SweetZRag

I need your help identifying root cause of this issue.

Symptoms:

1. Loosing oil (1.5 quarts per week) since rebuild (engine has 65K miles since rebuild).
2. Smell oil burning from tailpipe but no visible smoke.
3. No visible oil leaks.
4. No puff of blue smoke from tailpipe on first start up of the day.
5. Engine is pinging.
6. Failed emissions for excessive hydrocarbons.
7. #2 spark plug is oil fouled.
8. Other plugs appear normal to a little lean.
9. PCV valve is OK.

What I tried so far:
Pulled spark plugs and found #2 cylinder completely oil fouled.
Not able (or willing) to do compression test as not enough access to plug holes with headers in the way.

What I think is happening:
Oil is getting into #2 cylinder causing excessive emissions and spark plug foul. Once plug stopped firing, raw fuel is getting through to O2 sensor (right bank) which is causing engine to compensate by leaning out.

Since there is no smoke on initial startup of the day, I don't think there is a problem with valve stem seals. They were replaced during the complete rebuild and heads were completely reconditioned. I installed Total Seal gapless rings during rebuild. I suspect something went wrong with the rings in that cylinder. I plan to pull the engine and do a compression test once it is out because I believe it will need to come out anyway to fix whatever is wrong.

Can anybody think of any other possible causes or simpler explanations before I pull this engine?

eagle745

Sounds like a broken ring, if you let it idle for 5 minutes then stab it and see blue smoke ,most likely it valve guides. If you let the engine run and remove oil fill cap and you have excessive crankcase pressure(blowby) ,thats most likely rings, But the best way is by doing cylinder leak down test, that will tell you for sure...

shoebox

Do a leakdown test (though since you said you are not able or willing to do a compression test, you probably won't want to do it). But, it is how to diagnose your problem.

SweetZRag

Thanks guys. I tried to do a leakdown test and compression test last night but just could not get the hose into the plug holes without removing the shorty headers. I can pull the whole engine in a little more time than it takes to remove the headers so I figured I'll just pull it and do the tests with the engine sitting on the subframe (especially since I suspect the rings in that cylinder and will need to pull it anyway).

I did not feel any puffing in the oil fill hole. Maybe the problem is with the oil ring and not the compression ring? Would that cause 1.5 quarts of oil loss per week? It is a daily driver so lots of miles per week.

Mr99SS

what oil rings did you use and what gap did you set them at ?

Injuneer

Possibly a leaking intake manifold gasket at #2?

Oil in the combustion charge will cause detonation.

Is there any oil buildup in the throttle body, under the top cover plate? If there's a reverse flow in the line from the throttle body to the valve cover, it can contain entrained oil, and dump it in the top of the TB, where it drips down into the incoming air flow. It's possible that the path of least resistance for the oil drip as it enters the plenum is #2.

eagle745

^^^ very possible ,I would check this...

SweetZRag

I used the Total Seal rings (gapless). Here are the gaps:

Cylinder Compression 2nd Ring Oil Ring
1 0.018 0.023 0.029
2 0.016 0.020 0.030
3 0.016 0.019 0.027
4 0.016 0.0255 0.029
5 0.016 0.022 0.029
6 0.016 0.023 0.026
7 0.016 0.021 0.029
8 0.017 0.022 0.029

SweetZRag

I'll check this tomorrow night.

Thanks,
Jeff

PA94Z

You need the engine warm to do a compression or leakdown test. Cold will show inconsistent and low numbers.

SweetZRag

That's a problem. Even if I performed the compression test with the engine in the car, by the time I removed the plugs and headers, the engine would cool down. In fact, I would have to let it cool because the headers would be too hot to get near. I wonder how anyone could do a proper compression test with this generation Camaro.

After I inspect under the TB cover as Fred suggested, assuming no oil buildup, I guess I'll need to pull the engine.

PA94Z

Get a pair of welding gloves. Warm engine to operating temp, do one plug at a time. If the engine cools to much warm it back up and continue. There is no other way to do it.

SweetZRag

Unfortunately I can't get the compression tester hose into the plug holes. Just not enough room. Also, can't get the plugs out with gloves. I can't get my hands in there.

I pulled the engine last night. 3rd time only took 4.5 hours doing it myself. Getting faster ;-) Will be inspecting under throttle body plate tonight and pulling heads. Plan to inspect the rings in cylinder #2.

SweetZRag

I finally pulled the engine and remove the right side cylinder head. I have a lot of carbon buildup in all 4 cylinders. The #2 cylinder exhaust valve has a whit/grey buildup on the compression chamber side.

I am suspecting there is something wrong with the Total Seal rings that I installed.

I have not pulled the pistons to look yet. Does anyone have any ideas? I am assuming the oil loss caused the carbon buildup in the cylinder. There is a little buildup on the back side of the intake valves but a ton in the compression chamber (piston tops and cylinder head.

97WS6SCharged

Are the heads ported?