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I have a 1978 Atomic 4 and when I first start the engine there is blue smoke coming from the exhaust, which clears after running approximately one minute. I have been told that the cause is oil leaking past the valve guides. Any comments? I don’t have a lot of oil consumption possible ¼ quarts every 10 hours.
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The problem of oil leaking past valve guides and having to be burned off during the first few minutes of engine operation relates mostly to overhead valve engines. In overhead valve (or valve-in-head) engines, particularly with old and worn valve stem seals, oil does tend to drain down along the stem and into combustion chambers while the engine sits idle.
The Atomic 4 is a valve-in-block (or "L-head") design, which means that the valves are located in the side of the block, beside and below the combustion chambers. In this design, oil from the valve chamber (where the tappets and springs are located) would have to flow uphill to get into one of the combustion chambers. For this reason, designers of valve-in-block engines seldom (if ever) design oil seals around valve stems.
Your bluish smoke during the first minute or so of running is most likely nothing more than the result of your fuel mixture being a bit on the rich side until the engine warms up. You're also probably using your choke during the initial few minutes of operation, which will contribute to a rich running condition
In summary, in the face of otherwise good performance, low (normal) oil consumption, and the fact that the blue smoke clears so quickly, I would not undertake any corrective action at this time.
Best regards,
Don Moyer
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