Oil Pressure Question

[DollyDodge]

I took my B-2-C for a short trip on Sunday. She ran great. The oil pressure runs about 40 as long as the engine is running at at higher than idle. When it idles after the engine is warm the pressure drops to about 20, is that ok? I am paranoid about the pressure, given my fix with the spun rod (I replaced all rod bearings and emoried the journal where the rod was spun). I have run the engine at idle for about an hour every other weekend or so for several months, plus the one road trip of about 10 miles where the oil pump quit. I got the pump rebuilt and the rear brakes rebuilt and decided to take her for another spin, I only ran up the road a couple miles and back. She ran great. There is a picture of her this weekend out on the highway in my album.

[Reg Evans]

Sounds pretty normal. What oil are you using ?

[DollyDodge]

Just regular penzoil 30 wt.

I wasn't sure if the oil pressure dropping off at idle was to be expected or not.

My brother bought me a new oil pump for Christmas. I need to get that on as well even if the old one is good. At Christmas my family got all kinds of stuff for the truck. They all have driven her at one time or another over the last 40 years.

[JBNeal]

I agree, that sounds normal. I have deduced that the '49 1ton has a sticking oil pressure relief valve, as my oil pressure is 40psi at cold startup, but after letting off the throttle after driving it around for 10 minutes, the gauge hangs at about 20psi. Doesn't smoke, no crud in the oil, just a low gauge reading...another thing to get to on the to-do list.

[DollyDodge]

thanks

[Reg Evans]

If the engine hasn't been cleaned out inside for a long long time try some 40 weight non detergent. It's won't loosen the crud an bring it back into the system.

[jmooner3]

Is 30 weight the preferred oil of those of you "in the know"? I live in Vermont but only plan to drive my toys in the many seasons other than winter (that's the other 3 months of the year here where it's above 4o degrees .

[greg g]

Mud season is right around the corner isn't it????

The service manual states the its even normal to show no oil pressure on the gauge at idle. A bit disconcerting, but it also says 10 per each 10 MPH is good rule of thumb for normal.

[Fernando Mendes]

The instrument panel oil gauge indicates oil pressure delivered to camshaft,crankshaft,timing chain and connecting rod bearings when engine is running.Proper registration should be not below 10 on idle nor more than 80 at speeds above 10 miles per hour.

[DollyDodge]

Thanks for all the info. I feel better now about what I was seeing on my guage.

[1949P17BC]

CAUTION, let a sleeping dog lie (sludge) I would be carefull trying to break it up in the system, You will pump it thru the entire motor. If you are concerned, pull the pan and clean it that way

[aero3113]

In my 50 Plymouth manual it says any pressure above 0 is normal at idle.

[MBF]

My machinist recommended a 10-40 high quality hi detergent with a zinc additive for the cam/tappets. Dropping the pan is no big deal in a truck-did mine last week. Let the front suspension hang and support the vehicle by the front of the frame-this will give you more room to maneuver the pan in and out since the front axle will give you more clearance. Mike

[DollyDodge]

I pulled the pan some months ago, cleaned it out really well. The engine probably has about 10 hours on it since I put the new rod bearings on. The oil on the dip stick is still very clean. I don't think there is much sludge in the engine anymore. I was just curious about the oil pressure. That low pressure at idle kind of worried me.