can you guys tell me what I need to look for ? I have had a few engine rebuilt,about 4, over the years and ALL have smoked on start up and cleared up after running. The engines have all been early 350s sbc. I am assuming the the valves need to be replaced with new since the new retainers and seals have been replaced with new but still smoking on start up. This has pretty much been all the engines from a local big rebuilder. Any ideas?
if its oil smoke, oil trapped in the cylinders and combustion chambers might be the cause,
that has to burn off and rings need to seat..
but the smoke should not last more than a couple minutes MAX
on the first start-up, after that a newly rebuilt engines should have minimal or no smoke at start-up
if you are using old heads on a new block the valve guides or seals may be well worn.
black smoke is overly rich tune, water vapor/steam, out the exhaust might be moisture in the mufflers or cats,
but should also burn off in minutes or theres something wrong.
mis-aligned or poorly sealed intake gaskets can allow oil to be sucked into the intake runners from the lifter gallery,
you certainly would not be the first guy to have a busted piston ring,
a piston ring that was installed upside down,
pistons with excess side, bore clearance,
or incorrectly installed rings or valve guides or seals , or a bad pcv valve ,that caused oil control issues,
or having put several extra quarts of oil in the engine over what was required, either
a leaking transmission modulator can cause an engine to smoke,
a carb or leaking injectors can be an issue,
its all down to ISOLATE AND TEST
this link holds more info
Id suggest a leak down test
related threads
if your skipping over or ignoring the links and sub-links,
your skipping the majority of the related info you NEED!
http://garage.grumpysperformance.com/index.php?threads/blue-oil-smoke.12198/#post-59193
http://garage.grumpysperformance.co...oven-facts-if-your-in-doubt.13051/#post-84695
http://garage.grumpysperformance.com/index.php?threads/leakdown-compression-test.881/#post-56489
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