On Sun, 28 Oct 2007 13:10:50 -0700, hookipa
wrote:

Thanks to all for the suggestions. I pulled the oil cooler and the
oil pressure valves this weekend and all looks good. The Oil cooler
tubes are almost scary clean. I did change the oil, but the only oil
I can get here is a 15w-40 for diesels from BP. Believe it or not,
that or a 20w-50 is all that I can get here. I am getting about 10-15
psi at idle and about 50 psi at max speed. My manual says that I have
seperate senders for the warning light and the gauge. The time the
pressure really dropped off and the light came on was right after
pushing the engine hard for a while (on plane). After I change the
oil and checked the cooler and such, I cruised around for an hour or
so and the pressure never went below 15 psi.

The viscosity numbers mean that when the oil is cold it will flow as
well as 15 weight and when hot won't be any thinner then 50 weight. I
would doubt that is your problem.

You mention that "the pressure dropped off and the light came on"
which implies that both the gage and warning light circuits are
working correctly.

When you say that the oil cooler tubes are "almost scary clean" what
does that mean? The oil side should be full of nasty old engine oil,
it is, isn't it?

You say that you checked the oil pressure valves - plural? If you can
get at the oil pressure relief valve try sticking a washer behind the
spring and see whether that raises either the idle or full throttle
pressure. If it does then either the pump is worn or the spring in the
pressure relief valve is getting weak.


Bruce-in-Bangkok
(Note:displayed e-mail
address is a spam trap)

The viscosity numbers mean that when the oil is cold it will flow as
well as 15 weight and when hot won't be any thinner then 50 weight. I
would doubt that is your problem.

You mention that "the pressure dropped off and the light came on"
which implies that both the gage and warning light circuits are
working correctly.

When you say that the oil cooler tubes are "almost scary clean" what
does that mean? The oil side should be full of nasty old engine oil,
it is, isn't it?

You say that you checked the oil pressure valves - plural? If you can
get at the oil pressure relief valve try sticking a washer behind the
spring and see whether that raises either the idle or full throttle
pressure. If it does then either the pump is worn or the spring in the
pressure relief valve is getting weak.

I am with you on the gauge and warning lights being correct. There is
actually seperate senders for both. I was looking to get a mechanical
gauge sent out here, but I am in no rush to do that right now.

I must admit that I never looked at the oil side of the cooler (stupid
move). I was focused on the water side as a friend had 50% of his
tubes clogged. I guess I hoped my cooler looked like his, so I
blanked out on looking at the oil side when I sas it was so clean.
Now if the oil side was gummed up wouldn't my pressure be higher? Or,
would the cooler just get bypassed and overheat the oil?

There are two pressure relief circuits for this engine according to
the manual, one is for piston cooling oil and the other for engine
cooling oil.

If the washer raises the oil pressure, should I leave it there until I
can get parts? Or, do I need the parts right away if the pressure is
acceptable?

Kurt

On Mon, 29 Oct 2007 01:35:46 -0700, hookipa
wrote:

The viscosity numbers mean that when the oil is cold it will flow as
well as 15 weight and when hot won't be any thinner then 50 weight. I
would doubt that is your problem.

You mention that "the pressure dropped off and the light came on"
which implies that both the gage and warning light circuits are
working correctly.

When you say that the oil cooler tubes are "almost scary clean" what
does that mean? The oil side should be full of nasty old engine oil,
it is, isn't it?

You say that you checked the oil pressure valves - plural? If you can
get at the oil pressure relief valve try sticking a washer behind the
spring and see whether that raises either the idle or full throttle
pressure. If it does then either the pump is worn or the spring in the
pressure relief valve is getting weak.

I am with you on the gauge and warning lights being correct. There is
actually seperate senders for both. I was looking to get a mechanical
gauge sent out here, but I am in no rush to do that right now.

I must admit that I never looked at the oil side of the cooler (stupid
move). I was focused on the water side as a friend had 50% of his
tubes clogged. I guess I hoped my cooler looked like his, so I
blanked out on looking at the oil side when I sas it was so clean.
Now if the oil side was gummed up wouldn't my pressure be higher? Or,
would the cooler just get bypassed and overheat the oil?

There are two pressure relief circuits for this engine according to
the manual, one is for piston cooling oil and the other for engine
cooling oil.

If the washer raises the oil pressure, should I leave it there until I
can get parts? Or, do I need the parts right away if the pressure is
acceptable?

Kurt
Probably if the oil side was gunked up the pressure would be higher as
the oil cooler is usually between the pump and the engine.

Frankly, the engine will probably not blow up just because the oil
pressure is a bit low. I think someone said that idle oil pressure was
about 20 psi and you have nearly that.

I have no experience with your engine but usually there is a single
pressure relief valve located at the pump outlet, but if you have two,
and they are accessible I'd put a washer behind the spring on both and
see what happens. If the pressure is in the ballpark and oil
consumption does not go up then I'd leave it alone - at least for now.


Bruce-in-Bangkok
(Note:displayed e-mail
address is a spam trap)

Bruce in Bangkok wrote:


I have no experience with your engine but usually there is a single
pressure relief valve located at the pump outlet, but if you have two,
and they are accessible I'd put a washer behind the spring on both and
see what happens.

He says his motor develops something like 50PSI at higher rpms, so it
doesn't sound like the pressure relief valve(s). Maybe the pump is
worn, perhaps the main bearings are going, perhaps the ambient
temperatures are higher than he's used to and that's thinning the oil
some,,, maybe a bit of all of the above?



If the pressure is in the ballpark and oil
consumption does not go up then I'd leave it alone - at least for now.


Fair enough.

Cheers
Marty
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Thanks for all the replies. I am believing that it all comes down to
an old worn engine. The manual I found states 31-42 psi at idle, so
at 15 psi I am pretty low. 59-71 psi at speed. Not quite as low
there. I am hoping to be able to get at the oil pump with out pulling
the motor. Now, if the rain would just stop I could get to work.
cheers all,
Kurt