Too Much Oil Pressure?

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clifftt

clifftt

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I abandoned my engine break-in Saturday after five minutes due to an oil leak. Only lost maybe a 1/4 of a quart. Up to then it was running nicely. The first few seconds at idle the pressure was around 30 lbs. We then immediately started break-in, running the engine at 2000-2500 rpm and oil pressure was 70-80 lbs. After five or six minutes, we shut it off without incident other than the leak. The leak turned out to be a stupid mistake: I incorrectly had the cork seal not sandwiched between the adapter and the block.

For the engine build I set bearing clearances between .0015 to .002. Oil pump is a stock Melling, not a high pressure or high volume, just stock. For break-in I was running Rotella T 15w-40 and Red Line Break-in Additive and a Wix filter. A "Chevy" guy I know and trust thinks the 70-80 lbs is too high, says at that high of a pressure the oil is forced out of the sides of the engine bearings causing them to wear prematurely, and forcing oil up into the cylinders which could cause issues with the rings not seating properly. He suggested using a thinner oil, a straight 30w or 10w30 and looking into maybe something wrong with the oil pump.

Any opinons??
 
Was that at normal engine temps? My Dart will pump 70-75 at start up and with high choke position. At idle it will run 30 at idle in gear.
 
Was that 70-80 psi after the engine was up to temp. just before shutting it down. Does seem a little high especially with a stock pump. I run that cold with a HV pump then backs off to 60psi hot. This pressure you're reporting is that with a mechanical guage or electric and you didn't say what engine this is.

Terry
 
That oil pressure doesn`t seem too high for an initial start up with 15/40w oil and tight clearances. I think you`ll see the pressure reduce as the engine breaks in and loosens up.
 
my duster has about 75 psi at start up...and after warming up drop somewhat....and I have been driving it now for almost 4 yrs.
 
Sorry, thought I covered all the facts, but I missed some.
It's a stock 273 two-barrel. The water temp gauge was creeping up, but the engine never reached operating temp, maybe got up to 160. The gauge is a mechanical Stewart-Warner.
 
Yea I wouldn't worry about it and tell your chevy guy that his theory concerning the damaging effects of high oil pressure are just that. After she's got a couple hundred miles on her change the oil and filter and you might want to to back the oil down to a 10W-40 which will drop your pressure 5 pounds or so and another can of cam lube.

Terry
 
Thanks everyone. It sounds like I've got nothing to worry about other than to keep my eye on the gauges and make sure no more leaks occur.
 
There are engines that run at a lot more oil pressure than that, especially when cold.

My '04 Colorado, when cold runs over 90psi on 5w30. It runs 20psi at idle hot too.

Mine is 75 cold and about 15 hot....no issues so far.
 
Mine runs 75-80 cold with 10-30 in it, hot it idles around 28 on the gauge. It's been in the car for 8 years now with no problems!! If I remember right, ford ran 140 lbs in their cleveland hp motors and the bearings never failed!
 
My engine has about 12,000 miles on it and for start up at about 1500rpm, it reads 75-80 psi, and hot idling in gear its about 40-45 psi. Your chevy guy is full of it. His theory has NO logic. Longgone is right, your oil pressure will drop a bit, especially after the 500 mile break-in. Fix your leak and continue...
 
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