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In this Discussion
- BJ__TN January 2012
- Marconi January 2012
- merccrazy January 2012
- walts garage-53 January 2012
still smokin 390
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I've heard that I can drain a quart of oil and add a qt. of ATF to clean out the motor. Run it for an hour, drain it, fill it back up, run it for another hour, drain it again. I'm gonna try that, and see if it helps. The smoke isn't blue so I don't think it's the rings. I think the poor thing just needs to be cleaned out.
Any more advice is greatly appreciated and welcome! -
How many miles does it show on the speedometer? As far as using ATF to clean out the engine, it'll work but it takes a while. Try Marvel Mystery Oil instead, it's fairly inexpensive and works quicker than a lot of other products. If the car is relatively lo mileage, it could have stuck/carboned up rings. Let us know and good luck.
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I'm no expert by any means but, if it does not appear to be oil smoke, I am assuming it is a black sooty kind of smoke and that could indicate an overly rich
Fuel mix. If you do try the ATF and that doesn't help check out the carburator settings.
Bob Hickson -
BJ, in his other post he says that the smoke isn't coming out the exhaust but rather the oil fill pipe and dipstick tube, blowby.
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It has 85k, it's the compression rings I'm pretty sure. I know an ASE mechanic who looked at it while it was running. He saw the oil and how it pooled on the manifold. So he told me that I need the rings done.
I'm trying to decide on whether I should either spend the money and get the motor rebuilt, or buy one that's already done and swap motors.
Thanks for the info, I have until spring to decide.
I'm planning on taking it to Minnesota from Tennessee in June for th "Back to the Fifties" show at the Minnesota Fairgrounds. -
Think I'd try a couple of oil changes first with the Marvel Mystery Oil added. Even with new filters each time , you're only looking at an outlay of about 40 bucks! If the 85k miles is actual the rings shouldn't be that worn. I've seen 390s with well over 100k miles on them that still didn't pump much oil, they're a tough engine. The only downsides to them is they're heavy and the mileage is usually around 10MPG they're thirsty but produce lots of torque/power. Good luck.
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Being an X AMC man you have bad valve stem seals. Replace the seals and this can be done without pulling the heads off. They sell tools to remove the keepers and you can change the seals. You need an air compressor to do the job. Walt.
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All overhead valve engines have this problem after 60 to 70 thousands miles. That is up to year 1989. Chevy had the most problems with valve seals. Walt.
