quote:

Originally posted by TomR: I warmed the car up and made a pass. I watched the oil pressure drop to 40 at the finishline so I lifted and it went to zero. I clicked it off and drifted off to the side just in case I was leaking.

I went a 6.35@107. Was pretty happy with the ET but not the oil pressure.
Got home and cut the filter open, it looked perfect. No metal so thats a good thing.

^^^^^^ Disappointing. Any chance the pump pickup came loose?

Going to pull the pan and check it. I t was a new pump and pickup combo. Only has 6 runs on it.

Anything is possible.

What block? All galley plugs are in place?
Upper oil restricted?
Good oil returns in the heads and block?

Sounds like you either pumped all the oil up top, OR, it's over full and whipping the oil into froth.
Put less oil in it and see?


I've run a plain Z-28 pan with HV pumps and never had issues, 4 qts. plus the filter.

I run 6 qts. in the "7 qt." pans, always with a windage tray.

Refresh us on you entire oiling system details?

It's a GM 350 block with a Canton 7 qt oil pan (kick out and windage tray) and Moroso pump/pick up combo. The pan and pump are new, 6 runs.

Block was worked over pretty good, splayed mains, oil returns cleaned up, restrictors installed, etc.

I ran this short block for years without any problems.

Let us know what you find in the bottom end, TomR. Hopefully something simple and not damaged. Good thing you saw the low pressure and killed it, hopefully spared the internals.

quote:

Hopefully something simple and not damaged. Good thing you saw the low pressure and killed it

Agreed!!! When going down the track or even in the early part of the shutdown I’m paying too much attention to where I’m at on the track to follow gauges, but I have never missed this warning.

On a small block Chevy the oil does not drain back good in the heads. Heavier oil like 20-50 is even slower getting back into the oil pan.

You probably towards end of run have most of the oil on top of motor. Add a quart, too much and you will lose some horsepower. Also a thinner oil like 10-30 will drain back noticeably quicker. Of course you also need right weight oil for the bearing clearances you have.
You may need restrictors on top end to limit the oil up top.

I have added drain back holes in back bottom of head with hose that feeds back into oil pan and it helped some. Bigger dragster type pan will help but it needs baffles as when oil is low at end of run when you hit brakes you lose oil pressure. With all that said as long as you have pressure all the way down the track do not worry too much about oil pressure in shut down at idle.

quote:

Originally posted by TomR:
It's a GM 350 block with a Canton 7 qt oil pan (kick out and windage tray) and Moroso pump/pick up combo. The pan and pump are new, 6 runs.

Block was worked over pretty good, splayed mains, oil returns cleaned up, restrictors installed, etc.

I ran this short block for years without any problems.

Well, there we go!
Aside from one of the galley plugs behind the timing cover popping out, it kind of narrows the search area.

Did oil pressure come back at any time?

Pump by-pass stuck open. ?

Even if the pickup falls off, the pump is still submerged.

quote:

Originally posted by FootbrakeJim:
Let us know what you find in the bottom end, TomR. Hopefully something simple and not damaged. Good thing you saw the low pressure and killed it, hopefully spared the internals.

It ain't hurt.

I made a full 1/8th mi. pass, drove back to the trailer, and started it once more to verify that I saw the oil pressure gauge at zero before I parked it.
Snapped the pump shaft inside the distributor gear.

I'll be looking at those bearings sometime later this spring, but the engine went another 350-400 runs with no issues, until a valve seat shattered.

Damnedest thing I'd ever seen.

quote:

Snapped the pump shaft inside the distributor gear.

I cracked an oil pump shaft tang (ARP model) that was found when engine was being rebuilt. This was with a fixed distributor collar. Was unsure if this was an alignment problem and switched to an adjustable collar model afterwards.

Pulled the pan and everything looked perfect. No metal in the oil, filter or pan.

After talking with my engine builder, I bought a different oil pan and re-used the Melling oil pump and pickup. I also ditched the stock filter adapter with bypass for a billet one.

I had purchased a Milodon (not Canton as I stated above) street strip pan but it has an open sump. On the brakes, there was nothing to control oil and keep it near the pickup. The new Hamburger pan has baffles and trap doors, and an internal baffle to keep oil from going up the back on the pan on launch. Much nicer piece inside and out.

Had a nice long weekend to work on it, so I took my time and double, triple checked everything as it went together.

Will be out again this weekend.

Hopefully others learn from my mistakes.

Excellent upgrade Tom, and hope it cures everything.

I’ve never used anything but a Stefs 1021 pan on my sbc. With a Melling ST pump we did find that the Kevko 1004-10555 oil pump pickup tube worked the best in shutdown with no oil pressure loss at 142mph. Everything I attend now is 1/8 mile.

Tom, Good to hear you have no damage & hope your upgrades solve the issue!

I've ran a Hamburger pan(s) for many years on 2 different engines. They work great for us.

2BKING