MGB intake manifold end cap leaking??

[max71]

Talked to Jeff Schlemmer, the dizzy man. He went on about a story where anything above a #5 needles means there a vac leak or associated problem. He mentioned classic problems with the end caps on the intake manifold leaking.

He said he feels all of them leak to some extent with age. I don't think mine were removed but best to try and eliminate everything. Jeff says to just fill it up completely with JB weld. Performance is more important than perfect originality but can't I just run a bead of something around them? He has a good point that these are dissimilar metals with different expansion rates. He feels they leak once they expand.

He made it sound as though this is a well-known issue. Have you guys heard of this?

[Steve Simmons]

On other cars, yes. Haven't personally seen it on an MGB though. Not saying it can't happen because I'm sure it can. I'm sure you can test it with some spray oil, or perhaps starter fluid. Or just put the JB weld on since it won't hurt anything.

[max71]

His experience was putting richer and richer needles on and going crazy trying to find why it was running lean at higher rpms. He said he sprayed around the ends, soaped it, etc and nothing. Until he sealed it with JB weld and then he dropped down to #5 needles because that was the problem.

I guess caking on JB weld isn't very attractive. I was hoping to run a bead of silicon although with expansion/contraction I don't know if that would be right.

[Steve Simmons]

That would probably work, but I'd rather have something harder and more durable than silicon if it was supposed to seal permanently. The only things I've seen used for repairing this problem are new plugs, and JB weld. But again, not on MGBs.

[Jimmy]

It seems to me that if there is an expansion/contraction problem already, silicone would be superior to JB Weld.
But it would be tougher to make silicone look good, since JB Weld can be sanded, machined, etc.