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Old 12-09-2024, 07:34 PM
JJDeville JJDeville is offline
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Default 4oo engine is smoking

I have a Firebird with a 400 engine engine that has been in long term storage that is smoking pretty good. I changed the oil and drove it a few miles. It runs really good but smokes. I am wondering if the valve seals are causing this. I am sure they are old and hard, car sat undriven for 13 years. Is there a good way to check for this without pulling the heads and taking them to the machine shop?

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Old 12-09-2024, 07:41 PM
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Start with a cylinder leak-down test.

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Old 12-09-2024, 08:28 PM
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I will guarantee you it’s the valve seal O rings.

They where well on there way out even before the car sat for 13 years!
But yes the cylinder walls could have some rust putting on them and condition harms the rings when the motor is started .

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