Big Block oil pump Installed

[Josh Noser]

Hello all,

I changed the oil pump on my car this weekend, I put in a standard volume and pressure oil pump. For all the dreading I did of doing the job it turned out to be a piece of cake. So I primed the pump and started it up. At temperature and idle the pressure was 15-20 PSI and average pressure while driving was 35. I took a long drive and towards the end I let it rev higher and there was a small drop down at ~ 5 grand, it went from 45-50 PSI to 30-35 PSI. So I went home and added a 7th quart of oil and that seemed to solve the problem. So my question is...are these oil pressures ok for this engine (427 L-71)? I am running 10-w40 oil. Thanks to all who gave me advice prior do doing this job, it really helped in making things go smoothly.

Josh

[Jon #40768]

Re: Big Block oil pump Installed

Big blocks have an excelant oiling system. 35 psi is more than satisfactory, although mine runs higher as I installed a shim in the pressure spring in my high volume pump. I would be leary of running 7 quarts as to high of an oil level can have ill affects. High performance pans were 6 quarts. To high of an oil level can cause the oil to be picked up into the rotating mass of the crank and rods and induce airation of the oil. The foamed oil will not lubricate properly and can cause a lose of oil pressure.

Unless you are in cold weather, there is no reason to run an oil as low as 10w-40. I would run 20w-50.

I am sure that you will get differing opinions. This is just my opinion. It has been 25 years since I made a living building racings engines.

Jon

[Josh Noser]

Sorry I am running 10-w30 *NM* *NM*

[Dick W.]

Re: Sorry I am running 10-w30

I think that if you look back at the archives, Duke Williams makes a pretty good case for running 15-40 oil such as Shell Rotella T, Delvac, etc. All diesel oils. They have a significantly better additive package. The newer oils for passenger cars are designed to run in the cleaner engines of today. But I am reading of new cars properly maintaned and having severely sludged engines at 20K-40k miles. This was in an article in Automotive News last week.

I have run these oils in everything that I have owned since the early 60's with excellent results. Never had to rebuild anything, with the exception of a 454 in a tow truck. And that was due to an oil temperature related failure.