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MG MGB Technical - Manifold crack ' 79 B

Well it finally happened.....My manifold cracked on my '79B has anyone had luck getting one welded?
Anyone know a good welder in SOCAL? I don't want to pay $450 for a new one I would just go to a weber
instead
Thanks Pat
patrick bailey

Pat-
In theory cast iron can be welded, but in practice it's just not worth it, esspecially in an object that has to undergo repeated expansion and contraction from heat. Actually, consider it to be a blessing in disguise. That one-piece intake & exhaust manifold is just about the worst design in existance when it comes to permitting decent breathing for the engine. Now you can mount a worthwhile intake and exhaust system. I'd suggest stock exhaust and intake manifolds with a set of SUs.
Steve S.

Patrick,
Keep an eye out for a good used one they do come up every now and then. Steve I would agree that the later setup is not near as good as the early SU types, but given the Draconion emmission laws in California Patrick has no choice if the car is to be road legal. One of the main reasons my youngest MG is a 70 and not subject to SMOG laws (so far.)

Saftey Fast

Ron
Ron Smith

Barry Kindig posts here frequently -- he had a pic
somewhere of his custom intake manifold with the
standard Zenith Stromberg. This will give you
better performance than the one-piece manifold.
Barry?

Also, on the midget BBS, someone passed Calif. smog
using a single SU carb instead of a Zenith.
Apparently, the computer tells the tech to look
for a single 1.5" (Midget) sidedraft carburetor, but without
any information about the type of manifold, or
carb manufacturer.

Hence, a downdraft weber or twin SUs wouldn't pass,
but I bet a single 1.75" SU with custom manifold would.
Ronald

Patrick. Where did it crack? I recently examined four and all of them were cracked in the area just above where the cat hooks on. The inner corner of that sharp downwards and backwards bend showed cracking on the inside radius. Thus, cutting off the intake portion of the manifold and having a custom one fabricated would not solve your problem. You might be able to get away with a custom intake manifold, of which Barry spoke very highly, and a set of headers if you use an aftermarket cat in the system. But, before investing any real money in anything, I would check with the emissions people in your state to see what they will allow. Here in Arizona, a small measure of common sense is allowed and I have not been dinged for a Weber conversion on either RB car. Les
Les Bengtson

The Morris Marina (Austin Marina in USA) had a single SU on the 1800 engine (as well as twins) as did the Sherpa van. You might find a manifold in the US or we could find you one over here.

The Midget would have used something like a Mini manifold if it was an A series engine or a Triumph manifold if it was a 1500 Triumh engine.
Chris Betson

You might try contacting Dennis for a diagnosis at:

Kelly's Block Welding
12910 W. Washington Blvd.
West Los Angeles, CA 90066
310.827.6795

They have years (decades) of experience doing this sort of thing, including many BMC cars, and they
are familiar with the cracking problems with the late MGB manifold. Knowing Dennis, he'll probably
talk you out of welding/repairing the manifold and direct you to opt for another manifold design
altogether.
Daniel Wong

If the old manifold off my 1980 LE Stromberg single spec is of any help, you are welcome to it free of charge, subject to paying the shipping charge from England to the States, at cost. If interested will check, otherwise anyone else interested in it.

I'm planning on trashing it in the not too distant future because in England we can still get away w/ converting to twin SU's, so no one over here is remotely interested in it, even for free.

The carb is in Australia, he paid the shipping charge.
Mark Smith

Thanks for all your advice and i thank George Champion in Ariz who has offered a manifold for shipping only!This BBS is great
Pat
patrick bailey

This thread was discussed between 06/01/2002 and 07/01/2002

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