oil pressure

[crownfiretruck]

I am new to the forum. I have beenl reading and notice a lot of experience out there. I have a problem maybe someone can give me some advice.

I inherited a 31 coupe in pieces. I managed to put it together and got it driveable. My problem is that when I start the engine, I get 200 pounds oil pressure. After idleing for 5 minutes, oil warming up, it idles at 50 pounds.

I found out that it is a "B" engine and overhauled in 1973.

I changed gauges and the same results. I am running 30 W. oil, I am thinking about putting 10W oil in it, running it for a couple of minutes and then put 30W back in it. Maybe it will clean up a little.

Open to any advice and suggestions

[James Rogers]

Never seen even a modern race car run 200# pressure and 50# is plenty for any motor in a street engine. Your numbers are way off for some reason. A stock B will run about 10# at start and 6# when warm. A model A will run 4# when cold and 2# when warm. Even with full pressure on the rods and mains 40# would be plenty. I would check it again before you ruin something.

[MikeK]

That long oil galley gasket on a B will leak plenty at 20psi. Where are you taking the reading? Even blocked, I don't think stock B pump gears are fitted tight enough to hold 200psi.

[Cajun]

Do you have an side plate marked "Thomas" on the side?

[Jim Brierley]

With that much pressure the engine has likely been converted to full pressure oiling, but with no pressure regulator. Most of us run converted V8 pumps, they have larger gears and a regulator built into them.

[crownfiretruck]

Sponsored Links (Register now to hide all advertisements)

Thank you for the replies. I will try and answer the questions.

The readings are good, I have tried 3 oil gauges and get the same reading. I agree that something is going wrong.

There are no markings on the side plate. The plate has been drilled and tapped on the lower rear and that is where the reading is taken.

The gasket on the lower front, above the fuel pump plate has a small leak when starting but no leak after the 5 minute warm up.

[Cajun]

I think Jim is right about the modifications. My engine has a Dan 4 Banger oil pump. It puts up 75-80 psi cold and then settles out at 38-40 at run temperature. We have a full filter set up and restrict the oil pressure downstream of the filter with a relief valve dumping oil back into the pan.

The original set up on the D4B pump was a relief valve in the pan. I did not like this because you had to pull the pan if there was a RV failure. Dan generally requires that you use the Thomas side plate. That is why I was asking about it.

[Mike V. Florida]

Originally Posted by crownfiretruck

I found out that it is a "B" engine and overhauled in 1973.

Do you have any idea what was done during the overhaul.

[Allanw]

I'd be wary of putting 10 weight in it - if it warms up, it'll be too thin and may damage something (although with the pressure, it's unliekly)

Some 5W-30 or 0W-30 would be safer - it will lower the cold pressures, but won't get any thinner than you 30 is when hot - it'll give you roughly the same hot pressure. Might as least keep it runable for a while so you can do some diagnostics.

Sounds like there is something wrong though. There is either a massive pump, or there is a blockage which will be starving your bearings of sufficient oil.

[Mitch//pa]

I have seen pressure like that on modern stuff from a stuck oil pump pressure regulator valve or a broken p/r spring.

[1931 flamingo]

Time to pull the side cover or the pan to see what's in there. JMO
Paul in CT