Catch can smoke - normal?

[backeis]

As recently determined, the PO of my car routed the valve cover ventilation to a catch can instead of back into the carb. I noticed that it's smoking a lot. Is that normal? 

Here's how it looks. It often smokes even more than that.

 

https://www.youtube.com/watch?v=BQ3nq1W2-tg

 

I cleaned out the catch can yesterday, and it still smokes. So I guess that smoke is coming from the engine.

 

But... why would it smoke under the valve cover? Shouldn't that area be sealed, except for oil delivery? Are my valves not tight?

Edited June 20, 2018 by backeis

[TobyB]

Blowby.  The filter on top of the can may actually be hurting you here.

 

And adjust your valves.

 

t

 

[backeis]

Thanks Toby. Will look into valve adjustment. Could it also be distributor timing (too soon, too late) that contributes here?

If the filter hurts - what do you reco instead?

[02Les]

Maybe sell the smoke to Lucas.

[jimk]

2 hours ago, TobyB said:

And adjust your valves

Need an explanation on this.  How does the valve affect piston ring blowby?

Was this engine just warming up? 

How cold and humid was it when the video was taken?

Is this engine on it's last legs?

Rings stuck, need a high quality engine flush to loosen the rings?

[backeis]

35 minutes ago, jimk said:

Was this engine just warming up? 

No, it does this at all temperatures, from cold start to all the way hot.

 

35 minutes ago, jimk said:

How cold and humid was it when the video was taken?

This video probably at around 70F, and medium humidity. But it also does it at beyond 80F and high humidity. Haven't had a chance to test it under 60F.

 

36 minutes ago, jimk said:

 Is this engine on it's last legs?

I hope not! It generally runs very well. No backfires, no smoke out the tailpipe.

[kbmb02]

27 minutes ago, jimk said:

Need an explanation on this.  How does the valve affect piston ring blowby?

 

I suspect Toby's point was separate from the OP's post (in that, the audio suggested valves sounded loose).

[backeis]

19 minutes ago, kbmb02 said:

the audio suggested valves sounded loose

Is that an easy fix for someone who's never opened up an engine?

[Preyupy]

36 minutes ago, backeis said:

Is that an easy fix for someone who's never opened up an engine?

Sure, find someone that knows how to do it, buy them lunch and have them teach you how to do it.  It is really very simple if you have any mechanical aptitude at all.  My guess on the steam from the breather is the rings are getting tired or there is a lot of water in the oil.  When was the last time the oil was changed? 

[backeis]

11 minutes ago, Preyupy said:

When was the last time the oil was changed?

Probably 2-3 years ago, and car was stationary for 2 of those. Recently consumed 3 quarts of fresh oil due to leak at old mechanical fuel pump attachment point (since fixed).

Guess a full change wouldn't hurt...

[TobyB]

Adjust the valves, then, fresh oil, and go for a good hard drive.  Byron might be right, that might be steam. 

But the discoloration around the filter suggests it's been doing it a lot.

 

What I found with a catch can was that the length and diameter of the hose connecting to the can is relatively important-

when the engine's running, there's a certain amount of pulsation in the breather hose itself.  If the hose volume is greater

than that pulsation and there is no restriction on the vent at the end most of the oil and vapor is just moved back and

forth inside the breather tube.  Upset that balance, and lots more oil makes its way out, even on a healthy engine.

 

And yes, Jim, it was the soundtrack in the video that I was commenting on.

 

t

 

[backeis]

Thanks Toby!

 

If it's steam, it's very greasy - coats the hood with oil and everything else around the filter.

 

What's the idea diameter for a breather hose? And I'm not sure that the filter/vent provides much resistance. It's similar material to a carburetor air box, so probably designed for little resistance?

[Buckeye]

1 hour ago, backeis said:

Is that an easy fix for someone who's never opened up an engine?

It is not difficult job. If you have Haynes BMW 1602 & 2002 Repair Manual look up page 35.

https://www.amazon.com/1602-2002-1959-77-Haynes-Manuals/dp/0856962406/ref=sr_1_14?ie=UTF8&qid=1529521467&sr=8-14&keywords=haynes+bmw+repair+manual

[TobyB]

I have used 2' of 5/8" hose effectively.  And I once tried putting one of those gauze filters on,

and filled the catch can in a half- hour.  But you can experiment with it on and off- it may not make

that much difference at street speeds.

 

hth

t

 

['76mintgrün'02]

The breather tube that enters the stock air cleaner has a restriction at the end, where it is choked down to about a 3/16" hole.  I figured that created a nozzle to atomize any oily gooeyness coming through, before sending it through the carb.  I am not sure what that information adds to this conversation... but I thought I'd add it.  So, there you have it.

 

You can sort of see it in this photo