Oil Pressure question

[jimh1626]

Hello All,

Ok. I have a re manufactured 5.7 engine. I am testing it before dropping it in the boat. I bought a set of water temp and oil pressure gauges, and hooked them up. Water temp is ok I think at 140. Oil pressure is 52 psi at idle. When I rev it up to about half way WOT it goes above 80 psi. Not sure I want to go WOT. Does this sound high? Not sure if the pressure relief valve is working. Should I be worried?

Thanks for your time,

Jim

 

[cr2k]

Re: Oil Pressure question

Not really for a SBC It can go up to 80 plus but much over that and you will float your bearings. It is equipped with a high pressure or a high volume
pump? For marine you want high volume NOT high pressure. Filter will blow off around 90 - 100.

 

[mpdive]

Re: Oil Pressure question

Hello All,

Ok. I have a re manufactured 5.7 engine. I am testing it before dropping it in the boat. I bought a set of water temp and oil pressure gauges, and hooked them up. Water temp is ok I think at 140. Oil pressure is 52 psi at idle. When I rev it up to about half way WOT it goes above 80 psi. Not sure I want to go WOT. Does this sound high? Not sure if the pressure relief valve is working. Should I be worried?

Thanks for your time,

Jim

Hi Jim. Is that 140 on a warm engine? Seems a bit low. Thicker oil viscosity contributes to heightned oil pressure too.

 

[jimh1626]

Re: Oil Pressure question

Not really for a SBC It can go up to 80 plus but much over that and you will float your bearings. It is equipped with a high pressure or a high volume
pump? For marine you want high volume NOT high pressure. Filter will blow off around 90 - 100.

I am afraid it will get to 100 or more at WOT. I don't want to get it in the boat and have a problem. Is there a way to check the pressure relief valve?

Jim

 

[jimh1626]

Re: Oil Pressure question

Hi Jim. Is that 140 on a warm engine? Seems a bit low. Thicker oil viscosity contributes to heightned oil pressure too.

I have a 140 thermostat in it. It will go higher than that if I run it long enough. I just run it 5 or 10 minutes at a time.

Jim

 

[mpdive]

Re: Oil Pressure question

I would verify with the rebuilder on the specs of the pump. Make sure it's the right one. Any possibility the gauge is inacurate? Is this fuel injected?

 

[jimh1626]

Re: Oil Pressure question

I would verify with the rebuilder on the specs of the pump. Make sure it's the right one. Any possibility the gauge is inacurate? Is this fuel injected?

The engine came with the pump and the valve cover, timing cover and oil pan already installed. I thought that was weird and called them and they said they usually don't do that. I'm thinking someone bought this and returned it and I got it with their stuff on it. I will drop the oil pan and check the pump or just put mine in it from my old engine. Has a small oil leak at the pan anyway and I want that fixed before I install it and it gets worse.
The gauge is new and mechanical, bought them to test with and will install them in the engine housing for a backup to the original gauges.
No it is not fuel injected. Has a Rochester carb.

Jim

 

[mpdive]

Re: Oil Pressure question

Sounds like a good plan Jim..

 

[jimh1626]

Re: Oil Pressure question

Thanks, I will check the pump. Didn't really give that a thought until you all mentioned it.

Jim

 

[Bondo]

Re: Oil Pressure question

I have a 140 thermostat in it. It will go higher than that if I run it long enough. I just run it 5 or 10 minutes at a time.

Jim

Ayuh,... At that rate, yer worrin' 'bout hi oil pressure with Stone Cold oil....
Throw it in the boat, 'n Run it....
I'm sure the oil pressure will fall into line when put to Work, rather than free spinnin' on blocks...
Without a load on the motor, I feel yer goin' nuts over Nothing...

 

[jimh1626]

Re: Oil Pressure question

OK Bond-o. If you think it will be ok, I'll do it. Just don't want to ever have to pull that motor again. I was thinking that it might be lower with a load, but I just thought that was a high reading.

Jim

 

[Bondo]

Re: Oil Pressure question

OK Bond-o. If you think it will be ok, I'll do it. Just don't want to ever have to pull that motor again. I was thinking that it might be lower with a load, but I just thought that was a high reading.

Jim

Ayuh,... With a Stone Cold motor, 'n Stone Cold oil, my 4.3l stills shows pressures near that, at 1200hrs...
Run it til Everything is warmed up, 'n it's showin' 'bout 45/ 50psi or so at Wot, 'n 'bout 15/ 20psi at idle...

 

[jimh1626]

Re: Oil Pressure question

Ok. I will fix that pesky leak then run it till it is hot and see what happens.

Thanks for your time,

Jim

 

[joewithaboat]

Re: Oil Pressure question

Oil type- strait weight or multi
Oil temp-you prob haven?t run it long enough for pressure it to drop because of oil temp
Oil pump- high volume, high pressure or both... Most new pumps come with option to change to high pressure bypass spring
Oil filter - a defective one, not a common problem but happens
And lastly prob most important- BEARING CLEARANCE.... rods, mains and cam
Most rebuilders build on the loose side to keep from having engines come back burned up. Thats why rebuilt motors have a bad rep for not lasting as long. Some will put a high pressure oil pump to account for loose bearing clearances. Just in my exp, I worked in a high perf machine shop for a couple years. All that being said.......
I?m with Bond-o so far, i think your prob ok, put it in and run it.
Prob a good idea to change break in oil and filter.

 

[jimh1626]

Re: Oil Pressure question

Thanks Joe.
Going to change the oil and filter again after I fix the leak.

Jim

 

[Bondo]

Re: Oil Pressure question

Thanks Joe.
Going to change the oil and filter again after I fix the leak.

Jim

Ayuh,... Put 20hrs. on it, break it in 1st,... Then service, 'n inspect things....

 

[joewithaboat]

Re: Oil Pressure question

20 hours well if there was something wrong... ie bad parts,machine work etc. 20 hours would leave you back at square one. Now if NOTHING were wrong it might take that long for oil pressure to come down a little, bearings getting a little clearance and all. I guess this is where the o/p is at.

Im a little freaky on fresh motors (the more $$ i have in it the more freaky i get) i always use a magnetic plug, put a few magnets under vavle covers, breaking in with "Break in oil", sometimes cut open first oil filter or 2 (prob the most telling, if you know what your looking at). Then switch to full synthetic. That might be a can of worms.....:facepalm:

 

[Bondo]

Re: Oil Pressure question

20 hours well if there was something wrong... ie bad parts,machine work etc. 20 hours would leave you back at square one. Now if NOTHING were wrong it might take that long for oil pressure to come down a little, bearings getting a little clearance and all. I guess this is where the o/p is at.

Im a little freaky on fresh motors (the more $$ i have in it the more freaky i get) i always use a magnetic plug, put a few magnets under vavle covers, breaking in with "Break in oil", sometimes cut open first oil filter or 2 (prob the most telling, if you know what your looking at). Then switch to full synthetic. That might be a can of worms.....:facepalm:

Ayuh,.... so how long do ya run yer Break-in oil,..??

I didn't say "Don't look at the motor for 20hrs."....

 

[joewithaboat]

Re: Oil Pressure question

Break in oil...
Depends, with a flat tappet using break in lube on cam and or rocker fulcrums. That might have higher than normal valve sping pressures, not long. A few cycles of the t-stat or a couple dyno pulls. That stuff is hell on bearings!

Stock motor, that might happen to have hyd roller cam, so no added break in lube. I'd change and or cut open the filter (to look for mistakes), run oil for a while (few hours), then switch to full synthetic.
In the end that really depends on so many things, the clearances in the motor, type of parts,type of machine work. All in all though ive all ways valued my time and oil is still pretty cheap, so is cutting the filter and looking for metal. I think its worth it. I do however have a friend who is a penny pincher and never considers first 5 quarts
"break in" but he never keeps anything long enough to care.

I once pulled a rod nut out that was stuck to a magnetic drain plug, this was a 10,000.00 brand name crate motor. As it turned out it must have been "lost" by who ever assembled it and they just went and got another one and went on. Also had an almost stock rebuilt motor show alot of metal(rod bearing). We pulled the pan and found a mixed .010 with a std on a .010 under rod journal.

edit

To those that might be reading this (Bond-o included) i have read hundreds of post here, before posting, and bow down to the obvious knowlege of Bond-o esp when it comes to boats in general. His knowledge is FAR greater than mine. Oil disagreements and changing habbits will never die and i am just rambling.

 

[jimh1626]

Re: Oil Pressure question

Well I thank you all and I will take all advice and apply it. I am dropping the pan now because of the leak. I ran the motor for a good 30 minutes and got it up to about 3/4 WOT and it did warm up and the pressure did drop some, so I am sure I am ok there. I am going to fix the leak and install it in the boat hopefully next weekend. Got to go back to Atlanta and close on our house this week. When that is done I am totally free for a while.

Thanks to all for your time and knowledge,

Jim