High oil pressure question.....
 

I ran my engine for the first time since taking it out of storage today. It was about 50 degrees outside. Last year I put in new Livorsi guages, but never changed the oil pressure sending unit. Today, I had installed the new one before running.

At idle, cold oil, I was make about 55 psi oil pressure. Once the oil temp got to about 150-160 it came down to about 52 psi at idle. When revved up, i was going up to 70 psi. That seemed high to me. So I put the old sending unit back in. Idle was 42 psi, and when revved up it was going up to 60 psi. I'm not sure what to think of the pressures. I do have an oil thermostat on this engine, and it runs at 212 degrees.

Last year, when running 240+ oil temps, i was getting 50 wot, and 38 at idle.

Did something change on me here? Which sending unit sounds like it's correct.

I'm going to get a calibrated guage and hook it up, but am still concerned that the oil temps I am seeing this year are too high. Any thoughts..................

Install a manual gauge and see what it reads and go from there to determine the correct sending unit...

doesnt really seem that high to me. Cold mine runs 60+psi at idle. once warmed up it still runs 65-70psi at cruise speed and 40psi at idle.

It's worth checking it with a mechanical gauge, but those numbers seem fine to me...

think horses not zebras. when you parked the boat the op was fine. nothing changed that would affect that. on the other hand you changed the gage.

two electric gages are nothing but volt meters. each gage mfg calibrates their gage to their own sender.

so two things are true.

one... if you don't have the sensor that belongs w/ the gage you have bad readings.

two... if everything is ok and you change something and then something is wrong, 100 out of 100 times its the thing you screwed with that's the problem... ( in this case the gage package) not something else.

Tonight i put a calibrated pressure guage on it. I was reading about 52psi at idle with oil at approximately 150 degrees. If I gave it quick short bursts up to about 3500 rpm i could get as much as 65 psi.

With the sending unit installed and using dash guages, i was seeing about 54 at idle, and as high as 70 at the same 3500 rpms. I think the sending unit/dash guage is about 5 high. But if i can make 65psi at 3500, what the hell is it making at 5000??? I won't know for sure until i get it out on the water, but 65psi at 3500 seems overboard to me.......

But what do i know........

I installed some mechanical gauges in the engine room on my cousins boat. That way if we have any question on the senders for the electric gauges, we have the mechanicals as backup.

(I dropped the stbd gauge when I was installing it and screwed up the gauge. I replaced the gauge shortly after this pic)

http://i116.photobucket.com/albums/o...y/IMG_0194.jpg

5 psi diff between gauges is no big deal. Who says the calibrated mechanical gauge is correct? The pressure releif valve in the pump should limit your max pressure. What you see at 3500 shouldn't be much different than 5000

The mechanical guage is sent out yearly to get calibrated for the shop. It's possible it is off however. I'm not really too concerned about the 5 psi difference either. It is however, 10 psi different from my merc sending unit. Which just proves again, use the correct sending unit for the guage.