Very true, I have noticed this myself.

Here is my theory. When the engine is warmed up, there is less internal
friction so when shut off the engine spins down more freely and tends to
stop at a point when none of the valve springs are deeply compressed. If
you shut off when cold, the internal friction is greater and stops the
engine at spots it would not tend to stop at if warm. Those spots are
when a valve spring is more compressed and then the spring tension
gradually forces oil out of the lifter for that valve.

There is no doubt that the engine tends to stop in certain spots most of
the time. Just look at the teeth on a flywheel after many years of use.
The starter motor will have made worn areas on the teeth, 2 worn zones
180 degrees apart, where the engine was stopped when you started it the
next time.

Mark

Ken Lewis wrote:
> Greetings all,
> I have noticed the lifters are most likely to clatter if the day before the
> truck was started from cold and only moved a few feet. Just a data point.
> Ken Lewis
> http://neksiwel.20m.com/
> in statu viae
>