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Discussion Starter #1
I just added new heads, new cam, new cam bearings, new rod bearings, new main bearings and a rehoned crank to my 350 engine . Now there is very low almost zero oil pressure at idle and about 10 or so at higher rmp. I double checked with a manual gague.

what could be the problem there?
 

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Improper (too loose) bearing clearances with one or more of the bearings allowing the oil to get around the bearing and journal thus lowering pressure to the rest of the engine.

Did you replace the oil pump or install the original oil pump?

A bad pump could also cause incorrect oil pressure.
 

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Did you check the clearance between the oil pump pickup and the oil pan when you put the pan on? If it is hitting the pan, you might not be able to pull oil into the pump.
 

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Wrong lifters will do this too. I spoke with a guy at a Cruise last Thurs that built a Roller 3.8 motor in his 87 T-Type Turbo and the recommended lifters from Comp in the book were the wrong ones for the cam he bought.
 

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And the simplest cause no one has mentioned is too much oil.

That happened on a roadkill the I just watched a few days ago.
 

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Discussion Starter #6
re installed same oil pump and all oil pressure was good previous. The clearance from pan to oil pump pick up is same as it was, with same pan and pump.. Oil shows at correct level on dip stick
I am having a feeling the rod and main bearings the machine shop sold me are incorrect size for the crank they also sold me
 

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re installed same oil pump and all oil pressure was good previous. The clearance from pan to oil pump pick up is same as it was, with same pan and pump.. Oil shows at correct level on dip stick
I am having a feeling the rod and main bearings the machine shop sold me are incorrect size for the crank they also sold me
Did you check the connecting rod and crankshaft bearing clearances during reassembly with plastigage?

If not, you'll need to drop the oil pan to do so at this point to eliminate that as a possibility.
 

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Did you check the connecting rod and crankshaft bearing clearances during reassembly with plastigage?

If not, you'll need to drop the oil pan to do so at this point to eliminate that as a possibility.
Checking with Plastigage could also be the issue, especially on the rods. I checked my 383 with plastigage and after hearing a few things about it, decided to ease my mind by having the machine shop re-check with inside mics, etc. Good thing, as the plastigage was indicating that I was way tight (especially on the rods) when in actuality I was about .0024 across the board. Had I loosened up the bearings the way the plastigage was indicating, I would have been way loose and probably in a similar oil pressure situation.
 

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Did you "Hot Tank" the block? Were the galley plugs replaced?
 
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