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Smoke Diagnosis - 427 s/o
At initial start up there are no problems. The issue starts when the engine is turned off after driving, like after filling up at the gas station, and then started again. When it starts back up, there is an initial cloud of smoke, then again only after revving the engine. The smoke appears after the revs drop back to idle, not during the rev. The smoke is light colored, not dark nor pure white.
I had a small oil leak at the sending unit which I just fixed, so I can't yet tell if I am losing oil elsewhere. Coolant always seems to be slightly below the neck of the puke tank. The engine has a solid lifter cam with dual carbs, and 1,100 miles on it. The plugs need to be replaced and valve lash is due for adjustment. Any thoughts on what may be causing this, or where I should look? Does it sound like a potentially serious problem? The car runs great other than the slight smoke issue. Any insight would be appreciated. |
Valve guides or leaking intake manifold gasket(s)?
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could be valve guides going away?? oops already said.
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If it was either, why would it be more prominent after a recent start-up instead of all of the time?
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Oil seeping down and around while the engine's off and the oil's hot.
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Are you running a PCV? Sometimes this can also be caused by boring the block without stress plates? It takes a little longer for the rings to bed in.
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Valve seals.
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I vote for an intake manifold leak. If it was bad valve seals/guides, you would get the puff of smoke on every start up. But maybe the lifters and pushrods are splashing oil up around the intake manifold gasket. So a warm restart might be sucking the oil into the chambers.
Tighten the intake manifold to the proper torque using the correct sequence. If that does not fix the problem you might want to do a compression test (or leak down) to rule out valve stems/guides. Easy test before you take off the intake manifold and replace the gaskets. |
The problem is>>>>>
wtm442 Warren he is about to be a Father.:eek::rolleyes:%/ He is under massive pressure. At this time we are not going to let him play with the motor until the boss has delivered.;) He's about 25 minutes from me. Next month I will take a ride, and see what the problem is. Sounds like 2 things. The motor was built 20 years ago. The valve stem seals may be shot.%/They are umbrella's I bet. I think the oil returns also have crap in them from sitting. Will do the wiring trick to make sure they are cleaned out. Valves need adjustment also. How's the fishing? 8-10lbs doormats are in the bay now. :) He's hoping for an early delivery, I said it doesn't work that way.%/ The fun will be in the delivery room if she goes natural with no pain killers.:JEKYLHYDE Till have not heard the names or if it is a boy or girl. I hope that it is just heathy with 10 fingers and toes.:):D:D Rick L.
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Thanks for all the feedback guys. As Rick said, I am a little under the gun right now to get the nursery finished. As soon as that is done, Rick offered to swing by and take a look at the motor for me. Hopefully it will only require some minor tweaking, and not a major repair. I may still get some wheel time before the big day :D!
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Head gasket?
I had a head gasket go which gave me some oiley smoke (blue)but you say it is black which points at fuel. Tighten everything up and wait to start tearing things apart.You better pay attention to Mama first and the Cobra second. :D
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(Hey Rick, you have mail,.....READ IT) ! lol ;)
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Carbs leaking down due to heat soak. Fuel percolates out of the vent tubes or through the accel pump discharges. Try an insulating gasket under the carbs, insulating the fuel lines in the engine bay, lowering fuel bowl levels a bit - - and a different gas station brand.
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