Breaking in fresh 383; oil pressure got me worried

[Dr. Righteous]

When the engine is cold it will start up with 80psi of oil pressure. It will drop to about 65-70psi if it sits and idles several minutes until the temp get up off the cold line. BUT, when you drive the car and actually put a load on the engine, it runs a little hotter of course and eventually the oil pressurre will drop to about 25psi at idle. I am running 10w30 Havoline for the break in period. My oil pump is the original one. I didn't change it but I did add a high pressure spring.
I noticed that the rotor looked like it had a bit more slop in it than it should but at the time I was out of money so I didn't change it.
Now, when the engine cools back down to cold again you can crank it up (purrs like a kitten even with a much bigger than stock cam; its beautiful) and the oil pressure is back to 80psi. This is normal to a certain extent, but I don't know about dropping to 25psi, that has got me worried.
Or is it I worry too much.

[fox]

What main bearings are you using? Are they full groove or half? Are they big groove or small? If they are grooved, I would run the high voluume pump and more pan capacity than stock. I have never been a fan of just the high pressure springs, as it just pumps the pan empty faster, and the oil is all 'upstairs'.
fox

[pishta]

Man, 25 at idle sounds pretty good to me. On a hot motor, that oil gets thin, but 25@750 RPM or whatever with grooved bearings is plenty'o protection. Like I said in prior posts, "the oil light should flicker only at idle..." (1965 Valiant 273/4 owners manual)

[Runner1971]

if it omes right up right off idle i wouldnt worry about it, sounds about right to me

[powerwagon]

I probably would check the oil pump-also, check to make sure your gauge and sending unit are working properly, I have seen that cause faulty readings. By the way, don't worry-my powerwagon (w/ 20/50 oil) makes about 10 at warm temp, and about 5 when in gear w/foot on brake. The only time it makes 25 is going down the highway . The old girl still runs good, though.

powerwagon

MOPAR FOREVER

[TD]

With the motor at normal operating temperature and the engine at 2000 RPM, what kind of pressure do you have?

[Dr. Righteous]

With the motor warmed up, and at 2000RPM I would guess 35-45psi, I would have to look at it to be sure.
The Bearings are fully grooved Clevite trimetals.
I didn't think about that but those demand more oil volume. Hmm, I am feeling better.
I have a Mellings high volume pump on order, it should be here Friday.

[RDABIKE]

The rule of thumb from Mopar Performance is 10 psi for each 1,000 rpm. ex 3,000 rpm 30psi. Years ago I had a Dick Landy built supercharged 360. at a hot idle 800 prm I had 20 lbs of pressure. Of course it still met the 10 psi per thousand rule and I never had any problems.

Mark

[ZIPPY]

Dr.-
Don't worry. You have plenty of oil pressure, it'll be fine. Never have been a big fan of Havoline myself, but to each his own--you have plenty of oil pressure, at any rate.
~Z~

[PRO]

Try replacing your oil pump relief spring with a hd one,its a simple process and is accesible w/o pulling the pump,it sounds like its fatigued...PRO..

[amoparguy]

25 lbs at idle sounds fairly normal for fully grooved mains. Volume is the issue here, not pressure. Fully grooved bearings will bleed off oil pressure at idle. If you are really worried about the oil pump here's something you can do for piece of mind. Disassemble your oil pump and check the clearances. Using a feeler gauge, measure the outer rotor to pump housing clearance (should be less than .014"). Measure the inner to outer rotor clearance with the lobes at their closest point (should be .010" max). The final measurement is the face clearance. With the rotors installed in the pump housing, place a straight-edge across the housing and measure between the straight edge and the rotors (should be .004 or less). Dr. did you have the pan off this thing? If oil pressure drops while you are getting on it, there may be a restriction on the inlet side. Possibly a plugged pickup screen or not enough clearance between the bottom of the pan and the oil pickup (should be 3/8" or better).

amoparguy
"show those brand-X boys your tail lights!"

[This message has been edited by amoparguy (edited December 29, 2000).]

[Dr. Righteous]

The mellings HV oil pump came in today.
I will install it this weekend. I drove the car around some tonight. It has 60psi of oil pressure at 2000 RPM. Not too bad for a worn out pump after all.
I noticed the car didn't have any torque from a dead stop. At the same time it never shifted into third gear or so it seemed.
NOPE, it was never shifting into first gear.
I dropped it in first manually and hit the gas. IT imediately lit the rear tires up.
That was cool although that isn't what I intended.
The tranny is fresh so it needs some adjustments I guess.
Something else I have to figure out.
The engine STRONG and I have yet to tune it.

[440 Jim]

Your pressure was fine, 25 idle, 60 cruise, 75-80 cold. That is what I would expect with fully grooved bearings. Compare the new HV pump to the existing one. The HV pump should have taller rotors, otherwise you already had a HV pump.

If you don't have a 6qt oil pan (min), I suggest keeping the rpm below 5000 so you don't suck it dry, you might anyway...

[Dr. Righteous]

I didn't swap the pump yet. I was disgusted because the Lokar kick down cable kit I ordered from Summit needed a special bracket kit also to work. The ad in Summit vaguely referenced it but didn't state it was necessary for bolting up a MoPar install.
Now I have to wait another week. The hell with it. I let the cable hang and put 200 miles on the car today. It gets stronger with every mile

[Thunderhead]

It sounds alright to me. It wouldn't be a bad idea to upgrade to a hi-vol pump just as insurance, especially if you plan on running it hard. JMO!
Thunderhead