A couple of points, Skye...... any difference between valve clearance
setting procedures would not have anything to do with whether a car has
rubber bumpers or chrome bumpers. The different year engines might have
different valve clearances specified but that's about it.
As for setting clearances hot or cold (or warm, as Bentley apparently puts
it), this is a subject I feel strongly about. When an engine is running, it
is usually hot. Even if the original manufacturer specified a cold valve
clearance (as Triumph did), that pre-supposed a new-ish engine with
relatively unworn parts that would expand with heat at a uniform rate. Since
most of our engines are a number of years old now, internal parts have worn
to varying degrees, depending on when they were last replaced, how well they
have been maintained, etc. I believe this means that parts will not expand
as uniformly as the manufacturers originally expected. Consequently, valve
clearances should be set while the engine is hot, as it is important for
efficient combustion (and proper cooling of the valve head) that the valves
open and close at the correct times. A few thousandths difference in
clearance makes a noticeable difference in the time a valve is off its seat.
Experience has shown that a hot engine closes the valve clearances about 1
thousandth so I set Triumph valves (and any others where the factory
specified a "cold" clearance) one thousandth closer than the specified
number. In my mind, this results in their working at the correct clearance
when the engine is running.
Lawrie
British Sportscar Center
----- Original Message -----
From: "Skye Poier" <skye@ffwd.cx>
To: "MG Nuts" <mgs@autox.team.net>
Sent: Wednesday, March 20, 2002 9:24 AM
Subject: Re: Bad clacking in the B...help?
> Interesting.. I've never heard that before but on the other hand, the
> Bentley manual is pretty much authoratative and my knowlege of
> rubber-bumper cars is limited. It would seem to imply that they are
> adjusted when warm.
>
> My bad!
>
> Skye
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