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MG MGB GT V8 Factory Originals Technical - V8 leak!!

I am rebuilding my B V8 and had a water leak at the top corner where the cylinder head meets the inlet manifold, around where the triangular end of the rubber seal is.
I assumed I installed the gasket or seal wrong so have removed the inlet manifold and refitted with new seals and gasket.
I was very carefull when torqueing down but it is weeping again.
The first gasket was a composite one the second metal.
Any suggestions where I might have gone wrong?
Can I throw a can of Rad Weld in and hope the leak stops!!!
Any help would be appreciated.
Regards
Dave Tetlow
D M Tetlow

Dave,
You won't find a better gasket than the late Rover neoprene coated steel one which seals the lifter valley. If this is what you first used then go get an new one and also a tube of "Right Stuff" sealant (Permatex brand IIRC) preferably in the caulking tube dispenser and use that to seal the mating surfaces and your problems will be solved. If not, you have larger issues.

Jim
Jim Blackwood

I use Ultra grey silicon sealant. A very thin smear on both surfaces. Nothing wrong with other sealants, its just that ultra grey is the same colour as the alloy, so looks good(which doesn't hurt). I used it everywhere and have never had a leak. Silicon can get a bad rep' from people who think if a little is good more is better. Very thin smear only
Peter

According to the instructions that came with a FelPro valley pan gasket, a small dab of RTV should be applied to each end of the Neoprene end seals and a small bead around the water outlet holes.

It is important to tighten the bolts in a criss cross pattern, in 2 or 3 stages.

Following these instructions, I have never had a leak at the intake, regardless of the make of the valley pan gasket.

Myfist choice is the Rover composite gasket, second is the FelPro metal gasket.
Jim Stuart

Thanks Gents.
When I torqued it down I tried to follow the Haynes instructions which meant I did one side at a time.
The criss cross idea as per cylinder heads sounds much better though.
I have just ordered a new composite gasket, but when ordering I was given a choice of rubber end seals, 1 to suit the metal gasket and 1 to suit the composite one.
One thing I did not do is to use seal compound on the bolts. I actually did mean to, but forgot. I am not sure if this would make any difference as all the holes seem to be blind.
The water system is still pressurised 10 mins after turning off and the leak stops when the engine stops. It may be that I have the head gasket leaking from this corner! I am not sure if there is a water way
Regards
Dave
D M Tetlow

Nothing wrong with silicone, but the "right stuff" sealant was developed for OEM use and is a much better sealant than silicone, adheres much better, is tougher, and is not affected by oil or coolant and only minimally affected by fuel so it gives better performance than silicone. It also tacks off more quickly and is normally able to be put back into service immediately. It also works extremely well as a thread sealant, and for me it has completely supplanted teflon tape for that purpose. If you use too much and it squishes out it does not normally glob off and fall into the pan so it is safer than silicone. Use of this sealant has allowed me to begin building leak free engines, something I found elusive before despite using the greatest care in straightening and matching mating surfaces. I give it my highest possible recommendation, despite the cost. In the caulking tube however, it does go a long way. It is only necessary after use to squirt out a short plug, and next time pull that out of the end of the nozzle and go on. It also makes a really good, flexible waterproof glue and is a good substitute for two sided tape. Works extremely well for gluing spot mirrors onto the outsite rear view mirror for instance and doesn't let go as the two sided foam tape does. Very useful, versatile stuff, in terms of performance it reminds me a lot of the two part aircraft adhesive we used in the USAF for sticking antennas onto military airplanes.

My first guess would be that your torquing sequence has caused the problem. As for the leak stopping when you turn off the engine, it's possible that pump pressure added to static pressure is making the difference. Before doing anything else you might try just re-torquing the intake, working from the center outwards and side to side as Jim Stuart recommended. Then the neoprene gasket if that does not work. If you still have the one you tried first, it was a new one and it is not damaged it should be reusable.

Jim
Jim Blackwood

Jim,
I have ordered some "right stuff". It sounds like you use it as a general surface prep for gaskets as well as for sealing the valley pan seals and as a thread sealer, is that correct?
Any recommendations/suggestions? Will it also be good for sealing the timing cover, water pump and oil pan on a 94/4.2L as it appears there is no oil pan gasket for that engine?
Regards
Tony
Tony Bates

I have ordered some "right stuff" too.
All I could get here in the UK was Permatex Ultra Copper Max Temp Gasket Maker.
This seem to be similar to Jim's recomendation.
I will let you know how it works.
Regards
Dave
D M Tetlow

Tony,
I no longer use pan, valve cover, timing cover, or water pump gaskets unless either the spacing is critical or I want it to be easily removable. Which this stuff isn't, and in fact the one caution is that removal of pans and tin valve covers will be difficult, may require some bending of the flanges and some re-straightening before reuse. I've used it on just about everything except head gaskets and there aren't many jobs it doesn't excell at. As you get used to using it you'll see what I mean.

Dave, that Ultra Copper is silicone with powdered copper added to it. Better than plain silicone but with the same limitations for the most part. It's a little better at handling heat. If you check with your supplier he may be able to order the "Right Stuff (TM)" sealant from Permatex. It should be in his catalog.
Jim Blackwood

This thread was discussed between 20/08/2006 and 24/08/2006

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