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MG MGB Technical - Unbelievable inlet port!

Just took the inlet manifold off for the first time to have a look. And see what was hiding in one of the inlet ports! A large bolt! No wonder I have been having trouble getting the engine to run correctly. It must make a difference. Is it normal that oil leaks out from the holes for the stud bolts - on two there is oil.
/Moss

Moss

Good grief! Is it just laying there? It looks like it's screwed into something. If so, done to block a hole in the casting?
JM Morris

Fortunately the bolt was just lying there doing nothing. I could just lift it out. Here is a pic of it.
/Moss

Moss

I'm amazed it didn't cause some interference with the valves.
Dave O'Neill2

Must have been just big enough to not get under the valve. From the looks of it, it rattled around in there.
Bruce Cunha

Meget maerkeligt - The burring/polishing of the screwthread is telling. I suggest it has been rubbing on the valve stem. On your second question, I am not familiar with the oil channel layout on the 1800 head - Peter Burgess will know it backwards - I suspect yours may have had some work done on it - I would want to know why.
Roger W

Regarding the oil leak, YES oil can leak out of the stud holes. They go right through to the head stud holes and there is oil in there. With mine I removed the studs and sealed them with loctite.
Another possible problem, that I had, is when the manifold studs are replaced with threaded rod. If not careful, the rod can act as a grub screw on the head studs, making the removal of the head difficult.

Herb
Herb Adler

A lot of people have mistakenly replace stripped studs with bolts. This usually results in the head thread being stripped and having to be helicoiled. If studs are used as originally then when they are tighten into the head it stops the oil coming out of the threads.
Garth
J G Bagnall

I have had no leak of oil from the stud/bolt holes. Oil dripped out of the two for a short while I loosened them and took them out.
Moss

looks like the size of setscrew/bolt one would use to retain the backplates/stubstacks for the carbs.

Peter
Peter Burgess Tuning

That would be a reasonable explanation on how it may have gotten there. Taking off the air cleaner and somehow dropping in one of the back bolts through the front of the carb.
Bruce Cunha

Having now put back the inlet manifold and re-tuned carbs at idle, checked the timing with strobe and sorted out the after market Weber (32/36 dgva)accelerator cable connections etc there is a difference. The engine idles much better - i.e. evenly (according to my ears!) And dare I say it...the engine revs much better. There seems to be more power in the upper rev band from 3000 revs to 4000 revs.

Thanks for all the comments -
/Moss
Moss

Oil from the stud holes - yes fairly common - the holes go through to the pushrod passages which is why you get just a dribble of oil and not a leak as such.
Chris at Octarine Services

Hi Chris, thanks for input - I was quite concerned for a time...
/Moss
Moss

This thread was discussed between 08/06/2013 and 16/06/2013

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