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Old 05-03-2012, 08:46 AM
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Hello Gary,

First in my opinion your oil pressure is fine and good to go. I have seen newly rebuilt SBC engines with almost 0 oil pressure at idle after warmed up and only 30 psi under power or at cruise speed. They still ran fine. They were set up with the clearances on the high end for drag racing.

What you must have is circulation.

Very high oil pressure (i.e. 80-90 PSI) can actually be harmful to the engine as the oil is forced thru the journal area resulting in the shaft actually touching the bearing surface instead of floating on a film of oil.

Some reasons for low oil pressure: Excessive clearance between the cover plate and the gears in the oil pump body, main bearing clearances acceptable but on the high end, excessive clearances between the cam bearing journals and the cam bearings, internal leaks in the oil passages, missing oil passage plugs. Wrong viscosity oil can contribute. Your engine and the factory clearances were designed for straight 30 wt oil. Unless you have tightened up the clearances, you may have difficulty maintaining oil pressure at a level you think it should be, if you run multi viscosity oil.

Hope this info is helpful to you.

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Old 05-03-2012, 08:51 AM
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Frisco,you brought something to my attn---now that I think about it ,the end plate on the oil pump had been reversed once and it was scoured on both sides. The fellow that did the engine smoothed it out,but maybe that has something to do with it????It has 30 wt in it now,wonder if I should stick with 30 wt or go to a multi viscosity???
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Old 05-03-2012, 09:05 AM
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Quote:
Originally Posted by yragat
Frisco,you brought something to my attn---now that I think about it ,the end plate on the oil pump had been reversed once and it was scoured on both sides. The fellow that did the engine smoothed it out,but maybe that has something to do with it????It has 30 wt in it now,wonder if I should stick with 30 wt or go to a multi viscosity???

Smoothing out the plate is good. Was it checked for flatness as well? If it is warped it should not be used.

Replace the plate with one that has no scouring or scratches. The clearance between the plate and the face of the oil pump gears should be almost '0' to maintain the oil pressure. As the clearances increase, then the oil can 'by-pass' around and still circulate but not yield the oil pressure you could have with the correct clearances.

It has been suggested by others to stretch or shim the by-pass spring. Either can help increase the oil pressure provided that the ball or check valve the spring pushes against fits without leakage. If that doesn't seal correctly no amount of additional spring pressure will increase the oil pressure.

Even if you can locate a new oil pump, the clearance of the cover plate to the face of the gears should be checked and corrected if needed.

I personally do not recommend multi viscosity oils be used in an engine not designed for it. The choice is yours.
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Old 05-03-2012, 10:19 AM
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The main lines on the 390 a 428 blocks seem to have alot of issues, I just finished a 428 super CJ and I did measure the lifter bores and they showed alot of wear and had to bush them back to standard clearance with HYD. roller lifters is .0015 to .0018 This engine idles hot at 60 pounds with a HV pump.

The 428 had to be line honed twice more so because of alignment issues.

Good luck
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Old 05-03-2012, 10:48 AM
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Quote:
Originally Posted by CNC BLOCKS NE
The main lines on the 390 a 428 blocks seem to have alot of issues, I just finished a 428 super CJ and I did measure the lifter bores and they showed alot of wear and had to bush them back to standard clearance with HYD. roller lifters is .0015 to .0018 This engine idles hot at 60 pounds with a HV pump.

The 428 had to be line honed twice more so because of alignment issues.

Good luck
This is a 390 CADDILLAC--not FORD!!
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Old 05-04-2012, 04:41 PM
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So,everyone's been real nice suggesting different fixes BUT do you think this is serious enough to warrant tearing into things,or should the pressures I have be OK?
It has to be getting oil,there are no noises that would suggest that it isn't getting lubrication ????????
Thanks
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Old 05-04-2012, 04:58 PM
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As long as your pressure stays above 10-12 lbs. at idle you should be OK. If it gets up to 25-30 lbs. at cruising speed you should also be good.
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Old 05-04-2012, 05:33 PM
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Gary,

See my reply at post #16.
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Old 05-04-2012, 08:16 PM
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Quote:
Originally Posted by yragat
This is a 390 CADDILLAC--not FORD!!
Sorry I did not know I was suppose to be a mind reader!!!!!!!!!!!!!!!!!!!!!!!!!!!
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Old 05-04-2012, 09:02 PM
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Originally Posted by CNC BLOCKS NE
Sorry I did not know I was suppose to be a mind reader!!!!!!!!!!!!!!!!!!!!!!!!!!!
You are absolutely right!!!
I'm sorry,I thought I said it was Caddy,but I see I didn't---getting senile!!!
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Old 08-10-2012, 04:09 PM
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Well,got a little over 2000 miles on it and no problems ,pressure is between 18-22 no lifter noise or other problems!----Will pull the oil pump this winter and have it all checked out. Egge said they will check it for $20.00 this is what they said

We rebuild pumps here in our shop and have the capabilities to test your pump. We test at different RPM’S and with hot oil. Once the pump is tested you will know if the pump is the problem or if you have other issues.

Thank you,

Sounds good to me!!!!
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Old 08-10-2012, 05:49 PM
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Quote:
Originally Posted by yragat View Post
Just had my 390 (1960) totally rebuilt. Before rebuild it had around 20 lbs oil pressure all the time,Now it has 30 when engine is cold then drops down and hoovers between 18 & 22. I have an electric gauge---went & got a manual gauge& it read same thing. There is no engine noise,so I think its getting oil everywhere. Should I be real concerned about this and has anyone else had this happen,and I it is to be concerned about,what has to be done to correct it? Right now it has 30 wt break -in oil in it and will be changing it in about 300 miles. This is not a high revving engine,I have 2.79 rear gears and its in a light car,so when cruising at 50-60 on level it practically idling,but if I do rev it the pressure doesn't go up much
Thanks
Gary
For a 1960 Caddy these numbers are good for 30wt.

Bogie
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Old 08-10-2012, 06:05 PM
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?? book says 15 idle and 30-35 when driving
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Old 08-10-2012, 06:18 PM
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Originally Posted by yragat View Post
?? book says 15 idle and 30-35 when driving
Those are a minimum at below which point attention needs to be lavashed on the engine, your set up is a bit higher and that is just fine. It's not like the releif spring is stuck at a 120 psi and it just blew up the filter can.

You have to remember in their day these were stately automobiles for the wealthy or wanna be wealthy. Not that they didn't have a Jag, Bird or 'Vette for putting the peasants in their place on the street, but when taking the wife to the Ritz or the guys to the club it was the Caddy that lead the procession hence the complete effect from plush seating, to soft shifting that this machine was a mobile extension of your living room.

Sit back and enjoy.

Bogie

Last edited by oldbogie; 08-10-2012 at 06:25 PM.
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Old 08-10-2012, 09:06 PM
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Did you check the clearence on the crank with plastic-gage? If so what was your clearence? Try a heavier weight oil if you have a large clearence. That will bring your preasure up.
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