Blue smoke from exhaust

[Stuart Gray]

Hi guys,
Just noticed, after having to do an emergency accelerate (my
fault) in first gear up to the rev limiter, then changing to second (manual
box) that a huge puff of blue smoke, noticable from rear view mirror where I
was looking to make sure I was getting out the way, occurred as I changed to
second. Is that an indication of valve seals being worn, or piston rings? I
used to know the answer in my younger biking days when fuul throttle was a
way of life, but I seem to be forgetting more than I once knew, if you know
what I mean...

 

[Stewart Hargrave]

From a point at sea, to the circles of your mind, this is Stuart Gray:

Hi guys,
Just noticed, after having to do an emergency accelerate (my
fault) in first gear up to the rev limiter, then changing to second (manual
box) that a huge puff of blue smoke, noticable from rear view mirror where I
was looking to make sure I was getting out the way, occurred as I changed to
second. Is that an indication of valve seals being worn, or piston rings? I
used to know the answer in my younger biking days when fuul throttle was a
way of life, but I seem to be forgetting more than I once knew, if you know
what I mean...

Worn oil seals will be most vulnerable to letting oil past when
induction vacuum is at its greatest. Closing the throttle valve at max
revs as you changed gear would provide such a situation. Accellerating
afterwards would provide the conditions to burn off the oil that had
been drawn in, hence the blue smoke as you re-applied the throttle.

Another way of checking the valve seals is to roll down a hill, in
gear, with the throttle closed. The hill should be steep enough to
increase speed as you descend. This will create low induction pressure
at tend to draw oil past the seals. Accellerate when you get to the
bottom to burn off the oil and look for blue smoke in the mirror.

If it's any comfort, a little oil can make an aweful lot of smoke.


--

Stewart Hargrave

Faster than public transport


For email, replace 'SpamOnlyToHere' with my name

 

[Stuart Gray]

From a point at sea, to the circles of your mind, this is Stuart Gray:


Worn oil seals will be most vulnerable to letting oil past when
induction vacuum is at its greatest. Closing the throttle valve at max
revs as you changed gear would provide such a situation. Accellerating
afterwards would provide the conditions to burn off the oil that had
been drawn in, hence the blue smoke as you re-applied the throttle.

Another way of checking the valve seals is to roll down a hill, in
gear, with the throttle closed. The hill should be steep enough to
increase speed as you descend. This will create low induction pressure
at tend to draw oil past the seals. Accellerate when you get to the
bottom to burn off the oil and look for blue smoke in the mirror.

If it's any comfort, a little oil can make an aweful lot of smoke.

Damn, the only 2 downhills I know locally to accelerate the car on closed
throttle both have a blind 90 degree bend at the bottom and both definately
need eyes front if accelerating out of them. Must try with wife in passenger
seat looking backwards - if I can get her to trust me that much - she
usually sits with the passenger brakes on ; )

Stuart.