tr4guy

My 76 911S has two issues. It runs fine but every once in a while it backfires out of the blue....for no apparent reason.....anyone have some suggestions??
Issue #2....if it sits for a couple days without running, when I start it up, it smokes white smoke for a while then it goes away. If I start it the next day no smoke. Leave it sit for 3 or 4 days, it smokes for about 15 - 20 minutes and then quits......any suggestions or are these issues not to be concerned about??? Thanks for any help.

Makmov

#2

Valve guide/seal leak or ring issue. Something is letting oil leak into the combustion chamber after sitting for a while.

An early warning sign that your motor may be do for a redo.

theiceman

Well not so fast ... first of all it is a 911 .. smoke coming out after startup on a flat 6 may not be early sign of an engine rebuild and could be considered normal . Mine does it ( the blue smoke ) if I do a really hot runa then park it . The oil is so hot some seeps down into the combustion chamber over night ... if I drive it normally I never see it . I have no leakdown, high compresion, and don't even use 1 qt every 5K . i sure don't think I am getting the early signs of a rebuild ..

Secondly that is usually Blue smoke .. White smoke is usually just condensation in the exhaust and as soon as the exhaust warms up it evapourates away.

i say don't worry about it and enjoy your car ..

tr4guy

Thanks guys....I bought it about a year ago and it had a rebuild just before I bought it so hopefully as Iceman says it's just normal stuff.

theiceman

your fine .... even a puff of blue on start up is no cause for concern

ricster

Normal. The 911 flat design makes it happen.