[jhein]

Originally Posted by mgarblik

I wanted to add a little cautionary tale I discovered that would apply to all Pontiac V-8 engines. Just something to keep in mind. My SD dipstick says "5 Quarts, Do not Overfill". I know there have been numerous posts in other threads about proper oil level in our engines. So I started with 5 quarts of break-in oil and a full size filter. I ran the drill motor and the priming rod to prime the engine. This was on a dry engine first fill. Oil filter empty. Ran the drill at approx 400 RPM. It took about 10 seconds to show some oil pressure on the external gauge attached to the filter housing. I let the pressure drop to zero and then ran the drill again. After 25-30 seconds with the pressure showing 70-74 PSI , the drill motor changed sound and the pressure dropped rapidly to 15-20 PSI!!. I did this test 4 times. Each time the pressure would go to 70-74 PSI and then by 30 seconds later the pressure would be low. I let the oil settle and checked the dipstick. It was showing 1.5 quarts low on the stick. I added 1 quart and re-tested. I ran the oil pump for over 2 minutes several times and pressure was rock steady. Let the oil settle and checked the level. It showed 1/2 quart low. I added 1/2 quart to full line. So a completely dry engine needed 6.5 quarts to full. On my oil change to remove the break-in oil, with a new filter, it took 6 quarts to the full line.

Here are my conclusions: 1/2 quart of oil stays in the engine on a typical oil change. 6 quarts is the proper fill with a full size oil filter. If the dipstick says 1.5 quarts low, you are in the extreme DANGER zone. 1 quart low and running hard, braking hard, cornering hard, you may be in danger. Aftermarket heads and blocks with restricted oil returns compared to stock parts would be in danger sooner. Remember these tests were performed with the engine sitting still. Keep your oil near the full line to 1/2 quart low to be safe.

Thank you for that post. That's excellent information.

I had a thread recently about this general question but it was mainly related to aftermarket parts, heads, blocks etc.

So as far as the drain back issues related to aftermarket heads and blocks, doesn't that really not matter?

So what if the heads and the lifter valley hold a bunch of oil? Once you reach the oil retention threshold in those cavities and keep the crankcase full, what does it matter?