Blue Smoke at idle/deceleration, good compression, new-ish motor, new heads

All,

I've read through all the internet has to offer on this and now humbly come to you for advice on the issue. Here is what I have and what I have checked:

1968 Camaro with a Goodwrench 290/350 crate motor with 3,500 miles.
New (not reman) Vortec heads
Edlebrock 1405 600cfm carb
700R4 Transmission
Dual exhaust with x-pipe
Lunati 60102 cam with 219/227 @.050 468/.489 lift 112 lobe sep
Baffled GM valve covers with standand PCV/baffle set-up
Conventional 10w/40 dino oil (Castrol GTX)
Compression is within 10% on all cylinders

When I remove the PCV there is NO change in the amount of smoke

Plugs all look nice and tan with the exception of #8--it is a little sooty and has what appears to be a small 'fried' oil deposit on it.

At start up there is no smoke. Car starts fine and runs fine. After running for 20 seconds or so, blue smoke starts coming from the tailpipes. (I have an x-pipe). The smoke increases in volume if I get on it and hold the RPMs at 2K or more.

When I read the RPM's from my dial back timing light, the RPMs flucuate 30 to 40 RPMs and will not stay steady.

I replaced the intake gasket with a FelPro "problem solver" gasket and coated the bolt threads with Permatex Teflon paste. Torqued the bolts to 11lbs each.

I have had some local engine guys suggest valve seals. I had one guy say the heads might be cracked.

Does this sound like valve seals? Head gasket? Any other ideas?


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It sounds like valve seals or valve guides. However, I would still check the intake, as I battled with the gaskets 3 times before it sealed. Remove the carb and if you see oil in the plenum the gaskets are leaking. The only intake gaskets I found that worked were Edelbrocks. Do you have a vacuum gauge? This can be a helpful tool in helping you find the issue.
Blue smoke indicates oil so I don`t think you have a head gasket issue.
Try this Vac Gauge Page: http://www.secondchancegarage.com/public/186.cfm

If the auto trans vacuum modulator is connected to the vaccuum port on top of the #8 runner, it is sucking trans fluid. Check the PCV hose for oil.
Replace the valve seals. Intake manifold/ports sucking oil.
Broken piston ring land. (#8?) Blocked oil drain back hole in the head.

That's a great website--I will use it tonight to read the vacuum.

The plenum is clean of oil but I have not discounted that it could still be the intake. FWIW-I bought a new intake and installed it as well.

The head gasket comment by a local guy threw me off--I didn't think it would be that but wasn't sure...

I have a TV cable vice vacuum modulator so that narrows that down. The PCV hose is clean--no oil at all.

I'll check the oil drain above #8.

It looks like the valve seals are the next thing to replace...?

My compression is uniform--is a broken ring always reflected in the compression rating?

Brent

i dont think it is to do with the heads i would bet the rings in 8 didnt seat or one is broke if you are sure there is no vac from trans to engine

I have no vacuum from trans to engine...the compression is #8 is consistant with the others...would a broken ring normally reduce the compression in that cylinder? It seems that the fried oil on the plug is a major clue to the cause...

not a scraper ring they just pole the oil off the cylinder i seen ppl for get to put part of it on

you say it has around 3500 miles on it.so when or how long has it been smoking? cole

It almost sounds like a flat lobe on the cam. Put a vacuum gauge on a manifold port and see if the gauge bounces if it does you've got a flat lobe.

A broken ring is indicated by low compression and specificaly indicated if you drop some oil in the cylinder and the compression increases and then goes down again. cole

I was just about to post that--good question.

The smoke story has two parts. The first 2,700 miles it did not smoke at all--not a bit. The smoke started when I added a different set of heads.

Part 1: I installed remanufactured vortec heads and a new Edelbrock Air Gap intake. The white smoke started immediately after.

Problem: I pulled the plugs and found antifreeze in #5 (only). The head was cracked near a port, so I replaced both heads with brand new heads. Compression in #5 remains strong and the plug is clean (tan color, no oil).

Part 2: With the new heads, the white, sweet smelling smoke was gone, the blue smoke began. Thinking it might be the intake, I bought a new intake and used the $60 FelPro rubber/steel intake gaskets. The blue smoke still continues with no change at all...

I just cant help but to belive you have valve seal failure.with everthing you have done.thats what it still points to.it could be more tha one seal also. cole

It looks like I need to start with a valve seal replacement...

Dumb question, but how do I know what valve seals I need to buy?

It is a 350 crate motor with new vortec heads machined to take a .500 lift...

Closely check the offending cylinder's seals. No need to replace all the seals if only one got damaged, like when the springs were reinstalled- an easy enough mistake for the shop to make, in that they're hauling-a when they work. Local shop or Scoggins, either way.