Re: [FWDLK] Oil Pressure on 1955 Poly

Tom,

One reason it takes time to build up your oil pressure, is your oil is too thick. A straight 30 weight oil will be too thick to flow rapidly through the oil filter to the bearings when starting a cold engine. Try using a 10W-30 weight oil, or maybe a 10W-40 if your engine is high mileage and you drive mostly in warm weather. Do not use Penzoil.

All oils get thinner (lower viscosity) when hot. Multiweight oils are much better because they do not thin as fast as a straight weight oil. With a 10W-30 oil, it has the viscosity of a 10 weight when cold for quick oil flow at start up, and of a 30 weight when hot for good shear strength for bearing protection.

Ron is correct, your oil is probably draining back into your oil pan. This is common on older engines when the clearances inside the oil pump grow, allowing the oil to leak back into the pan. When the engine is started, the oil filter needs to fill up again before oil will be sent to the bearings.

One fix for this oil leak down problem is a modern spin-on oil filter. These have anti-drain back valves in them. This is just a flap of rubber that prevents oil from draining out of the filter back to the pan. With a full filter, oil pressure will come up much faster during start up, which is MUCH better for the bearings. Hot Heads (P/N 21002) sells these adapters:

http://www.hothemiheads.com/dodge/oiling_system/oil_filter_adapter_30d.html

Dave Homstad

56 Dodge D500

-----Original Message-----
From: Forward Look Mopar Discussion List [mailto:L-FORWARDLOOK@xxxxxxxxxxxxx]On Behalf Of Ron Allyn Swartley
Sent: Wednesday, October 04, 2006 11:57 PM
To: L-FORWARDLOOK@xxxxxxxxxxxxx
Subject: Re: [FWDLK] L-FORWARDLOOK Digest - 3 Oct 2006 to 4 Oct 2006 (#2006-17)

Oil Pressure on 1955 Poly engine Plymouth

Tom,

When the cars sits overnight the oil drains into the pan. When you start it up and the idle goes high,----- that is the mains rattling because the oil has not gotten to them yet. It is better when you change oil because the new oil travels faster then the old dirty oil.

I recommend that you maybe clean the screen on the pickup in the oil pan just incase it is a little clogged and maybe add a can of STP or my favorite Dura Lube. The Dura Lube will free your engine up and the idle will go up about 100 to 250 RPM just minutes after you pour it in your car. When you shut the car off it will stay on the metal parts.

Ron Swartley

-----Original Message-----
From: Forward Look Mopar Discussion List [mailto:L-FORWARDLOOK@xxxxxxxxxxxxx]On Behalf Of tom taylor
Sent: Wednesday, October 04, 2006 12:31 PM
To: L-FORWARDLOOK@xxxxxxxxxxxxx
Subject: [FWDLK] Oil Pressure on 1955 Poly

When I first start my 1955 Dodge with the 270 Poly V8, the oil pressure takes 5 or so seconds to get the guage moving and up to operating pressure. It runs around 45 pounds at idle once it builds up or at least that is what the guage shows. If I pump it and let it crank and idle and build up, no problems. If it goes up past idle at start, I hear what might be mains rattling. It seems to improve when I changed the oil. I run 30W in it.

Any ideas what the cause is?

Tom Taylor