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oil pressure gage bad or engine needs rebuild It starts our cold at 60 psi but when warm it down to 10 psi

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sim

sim

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so is this a bad gauge or engine rebuild? I do not hear any knocking and engine runs just fine. opinions please
 
You could certainly try a new gauge in there, but 10psi warm is, as you know, an issue. At just over 20psi my MGB didn't knock and seemed to run fine, but it was sure tired.

If you don't try a new gauge, I'd want to get into that engine and give things a real look over.
 
sim said:
so is this a bad gauge or engine rebuild? I do not hear any knocking and engine runs just fine. opinions please
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it been a long time since I had the oil pan off. what should i look at first. ? Can the cam shaft be pulled out with out pulling the engine?
 
Wild guess, but easier than a tear-down - could the oil pressure relief valve be sticking open when temps in the block get high? What happens if you let it come to operating temp at or just above idle so the oprv never pops open?

Bob
 
Where is this valve located? When I start it up cold , I get 60PSI but when it warms up while driving it drops off to 10 PSI.
You are suggesting I just start it up and let it idle to warm up
 
To see what and where to oprv is, look at the Moss catalog diagram. Yes on running it at or just above idle until it reaches operating temp to see if pressure continues at satisfactory levels when you have not opened the oprv.
Bob
 
An oprv is in a main pressure gallery coming off the oil pump. When oil pressure gets excessive, the valve opens from the pressure and lets oil drop back into the pan instead of continuing to add pressure to the lubricating system. Opening pressures are typically 65 or 70 pounds, but tinkering with the spring or replacing it can affect the pop off pressure.
Bob
 
I drove a lot of miles in my Midget (1500) with 10lbs of pressure at warm idle. That with a refreshed engine. Obviously 10 lbs at speed is a problem but, the pressure drops a lot on these puppies when warm. I finally replaced the oil pump (should have done it with the refresh - doh!) The best intermediate decision was that I run a quart of Lucas engine oil stabilizer with every oil change - made probably a 10 lb pressure difference.
 
sim said:
How old is you engine? Would this be too thick on new parts?
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My TF 1500 has had 20/50 Valvoline VR-1 ever since it was rebuilt, it runs 50lbs hot or cold. The relief valve is set at 50lbs. PJ
 
sim said:
How old is you engine? Would this be too thick on new parts?
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I re-did the engine around 2010. I don't know that it would be too thick but probably Doc or someone with a bit more experience could chime in.
 
Our local MG/Healey guru says they all need 20W50 and he has a lot of experience.
 
up date I changed to oil relief system. change oil using 20 50 new oil filter . I now have 100 psi at idle . I think I need to go back to 10 30 . Opinions please
 
100, even at high rpm, would be too much. There is no way such pressure is actually possible at idle. The relief valve is irrelevant at idle because the pump could not generate the pressure to open it at idle.Try another gauge to ensure that the gauge is not the problem. I would run 10w30, although if you have a workshop manual that says otherwise follow the manual. What was the oil pressure condition before the low pressure cropped up? Have you changed any other components?
Bob
 
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