To know if it is a valve guide or seal you need to run a leak down test.

If it was a bad valve guide or seal it would have to be be on an intake valve. What is odd to me is that it is constantly smoking. If it was a bad guide/seal it should only smoke when coming off idle when there is vacuum or at WOT.

Because your compression test varies so much that is where I would be worried. When you say you capped the PCV did you put a breather on the driver side cover? Did you you cap the pcv inlet on the passenger side with out having a breather or oil cap breather? I'm curious if there is a possibility that you capped off the system in such a way that crank case pressure became too high and you hurt your oil rings?

 

Thanks Yeti. Isn't a leak down test performed with the valve closed? If so, how would that show leakage past a valve seal? On the short drive I took, it smoked lightly at idle, a bunch coming away from a stop (even light throttle), and in park it smokes a bunch when I stabbed the throttle.

As for the PCV system, the drivers side valve cover was capped without a breather. The passenger side PCV hose was attached to the intake manifold downstream of the throttle body. With the passenger side still fully connected, I wouldn't expect the crankcase to build up too much pressure.

Generally............

White colored smoke = Coolant

Blueish colored smoke = Oil

Black colored smoked = Too much fuel

Thanks for the help! That was one of the first things I Googled.

 

Generally............

White colored smoke = Coolant

Blueish colored smoke = Oil

Black colored smoked = Too much fuel

 

I had a bad valve guide after having some head worked done. Car smoked like a chimney at start up and every time I gave it gas when coming off idle. But just cruising down the road/freeway there was zero smoke.

The cylinder that was having that issue had hella oil on the plug. All other plugs were fine.

Some times the smoke seemed white. Sometimes it had had a blueish hue. It was always just oil burning. Lighting plays tricks on the mind. That was 40000 miles ago though.

I'm still thinking bad rings.

When you do a leak down you need to hand crank the motor over to make sure that the valves are closed. That way you can listen for air running up and out into the intake manifold, or in the radiator, or out the oil cap. It will narrow down the issue.

 

If you have bad valve guides or seals, you would see blue smoke off idle or at start up, not so much while driving. If its your rings, you will see blue smoke constantly and it will get heavier with engine load and speed. When you perform a compression test, the first pulse should jump over 90 psi, this would indicate a good valve to seat seal. Put a small amount of oil down the cylinder and re check your compression, if the numbers go up from doing it dry, then that's an indication your compression rings are worn. A cylinder leakdown test would verify this. A leakdown test need to be done with the piston at TDC, and will also tell you if you have a bad head gasket or a bad seal at the valve(s).

 

You also need to make sure your PCV system is set up correctly, the way it is set up from the factory helps the rings seal.....

 

Come to think of it...... you do have a fresh air inlet coming into your PCV right? You should have a line coming from your valley cover to your intake, and another one coming from your passenger valve cover to a nipple just behind your MAF sensor. If all your doing is puling a vacuum on your crankcase then that would explain alot because your prolly pulling oil right past your rings with engine vacuum.

 

PCV system is back to factory setup. I will try performing a leakdown test and listening for where air escapes.

Thanks guys!

 

Well I don't have a fancy leak down tester with a gauge and all. However, I do have a hose that allows me to pressurize the cylinders. I removed the valve cover so as to watch the valves and rotate each cylinder to top dead center. I would then pressurize a cylinder and listen for leaks. Each cylinder had a slight hiss coming from the oil dipstick tube. None were particularly louder than the rest. To me that indicates that a specific cylinder's rings aren't bad. I don't expect the rings to have a perfect, airtight seal either. On one cylinder I had an exhaust valve that wouldn't fully seat, as I could hear a hiss travel through the header and out the tailpipe.

The cylinder with a fouled plug exhibited the most noise. In that cylinder, air was not leaking through the exhaust, or the intake, yet it was quite noisy. However, it didn't seem as if there was more noise than usual from the oil dipstick tube. Also, due to the fact that I had unburned oil in my exhaust, it seems to support the theory of a bad exhaust valve seal. If I was getting that much oil blowing by piston rings, I don't think it would hold as much compression as it did.

I think I am going to pull the heads for inspection. If nothing notable is found, then I can take a closer look at the block.

 

Sounds like a plan.

 

Holley valve covers will work just fine UNLESS you have an engine with AFM hardware (like a stock L76) and your PCV foul/oily air line connects to the valve cover.

Holley valve covers have no restrictor (orifice) in them to restrict oil from being sucked straight out of the drivers side valve cover, down the PCV foul air line, and into the intake manifold. They often do not have baffling, shielding the small nipple to stop large oil droplets from shooting out straight down your PCV line to the intake manifold.
Have a look at your stock left hand side valve cover...you'll see a small 3mm hole (restrictor) down the inside of this nipple pictured. You'll also find tin plate oil deflector baffling under the roof.

3mm hole down the centre is the PCV orifice (restrictor)


Put your stock valve covers back on and return the PCV plumbing back to stock configuration. Note the flow direction arrows for an engine with AFM hardware...that's how the system is supposed to work.
The nipple on the passenger side is for fresh (filtered and measured by MAF) air into the engine.

 

Here's a pic from underneath a stock GM right hand valve cover....the tin plate near the roof of the valve cover is a baffle to stop bulk oil from going out of the nipple.
Left hand valve cover with an AFM engine it's even more important to have a baffle because the PCV system "sucks" from the left side valve cover.

Pic of an oil deflector baffle being removed.

 

My initial guess would be blown head gasket or cracked block... Any water in the oil or oil in the radiator?

 

It would be better to properly do a leakdown test to diagnose the block prior to tear off the heads. At that point it would make it almost impossible to diagnose any further without disassembling the short block and measuring things with more expensive tools. Pulling the heads just to inspect will not positively give you a definite diagnosis on what your issues is. A proper leakdown test will, or at least tell you what you need to be looking for when you do tear it apart. Do yourself a favor and get a leakdown tester and check it BEFORE you tear it apart.

 

Known issue on holley valve covers. they dont have a restrictor or baffle. Need to valley cover instead, or put stock valve covers back on.

 

Well there you have it. Holley covers a re the culprit, but now you need to do a check for damage. Sucking oil into the cylinders is no bueno. Cats and o2s may be jacked up too.

 

TheAdamV was filling his catch can nearly every day with holley cover. Switched to the valley cover port and its been good since

 

Thanks all for the input guys! I didn't realize the differences between the valve covers. Paul, the photos are a great reference.

I did perform a proper leakdown test. All eight cylinders exhibited between 13 and 16% leakage. Listening carefully confirmed that air leakage was not across the valve seats into the exhaust or intake or between cylinders. Due to the low leakage rates and the narrow range I interpret that result as the rings and valve seats are in good condition.

I do not have cats, so risk of damage to those is not an issue. I will have to check for any o2 codes popping back up.

Paul's photos made me wonder if by plugging the driver’s side PCV port, I may have built up too much crankcase pressure and pushed oil past a valve seal? I dropped a lot of unburned oil into the exhaust. Seven spark plugs were evenly and slightly coated in oil. Cylinder #7 had a severe amount of oil on the plug. If it were only a PCV issue, I would expect all plugs to look similar. If I did damage a valve seal on cylinder #7, that wouldn't necessarily show up on a leakdown test because the valves are closed when tested. Right?

I’ll plan to reinstall the stock valve covers and start the car up. If it is still excessively smoking I will assume a valve seal is damaged and pull heads for a look see. At least I don’t have to worry about the bottom end.

 

Cylinder sevens plug could have just stopped firing due to the oil coating and that may be why it looks way worse. Could have been the cylinder that was back firing. I wouldn't worry about it being a bad valve seal if you didn't show any thing on the leak down that was out of whack from the other cylinders. Air would have found a way to escape.

 

So I reinstalled my Holley covers but installed an orifice into the drivers side PCV line to mimic that of the stock valve cover. I cleaned the spark plugs and tested each plug/wire/coil for spark. Everything checked out OK. I reinstalled everything, turned the car on, let it warm up and gave a couple revs. It still smokes. Very light at idle, more when revving the motor.

Again, leakdown results are acceptable. I still feel like the valve guide seal is not exposed to much pressure during leakdown due to the valve being closed. The plug from one cylinder was much dirtier than others. I can't think of anything else it can be besides valve guide seals on that cylinder.

 

Compression test yet?

 

Have you quit pissing with the holley covers yet and put stock on to rule that out a an issue