318 runs great...but low oil psi...is it ok?

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jhaas63

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My 318 in my 72 Dart works and sounds great. It has plenty of power and seems strong. I have an aftermarket oil psi gauge and it runs from about 25 psi to 10 psi. It is not low on oil.

Any reason for this?
 
Is the gauge electric or mechanical. General rule of thumb is 10 psi per 1000rpm up to a point. Mine runs around 30 when warm at idle and near 60 at cruise, and my engine has a lot of miles on it too.

Do you have any valvetrain noise (clacking) when running?
 
Electric or mechanical gauge? Could be you have a faulty gauge or sending unit.
 
How high does it get when you are on the throtle hard? 25 would be low at 5000 RPM but ok for normmal driving. How many miles on the motor? What pressue do you have with a cold engine? If it's signifigantly higher cold you might try going with strait 30 or 40 wt or perhaps 20W50. Worst case you can drop the pan and change the oil pump and also the bearings if needed without pulling motor.
 
25 sounds low , but what are the specs for a 318 stock ? The warning light goes off at 6 -7 psi at idle 10 sounds low , 25 should be okay at 2000 - 3000 , but borderline low , but maybe fine for stock 318 . Best find out what the stock spec pressures are before you start tearing things down. Try another oil , 15-40 ?
How many miles on the motor ?
 
jerry6 said:
25 sounds low , but what are the specs for a 318 stock ? The warning light goes off at 6 -7 psi at idle 10 sounds low , 25 should be okay at 2000 - 3000 , but borderline low , but maybe fine for stock 318 . Best find out what the stock spec pressures are before you start tearing things down. Try another oil , 15-40 ?
How many miles on the motor ?
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My engine is stock with the exception of the cam and external bolt on stuff, mine holds 25 - 30 at idle and close to 60 at cruise, with about 80,000 on the clock. I run 10 - 40.
 
Badsport said:
My engine is stock with the exception of the cam and external bolt on stuff, mine holds 25 - 30 at idle and close to 60 at cruise, with about 80,000 on the clock. I run 10 - 40.
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Those are good numbers , but 10 at idle 25 at cruise could be within spec but borderline at best . I'd hook up a known good mechanical gauge and check and make sure , thicker oil is not a soloution
 
I just wanted to post an update....

I just took the car for a long ride. When it starts up and probably for the first 3-4 minutes, it is around 50 PSI. Then, it basically goes with the RPM's on the car. So if the car is under 1000 RPM's, the gauge is right around 10 PSI. When the car is cruising at 60 MPH and at around 2300 RPM's, the gauge has the PSI around 25.

Now that I have a better understanding of oil psi, I am feeling much better as these numbers seem to fall in line nicely.
 
It should be adequate but does seem low. You never said what gauge you had. If it's an electric gauge sometimes you need to change the sending unit to match it, that might be why it seems on the low side.
 
Badsport said:
It should be adequate but does seem low. You never said what gauge you had. If it's an electric gauge sometimes you need to change the sending unit to match it, that might be why it seems on the low side.
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Im not sure if it is electric or manual. Any way to know?
 
Wouldn't hurt to drain the oil and check it for metal flakes. You might even cut the old oil filter in half and see what's in there. If you find nothing, stick a good quality filter on it and good oil back in it and drive it. You'll never cut the oil light on with that pressure. It'll be fine. If I remember right, some of those oil senders actually don't cut the light out until it drops below 3 PSI. I have always heard the old timers say as long as the gauge needle moves up at all at idle, that's good enough.
 
jhaas63 said:
Im not sure if it is electric or manual. Any way to know?
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a manual gauge will have an actual plastic or copper line letting oil travel all the way to your gauge, probably from behind the distributor on top of the block....if you have an electrical gauge..it'd be a little sending unit with a wire to the gauge.....my old moderate 318 had WAYY more pressure than that...as in 60 at startup when it was cold, then finally down to 30-35 when warm....i have heard of the stock oil pump spring going weak...causing low pressure...kinda like when a mech fuel pump starts to go...it'll still pump some...but not enough to keep up.
 
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