Heinrich, that is a phenomenal suggestion. I think that that is what I will do. I'll also run a compression test and see how the numbers come out. I don't know why I haven't done it before now, seems kind of silly to me now as I think about it...

 

What would a batch of bad gas behave like?

 

it wouldnt cause the car to smoke with bad gas, but it might make it ping and have an erratic idle

 

Gentlemen --

The intake port has flow that is hundreds of feet per second. It's like putting your head out of the airplane cabin. If the valve guides are pumping out oil, that oil will _NOT_ flow into the intake manifold. It will flow into the combustion chamber. This route is not the source of oil in the intake manifold. End of story.

For the same reason, any oil pooling in the intake manifold will be little by little sucked into the engine by the turbulent air flow. As long as the intake manifold is not clean, there is no way of knowing if more oil is introduced to the intake manifold. So I would not do much more without cleaning the intake.

After cleaning the intake, take a Coors Light can, open it, drink it empty, and cut a big enough hole on the top. Then hook up hoses yo the PCV outlets and feed them into this catch can. If the catch can fills quickly, you have an obvious problem.

Exhausting the crankcase fumes to the open air would not make the car run an worse than exhausting them to the intake manifold, quite the contrary. However, exhausting them to open air would be illegal.

Checking what's in the coolant is an excellent idea. Checking what's in the oil is also an excellent idea. Compression test will not hurt.

 

Okay well I checked for water bubbles on the dipstick and oil in the coolant tank, both before and after running the car, and found neither. I then did a compression test and found 3 cylinders on the low side, although I have not yet dribbled oil into these to see if the low compression disappears, chiefly because I need to drive to the auto parts store to get more oil and a dropper can capable of delivering oil down in there. my compression numbers are as follows, all numbers are after five pulses, except where noted:

1 178
2 165
3 169
4 150, tehn 155 after 7 pulses
5 160
6 140, then 145 after 7 pulses
7 175
8 168

Previous testing (my father using a different gauge) resulted in the following numbers, though I doubt they are comparable given the enormous number of different variables, still they may show a trend to someone:

1 166
2 161
3 150
4 146
5 145
6 150
7 165
8 151

These numbers show 4,5, and 6 as being the lowest of the bunch, just as my recent test indicates, and 1 and 7 as the highest. In retrospect, 4 and 5 apparently have had low compression for a while, and somehow I failed to notice (I must have made a math error). However, even with low compression in those cylinders, I never experienced anything like what I am seeing now.

 

I've been thinking about this some more, and I think that even the lowest number, at 145, seems a bit high to be a broken ring. Now, the rings may simply be worn, and I suppose I could do a leakdown test to see if I could separate blowby from valve/head problems, but what does everyone think of just running seafoam through the intake to try to clean out the valvetrain, then seeing if it fixes the problem. I ask this because it seems (to my untrained eye) that if a valve were not seating properly owing to carbon build-up that this could cause oil smoking. The oil would get drawn in on the intake stroke, but also some could get sucked in on the combustion stroke, and in that case there would be much less oxygen for the oil to burn with, which could produce more smoke. I know I'm way out on a limb here, but I'm just interested in trying to test out any alternative before I resign myself to a rebuild. I was thinking of just sliding a small hose through the MAF screen (which is broken anyway) and loading the Seafoam in through past the hotwire. Is this as good of an idea as it sounds or am I going to start a fire or something? Thanks!

 

Okay well, I ran the seafoam through it and boy did it make a difference, at least at first. I fed it in to the intake through the cast port on the side that the booster line fits onto, then shut it down, waited 10 minutes, then started it up and I got a HUGE cloud of white smoke, and then ran it at about 2k RMP for a few minutes to get most of the smoke out. I then took it out for a drive. Drove for about 10 minutes through city-like traffic, then hopped on the highway and blasted it out. I didn't see any smoke whatsoever after the first five minutes or so, and even launching from a standstill getting onto the highway from an on-ramp, I saw no cloud of smoke. I then went back by the same route, and continued to see no smoke cloud. Right as I was pulling into the parking lot of my apartment, the engine up and died on me. It took some coaxing to restart, and when I did, I got a giant plume of smoke out the back just like before I even messed with the seafoam. I am certain that I was not blowing smoke while I was driving around, but then the car died and I got a huge cloud. I checked the back of the car, and I could see the actual carbon on the rear license plate and bumper, so I know that the engine got something out of it. My question now is, what does it mean? Is this telling me something new? The engine is still too hot to look inside the intake and see if there is oil accumulation in the bottom, but I was wondering if anyone had any thoughts on what this could mean. Thanks!

 

Hi Thomas,

My '89 GT would ingest oil from the crankcase ventilation system when I would drive it enthusiastically. I was told it would smoke somewhat when under load by people behind me. Then when the engine was shut down, the oil would pool in the intake manifold. When restarted, I would get a cloud of smoke.

I went with the rerouting of the oil lines as shown in the diagram Zeus sent.

There is a good write up by Mike Schmidt about the breather system on Louie Ott's website.

http://www.performance928.com/cgi-bi...ss_parent=1128


http://www.performance928.com/cgi-bin/page_display.cgi?page_nav_name=breathersyStF&pass_parent=1128[/URL]

After making the change, my oil ingestion problem seems to be solved. I still use a tad of oil between changes, but nowhere near what I used before and I get no more clouds of smoke.

I got the parts a few years ago at Devek. Since they are no more, you can go to your current favorite parts source.

 

It does require an updated oil filler, valve cover breather hose elbow and some hose.

Cheers,

 

Yeah, I am going to get one of the sharkvent kits to remove that possibility from the equation. I guess my problem is that the problem went away, and then came roaring back. I went out again just now and restarted it, and I am seeing a great deal of the same oil smoke, even at idle. I will try pulling the MAF and seeing if the oil has re-pooled in the intake, although I am frankly skeptical at this point that this is the problem I am having.

 

Yep, it could be multiple issues. I'm not sure what path there is for oil to get into the intake and pool other than ventilation hose.

I guess it could be rings and valves, but your compression numbers aren't that bad.

The intermittent thing is puzzling as well.

 

Well, I think that it must be oil in the intake, because I seafomed the engine through the intake, so it may have cleaned out all the oil on the inside. After 30 minutes of putting it through its paces, the oil could have recollected. The only thing that bugs me about that explanation is that it seemed to take the engine suddenly, and not gradually. There was no smoke until after it died, but the fact that it ran with absolutely no smoke makes me think that it's definitely not rings, because seafoam wouldn't be able to reduce or eliminate that problem.

 

I'd like to look over the breather hoses and fittings on your car. If you have time some week or weekend day, we should get together. I'm about 40 miles from you. I'll be in the Stanford area on the 21st and October 6.