High Oil Pressure?

37Flat

37Flat

Senior Member
I've started my 221 several times now and all seems well except the oil pressure. I used a mechanical oil pressure gauge on my startup stand, as it's supposed to react faster. It shows pressure immediately after starting and I thought all was well, but the pressure shows to keep climbing until it pegs out at 100psi! I find it hard to believe that a stock 221 on idle would develop that much pressure with a stock 60# pump. Bad gauge? Any ideas?
Thanks for any help.
 
Could be the gauge. Are you sure the pressure relief valve in the engine valley is working properly?
 
Who assembled the engine? Maximum oil pressure shouldn't be higher than what the relief valve is set at. Guess the oil passages could be restricted to the point that it required maximum pump pressure to attempt to move the oil past the restriction. I would try a different pressure gauge but only run the engine long enough to get a reading (or try to get a reading without allowing the engine to start). If the reading is still high I would say the engine needs to come apart to see what is impeding the oil flow.
 
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I agree with JSeery and if the gauge is good, would first suspect the relief valve. Someone could have installed the relief valve incorrectly or used a wrong spring for it. I remember 'Ol Ron saying excessive pressure can damage the bearings. Using 10w-30 oil I get 70 lbs cold at idle but it drops to about 20 lbs at 175 degrees running temp at idle, and all that seems about ideal. Let us know what you find.
 
What I would do (after confirming with a good gauge that still reads high) is remove
the intake and all spark plugs. Remove pressure relief valve jump starter solenoid and
watch to see if you get a good flow of oil if not there is a blockage preventing the relief
valve to do its job. If all is good focus on the relief spring and valve. If all is not good
well you know whats has to happen. Maybe the first two cam bearings installed incorrectly???? I suppose you could put 60# shop air into the oil sender port & listen??
 
Even if the bearings are blocking the flow the relief valve should do it´s job unless the return path is blocked.
And the stock 221 pump is not putting out a high flow...so i agree on that relief valve is high on the list of suspects.
 
OK, I'll check the gauge first. The engine was rebuilt by an experienced mechanic - does lots of flatheads. The relief valve has a new spring (Mac's) and seemed ok when I put it in, but I guess I'll find out. Let you know what happens. Thanks for the help.
 
Ok, after a few delays, I have checked the gauge with 60#'s of air pressure and it held steady at 60. I pulled the relief valve - it seemed fine, but I went ahead and changed it out for the original one. Put it all back together, cranked it and it started right up, ran smooth and the gauge climbed to 100#'s. The picture shows how the gauge is hooked up, but I can't imagine how this would make it read high.

Any other thoughts before I go discuss this with my machinist? Thanks.
 

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Don't remember you saying you have an external filter. Remove the filter and jumper the oil lines across and see what happens. I would not keep running this engine if the oil feed is restricted to the bearings!
 
Are you using a 59AB oil pump? Also, I would measure the pressure at the inlet to the engine after the filter. I'm surprised that 100 psi doesn't blow the seal on the oil filter.
 
That doesn't look right. Although it looks like you have 1/2" lines those fittings in the block dont look like 3/8 NPT ? I could be wrong.. You definitely have the grub screw in place between the two ports. Shorten those lines as much as possible, double check they're on the right way round [Ask Ron ; o ) ]. I can't see how you can pull over 60 lbs the relief should be doing its job, unless you have a blockage in the pipe....maybe??
 
flatjack9 said:
Are you using a 59AB oil pump? Also, I would measure the pressure at the inlet to the engine after the filter. I'm surprised that 100 psi doesn't blow the seal on the oil filter.
Click to expand...

I have blown up oil filters, I also would be concerned about that.
 
Talkwrench said:
That doesn't look right. Although it looks like you have 1/2" lines those fittings in the block dont look like 3/8 NPT ? I could be wrong.. You definitely have the grub screw in place between the two ports. Shorten those lines as much as possible, double check they're on the right way round [Ask Ron ; o ) ]. I can't see how you can pull over 60 lbs the relief should be doing its job, unless you have a blockage in the pipe....maybe??
Click to expand...

Yes, they're 3/8 - Red's Headers Full Flow Kit. In on the filter is going to out on the block and vise a versa, assuming the machinist did it the way the directions said.
 
flatjack9 said:
Are you using a 59AB oil pump? Also, I would measure the pressure at the inlet to the engine after the filter. I'm surprised that 100 psi doesn't blow the seal on the oil filter.
Click to expand...

Yes, it's the one that came out of the engine. Everything was good, so I just cleaned it and put it back.
 
The center port on the remote filter should be connected to the "in" side of the engine. It looks like the out from the engine is attached there.
 
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