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IMO....I have a lingering issue that is puzzling me, and maybe one you folks have an idea. Its a mystery puff of blue from the exhaust.
On start and warmup there is not evidence of blue in the exhaust. Under normal operation their is no evidence of blue in the exhaust, and the plugs are looking pretty clean - no evidence of oil buildup on the plugs.
When I take the car out for a run after its been sitting for an extended period or idling in the driveway for an extended period (ie tinkering with the carb), at the first stop light after the engine rpms have been up to a city cruise for a few blocks, I get a very distinct cloud of blue. its not a puff, but a noticeable (and embarrassing) cloud.
It happens once and then will not occur again until its next extended period of sitting. It seems to occur that first time you let off the throttle back to an idle.
The car has a PCV but no EGR valve. CompressiIMO..on is good and balance between cylinders is good.
I am baffled - ideas to check?
I concur with the valve seals....but..... since you are not picking up any oil ash or residue on the spark plugs, it is likely that one or all of the EXHAUST VALVE seals or guides sre failing. IF you decide to replace the seals, I've had good results with the Perfect Circle Teflon seals with the garter spring....but...they USUALLY require machining of the guide to accommodate the seal and the clearance from the underside of the retainer to stem seal must be checked at maximum valve opening to prevent interference. If the guides are worn, I like aluminum-silicon bronze alloy replacements, but others will have their preferences.
BOB RENTON