oil pressure

[Joshua Nichols]

Well I finally got my high end miss under control.. Turns out to be dirty carb.. It's harder to remove from the engine than it is to rebuild.. Anyhow so since the engine was running so good. The gal and I went WOT more than normal(this 17ft will fly with the 4.3).. Engine ran perfect temp all day.. Pulled in to go get something to eat.. Coasted into into docking area.. Low and behold.. Low oil pressure. Can't give a exact number cause the gauge only has 30, 40, 60, 80psi on it.. now down past 30psi.. It has the red area.. Thats where I am at idle, after hard running.. I came back from getting a bite to eat.. Maybe 30min or so.. The weather was getting spooky and have learned that lesson last week.. I went and got the boat out of the water.. Fired it up.. Oil pressure 30psi @idle. Now temp is down. Id say 130ish.. Is this a major concern? When I bought this boat, the previous owner just did a fresh oil change(he didn't say he did).. There was black oil in the bilge and this engine hardly leaks a drop.. Plus the shiny new oil filter.. Maybe he was hiding something?. Oil is nice and clean.. Engine makes no noise. Runs smooth as silk.. Should I do my own oil change and go up in oil wt? What you fellas think? Engine replacement?

 

[Aloysius]

Re: oil pressure

Of course the oil pressure drops at idle, especially when the engine is warm.

 

[coheej]

Re: oil pressure

10 lbs of oil pressure for every 1000 rpms is fine. pressure will vary with temperature, but should not change significantly from previously noted pressures. If pressure is suddenly 10 lbs below what it used to be, then I would watch it closely.

 

[zbnutcase]

Re: oil pressure

Put a temporary mechanical guage on it and see what it really is.

 

[Joshua Nichols]

Re: oil pressure

Yeah real gauge is a idea... It is hot here in Texas and I was also wondering if heavier wt oil would help..

 

[NHGuy]

Re: oil pressure

Mine does something similar so I did some reading and the OE book said 25w40 or straight 40 for use over 50 degrees outside air temperature. I had a bad spark plug last month so I was changing my oil in case some gas might have gotten in crankcase. Being the cheap jerk that I am I got some straight 40 weight. It does the same thing at idle as the 10w30 I had had in there, goes kind of low when hot. But there's always pressure on the gauge. Both oil weights shoot up to nice pressure once above idle. Even fully hot. Just run it, you are good.

 

[Joshua Nichols]

Re: oil pressure

Cool deal.. I don't need engine troubles.. I got outdrive problems now. I prefer one problem at a time

 

[Aloysius]

Re: oil pressure

You don't need high oil pressure..in fact, you don't want it. 10#'s per thousand rpms is all you need. You DO want oil flow to remove heat from the bearing surfaces.

High oil pressure is one of those urban myths that isn't necessarily true. If you've got 40#'s or more at speed, and 10 lbs. at idle, you're ok.

 

[Howard Sterndrive]

Re: oil pressure

previous owner just did a fresh oil change(he didn't say he did)..
...
Should I do my own oil change and go up in oil wt?

hard to go up, if you don't know what weight is in it. could be something too thin like 5W30 in there.

I'd start with an oil change using 20W50, 25W40 or straight 30 and verify pressure with bourdon tube gauge

 

[sethjon]

Re: oil pressure

Well I finally got my high end miss under control.. Turns out to be dirty carb.. It's harder to remove from the engine than it is to rebuild.. Anyhow so since the engine was running so good. The gal and I went WOT more than normal(this 17ft will fly with the 4.3).. Engine ran perfect temp all day.. Pulled in to go get something to eat.. Coasted into into docking area.. Low and behold.. Low oil pressure. Can't give a exact number cause the gauge only has 30, 40, 60, 80psi on it.. now down past 30psi.. It has the red area.. Thats where I am at idle, after hard running.. I came back from getting a bite to eat.. Maybe 30min or so.. The weather was getting spooky and have learned that lesson last week.. I went and got the boat out of the water.. Fired it up.. Oil pressure 30psi @idle. Now temp is down. Id say 130ish.. Is this a major concern? When I bought this boat, the previous owner just did a fresh oil change(he didn't say he did).. There was black oil in the bilge and this engine hardly leaks a drop.. Plus the shiny new oil filter.. Maybe he was hiding something?. Oil is nice and clean.. Engine makes no noise. Runs smooth as silk.. Should I do my own oil change and go up in oil wt? What you fellas think? Engine replacement?

30 at idle is great. check the oil to be sure the level is right.

 

[Joshua Nichols]

Re: oil pressure

30 at idle is great. check the oil to be sure the level is right.

Yeah but its only like that when the engine is cool

 

[Joshua Nichols]

Re: oil pressure

hard to go up, if you don't know what weight is in it. could be something too thin like 5W30 in there.

I'd start with an oil change using 20W50, 25W40 or straight 30 and verify pressure with bourdon tube gauge

Yeah I may do that.. no telling what he has put in there.. I need to get a oil sucker.....

 

[Alpheus]

Re: oil pressure

30 lbs is great considering the manual calls out for a minimum of 4lbs at idle.

Change the oil anyway. At least you will know that its right...

 

[Joshua Nichols]

Re: oil pressure

Dang four pounds????? Yeah going to go ahead and do it.. I have nothing better to do while I am waiting on other parts.. I always wanted to try some of that lucus oil treatment... Looks like good stuff...

 

[Aloysius]

Re: oil pressure

don't waste your money on oil treatment. Besides, it won't work unless you install Splitfire plugs and a Tornado in your intake.......

 

[wca_tim]

Re: oil pressure

you're fine. just keep the oil changed with the correct grade, check the level often and enjoy the boat. evenn with an oil cooler, mine drops to below 10 at idle after a long hard run... and the post above regarding pressure and flow is on target. in an engine that is in good repair, lower oil pressure at a given rpm means higher flow. As long as you have thick enough film, more flow is better because it removes heat. getting oil pressur eto be higher by adding thicker oil is actually worse than running the correct oiland letting it be a little low. imho

 

[Joshua Nichols]

Re: oil pressure

you're fine. just keep the oil changed with the correct grade, check the level often and enjoy the boat. evenn with an oil cooler, mine drops to below 10 at idle after a long hard run... and the post above regarding pressure and flow is on target. in an engine that is in good repair, lower oil pressure at a given rpm means higher flow. As long as you have thick enough film, more flow is better because it removes heat. getting oil pressur eto be higher by adding thicker oil is actually worse than running the correct oiland letting it be a little low. imho

Gotta like more flow.. I don't care who you are.. I am use to Fords and they always have steady oil pressure.. This is my first GM anything in a longtime..