The 85th Post about Smoke!

[Santawillis]

Hello!

 

There are a variety of posts related to smoke, I am experiencing the good old "it smokes when it warms up" version of it. The reality is, that I want to enjoy the car and not worry about any potential catastrophic failure. I am not looking at a concours-level car nor an engine that is flawless.  To that end, is this smoke related to any potential issues that may leave me on the side of the road? The color is "grey-ish" and it does puff when it accelerates, am I running too rich? Is it a combination of rich and piston rings? See a photo of my Scheiße kacken in all its glory surrounded by smoke!

 

[Mike Self]

A little bit about automotive smoke (Cliff notes)

 

Color: 

• grey is usually oil smoke
• White can be a couple of things

1.  hold a paper towel or Kleenex over the tail pipe; if it blows out with moisture, antifreeze is  being sucked into a combustion chamber.  Kind of a sweetish smell
2. Other option is brake fluid from a bad M/C being sucked through the brake booster into the engine

• Black:  engine running way rich

When:  

• Acceleration:  grey smoke is usually worn rings
• Overrun (coasting, throttle closed):  usually worn valve guides and/or stem seals.

There are lots of other permutations and subtleties, but those are the basics.  I'm sure others will add to the basics...

 

mike

[Santawillis]

28 minutes ago, Mike Self said:

A little bit about automotive smoke (Cliff notes)

 

Color: 

• grey is usually oil smoke
• White can be a couple of things

1.  hold a paper towel or Kleenex over the tail pipe; if it blows out with moisture, antifreeze is  being sucked into a combustion chamber.  Kind of a sweetish smell
2. Other option is brake fluid from a bad M/C being sucked through the brake booster into the engine

• Black:  engine running way rich

When:  

• Acceleration:  grey smoke is usually worn rings
• Overrun (coasting, throttle closed):  usually worn valve guides and/or stem seals.

There are lots of other permutations and subtleties, but those are the basics.  I'm sure others will add to the basics...

 

mike

Question on worn piston rings - Is this a terminal condition? 

 

Add oil and hope it doesn't get worse or start saving for a full engine rebuild?

 

Rafael

[TobyB]

The usual way to judge these things is by tuning the car-

 

getting the mixture right via spark plug color, o2 meter, CO meter, seat of the pants, and intuition,

 

putting a timing light on it and getting the timing into a repeatable powerful ballpark,

 

and then driving the hell out of it and see how often you're adding oil.

A quart every thousand miles is fine.  Every tank is too much.

Any coolant loss is too much.

Any brake fluid loss is too much.

 

The ENGINE actually likes  bit of oil going through it- as long as it's not so much

that it clogs ring gaps, reduces fuel octane and closes up the plugs,

a little 'top cylinder lubrication' doesn't hurt anything.

 

So drive it!  BMW engines like to be worked, and if they're not, they tend to 

gunk up and burn more oil.  I put a junkyard engine in the track car once,

and after a day of being called in for oil burning,  the thing settled down

and didn't really consume any more than any other engine I've run.

 

The good news is that oil consumption alone can be lived with for a very, very long time.

By some people. 

Others freak out and do a Tesla retrofit, which is very cool in its own way.

 

t

 

[Santawillis]

@TobyB and @Mike SelfThank you for the wise words