On Sat, 4 Jul 1998, Dave Houser wrote:
> Has anyone tried to use the MGA/MGB round steel gaskets that fit between
> the bottom of the exhaust manifold and the exhaust pipe on a TD? I must
> have replaced the triangular gasket about 8-10 times over the years!
> Keeps blowing out in relatively short periods of time. Yes, both
> surfaces seem flat. I just thought that having a round gasket like that
> might help keep the gases contained and directed through the exhaust
> system. Any other thoughts?
Even if the flange surfaces are perfectly flat you'll still have gasket
failure if they don't align correctly with each other. That's difficult
to accomplish when the exhaust manifold is clamped firmly to the engine
and the lower end of the header pipe is clamped firmly to the chassis and
the rest of the exhaust system. Have you tried loosening up the lower end
of the header pipe to provide some give? Often that will let the flanges
pull up tightly against each other.
I'm not familiar with the MGA/B setup, but some older MG models use a
round ring with the outer diameter machined into a shallow double cone
which forces into similarly machined countersinks in the manifold and
headfer pipe flanges. This works pretty well when new, but once the
assembly rusts (and it WILL rust) it can be hard to get apart. Also, once
the countersinks in the flanges become rust-pitted, it can be difficult to
get a good seal. Ideally the ring should be machined from stainless steel
to avoid some of these problems.
I prefer a standard flange gasket, with the flanges bolted together before
the rest of the exhaust system is secured. Actually what I really prefer
is a Derrington-style tubular header that does away with the separate
header pipe, but that comes with its own peculiar set of installation
problems.
-----------------------------------------------------------------------
Chip Old 1948 M.G. TC TC6710 NEMGTR #2271
Cub Hill, Maryland 1962 Triumph TR4 CT3154LO
fold@bcpl.net
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