Minimum oil pressure question.

[bherman]

Hi Guys", I put this post over here because I felt that you guys' focused more on engine related concerns than most areas on the site. I have a stock block 400 based 470 stroker that I'm in the process of de-bugging. This engine is fitted with Indy EZ cylinder heads and utilizes an Indy remote pick-up oil pump assy. After the cam break-in was performed and we adjusted the carb for a satisfactory idle I noticed that when the engine is fully warm it only had about 20-25 PSI oil pressure at idle (850 rpm). The oil pressure rises immediately off idle 45-50 lbs @ 2000 and 50-55 lbs @ 3000, above 3000 the pressure seems to level off about 70-75 lbs. The engine had 30W Brad Penn break-in oil in it at that time. I called Indy and talked to Russ, he recommended restricting the oil to the cylinder heads (the heads are externally oiled). I restricted the oil to the heads, no significant change. I changed the oil to Lucas 20W-50 break-in oil and did see an increase in oil pressure at warm idle and lower rpms of about ten lbs. I'm now seeing 30-35 lbs @ idle, @ 2000 and 3000 rpm it has approximately 50-55 lbs and 55-60 lbs respectively. Above 3000 rpm the pressure seems to be stable @ 70-75 lbs.

After the cam break-in I cut the filter and didn't see any indications of a problem, it sounds fine, guess I don't have enough experience to know if I should be concerned or not. All advice welcome, thanks, Brian.

 

[1967coronet440]

Seems Normal to me

 

[65hemi]

Main bearing clearances on the high side?

 

[bherman]

Main bearing clearances on the high side?

65hemi, I don't know, I purchased an assembled short block and put the top end together. Do those oil pressures seem low to you? Thanks, Brian.

 

[65hemi]

IMO, don't seem too low for fully warm. But I think my 500 wedge is over 30 at warm idle and over 80 at speed.
A buddy has bigger clearances in his hemi for some reason and he only has 10 psi at idle warm. That was more concerning.

 

[747mopar]

You should be fine. Look at it like this, if you have any pressure at all it clearly means the pump is supplying more oil than the oil system can use or there would be zero psi. 30-35 psi is normal at idle on most cars.

 

[Yatzee]

Hi Guys", I put this post over here because I felt that you guys' focused more on engine related concerns than most areas on the site. I have a stock block 400 based 470 stroker that I'm in the process of de-bugging. This engine is fitted with Indy EZ cylinder heads and utilizes an Indy remote pick-up oil pump assy. After the cam break-in was performed and we adjusted the carb for a satisfactory idle I noticed that when the engine is fully warm it only had about 20-25 PSI oil pressure at idle (850 rpm). The oil pressure rises immediately off idle 45-50 lbs @ 2000 and 50-55 lbs @ 3000, above 3000 the pressure seems to level off about 70-75 lbs. The engine had 30W Brad Penn break-in oil in it at that time. I called Indy and talked to Russ, he recommended restricting the oil to the cylinder heads (the heads are externally oiled). I restricted the oil to the heads, no significant change. I changed the oil to Lucas 20W-50 break-in oil and did see an increase in oil pressure at warm idle and lower rpms of about ten lbs. I'm now seeing 30-35 lbs @ idle, @ 2000 and 3000 rpm it has approximately 50-55 lbs and 55-60 lbs respectively. Above 3000 rpm the pressure seems to be stable @ 70-75 lbs.

After the cam break-in I cut the filter and didn't see any indications of a problem, it sounds fine, guess I don't have enough experience to know if I should be concerned or not. All advice welcome, thanks, Brian.

I've got a 400 block blown out to 512 stroker and my oil pressure at 800 is about 25 P.S.I. Been that way for quite a while. I did port the oil pump to remove the possibility of poor oil delivery and entrainement of air. Nothing special about the pump, neither high volume or high pressure. I peak at 65 - 70 p.s.i. - more than enough. The Problem with Mopar's is they oil from the top down so you can get quite a lot of oil under the rocker covers and in some cases you can put it up there faster than it can drain back, leaving a somewhat low level in the sump. Not good under hard acceleration, quick turns or powering uphill where there's the possibility of exposing the pickup to air. I like the idea of an external pickup right at the back lower section of the oil pan but I'm not big on external oil pumps on a daily driver. You really need to invest in good cover gaskets even with aluminum covers or a leak develops at the rear corner of the covers where the pumped up oil is the highest waiting to drain down through the rear oil return hole in the heads. To me, your oil pressure is more than adequet, maybe excessive. For anyone using the original pump shaft and gear keep in mind the stress they are under with high volume/high pressure pumps, more than they were ever meant to endure.

 

[Zeppelin264]

10lbs per 1,000rpm is a good base line. The top end is getting oiled at anything over 5-8lbs. If your seeing low numbers when warm then you have a bearing clearance issue.

Personally I run 20-50 Brad Penn and see 80 at cold start, 75 cruising hot, 25-30 warm idle, and 50-75 ish as the engine and oil are getting to temp, at idle. Running a Mellings High Volume pump and 8qt pan so it doesn't suck it dry.

Example of low oil pressure is the 22r by Toyota. Idle is like 6 lbs of pressure and they last forever. I'd be more worried about sucking the system dry and having it all in the top end(like already mentioned in this thread).

 

[RT K_line]

Mine is about the same and now has a little over 10,000 miles. it should be fine.

 

[terzmo]

I run brad penn 20/50 in all 440 and 426 strokers...your oil pressure seems fine...the old idiot lights didn't come on until pressure dropped below 8 lbs....I call them..."it's too late" lights

 

[dvw]

I do not run the thick stuff, use 5W30 synthetic. Bearings were pounded for 300 passes in my 572. Rods looked like new, mains were do for a change. Ran 65psi@7100. Idle pressure means nothing, just showing internal bleed. Guaranteed it's upper end. Lifter bores, rockers, shafts, etc. Current set-up uses a Indy pump. Holds 65@1200/75@7000 (still to high) with .003" rod, .004" main clearance. The upper end is pushrod oiled and restricted, lifter bores are bushed. You'll be fine.
Doug