably rebuild the 120 head.
Can any math experts calculate how much of a compression difference
that thick of a gasket would make? Not positive of the compressed
thickness, but I would guess at least .050, I know it was over .045.
As a side note, I’m rebuilding a 1275cc for my 64 Austin
Countryman, and I have seen Cometec(sp?) head gaskets on ebay, they
start at twenty-some thousands, and go up to seventy something.

Bill Seibold–
Bill 120 OTS
New Philadelphia, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–

2

Bill,
Gosh, I feel rusty, but I did try to go through the numbers.
Assuming that your bore and stroke are stock, and that your compression ratio starts out at 8:1, and further assuming that your compressed gasket was 0.017" and is now 0.050", your new compression ratio will be 7.63:1
Somebody better check the numbers and keep me honest!
Roar— On Tue, 7/20/10, BS wseibold@roadrunner.com wrote:

From: BS wseibold@roadrunner.com
Subject: [xk] Update; shrunken timing chains
To: xk@jag-lovers.org
Date: Tuesday, July 20, 2010, 1:53 PM
Finally got back to the Xk120, had to
get away from it for a while
to calm down, plus a trip to Chicago area to visit daughter
and son-
in-law. Removed the head and measured the composite gasket,

measured from .075 to.080 at various spots, compared to
.017 for
the stock gasket. Then I put on an old 120 head that had
been
surfaced at least once, with the composite gasket and had
no
trouble hooking up the timing chains. Called the supplier
to find
out if they carry the composite in different thicknesses
only to
find out they have but one size(thickness). Not sure of my
next
step, will probably rebuild the 120 head.
Can any math experts calculate how much of a compression
difference
that thick of a gasket would make? Not positive of the
compressed
thickness, but I would guess at least .050, I know it was
over .045.
As a side note, I’m rebuilding a 1275cc for my 64 Austin
Countryman, and I have seen Cometec(sp?) head gaskets on
ebay, they
start at twenty-some thousands, and go up to seventy
something.

Bill Seibold

Bill 120 OTS
New Philadelphia, United States
–Posted using Jag-lovers JagFORUM
[forums.jag-lovers.org]–