Re-torquing of a cast-iron head should be done when it is hot.
Re-torquing of an aluminum head should be done when it is cold.
In my experienced (and not-so-humble) opinion, valves should always be
adjusted when they are hot. After all, they do their work when they are hot
and that's when the clearance is critical. Who cares what the clearances are
when the engine is cold and at a standstill? And, yes, I know a lot of shop
manuals state that clearances should be set when the engine is cold, but
they were written when all the valve train components were new and
co-efficients of expansion throughout the valvetrain could be relied upon to
be fairly uniform. We are mostly dealing with old, worn engines where some
things may expand at different rates than others. So, if the book gives a
"Cold" valve clearance, just subtract 2 thousandths from it and set the
clearances when the engine is at running temperature.
Lawrie
British Sportscar Center
-----Original Message-----
From: frank krajewski <frankk@intap.net>
To: MG List <mgs@autox.team.net>
Date: Tuesday, August 17, 1999 7:25 PM
Subject: Re-Torquing
>Just replaced a head gasket, pistons, rings, etc., on my MGBLE. I have
>drived the car enough to warrant re-torquing the head and resetting the
>valves. Question: Is the re-torquing and valve adjustment better done
>with the engine warm or cold? I have heard both ways from numerous
>sources. Does anyone have the definitive answer?
>Frank "Swamp Yankee" Krajewski
>
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