TO 20 Oil Pressure Question

maxazillion · Apr 24, 2015

Hello All,
I just got done rebuilding my TO 20 engine. Had machine shop rebuild the head, oil pump, etc. The engine runs good but I have real high oil pressure. When I start it I have over 100 psi according to 2 different gauges. My question is will it damage the motor having this high oil pressure? Thanks for any replies.

Steve@Advance · Apr 24, 2015

That's not good! Something will eventually give, like the oil pump, or "wash" the babbet off the bearings. There is an oil pressure relief valve, on the Z134 it's in the bottom of the oil pump, not sure on your engine, someone will know. The valve is stuck or assembled wrong.

Richard L · Apr 24, 2015

The Owners Manual says: A relief valve in the pump body by-passes oil if the pressure exceeds 30 pounds.

Tom H. · Apr 24, 2015

Pull off the pan and remove the cotter pin on the bottom of the oil pump. That is the pressure relief valve. You may have an added washer there to increase the pressure. Go with just the spring and one washer and see how it is. Or pick up a oil pressure tester (harbor freight) $20. And then check it. Still may be an over tightened pressure relief spring.

Bruce(OR) · Apr 24, 2015

I have heard of eating out the bearings.

Steve@Advance · Apr 24, 2015

Tom, that makes sense, someone was probably trying to get the pressure up on a worn out engine, blamed the pressure relief, stretched out the spring or added shims. Now the engine is right and the relief is wrong.

TO 20 Oil Pressure Question

maxazillion

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Steve@Advance

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Richard L

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Tom H.

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Bruce(OR)

Well-known Member

Steve@Advance

Well-known Member

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