Bad experience with small crankcase breather

[paul]

I just posted this in a reaction to an other post.
Maybe it's a good idea to post it also as a separate thread.

Last summer I have had a bad experience with the small crankcase filter.
On a holiday trip I drove in the rain and the filter got moist.
Well heavy rain, here is a photo of me driving on the autobahn.



In about 400 miles I lost 3,5l oil.
Exactly all of it, red light on.
After putting all the oil in I had with me, I looked for a petrol station.
This is how much oil was leaking, after standing still for a few minutes.



Not sure what the reason was, I took of the breath filter.
My oil leakage disappeared.
I'm pretty sure the moisture together with the oil fumes created over pressure.
This resulted in the leakage on the crankcase seals.

 

[htfx19]

How odd

I have never experienced or heard pf such a case.
I also never met a guy who in the midst of crises and rain had the cool to take pictures. Hurray to you Paul.
Enjoy-

 

[fiatmonkey]

I have never experienced or heard pf such a case.
I also never met a guy who in the midst of crises and rain had the cool to take pictures. Hurray to you Paul.
Enjoy-

Second that!

I had a bad experience with a small one that simply popped off during an auto-x. ****e everywhere. I quickly traded it for a catch-can and a better filter at the other end of the can.

 

[Black-Tooth]

Are you speaking of the Crankcase BREATHER?

Usually it does not vent to atmosphere, but is plumbed back into the intake.

That breather?

Whether it vented back or vented to atmosphere is not the issue, its the fact that you had so much blow-by and pressure that it blew out al the oil as well!

I've seen and had similar problems but to the "nth" degree that you speak of here. And I've never heard of it being that extreme... and THEN, the problem goes away?

I think the Lord must've been mad at ya for a time there... nothing else seems to explain it! (Were you speeding, again?)

 

[Mark Plaia]

I once had a similar issue.....

The small flame arrestor cage in the breather hose on my fuel injection Brava had coked up and blocked the hose. The car pumped oil out of the shaft seals due to high crankcase pressure.

Of course it was on a long trip. Cleaned the flame arrestor, and everything was okay for many tens of thousands of miles.

I think your assessment is correct.

Ciao,

 

[budgetzagato]

Somehow I'm not surprized...

The relatively small "breather" filters aren't really a good solution to the crankcase pressure/fume problem. The stock system uses a fairly large hose that routes back to the intake on either carbureted or injected models. In the hose is a flame arrestor, in case of backfire through the intake. The relatively large diameter of the hose and the fact it's routed back to the intake means it's designed for pretty good air flow if needed.

A small K&N style gauze/mesh/oiled filter on the end of that hose instead could easily clog with aerosolized oil which result in pretty good back pressure. Especially at high/sustained revs. Autocrossers and others who use their cars in bursts would probably not have this problem

FWIW, I don't think it had anything to do with water, which would be pushed out of the filter media pretty easily compared to oil. Might depend on where it is in the engine bay (I would think a higher placement would be better) and the use of stock splash guards.

 

[Matt Brannon - Midwest Bayless]

Speaking of the breather system.....

One thing that is interesting about the design of the breather system in the SOHC and DOHC, is the steel breather tube down into the oilpan.

With this configuration, when the crankcase builds up excessive pressure from piston ring blow-by or other reasons, the pressure must build to the point that it pushes crankcase oil up and out out of the tube into the upper area of the block where it can then disperse, allow the air to escape and the oil drain back into the crankcase. This is why the aluminum cyclonic trap is so often completely sludged up and gross when one removes it after many thousands of miles.

The oil within the tube acts like a PCV valve allowing excessive pressure out without allowing crankcase internals to be exposed to the atmosphere, however it is the leading cause of oil pumping/puking with a worn-out motor.

-Matt

 

[paul]

I also never met a guy who in the midst of crises and rain had the cool to take pictures. Hurray to you Paul.
Enjoy-

Hahah...it was not easy to keep the car between the white lines, looking in the mirror to see the back of the camera, and pointing it in the right direction

One fun fact while driving at that time was that no one followed me close.
They passed me or kept their distance.
First It puzzled me, later I solved it.
The car is lowered and spacer on the back wheels.
And because of the heavy rain I had two beautiful V like sprays behind the car

 

[paul]

The small flame arrestor cage in the breather hose on my fuel injection Brava had coked up and blocked the hose. The car pumped oil out of the shaft seals due to high crankcase pressure.

Of course it was on a long trip. Cleaned the flame arrestor, and everything was okay for many tens of thousands of miles.

I think your assessment is correct.

Ciao,

Sounds indeed very similar.
Since I have driven almost 1000 miles with minimal leakage.
Only thing changed was removing the filter.

 

[paul]

The relatively small "breather" filters aren't really a good solution to the crankcase pressure/fume problem. The stock system uses a fairly large hose that routes back to the intake on either carbureted or injected models. In the hose is a flame arrestor, in case of backfire through the intake. The relatively large diameter of the hose and the fact it's routed back to the intake means it's designed for pretty good air flow if needed.

A small K&N style gauze/mesh/oiled filter on the end of that hose instead could easily clog with aerosolized oil which result in pretty good back pressure. Especially at high/sustained revs. Autocrossers and others who use their cars in bursts would probably not have this problem

FWIW, I don't think it had anything to do with water, which would be pushed out of the filter media pretty easily compared to oil. Might depend on where it is in the engine bay (I would think a higher placement would be better) and the use of stock splash guards.

Interesting you could very well be right that rain had nothing to do with it.
I have been using the small filter for some time.
The 1300 was indeed pushed.
More than 4 hours between 4500 and 5000 rpm.

Afterwards I tested the breather by blowing into it.
I could feel some resistance.
It seemed to have a threshold of minimum pressure to open up.

 

[paul]

The oil within the tube acts like a PCV valve allowing excessive pressure out without allowing crankcase internals to be exposed to the atmosphere, however it is the leading cause of oil pumping/puking with a worn-out motor.

-Matt

Great info, didn't know and realized it was working this way.
My 1300 has some blow-by.
I thought it's not uncommon with 1300's.
To be sure I had the compression checked.
It looks okay, here is the print out.

 

[pyrraxis]

Great to hear you got it figured out and fixed! My '78 (my first X) did something similar and I couldn't get the issue solved. The pressure would build up in the crankcase and kept popping the dipstick out. It would spray oil all over the place. I ended up selling that car. That was back in 1990, long before this forum came to be. Now I know better - and still kick myself for selling that car!

 

[Bill_Alber]

Pluged Crankcase vent

THanks for the thread Paul. I just spent 1 1/2 hr. in the garage cleaning out my system as a prevention. Pretty dirty but clear except for the small diameter tee/side arm. Got it all together but un-tested.

Bill

 

[dcioccarelli]

Sports air filter.

Just resurrecting this post.

I seem to have a similar problem with a car that is a twin of Pauls (except that it resides in the southern hemisphere). In my case, I have the crankcase breather vented into a "ramflo" sports air filter, similar to this:

The crankcase is vented into an inlet in the air filter, although I seem to get oil accumulating in the filter itself and I seem to be loosing more oil than before. Admittedly, we are talking about a motor with 250,000 KMs, so I could have a lot of blow back, but I could swear that I have higher oil consumption with this filter.

In any case, I'll be reconditioning my engine (and fitting my new carburettor from Steve and 4:2 header) on my next trip down under. I'd still be interested in why a sports air filter could lead to higher oil consumption (and where the oil is going).

Cheers,
Dom.

 

[lookforjoe]

This is the FI version -

after 120K, full of small coked oil deposits.

I thoroughly cleaned mine out when I did the head work last fall

looking through the screen after removing & cleaning..

On older Volvo's a clogged flame trap would blow out the rear main seal or the cam plug in the back of the head, common occurrence on poorly maintained (lack of regular oil changes, mostly) cars.

 

[Eastep]

I replaced the rubber hose, but still have the spiral trap thing installed in the metal tube. It collects its share of oily stuff.

 

[Mark]

Matt, do you consider this a good system, or is there a mod that works better? Just wondering, because once a long time ago a friend had an issue with a Scorpion that spewed oil out the breather.

 

[dcioccarelli]

Cleaned the flame trap...

... and indeed it was dirty. I also relocated the intake on my after market air filter to vent the fumes in a location where there will be more suction.

I have a few of questions though:

- If the flame trap was indeed clogging the breather hose and causing oil to come out of the crankcase seals, will prolonged leakage / pressure have resulted in permanent failure of these seals?

- does the air coming from the breather need to be filtered before being sucked into the carb, i.e. should it be on the inside or outside of the filter element?

- how do you get this thing:

... off? I undid and removed the bolt and pulled at the breather but it won't budge. I didn't use extreme force. Is there any trick to getting it off? Also, is there anything to clean in there once I remove it?

Cheers,
Dom.

 

[halojm]

Answers

Dom,
- If the flame trap was indeed clogging the breather hose and causing oil to come out of the crankcase seals, will prolonged leakage / pressure have resulted in permanent failure of these seals?
It could, especially if it pushes the seal's lip outwards (so it would no longer have the little spring lip inside holding pressure onto the sealing surface.

- does the air coming from the breather need to be filtered before being sucked into the carb, i.e. should it be on the inside or outside of the filter element?
No. The way the crankcase evacuation system was designed by Fiat is not filtered, but rather goes up into the already filtered area of the air cleaner assembly where the vapors can be sucked thru the carb and burned.

- how do you get this thing off? I undid and removed the bolt and pulled at the breather but it won't budge. I didn't use extreme force. Is there any trick to getting it off? Also, is there anything to clean in there once I remove it?
Once you have the bolt off, it's only held on by the very well stuck gasket. A little tap with a plastic hammer should break it free. Clean as much of the goo you can see, then put it in carb cleaner for an hour and it should be perfect. Also, make sure you install the cyclonic trap (that little spirally thing) near the top of the crankcase breather hose, because that's where it's supposed to do its job.
Dave

 

[budgetzagato]

All true..

Please allow me to clarify a couple of things.

The cyclonic trap is the metal housing at the bottom as pictured in Dom's post. It directs the crankcase vapor in a spiral direction within the housing and this causes oil particles to adhere to the outer wall, and allows it to flow back down into the pan.

The spirally wound wire gizmo inside the hose is a flame arrestor designed to stop flame spread in case of a backfire through the intake. This is why it should be near the intake side of the breather hose. Carbs usually also have this flame arrestor.

Hope that helps. :bla: