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May 31, 2018 11:09 pm
May 31, 2018 11:09 pm
Subject: Exhaust Manifold Gasket
This engine never fails to surprise. Some time ago, for no very good reason, I gave the manifold new Club gaskets plus new Club brass nuts. I did the usual things that have always worked: cleaned surfaces, checked for warping, pulled up the gasket with plain washers under the nuts. And tightened again after the first thermal cycle.
On the recent Fougeres, I sprang a gasket leak unlike any other I've known - so noisy I at first thought the little ends had gone. No gas could be felt around the manifold. Tightening the nuts cured matters for a few tens of km but then the cycle would repeat. Eventually, I contrived to strip a couple of the brass nuts but replacing these with steel ones got me home reasonably quietly.
Opening up, the gasket is intact - no splits or cracks. Is there any particular technique for the 2 Litre that I should know about? Spring washers over the plain ones have been suggested but the efficacy of spring washers seems to be in doubt these days. I would really welcome any guidance on the sequence for tightening the nuts and the permissible torque. I've never used "goo' on exhaust manifolds but one of the Loctite products has been suggested though its upper temperature limit is only 350 celsius which I would have guessed would be inadequate.
I really never thought an exhaust manifold joint would present problems. Only on a 2 Litre...
John
This engine never fails to surprise. Some time ago, for no very good reason, I gave the manifold new Club gaskets plus new Club brass nuts. I did the usual things that have always worked: cleaned surfaces, checked for warping, pulled up the gasket with plain washers under the nuts. And tightened again after the first thermal cycle.
On the recent Fougeres, I sprang a gasket leak unlike any other I've known - so noisy I at first thought the little ends had gone. No gas could be felt around the manifold. Tightening the nuts cured matters for a few tens of km but then the cycle would repeat. Eventually, I contrived to strip a couple of the brass nuts but replacing these with steel ones got me home reasonably quietly.
Opening up, the gasket is intact - no splits or cracks. Is there any particular technique for the 2 Litre that I should know about? Spring washers over the plain ones have been suggested but the efficacy of spring washers seems to be in doubt these days. I would really welcome any guidance on the sequence for tightening the nuts and the permissible torque. I've never used "goo' on exhaust manifolds but one of the Loctite products has been suggested though its upper temperature limit is only 350 celsius which I would have guessed would be inadequate.
I really never thought an exhaust manifold joint would present problems. Only on a 2 Litre...
John