Blue Smoke on occasional start up

[FenderGuy]

I sometimes get blue smoke at start up sometimes when it's cold. It doesnt always happen, but I have noticed that I get this blue smoke when its colder outside.

I purchased this engine from a fellow on the board, the engine had broken head studs. He pulled it apart and installed all new Raceware studs and replaced the rings and seals. Also installed were new Carrera oil fed tensioners. The engine had only 79k orig before this was done. He said the bottom end and heads were not touched and did not need it. He ended up fully assembling the car and driving it less than 500 miles total. He said engine ran flawlessly with no smoke or leaks.

Ive had this smoking issue since getting the engine, the engine does feel better, but should I feel worried about this blue smoke?

[81 911 SC]

A little blue smoke is fine. Were the valve guides replaced while the previous owner was doing this work? Do you get blue smoke on deceleration? If so your guides are getting worn and probably need replacement. How often do you have to add an additional quart of oil?

[FenderGuy]

I have no clue if the valves where replaced to be honest with you, the seller said the engine was fine, I believe him because he has a good rep on the board, but I did tell him the car smoked on occasional start ups.

I only get blue smoke on start up and it's a puff that goes away... the car does not smoke when I drive it, or maybe I can see it...

I add a quart about a month ago because the OEL gauge was bothering me, but I think its just malfunctioning....

[81 911 SC]

Always check your oil after the car has gotten up to temp and check with the dipstick. If the gauge is reading in the middle when up to temp 180 degrees or higher then your oil level is fine.

[scottb]

Does it give you a blue puff every time you start, only after it's been sitting for a few days?

[cbeers]

Have you tried the "idle before shut down" trick?

works every time for me.

-Chris

[john d 81SC]

Chris,

Please explain the "idle before shut down trick". TIA

[AirCooledExcellence]

Originally posted by john d 81SC
Chris,

Please explain the "idle before shut down trick". TIA

I'll have a wild guess at that one and say that you let the car idle for a while before shutting it down

[Venetian]

Just a point of reference-I had the valves and guides done on mine and it only smokes occasionally now on start up. Previous to the rebuild, it would smoke on all start ups. Also oil consumption went from 700 miles/qt to 3000 miles/qt.

[porsche930dude]

If your going by your oil guage on the dash to determine oil level then you probrobly overfull possibly causing the smoke. If not im led to beleive a little smoke is normal at startup because of the design of the engine

[Paul Ferradas]

Many have said on this board that if it's a puff of smoke on start up that it's normal.

Because of the way the pistons sit, and with the expansion of the engine with heat, oil can seep through the rings and or valve guides and come to rest inside the cylinders. the next day when you go to start the car, it will burn that oil. Atleast thats what mine does. Mines isn't a puff though, it goes on for a couple of minutes. SUCKS.

[aigel]

It is very common for these engines to give you a puff of smoke at startup. Don't be alarmed. But you will want to keep an eye on oil consumption. If the engine keeps drinking oil while you drive the car, that's not good. Anyting over 1 quart per 1000 miles consumption points to wear.

There is always oil finding it's way past valves and also past the rings. When the car sits for extended periods of time, the oil from the tank will slowly go back into the sump and case. From the case the oil will leak into the cylinders and some of it will get by the rings. When you start, the oil will get burned.

That said, those effects described above account for only a litttle oil which is negligible in overall consumption.

Good luck,

George

[pjv911]

Hey Frank, I agree with the above responses about whats considered normal. Just to note in the event I forgot to tell you. The rings were replaced and the cylinders are the Alusil type. There have been board members that had bad experiences getting new rings to seat with this type of cyliner liner. I know from my experience with this engine that they show no sign of this issue because it never smoked regardless of engine rpm or load. In short they are not contributing to this start up smoke. As for the valve guides they are the originals (not replaced).
I personally have had much experience owning dozens of these cars and honestly 90% of my past and present cars let out a puff large enough to cloud a single car garage at cold start up. Its very rare to have a 911 that wont.
My suggestion is to learn and love that little puff and enjoy the many miles that engine will provide you.
Between the perfect leakdown #`s and raceware head studs the engine will prove very reliable for years to come.
And thanks again for a easy transaction. It was a pleasure dealing with you.

Kurt Williams

[disfin]

I get a puff every time the engine is cool, and like Paul described sometimes it lasts a minute or two. However, its hard to say how much it really burns since I don't drive it on long distances. My plan is to take it out for a nice long weekend, put a few hundred miles on it and see how it does.

I agree the smoke at startup sucks...

[FenderGuy]

Sorry was out town this week..

Thanks Kurt for the comments I do believe you sold me a good engine, just wasnt sure why the puff of smoke was happening and reading the board some experienced wear to the valves which I do not want to experience at all...

Thanks for all the other comments from the board members...

I'm driving it almost everyday since getting it installed...it feels better then the engine that was it in before hand

[cbeers]

john d

When you get home (or your destination etc.) simply allow the car to "idle down" for about 15-30 seconds, depending on how you were just driving. You can actually see the oil level rising as more oil is returned to the oil tank from the block. This seems to allow any excess oil to get back to the tank and this greatly, if not completely, eliminates oil "puffs" at start up. At least, in my case it did. If you have engine issues, this might not make a bit of difference. Small trick that has served me well

-Chris

[TibetanT]

I agree with Chris and everyone else above regarding oil levels via gauges sometimes not telling the truth. As Wayne said in his book, when installing the pistons into the cylinders "make sure that the rings are pointed up."
I rebuilt my 3.0L twice, the first time number one rings were pointed down so I got some oil into the cylinder each time I shut down for the night and number 1 spark plug was a little oily looking at service time and blue smoke at startup for a minute.
Once I took care of that all is well now, but sucks that I had to do it twice.
It's that gravity thing you know, comes back to bite yah.

[DW SD]

Originally posted by TibetanT
I agree with Chris and everyone else above regarding oil levels via gauges sometimes not telling the truth. As Wayne said in his book, when installing the pistons into the cylinders "make sure that the rings are pointed up."
I rebuilt my 3.0L twice, the first time number one rings were pointed down so I got some oil into the cylinder each time I shut down for the night and number 1 spark plug was a little oily looking at service time and blue smoke at startup for a minute.
Once I took care of that all is well now, but sucks that I had to do it twice.
It's that gravity thing you know, comes back to bite yah.

Tibetan,
There are some that say the rings rotate with use. I believe that is common understanding. In fact, I believe the rings being spaced about the piston is just a good practice, but doesn't last more than a few minutes upon initial startup.

It is interesting that your experience suggests very different!
Not trying to debate, just thought I'd drop the comment. I will try the idle before shut-off trick - thanks Chris!

Good luck Fender!

Doug

[aigel]

I also believe that rings rotate. However, in every engine I have built, I alway would space the gaps 180 from one another. It's just a might as well practise. After a few hundred miles, the gap locations should be all over the place.

George

[aigel]

Originally posted by cbeers
john d

When you get home (or your destination etc.) simply allow the car to "idle down" for about 15-30 seconds, depending on how you were just driving. You can actually see the oil level rising as more oil is returned to the sump from the block. This seems to allow any excess oil to get back to the sump and this greatly, if not completely, eliminates oil "puffs" at start up. At least, in my case it did. If you have engine issues, this might not make a bit of difference. Small trick that has served me well

-Chris

Chris,

Looks like you are confusing the sump with the oil tank. The sump is in the bottom of the crank case. The oil tank is in the rear fenderwell (on most 911s).

Cheers, George