260 Oil Pressure

[Tudelum48]

I have been trying to get my Comet running again after several years of sitting. After I started her up I noticed my oil pressure was lower than I remembered? I had never noticed it years ago so I'm assuming it wasn't running low then. Anyhow I put a pressure gauge on it and it's running about 13 psi at warm idle and 27 giving it enough gas to simulate running down the road.
Anyhow I have pulled the oil pan off to put a new oil pump on it and all looks good with no shavings or metal in the pan so I'm hopping it might be the oil pump? I'll find out in a day or 2.

How much oil pressure are you running on your 260's? Book I have says 35-55.
Also are you running 10W30 or 10W40?
Thanks Gary

[Groover]

Seems like mine runs about 20-45 when I hook up a gauge with numbers on it. When I run the stock gauge it's just barely into the middle range (closer to the left mark).

My engine is fresh rebuilt though.

I run 10w-30

[Comechero65]

Not to steal this thread but I'm curious what most see on their comet dash oil pressure gauge. Where on the gauge do most read and what values do the different marking translate to. Since I got mine going my gauge always reads near the top mark. I did calibrate all the gauges and have a new CVR installed. It's a new engine with everything new including the oil pressure sender. I don't think it's normal for the gauge to register that high but I can live with it that way. Have no idea what the actual pressure is as have never hooked up a gauge to check it. Just wondering.

For many years my mustang always registered near the bottom mark but never a problem so I never worried about it.
Ron

[Tudelum48]

Mine would come up about 2-3 widths of the gauge indicator past the low mark and the gauge when I installed it was,about 27 psi at that engine speed.
My motor is a fresh rebuild also but it was done 11 years ago and then sat.

[65clevorcyclone]

When the rebuilt 289 thats in my falcon was in the comet it would peg the factory guage all the time. With an autometer guage it reads 75psi cold and 45 hot at idle.

[Tudelum48]

Well I switched the stock pressure oil pump for a new stock pressure pump and also went with 10W40 oil instead of 10W30 weight oil. My pressure dropped from 13-27 to 6-20. Looks like I'm going to have to pull the motor. Doesn't make sense the pressure dropping? Any ideas?

[Comechero65]

You did replace the gasket between the pump and block I would think. Could be just a defective pump. No other explanation. Changing oil visc shouldn't make the difference.
Ron

[Tudelum48]

Yep I put both gaskets on. Suction and block side. I did clean on the suction tube some but it was clean and clear. Makes no since that it would drop.

[Comechero65]

If the replacement was new it should be equal if not better. 3 choices, leave it as is, put the old one back in, or get another one. Pain no matter what.
Ron

[65clevorcyclone]

i run 15w-40 in my engines. It picked up about 10-15psi from 10w-30 oil i used for breaking it in.

[Comechero65]

i run 15w-40 in my engines. It picked up about 10-15psi from 10w-30 oil i used for breaking it in.

I don't doubt that at all. I run 15W-40 RPM Delo in my diesel.
Ron

[Tudelum48]

Well we are bracing for a cold spell coming through right now, not like in the north but still single digit's. It might be a few days before I get up the nerve to go out and build a fire in the shop. I guess I'm going to pull the motor and do some checking on the mains and rod bearings. If that doesn't show up a problem I will take a look at the cam bearings.
I got in contact with my ex-neighbor that rebuilt the motor 11 years ago. He was the guy all the stock car guys came to for rebuilds and info. He had a good reputation of quality work. He had the heads redone with valve seats for unleaded gas, bored first over with new pistons, and all new bearings in the cam and mains and rods.
New oil pump and fuel pump.
He said it had good oil pressure when he started it so something must have happened when I restarted it 11 years later.
11 years ago I didn't have time to rebuild it myself between work and kids so I left it up to him. I didn't even remember what he had done to my motor?
Well with the oil pressure dropping from 13-27 to 6-20 after adding a new oil pump I'm pulling it and putting it on my engine stand that's sat unused for 20 years LOL.
I have time now.

[gmsnowball]

Just for grins and giggles why not try another oil pressure gauge first. My 260 had low oil pressure or so I thought. It prompted me to pull the motor and overhaul it. Long story short, there wasn't anything wrong with the motor, other than having 109,000 miles on it. The pressure showing low caused me to think I needed to rebuild it. My gauge read exactly like Groovers.

Made the best of the situation by installing several goodie go fast parts that only makes it sound better and run only marginally faster. There is just only so much you can do with an engine that has small holes and heads. Good luck on whatever you decide.

[65clevorcyclone]

What oil filter?

[Tudelum48]

Oil filter is a Motorcraft FL1A. I also changed it when I switched the oil pump and went with 10W40 oil.