Thread: blow by and swirly port heads.

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Hey guys n gals,
i have a very annoying problem i have never experienced before. i am going to be extremely detailed to avoid confusion. here is goes. i purchases a sbc 350 that had some miles on it, it was burning excessive oil but ran well. i originally thought it had vortec heads but i have now become aware they are not. they are 1994ish swirl port heads #10110810 from a tbi truck. anyways the engine was rebuilt bored .30 over magnifluxed block and both heads. crankshaft grinded .010, resurfaced cylinders .007. knurilized valve guides. new flat top pistons, moly rings, new oil pump, oil pump shaft, main baring, rod baring. comp cam 12-238-2, int .462 ext .469 comp lifters. broke in cam with the recommended oil. here is where it gets interesting, engine runs great almost perfect, but it is still burning as much oil as before the rebuild! ill be honest it has alot of idling time as i was still working on the rest of the truck. i did not notice any oil burning, until i finally took the vehicle out. once warm it burns 1ltr every 100 miles. concerned i completed a leak down test cold. i have 20% leak on each cylinder. new pcv valve on drivers side cover, breather on passenger side.holly 4160 750 cfm, edelbrock intake. the intake center 4 holes have been reamed out to bolt to the swirl heads, i have removed the intake to review the gaskets. installed new fel-pro gaskets and confirmed they are sealing around the EGR port, as well as everywhere else. heat gauge reads 180, but some spots when skin touching valve covers are hotter then others. i see the puffs of steam out of valve cover breather and pcv valve when i pull them out and rev the engine.it appears i am getting excessive blow by on all 8 cylinders, all plugs are wet with oil. i only notice blue smoke when warm, it becomes more as the engine warms. im at a lose any ideas are appreciated. some extra info, it burned about the same amount of oil before rebuild, i found excessive carbon under intake before rebuild, im already seeing how this is continued after rebuild. i do not know what else to check? what other reason can be causing the blow by? maybe the rings did not seat? its peppy, and if it were not for the blue smoke i wouldn't think i had an issue its running very well

What type of seals were used on the valve stems?
And see if you can verify the intake to cylinder head angles, It could be pulling in oil mist from under the intake along the lower edge. I didn't see anywhere if you were using a stock intake or aftermarket.

Originally Posted by dontaskagain

knurilized valve guides. edelbrock intake. the intake center 4 holes have been reamed out to bolt to the swirl heads,l

Agree with 34_40, intake angle and stem seals could be the problem.
Reamed out bolt holes to match heads??? knurled guides need really good stem seals.

I see it now! Edelbrock intake. Still need to verify the angles are a match.

Originally Posted by dontaskagain

i see the puffs of steam out of valve cover breather and pcv valve when i pull them out and rev the engine.

STEAM, or blowby?

Originally Posted by dontaskagain

i have 20% leak on each cylinder.

JMHO, 20% is pretty high for a new rebuild.

Not trying to nit pick, but if you break your posts up a little (paragraphs), it will be easier to read and you'll get help faster.

Welcome to CHR!

I see I'm a bit late to this party but what I read is rings not seated - 20% leak down means when you're engine is running you are really pressurizing the crankcase. the puffs you see out of the breather are, in all likelihood, atomized oil. If the cylinders were properly honed, the the rings should seat within the first 25-30 miles. If you've gone 100 miles, there is little chance they will seat beyond where they are right now. Do you know if the bores were honed to a 45 degree cross hatch after the bore?

Refinished cylinder walls .oo7? what grit and pattern????? piston clearance----you said .030 over ------------what size rings? maybe some upside down? end gap alignment?
You can aid ring seating by sprinkerling BonAmi powder into the intake while engine running--it might take a while--------
were the rings the correct size for the piston groves and radial depth??

Originally Posted by jerry clayton

You can aid ring seating by sprinkerling BonAmi powder into the intake while engine running--it might take a while--------

We used to use Borax! Lol, those were the days!

Knurled guides are seldom an effective way to fix a head. Plug in your air source to the cylinder at about 80 PSI, remove the valve cover and check for air coming around the valve stems on the valves that are open. With 20% leakage you should be able to hear the air either around the valves or in the oil pan.

First thanks for all the replies, and to clear it up I did not do the heads or the block a engine builder who is known for doing good work was recommended to me i dropped it off and I'm relaying you all what he documented was done. So im just trying to get to the bottom of it, putting my trust he did the engine correctly
I talked to the engine builder today he assured me the valve guides are not my issue.(still could be) I did look up the part numbers on the rings and the rest to confirm the right size was used. All good.
I have learned from you folks alot about a leak test... my tester is misleading and its my first time doing one. It claims the green "good range" right up to 40% so I figured 20% was not terrible, but now thinking about that thats quite excessive. Leaning me towards glazed cylinders. Due to my break in. Like I said I followed the cam instructions and changed the oil right after(comp break in oil) then used 10w-30, and basically built a truck around the engine. I did make the mistake of idling over a few months maybe 30 minutes total before taking it out to the highway and ran it maybe 20 miles noticing the oil consumption. At about 1/4 Ltr.
The amount of smoke is misleading it does not smoke on start up it does not smoke until its good and warm. And I've had vehicles that burned a hell of lot less oil with a hell of a lot more smoke when the rings are the issue. Its not dark blue its light blue and smells like fuel it also uses way to much fuel. carb is set good.
I quess if it walks, and quacks like a duck... its a duck. But I feel like something is off here I'm not seeing. I'd hate to pull it out if I can fix this before its too late its only got 20-30 miles on it. But I can't belive the amount of oil that is disappearing even with 300000km worn out rings i haven't seen this much oil disappear and with not much smoke...
Ps I've already confirmed its not an intake issue and I do not have any unwanted crank case pressure until its been at 180 degrees for about 5 minutes and then I start to see the puffs of steam/oil from the valve cover breather and it comes at the same time as the smoke starts to come???

Originally Posted by dontaskagain

Its not dark blue its light blue and smells like fuel it also uses way to much fuel. carb is set good.

Interesting, but not to funny!
This could be fuel wash. What's your fuel pressure? Does your oil smell of gas?

Originally Posted by dontaskagain

I do not have any unwanted crank case pressure until its been at 180 degrees for about 5 minutes and then I start to see the puffs of steam/oil from the valve cover breather and it comes at the same time as the smoke starts to come???

Is there water in the oil or visa versa?

Have you tried to retorque the head bolts?

Definitely smell the oil for gas.