James Crabb wrote:
>Hi everyone,
>I found a crack in my exhaust manifold.
>I am going to install a new one, but I would like to ask for any tips hints
>or problems I may encounter .
>
You may find that the exhaust manifold is NLA. You don't write which MGB
you have, but if you have the twin SU carb setup: I've been there, too!
Fortunately a good professional welder can repair this
(depending upon the condition, of course),
but he definitely needs a lot of skill (and/or luck).
He will need special cast-iron welding rods for this job.
Shouldn't take him more than one hour or so including preparation / fixing up.
Check that the threaded holes for the studs are still OK.
Note:
If I remember correctly (without checking), the studs are 5/16"UNC at the
manifold end
and 5/16"UNF at the downpipe end.
Don't confuse them with the (both ends 5/16"UNF) studs that fix the manifold
to the head.
In case the threads in the manifold are damaged, you can cut 3/8" UNC into them.
Special oversize studs (3/8"UNC + 5/16" UNF) (off the shelf and cheap) are
available from M&G Int'l / Moss et al. for this purpose.
The exhaust downpipe should be fixed with rather special,
1/2" high brass nuts (otherwise rust will weld stud and nut solid together).
Hope this has been of interest to you.
Bert Palte
70 MGB
Hey look! The sun is shining on this Eastern day! Let's burn some rubber!
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