On Fri, 18 Nov 1994, Lewis Dunbar Dove wrote:
> Scotty,
> IMHO, your low compression readings show that the rings have
> not seated properly. I have always heard that you check compression
> Anyone else want to jump in on this? I don't want to be held
> responsible for a siezed engine! The usual disclaimers ---
> Lew (what the hell do I know?) Dove
I don't think your suggestion that straight 30 weight be substituted for
multiviscosity oil for 1000 miles will result in engine damage, but I have
doubts about its helping much. The rebuild was 3 years ago; if the rings
have not seated I doubt that they are going to. If that is the problem,
the cylinders may have been honed incorrectly. Or possibly rings were
broken upon installation or shortly after startup (cylinder ridge not
relieved properly, ring grooves stepped or not clean, or something of that
sort).
However, I believe in exploring the cheap possibilities thoroughly before
assuming the worst and tearing everything apart. Given the uniformly low
readings on a recently rebuilt engine, the very first thing I would do is
recheck everything with a compression tester that is known to be good,
following procedures from a handbook for the specific car. I know a quick
check of the tester was made, but it would be a prime disaster to redo
everything because of a bad tester or inappropriate technique.
For example, air has to get into the engine to get an accurate reading.
On a car with SU or Stromberg carbs is it sufficient to open the throttle,
or must one also block the pistons in the up position? Which did you do,
Scotty?
(For many years, I've prospered with the philosophy that serious problems
are more often electrical than due to fuel delivery, and I've considered
Carburetor to be a French word meaning "don't touch me." But maybe I will
have to rethink that now that I have a car with SU carbs. Clearly it is
nice to know how they work.)
Ray Gibbons
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