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Very high oil pressure causing leaks

9K views 58 replies 8 participants last post by  Pupsvette76 
#1 ·
OK guys need some help here, i have an issue with my 70 nova that makes it undriveable due to its smoking, it leaks oil out of the valve covers but not the gasket its coming out of the breather holes. my oil pressure is crazy high it reads 99psi at WOT but the digital gauge only goes to 99psi so it may be higher. At idle its 60-70psi and that with 5w-30. Last time i took it out i drove it hard and had to come back home because it was smoking so much. it has a SBC 355 roller cam with AFR heads professional products EFI and a GT45 turbo on it. I have an oil filter sandwich adapter on it that i have the two port plugs on and a oil restrictor on the feed line for the turbo... just wanted to mention that because they are in the oiling system. Thanks in advance guys
 
#36 ·
Gen1 engines are generally considered to be the standard coolant flow engines produced from 1955-2000. The Gen2 is the LT, reverse flow family. Gen3 the LSx.

I dont know what engines you're working on, but I'm staring right at a 1996 Vortec truck engine long block that was replaced under warranty by GM for oil consumption and it uses the same bolt on oil filter/bypass component commonly found on the Gen1 engines.
Maybe the Gen2 engines use the setup you're referring to? I've put distributors,cams, heads and headers on LT engines but I dont know if I've ever changed the oil in one.
 
#37 · (Edited)
1980 - 2005 engine in GM cars and trucks have a oil filter by-pass in the block and use a oil filter that does not have a by-pass. Such a filter would be a WIX 51036, which has no by-pass.

The 502 CI Chevrolet engine has two by-passes in the block. One if for the oil filter and the other is for the oil cooler. By-pass valve part numer GM-25161284
 
#41 ·
Excessive oil pressure does not relate to excessive crank case pressure. Excessive crank case pressure will push oil past seals. If your oil pressure is actually 99+ then that is a problem but i dont think it is causing your valve cover leak.
 
#42 ·
I may have more than one issue one being the oil pressure and the other being the oil coming out of the breather hole on the vc just thought they may be connected.... Since the last time I drove it I have added the evac kit and baffles in the vc hole so the oil spraying out may be fixed but I'm trying to deal with the oil pressure issue now because I don't want to drive/run it if the engine is not in good running condition
 
#55 ·
sounds a little high, but not far off from normal. usually you're looking at about 40psi at idle, 65psi at WOT.

with your high pressure some people would move down a weight in oil viscosity- you'll see a little more flow that way and your pressure will drop a little. There are other factors to consider of course but it can be worth some power and mileage.
 
#58 ·
a good turbo can handle 0w-30 or 0w-20 with no problem provided you're not overheating anything and your tune is good.

An ebay turbo... I don't know. I'd probably run it at 0w-30 if I were you as it'll provide adequate pressure and more flow, and more flow is a good thing.
 
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