dont make sense
12-26-2010, 10:59 PM
#1
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dont make sense i have a 2000 camaro z28 cam only car high miles.
some times when u let off the throttle after a wot pass it smokes then clears up.
when its at idle after it warms up to temp u can remove the oil cap and see blow by.
pvc has been removed and just left open.
ran a compresion test highest reading was 200 lowest reading was 180.
any ideas?
u cant really tell what color the smoke is also the plugs show no signs of burning oil
some times when u let off the throttle after a wot pass it smokes then clears up.
when its at idle after it warms up to temp u can remove the oil cap and see blow by.
pvc has been removed and just left open.
ran a compresion test highest reading was 200 lowest reading was 180.
any ideas?
u cant really tell what color the smoke is also the plugs show no signs of burning oil
Last edited by slolt1; 12-26-2010 at 11:10 PM.
12-27-2010, 12:23 AM
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First, whaddya mean the pcv is just "left open"? Just breathers?
Second, any high mileage engine with have some smoke here and there. Everything is worn out.
Second, any high mileage engine with have some smoke here and there. Everything is worn out.
12-27-2010, 12:27 AM
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Snapping the throttle closed at high engine speed creates the lowest pressure (highest vacuum) that the engine ever sees in the intake.
The high RPM also puts more oil in the heads than normal running.
On a high mileage 10 year old engine I would look at valve stem seals first.
they are cheap and moderately easy to change compared to the other things that might create your smoke.
I would do an accurate leak down test on all 8 cylinders first and if I found no trouble I'd replace the seals.
Bad stem seals usually exhibit other symptoms that you did not describe.
After idleing for a bit you'll usually get a "puff" of smoke at throttle tip in.
Sometimes it will smoke at start up and clear after the engine gets warm. This is more noticable during the winter months when it's cold out.
I'd run the normal PCV system in a car used as a daily driver. Normal PCV systems do not activate at WOT as manifold vacuum should be below the PCV activation point.
On a high mileage car the valve guides themselves may be worn to the point they are contributing to the problem. Fixing these requires full teardown of the heads and machine work.
Putting new seals on partially worn out guides should reduce the problem dramatically; they just will not last as long as new seals on fresh guides.
If I was at the point of replacing the guides I'd be doing a "full on" head with port work and other mods.
You have to determine what "color" the smoke is. It's usually easy. Excess fuel is dark (almost black) and water consumption is brillant white and dissipates instantly. Oil consumption (which is what I believe your reporting) is dirty white, maybe a bit gray or blue-ish and lingers in the air. I can also tell the difference by smell. Trust your senses, they are better than you think.
Hope this helps
Rick
The high RPM also puts more oil in the heads than normal running.
On a high mileage 10 year old engine I would look at valve stem seals first.
they are cheap and moderately easy to change compared to the other things that might create your smoke.
I would do an accurate leak down test on all 8 cylinders first and if I found no trouble I'd replace the seals.
Bad stem seals usually exhibit other symptoms that you did not describe.
After idleing for a bit you'll usually get a "puff" of smoke at throttle tip in.
Sometimes it will smoke at start up and clear after the engine gets warm. This is more noticable during the winter months when it's cold out.
I'd run the normal PCV system in a car used as a daily driver. Normal PCV systems do not activate at WOT as manifold vacuum should be below the PCV activation point.
On a high mileage car the valve guides themselves may be worn to the point they are contributing to the problem. Fixing these requires full teardown of the heads and machine work.
Putting new seals on partially worn out guides should reduce the problem dramatically; they just will not last as long as new seals on fresh guides.
If I was at the point of replacing the guides I'd be doing a "full on" head with port work and other mods.
You have to determine what "color" the smoke is. It's usually easy. Excess fuel is dark (almost black) and water consumption is brillant white and dissipates instantly. Oil consumption (which is what I believe your reporting) is dirty white, maybe a bit gray or blue-ish and lingers in the air. I can also tell the difference by smell. Trust your senses, they are better than you think.
Hope this helps
Rick
12-27-2010, 12:45 AM
#4
Snapping the throttle closed at high engine speed creates the lowest pressure (highest vacuum) that the engine ever sees in the intake.
The high RPM also puts more oil in the heads than normal running.
On a high mileage 10 year old engine I would look at valve stem seals first.
they are cheap and moderately easy to change compared to the other things that might create your smoke.
I would do an accurate leak down test on all 8 cylinders first and if I found no trouble I'd replace the seals.
Bad stem seals usually exhibit other symptoms that you did not describe.
After idleing for a bit you'll usually get a "puff" of smoke at throttle tip in.
Sometimes it will smoke at start up and clear after the engine gets warm. This is more noticable during the winter months when it's cold out.
I'd run the normal PCV system in a car used as a daily driver. Normal PCV systems do not activate at WOT as manifold vacuum should be below the PCV activation point.
On a high mileage car the valve guides themselves may be worn to the point they are contributing to the problem. Fixing these requires full teardown of the heads and machine work.
Putting new seals on partially worn out guides should reduce the problem dramatically; they just will not last as long as new seals on fresh guides.
If I was at the point of replacing the guides I'd be doing a "full on" head with port work and other mods.
You have to determine what "color" the smoke is. It's usually easy. Excess fuel is dark (almost black) and water consumption is brillant white and dissipates instantly. Oil consumption (which is what I believe your reporting) is dirty white, maybe a bit gray or blue-ish and lingers in the air. I can also tell the difference by smell. Trust your senses, they are better than you think.
Hope this helps
Rick
The high RPM also puts more oil in the heads than normal running.
On a high mileage 10 year old engine I would look at valve stem seals first.
they are cheap and moderately easy to change compared to the other things that might create your smoke.
I would do an accurate leak down test on all 8 cylinders first and if I found no trouble I'd replace the seals.
Bad stem seals usually exhibit other symptoms that you did not describe.
After idleing for a bit you'll usually get a "puff" of smoke at throttle tip in.
Sometimes it will smoke at start up and clear after the engine gets warm. This is more noticable during the winter months when it's cold out.
I'd run the normal PCV system in a car used as a daily driver. Normal PCV systems do not activate at WOT as manifold vacuum should be below the PCV activation point.
On a high mileage car the valve guides themselves may be worn to the point they are contributing to the problem. Fixing these requires full teardown of the heads and machine work.
Putting new seals on partially worn out guides should reduce the problem dramatically; they just will not last as long as new seals on fresh guides.
If I was at the point of replacing the guides I'd be doing a "full on" head with port work and other mods.
You have to determine what "color" the smoke is. It's usually easy. Excess fuel is dark (almost black) and water consumption is brillant white and dissipates instantly. Oil consumption (which is what I believe your reporting) is dirty white, maybe a bit gray or blue-ish and lingers in the air. I can also tell the difference by smell. Trust your senses, they are better than you think.
Hope this helps
Rick
12-27-2010, 11:08 AM
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First off as said above you need to figure out what color the smoke is. If its black then it could be running too rich or there could be a problem with the cats. Are you running nitrous on the car? If so the tune could be rich for the nitrous and the smoke you are seeing could be from too much fuel again. I would follow the above posters advice to track down the problem, but first figure out what color the smoke is.
12-27-2010, 12:24 PM
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no nitrous on the car. has the pvc just left open. i have had several people follow and when it smokes it dont stay long so the color is hard to tell and it dont do it all the time. i just put a p1 on the car havent got it tuned yet so unable to drive right know.i did notice a peice of the plastic from the knock sensor on the harness had broke away and got in between the intake and head at the bottom of the gasket. dont know if that sucking air there would couse the problem or not.
