73-87chevytrucks.com
General Site Info => General Discussion => Topic started by: Layne on January 23, 2010, 04:47:51 pm
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Let me give you guys a little background... I inherited the car in Oct. '04. It had been sitting for about 6 years. I put a new battery in there and it fired right up. I started it about once a week for 3 years until it became my daily driver. It's always used a little oil between changes (about a quart). At first, I got a dab of oil in the air cleaner assembly, but I started using Lucas every oil change and that's a non issue. The car has no cat, and a fart can. ::) It's always had this erratic idle, but that's a non issue, too. Last summer it'd smoke terribly going down hill in 4th after I gassed it. Valve seals??? Smokes on start up too. I retired it at the end of last summer when I bought my headache sierra. Well, this is a restoration in progress, and I'd like to get it to stop smoking before I start body work. Oh yeah, I got with 50,000 miles and now have almost 90,000 on it. Heres my dilemma-
Comp test- #1 155 psi wot
#2 120
#3 145
#4 150
Vac. test 17-19 in at idle. Usually 19, but that's where my erratic idle comes it.
I'm thinking valve seals, but I wouldn't doubt the rings either. My grandpa drove this really nice and I was sixteen when I got it. I don't really drive it so nice. :D
On a side note, I don't know if it's related my aftermarket temp gauge goes to 230 F before the electric fan comes on to bring it down to 190. The fan never, ever comes on going down the road in the summer, and it runs at 195 all the time, unless I idle for a while. I'm a stickler for scheduled maintenance on this car, too.
SO- Rings, Valve seals, or Head gasket???
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What color is the smoke? Pull the vacuum hose off of the vacuum modulator and see if there's any transmission fluid present.
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It's a stick. It's whitish. It's oil for sure. Never had an antifreeze leak/burn
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White smoke is coolant or automatic transmission fluid
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It doesn't smell sweet or anything. Why would it only smoke at start up and gassing it after going downhill for a while? I figured a head gasket leak would smoke all the time. It's never, ever been low on coolant. Just oil. And my oil turns jet black after 500 miles.
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Oil smoke is bluish grey
Coolant and ATF is White
Rich fuel mixtures is black smoke
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I just fired it up, and it's bluish I'd guess. Maybe all that condensation is throwing me off. You know the steam from the exhaust in the winter.
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Plug num 1 was orangish. 2,3 and 4 were the grayish good burning color. If that helps any
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so the smoke at start up could that just be condensation?
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I first noticed it starting in the summer. But the condensation was throwing me off now. I noticed it in the summer, but never really paid attention to the color.
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It'd be a good candidate for a 2.8, 3300, or 3800 transplant! Valve seals I would think would be the most likely candidate if it smokes on startup and if my memory serves coasting downhill with your foot off the pedal causes a high vacuum situation in the intake tract, allowing it to suck in oil through the valve guides, but I could be wrong.
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I was thinking about the caddy 4.9L :o 8)! But that's for another day. I know you can do valve seals on the motor, but can you do valve guides too?
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Ive done the seals, but I dont think the guides can be done.
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You can't replace/recondition valve guides with the heads on the engine. Is that what you're asking? That's a job for the machine shop.
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Event- yeah. That stinks. Is it pricey?
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Valve guides is a common part of the head rebuild. No biggie there, but you might want to snoop around a little more before you yank the head off and send it to the machine shop. You can buy a leakdown tester or just adapt and pump compressed air into the spark plug hole with the cylinder in question at TDC on compression stroke. Then air will escape either through the exhaust valve, intake valve, rings, or head gasket. Look up the instructions for a leakdown test for more detail. If you want to try and fix this without pulling the motor, you need to verify the bottom end. My guess is that you need more than just a head rebuild, but you never know.
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i would think that the same spark plug would get fouled periodically if you have a bad valve seat. Is this not true?
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They've never fouled. Had them in there about 4 years now. They were always gray except now #1 is orangey
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run some seafoam in the oil for about an hour before you change the oil.