incubator16

ok... go easy on me, im new

i bought a 92 rs with a 350 tbi in it... the guy said the engine was a 4bolt main from an rv previously and did not know the millage and the car sat for a year. engine has a leaking front seal. My first question is about blow by...what are some dead give aways... other than exhaust coming out of the valve cover. They put a breather filter on the valve cover and it will smoke a tiny bit, not sure if this is normal or not. oil pressure is good until its warm then its very low. and it blows a puff of blue smoke on start up and thats it. we are going to rebuild the engine when the weather breaks so im just wondering if there is anything i can do to kinda fix it for now?

and can a bad front seal cause low oil pressure? i check the oil every time i start it so i know its not low?

Apeiron

A small amount of smoke from the breathers is normal. Put a working PCV system on it instead.

Smoke on startup is from leaking valve stem seals.

A bad front seal won't affect oil pressure.

incubator16

alright, i guess it could just be worn cylinders or rings for the low pressure. ill try a manual guage or a compression test.

Apeiron

Cylinder and ring wear won't cause low oil pressure either.

incubator16

what would then? bad oil pump?
the car was sitting for about a year so im doing a tune up this weekend. the oil has a little gas smell just after changing it, maybe that will help a good bit with the problems

Apeiron

Why do you think it has low oil pressure?

incubator16

just from the cluster and paranoia haha. start up it idles slightly above 20 psi and driving it stays around 40. once the engine is warmed up the pressure is sightly above zero at idle (no knock) and driving maybe about 5. the gauge does jump around right before the engine is hot then it stays low and still fluctuates with the rpms. i know gm is known for the bad (inaccurate?) sending units, but i thought it was more of the gauge just staying not working at all?

Apeiron

The absence of clattering and knocking says more than the reading on the gauge.

incubator16

Good point, I'll try a manual gauge just to be sure with the pressure. It's not a daily driver, but I'd like to drive it a bit before we build it. Thanks for the help

Beef

iTrader: (1)

Main bearings and cam bearings are the normal culprits for low oil pressure, especially if the change is dramatic with temperature, yours seems a bit low even with cold oil. The pump is rarely the problem. Pressure can be really low before you hear any valvetrain or rod noise, doesn't mean damage isn't happening. However GM senders have done strange things many times before, and heat can/will effect impedence.

incubator16

since this engine is out of a truck do i need a different rebuild kit? is there a difference between a truck block and a car block? i cant see the serial number on the back so i think i have to wait till we pull it

Apeiron

Blocks are the same.

RBob

iTrader: (1)

As for the front cover seal leaking, make sure that it isn't the bolt hole that is typically used to mount the AIR pump. It is open to the push rod tunnel for a mechanical fuel pump.

The bolt hole is on the front of the block on the passenger side. Note that there are two there, with one of them going into the fuel pump push rod tunnel.

RBob.