oil pressure concern

71 coupe /350/Auto
I have noticed as of late, that my oil presure guage is showing that my presure is lower and lower. While driving the guage indicates about 17 to
20 and when I come to an idle or stop, it drops to 0. I have checked the oil and its full as it should be.
The previous owner did put on new valve covers (Chrome) and I had to find a filler cap as there wasn't one on it.
could my presure issue be due to the filler cap not being one that came with the covers or am I starting to see issues with the oil pump or totally something else.
Thanks in advance.
Joel 71 coupe project
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35 year old engine. How many miles?
Does it smoke? Missing oil filler caps do not cause low oil pressure.............. How much oil are you adding between changes or by the month, week day?
Could be a lot of things ware related in the engine or something simple like a bad sending unit to the gage.
brian
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I believe a '71 is still a mechanical oil gauge. However, mechanical gauges do go bad with age and it is 35 years old.
1. What is the pressure cold, or when you first start up?
2. Does it drop from the cold pressure to the hot pressure?
3. What weight oil are you running? Dino or synthetic?
Get another mechanical gauge, preferably one you know is good. Go buy a cheap oil gauge at AutoZone, Pep Boys, whatever and hook it up. The oil connection is on the back of the block near the distributor on a small block and on the lower left side by the oil filter on a big block. Then see if the pressure is the same.
If it really is zero, it is time for a new oil pump. Do not buy a high volume, high pressure pump. It really isn't needed and wastes horsepower.
It is relatively easy to change on an old Corvette.
Turn the front wheels to the right.
Disconnect the ilder arm on the tie rod from the frame.
Turn the wheels slightly left while someone pulls down on the tie rod. The idea is to get it to drop v-shaped much lower than the engine.
Drain the oil and remove the filter.
Remove the oil pan.
Remove the oil pump at the rear of the engine.
Remove the screened pickup tube from the old pump.
Install the pickup on the new pump. If loose, use safety wire to tie it on or drill a VERY small hole in the pump and tube to pin it. Small meaning like 1/6 or less.
Install the pump.
Install the pan with a new gasket.
Turn the wheels and reinstall the idler arm.

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Ususally around 17 to 20 or so. The engine does have 94K on it and it is the orginal motor. It does smoke just a little bit, but mostly when I idle.

Seems that it is much lower when the engine has warmed up.

I am running stamdard 10W-30 Penzoil

I will try this out as it should be an easy thing to check. Didn't think about that.

Thanks Tom and Brian.
Joel
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1/6 inch would be a huge hole. 1/16th inch is about .0625 and that would still be big, except the wire or pin will fill much of it.

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