Your question regarding checking compression on that TR6 you were interested in
buying got me thinking of some simple things to look for when checking checking
out a car to buy withouthaving to use test equipment, and I came up with just
a few:
1) Oil pressure is a good indicator of engine wear, but is only really useful
after the engine is well warmed up and driven at road speed for a period of
time, long enough to get to normal operating temperature. It should hold steady
psi at 2-3K RPM, and only drop by about 20 psi while idling. The minimum psi
for adequate oiling, I've been told by "experts", is about 5 psi per cylinder,
but this may be a little on the low side. The oil should be examined for
evidence of additives which would thicken the oil and add some pressure.
2) Try to turn the engine over by hand, using the fan (if direct coupled,
without torque converter) or putting it in 4th gear and pushing the car.
Admittedly not very scientific, but a good tight engine with full compression
will be quite hard to roll by hand. Make sure the ignition is off, and don't
get your hand anywhere where it could be taken off!
3) Check the clutch by revving the engine to about 3000 RPM and slowly
releasing the clutch while in 4th gear. The engine should stall.
4) Look for oil leaking from the rear seal, an indication of "blow by", caused
by worn rings.
5) Of course, look for smoke from the tail pipe: Black means rich mixture (no
problem), grey means worn rings or water in cylinders (big problem).
6) Some sellers will "warm up" a car with problems prior to showing it, so that
it will start easily. Feel the hood to make sure it's cold.
No expert here, just common sense things I've discovered over the years, and
there are probably a lot more items I've forgotten to mention. Good luck, and
welcome to the group!
Regards.
Richard
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