The place for technical discussions about GA and flying.
Forum rules: Technical discussions about GA only, please.
User avatar
By T67M
#1692847
Oil pressure relief valve could be stuck or simply need adjusting. Worth getting fixed, but probably not overly complex unless it's a symptom of something else - eg the valve is stuck due to metal in the oil.
#1692924
Some numbers and background info might help.

What pressure are you seeing now ?
What is 'normal' Oil pressure/temperature for that engine?
Engine type?
Has anything been done ( changed) recently?

Even an apparently insignificant a thing such as a like for like oil change will produce higher pressure on our IO-360 compared with oil that is about due for a change.
#1692946
Charliesixtysix wrote:Some numbers and background info might help.

What pressure are you seeing now ?
What is 'normal' Oil pressure/temperature for that engine?
Engine type?
Has anything been done ( changed) recently?

Even an apparently insignificant a thing such as a like for like oil change will produce higher pressure on our IO-360 compared with oil that is about due for a change.


a) pressure at the top of green/bottom of red at anything other than idle power (estimate 90 PSI)
temperature 190 ish

b) pressure normally sits 3/4 up the green (75PSI)
temp normally 190

c) Lycoming O-360
nothing changed
previous 2 legs behaved normally

just noticed the pressure slowly creeping up in the cruise at constant RPM (2450 rpm)

editted to correct gauge readings
#1693063
Temporarily plumbing a known good mechanical guage into a spare oil port would double check your cockpit readings (and might point to a faulty sender).


If you do find high pressure on test gauge first port of call for peace of mind for me would be to change the filter and cut the old one for inspection.
Assuming all OK, it would be worth looking at ( as perviously mentioned) at relief valve function.
Nick, mmcp42 liked this
#1695902
engine update:
took LX to engineers for them to do engineering stuff
they checked the oil, filter and scavenge pump(?)
all good

however they did notice that it was not easy to turn the prop by hand, especially when the engine was hot (after an engine run)

discussions with "engine man" suggest that the camshaft is to blame

engine now in tender care of "engine man" to see what he finds

:(
#1695915
Sorry to read that.

The engine is not that old is it?
#1706442
Latest news
Now happy to report LX is flying again
Apparently the problem was that one of the bearings in the crank case had moved round, blocking one of the oil ways
That’s why the pressure went up
Crank case and bearing had to be replaced
Slightly concerned that the oil pressure was again high when I first fired it up
But it soon settled down , as predicted by the engineers
No running in required as the cylinders and rings were untouched
Just run on straight oil for 25 hours then an oil change
So bunny[happy]!!!
Flyin'Dutch', flybymike, Boxkite and 2 others liked this
#1706800
mmcp42 wrote:Crank case and bearing had to be replaced


Under warranty? Sounds expensive. I would find it difficult to be a happy bunny after only a couple of hundred hours.

Still, there's certainly a lesson there for all of us. It was telling you something that could be too easily ignored if you weren't already familiar with its normal traits.
#1706898
Many thanks for completing the story, and an excellent lesson to us all not to just ignore something that isn't "quite right". In this case, whilst the repair won't have been cheap, doing the right thing probably saved you from a bigger bill in a few tens of flying hours more, and may have saved you from a catastrophic in-flight engine failure.
mmcp42 liked this