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Head nut torque with solid copper gasket
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peter scott



Joined: 18 Dec 2007
Posts: 6177
Location: Edinburgh

PostPosted: Thu Oct 02, 2008 8:01 pm    Post subject: Reply with quote

Hi Glenn,

As has been said already, the 45lb-ft torque will have been specified for the studs and their anchorage in the block. Clearly there will be some factor of safety in the 45lb-ft figure but I'd be surprised if this took you higher than 60lb-ft. and if the failure mechanism is the block giving way then increasing the torque may be counter-productive as it will start to raise the areas around the studs like a meniscus thus reducing head contact elsewhere.

Peter
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Glenn Crawford



Joined: 06 Dec 2007
Posts: 68
Location: Dorset, SW England

PostPosted: Tue Oct 07, 2008 8:40 am    Post subject: Reply with quote

I get the message! I'll use the original 45 lb.ft torque figure when I refit the head, regardless of whether a copper-asbestos or solid copper gasket is used. At present the head is away for inspection and the solid gasket, if re-used, will be freshly annealed.

By the way, to answer an earlier post, it was not just a plain sheet of copper, it had a reinforced ring around each cylinder seemingly achieved by "crimping" the copper sheet as part of the manufacturing process - Glenn
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peter scott



Joined: 18 Dec 2007
Posts: 6177
Location: Edinburgh

PostPosted: Tue Oct 07, 2008 9:09 am    Post subject: Reply with quote

Glenn Crawford wrote:
it had a reinforced ring around each cylinder seemingly achieved by "crimping" the copper sheet as part of the manufacturing process - Glenn


I believe what you are describing is a Corrujoint gasket. Quoting from the manufacturer's Service Manual for my car, that also uses such a gasket, "Always use a new cylinder head joint" "Jointing compound should be used sparingly round the water passages only."

My understanding has always been that these gaskets are NOT re-usable.

Peter
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Jim Walker



Joined: 01 Oct 2008
Posts: 124
Location: Chesterfield, Derbys.

PostPosted: Wed Oct 08, 2008 5:07 pm    Post subject: Reply with quote

You are right Peter. I did not consider crimped gaskets when I said copper gaskets could be re-used.

My apologies.

Jim Walker.
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Glenn Crawford



Joined: 06 Dec 2007
Posts: 68
Location: Dorset, SW England

PostPosted: Sat Oct 25, 2008 7:07 pm    Post subject: Reply with quote

Having just reassembled the engine I thought I ought to round off this thread nicely by reporting back.

In fact I was more or less an observer, the specialist in Riley Nine engines who has carried out a lot of work on this one in recent years came to my workshop to give it his personal attention. He used a new, freshly annealed solid-copper gasket made by a tuning firm, with a smear of Wellseal assembly compound on both sides. The gasket makers also provided four thin copper rings (just individual strands of 0.2mm car electrical wire soldered into a ring) to place around each bore to give some localised extra "bite".

The surface of the head had been checked and was "true", and the head was torqued to 45 lb.ft, just as if it were a conventional gasket (the head studs are 3/8in).

I've been for a preliminary test run and - fingers crossed - the problem of head gasket seepage seems to have stopped. Is it fixed permanently? Ask me again when the owner has had a chance to cover 500 miles!

Thanks to all for your helpful comments and advice during this mini-saga, and I'm really sorry "Uncle Joe" took umbridge at the fact that I receive payment for fixing other peoples' cars - hopefully he'll come back in from the cold one day.
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Glenn Crawford



Joined: 06 Dec 2007
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Location: Dorset, SW England

PostPosted: Thu Nov 06, 2008 11:35 pm    Post subject: Reply with quote

Oh yes, and the owner came and collected the car and drove it home, 135 miles from west Dorset to Teddington in 3 hours on the road and without a hitch.
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peter scott



Joined: 18 Dec 2007
Posts: 6177
Location: Edinburgh

PostPosted: Fri Nov 07, 2008 12:47 am    Post subject: Reply with quote

The copper wire rings are an interesting approach. I'm glad it worked out well. Thanks for the update.

Peter
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