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rebuilt 350, burning oil just like the engine I replaced?

8K views 22 replies 7 participants last post by  JesseShredd 
#1 ·
Rebuilt engine, has 7000 miles on it. Replaced an engine with oil leak in #1 chamber. When running hot it burns oil just like the first, could this be due to oil from the last Sbc remaining in the pipes? Also what comes to mind is that there is no clearance between my y pipe and oil pan...not sure if that could be related. Engine is also running at 230-240 degrees with fan on. Thermostat is fine, water pump is new, not sure what the issue could be. Any opinions are appreciated! Great to be part of this board! -Jesse
 
#4 ·
I didn't do the rebuild. It was professionally done. I do know he installed umbrella seals. I'm assuming once the engine is up to normal running temperature, its just burning all the feud from the cat, back. Inside my tail pipes are thick of black crud.
 
#8 ·
oil burning

I had a similar situation with my 357 sbc using an aluminum intake on iron 041heads and felpro intake gasket set. When my engine got hot and then cooled the intake swelling from the heat would literaly tear the gasket allowing oil to leak into the combustion chamber. I know it sounds funky but after installing new intake gaskets that have metal in them the tearing stopped and thus the oil burning. The heat must also be dealt with asap. Mine smoked noticably and was freaking me out with all the dough I spent meticulously assembling my motor. I thought I knew everything but this was a learning lesson for me! I will find the part # of the gasket set that only cost $10 from my machine shop here in Portland and post it as soon as I can. Cortect I think is the MFG? Timing can effect the overheating also, you might want to confirm you are where it should be for your cam. I run at 11 degrees and added a cross flow aluminum radiator that cured my problems. 400hp, th400 (chirpomatic), 373 10 bolt open gear (crash prevention). Posi coming though! Hope this helps.
 
#13 ·
YES, you need a V8 cooling system.

Are you just letting the car sit and idle until it gets Hot? You should at least have a house or shop fan blowing across the radiator.

Before you start swapping parts, check the timing, pull the plugs and inspect them. Also do a compression test to check the condition of the motor.

Report back and we'll help from there.
 
#15 ·
Will be replacing the intake manifold gaskets with edelbrocks. I will let everyone know how it turns out. In the meantime, Amy suggestions on what to do about the engine running hot would be appreciated. I let all the air out of the system yesterday, which didn't make a difference.
 
#18 ·
you definately need a v8 rad. also. if you don't have info on the rebuild, check to see if there is a rebuild tag or work order number stamped somewhere on the block. ask around who might have that kind of stamp. you may be able to get some info from the builder. when you take the manifold off to replace the gaskets, check to see if the intake fits the heads. sometimes the head gasket surfaces get machined and that makes the mating angles to the intake manifold wrong. it can leak oil or air. both could cause the problem you are having. a lean running engine will run hot, also oil sucked into the manifold plenums will cause smoke. it happened to a friend of mine who had an olds engine. the shop had to plane the heads a bunch and put them on anyway. mostly because they couldn't find another set to fit. it ran hot and smoked, aspecially when hot because the oil got thinner maybe.
just a thought.
 
#20 ·
make sure to check the intake without a gasket so you know for sure about any spaces etc. also, make sure the gasket is installed right becaus those rear ports are sometimes covered so the coolant flow goes the right way without short cutting.
other things to check
-pcv valve and baffled cavity in valve cover under the pcv to make sure it isn't sucking oil in that way. some aftermarket covers don't have much for baffles under there.
-auto trans vacuum hose (if equipped) to modulator valve. if modulator valve is leaking the engine can suck up trans oil.
-document how much oil is being used. check it the same way every time-like if it is hot and just shut off or, if it is hot and has sat for several minutes so the oil has had a chance to find it's way back to the oil pan- making the level higher than if checked right after shut down.
-make sure it is engine oil and not trans fluid or coolant.
-pressure test the cooling system to make sure you are good to go there. did you flush the rad etc before assembly was finished? is the core clean on the inside?
-are all the plugs burning the same as far as what colour they are when you take them out? a dark plug can tell you that cyl is getting oiled or fueled more than the rest. make sure to have the proper reach on the plug and correct heat range. too long of a reach can cause hot running, as can too hot of a heat range.
keep us posted.
 
#22 ·
go with the 3 core rad. you know what they say, go big or go home. also have a new thermostat installed at the same time, and not one of those knock offs, a real gm thermostat. I have had lots of trouble with the cheap thermostats and then finally put in a gm one and problem is solved.
 
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