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I have been trying to figure out a smoking on start up issue since I bought my 72 four years ago. I have replaced the valve seals and that didn't fix the issue, the guides felt good. The car is a 4 speed so it can't be the vacuum modulator. At this point I think it's either rings or an intake gasket issue. There is an old post here from last year with more info (Old post....) I pulled the plugs getting ready to do a compression test, they look pretty good to me but would like some other opinions by much smarter folks than me. Anyone see anything that jumps out as an issue....?
How much oil are you using/going through, if any? None to very little = valve guides. Lots = rings. Startup only = valve guides. Rings will smoke all of the time. Your plugs look wet on the threads only, and look new. How many miles were the plugs in there? Maybe not long enough to get oil fouled. PCV puking oil into manifold?
Except for #7 pic being omitted, those plugs don't look to be fouled, burned, or have any other serious problem. If anything, they are burning a bit 'rich' or a bit 'cold'. Ideal appearance would be a little lighter in color...toward tan.
There are not many miles on the plugs....I don't drive it much maybe 200-300. It may smoke a little all the time but if it does it's hardly noticeable....On start up if the engine is cold it smokes like I'm fumigating for mosquitoes. It's also not using much oil but again I don't drive it enough for that to really show.
Charlie...I was having a real hard time getting all these photos posted last night.....It seemed like every time I thought I had them all I would have to go back and retype something or add another. I see a photo for plug #7 above but it was one that gave me problems.
Once I get the compression test ran I'll post back the results.
Your fingers are partially blocking the plug part number but it looks like R44T which is the wrong plug. Not saying that is the cause of your problem but you should be using R45TS which is one heat range hotter and has a projected tip.
My Vette was putting out an embarrassing blue cloud on initial startup after sitting for extended periods of time. I have a leak down tester which allows you to determine the health of the rings and valve seats. My motor had less than 3% leak down. which would indicate that it was just like a superior newly rebuilt motor. I have a high lift cam and the motor gets run pretty hard. So the oil was leaking around the valve stems. Like you I couldn't feel any discernable slop in the stem to guide clearance, but I took my heads to a machinist friend and they got new guides and PC valve stem seals. My motor doesn't put out any smoke now.
When I was young I tried just replacing the baked and cracked valve stem seals. It did not work and was a wasted effort. By the way how many miles are on the motor? Neglect and abuse by a previous owner can ruin a relatively low mile engine.
MelWff....Thank you for pointing that out....I replaced them but I'm not sure if I just matched the number on the old plugs or just asked the parts guy for the correct plugs. I'll put the correct set back in but like you said I don't think it has anything to do with my smoking problem.
gkull....I have no real way to know how many miles are on it.....The story I was told by the 2nd owner (1975-2015) was that he put a crate motor in in the late 90's but didn't drive it much between then and 2015 when he sold it to the guy I bought it from. He said max would be no more than 10,000. I don't think he had any reason to lie to me but I really just don't know. All the signs point to valve seals but I would think they would stop the leaking for a few hundred miles.....I saw no difference in the smoke at all.
I have a leak down tester as well....I'll run that after the compression test.
I have a leak down tester as well....I'll run that after the compression test.
Brian
I don't even own or believe in compression testing. It is a waste of time. For leak down you have to have the pistons at TDC or your motor will rotate. Have a compressor that supplies a constant 100 psi.
Help reading plugs.....
