The day after Christmas I took the TA to run around town a bit. It was roughly 30 degrees outside...which is unusually cold for Houston. I couldn't have been driving around for more than 10 minutes (casual driving) when I noticed some white smoke coming from under the hood at a stop light. I pulled over to take a look and saw the smoke out of the breather on the passenger valve cover and out of the oil stick. I drove home and noticed the smoke dissipated as I started moving. Once I got home, I popped the hood and it was still smoking. I revved the motor and it appears to lesson. Car is running fine. Good vaccuum on the boost gauge, good A/F on wideband, and 'normal' idle for the car. Accelerates smoothly. No smoke out of the tail pipes either.

At the risk of getting flamed, I have no PCV system on the car...just the breather on the valve cover. Has this finally caught up with me?

I didn't drive it again until today, and exact same situation occurred. I beat on it a bit and the car runs just as good as it ever has, but smokes when I come to a stop. Oil level was within range when I checked it and not blown up the dipstick...as in the crankcase isn't getting pressurized. Oil color appeared normal and smelt like oil.

All that being said, is this just what happens eventually with blower cars and I need to put a PCV system on it. I know it is hard to justify what is 'normal' blowby, but some guys say smoke is expected and you need a PCV system, and others state that smoke means your rings are shot (both from forum readings).

I guess my questions are:

Why would the car seem completely fine except for the smoke if the rings are bad?...and by 'fine' I mean the AFR, vacuum, and power are consistent with what they have always been?

What is a decent PCV setup without getting unmetered air in (yes, i have searched)?

The motor is not 5k old and I have had no other issues. Unfortunately, it sits for extended periods (1-2weeks at times) and never gets driven extended distances (under 15mi spurts).

Any ideas?

 

Hate to say it, but that sounds a lot like broken ring lands. You need to do a leak down test on it and see whats going on. At a minimum, a compression test. A leak down will be better. That will tell you how much your cylinders are leaking. PCV or not, you shouldn't be blowing as much smoke out the breather at idle as your saying. Keep us posted.

Ken R.

 

That's what I'm starting to accept...even though that's not what I want to hear .

Leak down test this next week.

 

Was it smoke or steam?

 

At times it gets faint enough that I thought it was steam...that's why the first time it happened, I didn't think much of it besides my car had been sitting for too long. However, it doesn't seem to be clearing up.

How long would it have to be at operating temp do you think to get rid of any water vapor in the crankcase?

 

Mine usually smokes some and I have read that it's pretty normal on fi motors. That being said though it's never really enough smoke that it comes out the hood when only being stopped for a short time. Keep us us posted with leakdown test results. Or maybe get us a video of it actually smoking.

 

Well the temp. needs to get to at least 212* to boil off the water. Do you have a low temp. thermostat?
It has been cold, with the high humidity and we just had all that rain, so I don't think this is too surprising. Have you checked the filler cap to see if it's "milky".
Might do a leakdown just for the warm fussy.

 

I have a 160 t-stat, but I haven't done a scan yet to see the oil temp.

I checked the dipstick and didn't see any 'milky' appearance.

Leak down coming soon.

Does anybody have a theory yet why everything seems to be running fine despite the smoke?

 

Mine went 12.4 with two busted pistons and a head gasket on the way out. So they will run like seemingly good for a while before they comepletely self destruct. What may have happened is that your car got lean in the cold weather, made a crap load of power which was too much for it, probably and that was it for the stock POS pistons. But that's all just a swag, assuming your lump is stockish inside.

If yout take off the oil cap, is it huffing noticeably out of there?

 

I had somebody else do the compression test.

Results:

Driver's Side:
All ~165psi besides #7, which was 50 psi

Mechanic said he will get the other side tomorrow. He thinks valves and not rings from what he has seen. He said he will do the oil test on any low cylinders tomorrow to asses for rings...followed with a leakdown test.

Thoughts?

 

If your doing a compression test, it only takes an extra few minutes to do the leakdown while you have the fitting in the head... as long as your fittings are interchangable on compression gauge and leakdown tester. Just wondering why he didn't do that to investigate the 50psi??

 

sorry to say (i have been there many times) it's the puff of death ... worn rings or a broken ring land can you take a video of it thx jim

 

My thoughts is that it isn't the valves. #7 is one of the ones that always breaks the lands. I'll be interested to see what it turns out to be, but a lot of us have been down this road before which is why it doesn't say Supercharged 350 in our signatures..

 

I will keep you guys posted. I got a text from him saying the passenger bank cylinders all checked out fine, but he didn't mess with it anymore.

I'm not rushing him to get it diagnosed, because I don't have the funds to rebuild right now. That's part of the reason it sat a lot this past year because I wouldn't have the money if something broke.

Any thoughts on why #7 is prone to breaking rings in a 350?

...and sorry no vid. The car is at the shop and I haven't been by.

 

Not sure #1 and #7 get the same air/fuel as the other cylinders with the way the manifold is set up - especially since #7 fires right after #5