Strange Oil Pressure Problem
 

Hello All
I have a strange oil pressure problem. First I must tell you this is a 327/295 combo, that came in a car that I bought. The Motor was originally done by Jeff Stealey. The only thing I changed on the motor was the oil pan. The Oil used is 10/30 Brad Penn.

When the motor was started up it had 55 to 60 LBS oil pressure.
Once the motor reached operating temp around 160/170 degrees, the oil pressure started dropping down to 20/25 LBS of pressure. even if you rev it up, it would only go up about 5 LBS then fall right back down. (this happened while the motor was idling at 1300 RPM)

Cutting the motor off for a few minutes and starting it back up, the oil pressure would again be at 55 to 60 LBS. Once it would run for a few minutes it would drop down again to 20/25 LBS.

I say ok need to replace the oil pump, so that what we did. Guess what it did the same exact thing.
Slightly confused, any ideas?
Would it help if I put 20/50 oil in it?
O yea it never totally lost oil pressure.

Thanks for any ideas or explaintion
Cal

Re: Strange Oil Pressure Problem
 

Oil pickup height vs oil pan depth? How mant quarts of oil?

Re: Strange Oil Pressure Problem
 

As Glen mentioned, it sounds like the oil pump pick up too far off the bottom of the pan. Pour another at of oil in it, see if that helps. If so, what Glen mentioned would be your problem.

Re: Strange Oil Pressure Problem
 

What oil filter you running? I had the same problem one time and pulled the Fram filter off and installed another brand.....problem went away. Not sure what it was with the filter but never went back to Fram.

Re: Strange Oil Pressure Problem
 

I had the same problem with a fram filter and have never used one since....Low oil pressure after changing oil.

I also took an engine apart for someone else that hurt the bottom end and the filter was a Fram and the filter media inside the filter was out of position.

Re: Strange Oil Pressure Problem
 

How about trying a different oil pressure gauge and that it be a mechanical type.....

Just sayin'

Re: Strange Oil Pressure Problem
 

Thanks guys
The pick up should be 1/4" off bottom of pan, if my measurements are right!!!
I use Wix's oil filter # 51060R. 6 quarts of oil plus 1 in the filter.
I will try adding another quart of oil and run it again.
Also guess I'll try 20/50 oil to.
Racing what "FUN" LOL
Cal SST 1177

Re: Strange Oil Pressure Problem
 

Might be the oil is having trouble draining back to the pan . Does the engine have modifications to the drain backs , or something like a magnet has moved blocking drain back holes ?

Re: Strange Oil Pressure Problem
 

Cal, a quarter inch is awfully close. I personally would not put thick oil in it with the pick up that close.

I don't claim to know everything, but for years have used 1/2". Too close, I would worry that oil may not flow under the pick up fast enough.

A professional engine builder may say I am full of crap. Heard that one before. LOL

Re: Strange Oil Pressure Problem
 

Never liked a filter with a micron rating of 61 that .002 piece of debris.

I run the 1061 NAPA gold or the WIX 51061 in all my racing engines 21 Micron rating with the filter bypass plugged or I run the billet adapter.

I have seen this before with a spun cam bearing.

Re: Strange Oil Pressure Problem
 

1061 NAPA filter has been great for me, for many years.
I have used Fram filters before going to the 1061 NAPA, but have never seen the oil pressure issues mentioned here.

I cut my oil filters open after each day of running my car. I started doing that in the 1980s, while running my old dirt track sprint cars. Still do it now. Used Fram back then, until I cut the first one apart. Ditto AC. Do that, then cut a NAPA filter apart. You won't use another Fram. I used to know who makes NAPA's filters, but right now that name escapes me. Listen to Carl.

Re: Strange Oil Pressure Problem
 

WIX made. NAPA filters in the past they still do make the Napa gold and platinum on the same assembly line . Fed387

Re: Strange Oil Pressure Problem
 

Wix does make Napa filters and the numbers are the same but with an added prefix number for Wix denoting what type filter it is...

For example

Wix.....51061
Napa...1061


Add a 5 for oil
Add a 4 for air
Add a 3 for fuel...


We use Wix pretty much exclusively at our place of business and I use Wix 51061 R on my own race engine

Having low oil pressure on a warm engine usually indicates very loose clearances or an internal leak.

Re: Strange Oil Pressure Problem
 

Based on an embarrassing experience, have you double checked with a second oil pressure gauge? I once had an Autometer mechanical gauge fool me into pulling an engine due to flaky low oil pressure readings. Actual cause was the light bulb in the gauge rubbing on the internal bourdon tube making it read low.

Re: Strange Oil Pressure Problem
 

Cal,

Like I told Dave yesterday at the shop I think you guys need to pull it out and check some clearances and make sure all the oil galley plugs are there. I have had an engine with a missing oil galley plug have the exact same symptoms. I know because I was the one that put it together and had to fix it :)

Either way is it worth taking a chance on killing it completely when it might be a simple fix ?

Re: Strange Oil Pressure Problem
 

I agree. I certainly would not leave in the car, or try to run it again.