Blowin some smoke

[Dark_Horse]

My bullitt has been smoking bad since I put the MAC o/r h + MIL eliminators and i'm wondering if it is leading up to something bad. It seems to be getting worse from time to time and it only does it right after startup or after its been ideling for a period of more than 5min. I happened to take a video after it had been ideling for about 10min and then gunned it to about 3500rpm:

http://youtube.com/watch?v=h2sFIj8iEeI

What im worried about is possibly a piston ring getting ready to let go, or maybe something worse than that. I was thinking that maybe the MIL eliminators were causing it to run rich but after looking at the black soot that has accumulated on the tailpipes it seems to be oil rather than unburnt fuel. Any advice for a rookie mustanger?

 

[Killa]

did you loose any oils or coolant ? if you drive around for awhile, turn off the car and see if you see any smoke in the pipe.

 

[pete1665]

mostly likely the valve stem seals. Oil leaks down past the seals into the cylinder after it has been sitting for a while. It wont really harm anything other than having to watch your oil level and probably a little less gas mileage. I just got done replacing the seals and valve lash adjusters and that pretty much cured the problem that your talking about.

 

[Dark_Horse]

did you loose any oils or coolant ? if you drive around for awhile, turn off the car and see if you see any smoke in the pipe.

As far as I know I haven't lost any oil or coolant - everything is still topped off. It will smoke pretty bad at a stoplight sometimes and it has a really thick oily stink like it is burning a bit of oil but for some reason I cant detect it. As far as driving it around then checking the pipe - when I shut the engine off it usually lets out a wisp of blue-ish smoke. This leads me to believe that it has nothing to do with the midpipe install, but rather a rotating assembly probelm

 

[Dark_Horse]

mostly likely the valve stem seals. Oil leaks down past the seals into the cylinder after it has been sitting for a while. It wont really harm anything other than having to watch your oil level and probably a little less gas mileage. I just got done replacing the seals and valve lash adjusters and that pretty much cured the problem that your talking about.

You know, I never thought of that. I was thinking it was due to a bad piston ring or something. How critical is it that I fix a bad seal? I'm going to be putting the bullitt through the ringer this summer with SCCA, multiple drag strip runs, and possibly even some road racing. Is this something that is going to prevent me from racing or should I just be mindful of it? Thanks for the help pete

 

[pete1665]

You know, I never thought of that. I was thinking it was due to a bad piston ring or something. How critical is it that I fix a bad seal? I'm going to be putting the bullitt through the ringer this summer with SCCA, multiple drag strip runs, and possibly even some road racing. Is this something that is going to prevent me from racing or should I just be mindful of it? Thanks for the help pete

its more of an annoyance than a critical problem. Really the worst that can/does happen is the oil that leaks into the cylinder actually lowers the octane of the gas being burned in that cylinder (less power), and can eventually cause carbon build-up on the valves/pistons. For everyday driving its not a big concern, but from what your looking to do this summer, you may want to consider replacing them.

 

[Thundermouse]

How long since you put on the midpipe?

 

[Dark_Horse]

6 months. The video was taken about 2 months afterward and if i were to take a video now youd prolly see substantally more smoke. I may have to get new seals prior to running it at the strip

 

[the98stang]

That smoke LOOKS blue, but I can't tell for sure. If oil gets past the rings and into the intake system you'll see blue smoke come out the back. I would do a compression test and leak down test. That would tell you if the rings and valves are good or not.

 

[pete1665]

That smoke LOOKS blue, but I can't tell for sure. If oil gets past the rings and into the intake system you'll see blue smoke come out the back. I would do a compression test and leak down test. That would tell you if the rings and valves are good or not.

+1... we can only guess without doing the compression test.

 

[Dark_Horse]

Is a compression test something I can get at a local shop or the ford dealer only? Got any idea how much that might run?

 

[the98stang]

Is a compression test something I can get at a local shop or the ford dealer only? Got and idea how much that runs?

It is a very simple procedure. You hook up a compression test guage to the heads (threads in where the spark plugs go). You can pick up a gauge at any car parts store like Pep Boys or Auto Zone for like $30. The test takes about 45min-hour.

 

[Killa]

im very sure its the valve seal or ring, its smoke when you come to stop right ? and its smoke bad when you stop and go on traffic right ? my car did the same and it drink haft quart every week.

 

[Mustang92]

On the earlier Cobra's (96-98's) with MAC longtubes this was a common problem. The exhaust was scavenging too much and litterally pulling oil though the seals. I've only heard of it happening on a couple of GT's but tons of others without any issues at all. If you are seeing light blue smoke it's defintely oil.

Bill

 

[Dark_Horse]

The soot thats being ejected is definately oil. I just washed the bullitt a few months ago and I THOROUGHLY cleaned the taipipes (i use an stainless metal polish) when I detialed her. I took some pics of the tailpipes today:

These arent real good pics per say but you get the point. I am changing the spark plugs soon so I'll get a good idea of which cylnder is having the problem by the color of the plug. Plus I might as well get it compression tested while im in there.

But the question that sticks out in my mind is, if I do have bad compression in one cylnder, how can i be sure its a leaky valve seal rather than a bad piston ring?