Enough people have asked me about this off-list that perhaps I should share
it with everyone.
First, let me point out that I did this as a solution to a specific problem.
I do NOT recommend it be done to all engines. Nor is it the best solution
to the specific problem, it's just the one I chose (mostly because it was
quick, easy and cheap) at the time.
The specific problem was a TR3 motor that always leaked compression, in
spite of numerous attempts to fix it (including different gaskets, different
gasket treatments, different liners, head milled, new fig 8 gaskets, etc.)
That problem was eventually traced to the liners not sitting evenly proud of
the block, and being too low on one side (which of course was the side I
didn't check the first few times). Appears to be a manufacturing defect in
the block (?) since the problem is on all cylinders and the liner seats
don't appear to be badly corroded or have been recut. The block was from a
56 TR3 I bought for it's overdrive, and didn't appear to have a great many
miles on it. Perhaps this is why.
I got the wire idea from Ken Gillanders at British Frame and Engine, who
said the racers sometimes do something similar when they can't keep the head
sealed. Of course they are generally using modified solid metal gaskets
while I had to use (for other reasons) a stock (TR4) composite gasket. The
wire ring may also be written up in the Competition Preparation manuals, but
I don't have one handy to check.
I used 26 AWG bare copper wire from McMaster Carr. ISTR Ken saying "half
hard" but I don't recall what MMC called it. The roll is still out in the
garage, I might be able to find a part number if you want. I prepped the
gasket first, by cleaning with a Scotchbrite pad where I was going to solder
to it, and then painting it with flux. Then I used rosin core eutectic
(63/47)
electrical solder and a Weller soldering gun (just what I had handy,
probably makes no difference at all) to tack the wire in place around each
cylinder, right next to the crimp in the original gasket. Didn't run a
continuous bead, just tacked it often enough to hold it in place securely.
The ends were overlapped slightly, and buried in solder together. Remainder
of the installation was as normal, no 'magic' chemicals or anything.
The result has worked fine for quite a few years now, I've even reused that
head gasket twice and it still doesn't leak. I really hadn't planned it as
a long-term solution ... long term solution was to rebuild a different block
... but I still haven't done that (yet) and the copper ring has worked out
perfectly.
Ken later suggested super glue instead of solder to hold the ring in place
on the gasket, but I've never tried that.
I've also read of a similar trick used on supercharged motors, where they
machine a small groove into the head around each cylinder and pack the wire
into the groove. I think my mod has the same effect, but saves getting the
head machined.
YMMV of course.
Randall
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