"Mike Spera" wrote in message
...
Ever since getting the overhauled engine (Lycoming 0-320-E3D), I have high
oil pressure at full throttle for the runup and takeoff. I don't recall it
ever making it to the red line until the last year or so and I have put
800 hours on it. It was always just below the red line at the first (0
SMOH) full throttle runup of the day. Now, it has moved up one needle mark
to sit right on the red line at 100lbs or a wee bit to the left and not
quite on the line. Idle pressure is just inside the green (60lbs) and
cruise is right in the middle of the green arc - both normal for this
engine. The previous engine never went this high because it was pretty
worn when I bought it and got worse until we finally swapped it with an
overhauled unit.

I am also noticing a slightly higher oil temp lately. The former engine
and this one would be rock solid on 180 degrees until the outside temps
went higher than 85 or lower than 55. Now, anything over 70 degrees and
the temp is a needle mark or two higher than 180 degrees. Under 65 degrees
outside and the oil temp is just under the 180 mark.

Could these two things be related? They appear to have surfaced at the
same time. Clogged oil cooler? It IS 33 years old and has never been
cleaned out. A partially clogged cooler might explain why the idle and
cruise pressures are normal, but FT is a bit higher. It also would explain
the temps being a bit off in both directions. When the oil is hot, the
pressure will not go up to the red line. This would also suggest something
is restricting the oil when cold.

I believe the 2 oil controls (pressure and temp) are independent. The
Vernatherm and oil pressure relief valve are separate in this engine if I
recall. If true, the only thing common to both is the cooler.

Or, are these gauges inaccurate enough to account for this drift?

Any ideas?

Mike

I doubt that the problems are related. The vernatherm should preclude much,
if any, flow through the oil cooler until your engine's oil has warmed, so a
clogged oil cooler shouldn't have much impact on pressure until the engine
warms.

As far as the overall oil temperatures go, yours sound perfect. The
vernatherm tries to keep the temperature at 180F, so anything near that
number tells you that the vernatherm is doing its job, as is the rest of the
oil cooling system.

However, after 30+ years, it wouldn't be a surprise if your oil cooler was
underperforming due to clogged passages, etc. That might explain the slight
temperature increase you're seeing. Flushing it out could certainly help.
If you have a friendly A&P, you could do the work, and s/he could sign it
off for you.