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A few months ago there was a debate on best head gasket sealant— locktite 5920 RTV Copper Silicone gasket maker was recommended by several people. I made a note of this, knowing that a gasket change was due on my 1937 Opal. So I got a tube of the aforementioned and yesterday happily did the job.
My slight reservation is the note on the packaging which says, “ not recommended for use on head gaskets or parts continuously immersed in gasoline “
I’ve use it sparingly and spread a thin coat over the C&A gasket and torqued the head down at a bit under 20lbs — the instructions say re torquing is unnecessary.
I suppose what I’m looking for is some reassurance that I’ve used the right stuff!
Charles
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Location: Darkest Bedfordshire
I won't comment on the sealant Charles because I don't use it; but I would say re-torquing the head nuts - cold - after initial running is at least advisable. It's hardly much effort.
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Location: On a hill in Wiltshire
I have used it, tightening down 3 or 4 times after fitting.
I has allowed me to successfully re-use head gaskets.
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Location: Herefordshire
I've never sealed a head gasket - I just put a very light smear of general purpose grease on both sides before fitting. I do check the tightness of the cylinder head nuts after the first run, but I have to admit that I've never used a torque wrench anywhere on an A7!
Joined: Aug 2017 Posts: 848 Threads: 22
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Location: Near Cambridge, UK
Car type: 1928 tourer (mag type), short chassis Gould Ulster
I would suggest that the comment about re-torquing being unneccessary is in relation to the gasket materials used on modern cars. I have found it desirable when using A7 gaskets, especially the modern non-abestos ones.
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Many thanks for your quick responses — very useful to know that it’s a good idea to tweak up the nuts after a few miles.
Re torque wrench — I’ve never bothered with one of these over sixty odd years of tinkering with Austin Sevens, always believing that if you use small spanners you can’t go far wrong. Though this is undoubtedly true it’s nice to know that all the head nuts or big end bolts etc are at the same ( and recommended) weight.
Just need a glimmer of sunshine now to get a few more miles on the clock.
Charles
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Location: Cheshire
Car type: Race Ulster, 1926 Special, 1927 Chummy, 1930 Box
I’ve used loctite 5920 for years. It’s in lots of engines I built. Strictly, with good parts it shouldn’t be needed but if you were going to grease the gasket why would you not use 5920 instead? Come to that why would you not use a torque wrench? Unless you don’t have one, that is.
Alan Fairless
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Charles
I use Copper silicone and 19 ft lb with a torque wrench. Recommended to me by Steve Jones.
I recheck the tightness next day.
With this simple method I have had no issues (touch wood).
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Many thanks Nick and Alan — it’s so nice to be back on the forum after all those logging in problems!
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i've just taken a 5920'd gasket off to diagnose other problems. Worth emphasising that you have to be careful not to use too much - I had two partially blocked minor water channels. With clean surfaces there isn't a great deal of space for it to compress into other than 'out'.
