autoalain

folks, block new 60 over pistons/rings(checked end play on rings)heads totally redone, gas clean (no oil), stated up, no smoke for 1 min, then she smokes bad both sides of engine, verified 100% rings done correct(rite side up), removed heads, verified cylinders walls look good, started up again, rev at 1500 for 20 min, still smokes bad, vacume runs at 17lbs, runs very smooth, very very fed up, how can I tell what is wrong?, timing correct, dwell correct, I have done over 20 motors in my 70 years of life and have never had this problem with the 283, need some real good help on how to diagnose this issue. Thanks

autoalain

Note to above, no pcv valve on this engine, should I install one? I think I may install another intake, this will be last try, then I sell the whole dam car.;

jimh_1962

You are having a rough time with that engine... Feel for you since I went through some problems with mine too.

Spark plugs are probably fouled. Did you check the compression and do a leak down test? I remember I had the wrong intake gaskets and it caused issues with mine.

AZDoug

Sounds like you are sucking oil from either really worn valve guides or the bottom of the intake manifold/cyl head interface.

You are sure it isn't coolant smoke?

Doug

DansYellow66

I would second checking the fit of the intake and sealing of the gasket. May be sucking oil into the intakes. Possibly the block, intake or the heads or some combination have been machined and not matched back properly. If you pull the intake again look in the head intake ports to see if there is oil in them.

You definitely need some sort of breathing inside the engine. If no PVC maybe you have breathers on your valve covers - you didn't say. But on a new engine that isn't broken in yet your crankcase pressure may get a little elevated from ring sealing.

Good luck

GTOguy

Step one would have been to do a leakdown test prior to tearing it down again. Step two is to run a PCV valve. Not running one reduces engine performance and causes oil leaks. A leakdown test will tell you if it's rings or something else.

Frankie the Fink

X2 - I recall a thread not long back where this issue was causing oil consumption on a member's rebuilt engine..

autoalain

compression is 125 all cylinders, #1 plug and #4 plug show a litttle oil on them, others
are dirty but no oil, blue smoke, not white, started again this morning, ran 2 min them oil started bad again. I will change intake today, this will be the last straw, then I burn the f***king thing.

jimh_1962

Calm down, I need you cool. Do not set it on fire... Do a leak down test. Check the manifold and make sure it fits properly. You might want to make sure you are using the right intake gaskets. I know how you feel...

domenic tallarita

Had that happen back in the 70's after rebuilding a SB at the dealership.
Everything was in order. Found that the crank case breather was plugged up and it built up so much crank case pressure that it forced oil past the rings.
Followed the instructions on the work order but really didn't find the cause of the oil burning.
Really didn't need to be torn down. Like said above, many other reasons. You will find it.

Dom

DansYellow66

125 lb compression sounds a little low in an engine with a cam that will pull 17 inches vacuum. But if it's uniform across all cylinders maybe it's just the way you performed the test.

I leak down test is a better test of engine condition and worth running before getting too crazy. I don't think it will help much in detecting a bad intake gasket as air would have to leak past the intake valve first and is more likely to be apparent through the carb than to make it's way through the gasket to the engine valley and a breather - either one of which would be confusing.

GTOguy

You need to do a LEAKDOWN TEST, not a compression test at this point. A compression test will tell you zip about your oil issue and is not the same thing as a leakdown test.

autoalain

Ok update, did wet compression test. same 125 lbs...BUT.. all intake holes on head appear WET WITH OIL, after I just took off intake for 3rd time, I did not use the rubber gaskets at each end, now I suspect the intake gasket then sat a little low when installed, I am now going to install an aluminum intake WITH rubber gaskets at end, keping my fingers crossed,
so with new intake and gaskets sitting higher up this may fix it. will advise

AZDoug

Those 283s have little tiny ports. Dunno what intake you are using, but make sure the head side gaskets work with both the heads and intake ports, and are not too close to any edges to allow leaks.

GM, or similar, factory gaskets would be better choice than FelPros with giant runner port holes.

You didn't say if the heads were milled, or how much if any, the block was decked.

Doug

MikeM

I would suggest you set the intake on the heads/block and make sure you have a gap between the intake and block. If you don't (or don't have room to compress the rubber gaskets, that can hold your manifold away from the ports. Can also get you a cracked intake.

There are thick gaskets made for between the intake and heads. That may be what you need to fix your problem.

tbarb

If the block was decked or heads cut too much the intake manifold may not be siting flat or completely sealing around the intake valve ports and engine vacuum is sucking oil out of the lifter galley.

Do some internet research on the method but it may be a good idea to install the front/rear rubber gaskets only and some putty around the top and bottom of the intake ports then sit the manifold down on the engine and snug the four corners. Remove the manifold then check the putty to see how even the putty is pressed down around the intake ports. If it's out of alignment get some help from a machine shop because they can cut the front, back and sides of the manifold to get it to sit even and flat.

If you wrap the putty in aluminum foil or plastic wrap it will not stick so you can measure it. 125psi seems way low for a new engine, I would think 160 to 185 would be more like normal cranking pressure. Did you do the compression test with the throttle blades open?

autoalain

good idea, might try, heads milled, not block, I think rings have not set in yet due to the oil coming in from the intake area(oily tunnels) and throttle was open, today another day, will keep posted.

BROKEN RODS

I sonic test every OEM block that goes through my shop and I don't find many that are safe for performance build, I am sure it wasn't plate hone which intensifies the problem. Weak cylinders at .060 over once the heads are bolted on there is a lot of cylinder wall distortion which makes for poor ring seal. A leak down test @ TDC and about 40 degrees before or after TDC.

Here is a thread to look over
http://www.chevelles.com/forums/18-e...l-spacers.html

AZDoug

Factory blocks weren't plate honed. They made hundreds of millions and didn't have problems. a 283 should ahve pretty thick walls that .060" shouldn't weaken.

Plate honing only affects the very top part of the cylinder and may help the compression rings seal a little bit better, but oil control rings operate a little further down in the bore and scrape the lower swept area of the stroke.

The issue, as indicated by oily intake runners, seems to be a manifold seal.

Doug

desertpilgrim

I'm taking my cue from the fact that you say the oil starts appearing 1 or 2 minutes after startup........had this motor been blowing oil for a long time before the rebuild? If so, is it possible that the inside of the tailpipes and mufflers are coated with oil and require some "warming" before starting to exit?