Pat,
Experience has taught me that blue smoke on deceleration and/or
descending a hill, is most often an indicator of worn valve seals/guides.
Leaky valve seals allows small amounts of oil to get past the valve stems
and into the cylinders and cause the smoke. Granted, some oil gets by
under normal load conditions but the fuel flow is higher so the oil burn
morer completely, leaving less visible smoke from buring oil.
When decelerating, the fuel supply is reduced, combustion not as high
and burning oil leaves smoke.
A fair rule of thumb, blue smoke = oil burning. Black smoke = fuel and
white smoke =moisture, a real problem.
There are additives on the market which are supposed to "expand" seals
and stop smoking engines. A chemical process which actually softens the
rubber. I have never had much luck with these.
Best solution is a valve job so the valve stems, guides and seats can all
be checked.
Sounds like you may be able to get away with a simple valve job. i.e.
clean head, lap valve and replace seals.
Good luck.
Tony R.
69GT6
68GT6
64TR4
TTFN
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