Loss Of Oil Pressure

LocuMob

Fluid Technician with a hat
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Driving the Polara the last few times I noticed a drop in oil pressure when I ran through the gears hard, and once when I too a left turn quickly. Pressure came back up right away and with my exhaust leak I didn't hear anything and it felt fine, no obvious signs of having no pressure. I thought my cheap gauge was the issue. On Monday I fired it up and headed to th gas station for a splash and go. Came out and fired it up again, no pressure, clackity clack rat tat tat. Shut it off and checked the oil, just below the fill mark and looks clean, only 400-500 miles since I changed it. Climbed in again and turned the key, same noise, threw it into gear and after a foot I had oil pressure, still making a racket. I live 7 blocks away so I nursed it home. Well I just started the car again and it didn't have pressure for about 20 seconds and then it got pressure and got quiet. I'm planning worst case scenario, that the engine will.meet it's demise soon. Maybe not but I'm no expert.

What would cause oil pressure to drop off, then come back, and why would any knocking/ticking fo away? My previous experience the noise only went away for about 10 seconds before "Boom!" occurred.

Wondering how bad it might be. Any thoughts?
 
Clickity clack should be from your valve train and will go away once pressure is built because your lifters are then pumped up. You likely haven't heard a substantial knock yet because there is still a film on your bearings. I wouldn't run it again at length till you can figure your pressure problem.

Check around your pump and around any fittings going to the gauge first. Sometimes the cheaper mechanical gauges can leak and cause a void in the line which will lower pressure until the pump can catch up. Weird thing is that usually once the engine is run up to pressure for long enough, it takes a while for the lifters to loose pressure.

Anything else replaced in the oiling system recently? How many miles on the engine in total?
 
Original timing set with plastic teeth?
 
Don't know total miles, I put it in my car a couple/few years ago. 75 I think, out of a barge. I out a Melling HV pump on, it's what I had. Guage fittings feel tight. I don't remember if I went to synthetic last oil change, that would be my only deviation, other than using a Mopar filter rather than a Champion.
 
All I did with the engine when I got it was to swap the intake to an Edelbrock Performer, and Edelbrock carb, stuck a .484 purple shaft cam in, and later added tti headers. Drove fine the last 3 years or so since I dropped it in. Occasional blasts and a fee quarter mile blasts, nothing crazy and always try to keep the rpm under 5500.
 
Ok ... a few things..
You say you have a HV oil pump and that you may have changed oils.
- Would you have had changed viscosity?
- Do you have a windage tray?
Is it possible that your pump is sucking dry due to the oil's inability to drain back in a timely fashion? I ask because if the level is low in the pan because of improper drain back, you could definitely have a loss on cornering as well.
 
Driving the Polara the last few times I noticed a drop in oil pressure when I ran through the gears hard, and once when I too a left turn quickly. Pressure came back up right away and with my exhaust leak I didn't hear anything and it felt fine, no obvious signs of having no pressure. I thought my cheap gauge was the issue. On Monday I fired it up and headed to th gas station for a splash and go. Came out and fired it up again, no pressure, clackity clack rat tat tat. Shut it off and checked the oil, just below the fill mark and looks clean, only 400-500 miles since I changed it. Climbed in again and turned the key, same noise, threw it into gear and after a foot I had oil pressure, still making a racket. I live 7 blocks away so I nursed it home. Well I just started the car again and it didn't have pressure for about 20 seconds and then it got pressure and got quiet. I'm planning worst case scenario, that the engine will.meet it's demise soon. Maybe not but I'm no expert.

What would cause oil pressure to drop off, then come back, and why would any knocking/ticking fo away? My previous experience the noise only went away for about 10 seconds before "Boom!" occurred.

Wondering how bad it might be. Any thoughts?

Sounds like the pickup may be clogged or it fell off partially.
 
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I noticed a drop in oil pressure when I ran through the gears hard, and once when I too a left turn quickly.

This makes me believe that you are uncovering the oil pickup or the pickup is clogged.

That could mean a few things... But I'm thinking the high volume pump is just sucking the pan dry. The other thought I have is if the pan came out of a C-body or something like that, there's no baffles and the oil is sloshing away from the pickup. An easy fix might be to put an extra quart of oil in it.

I'd put a quart of oil in it to try... It can't hurt. If that works, I'd look at replacing the HV pump with a stock pump. The stock pump takes care of your oiling needs quite well... and even takes less horsepower to drive. I would also put a baffled pan in the car.
 
This makes me believe that you are uncovering the oil pickup or the pickup is clogged.

That could mean a few things... But I'm thinking the high volume pump is just sucking the pan dry. The other thought I have is if the pan came out of a C-body or something like that, there's no baffles and the oil is sloshing away from the pickup. An easy fix might be to put an extra quart of oil in it.

I'd put a quart of oil in it to try... It can't hurt. If that works, I'd look at replacing the HV pump with a stock pump. The stock pump takes care of your oiling needs quite well... and even takes less horsepower to drive. I would also put a baffled pan in the car.

This would also be a good time to pull the oil filter and pour out the contents to check for metal shavings or other debris. Sometimes on a well worn engine, synthetic oil can break loose a bunch of crud and clog the pickup screen on the pump. From the symptoms you are describing, it sounds more like your high volume pump is sucking the pan dry. This is more likely if your are running 20-50 viscosity oil as this oil has poor drain back characteristics until it warms up. Adding an extra quart of oil as mentioned above will verify if that is what is happening as your oil pressure problem should go away due to the increased volume of oil. May want to consider a baffled six quart pan as mentioned above or 10-40 oil.

Dave
 
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Start simple first. you say it's only been 400-500 miles since the oil change? Go get another filter, prime it and swap em out. Might get lucky and simply have a crap filter.
 
Thanks for the responses! Trying a stock oil pump is right up there on my list of things to try, I thought of that right away, sucking air with the low level, yes no baffles in the pan, came off the stock 383-2 engine. I'm kind of curious though how I lost so much oil in such a short time, I'll go back to the cheap dino juice.

I sure hope the pickup isn't clogged or loose. It was clean as a whistle when installed and tight as a Marines bed, and the engine was really clean inside before installing. I'll get some oil and top it off and see what that does.

I hope the filter isn't crap, that's why I went with a Mopar filter, and I should have primed it when I put it on.

I won't get to it until tomorrow morning but I'll let you know the results. Thanks again!
 
well a bud of mine did the synthetic oil in his 66 polara rag . and it started a knockin . we pull it down to find that the oil had loosened up all the crap and the thick slug was filling up the pickup screen and not enough oil was getting through . thats not a good thing . looks like another project in the wings . sorry for your issue bud .
 
well a bud of mine did the synthetic oil in his 66 polara rag . and it started a knockin . we pull it down to find that the oil had loosened up all the crap and the thick slug was filling up the pickup screen and not enough oil was getting through . thats not a good thing . looks like another project in the wings . sorry for your issue bud .
I'm leaning against it being sludge, the engine was really clean, but it could be. Thinking of dumping the oil and looking in there with my camera scope to check it out for sure, won't hurt.
 
Right there...
I'll wait to fix that until the stub frame swap next year, the car only has weeks left to drive so if it's a simple fix I'll just drive it to storage and mothball it for the year.
 
at least you gone nearly the season out of it , new subframe ha ? after market or oem disc setup ? i grabbed a 70 nyr disc front end for my 65 880 rag , and these is a motor that needs to get built as well , and swapping out the 727 four an a833 4spd . got a swapout of a 66 sport fury too do it with , column to the peddles z bar linkages hurst shifter even the bellhousing n flywheel/clutch core . just started this deal with a cam grinder buddy , building nice engines for a fair price . alot of leg work involved but if it pans out , i'll be having fresh motors in everything .

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