heater hose for crankcase breather-to-intake? (1 Viewer)

[amaurer]

I'm ditching my catch can and am going to cut the crankcase breather pipe off and plumb it to the intake.

Any problem using heater hose for this? Its a long trip through the engine so I'd imagine the blowby isn't as hot as the exhaust, does anyone have experience as to whether heater hose can take the heat?

 

[cruiser_guy]

I'd be more concerned about trapping oil and the effects of oil on the rubber. If you're going to do this use an oil resistant hose.

 

[Chang-kuao-lo]

I used a silicone heater hose and haven't had any problems. Good heat and oil resistance.

 

[tater]

I have a buddy that had a VW rabbit that the breather ran into the intake and the engine would not shut off because it was running off of the blow by. I like the idea though and am most likely going to do it to mine. I'm going to run an air/oil separator inline. and then into the airbox.

 

[Chang-kuao-lo]

Wow, it must have been puking a lot of oil out the valve cover.

 

[lostmarbles]

I'm ditching my catch can and am going to cut the crankcase breather pipe off and plumb it to the intake.

Any problem using heater hose for this? Its a long trip through the engine so I'd imagine the blowby isn't as hot as the exhaust, does anyone have experience as to whether heater hose can take the heat?

Be aware of the risk you run if you follow through with this idea Drew.

I believe a rollover can result in your engine self-destructing by burning the oil that it is being fed into it via that breather hose and leaving you with NO WAY in which you can shut it down or even limit its revvs.



PS As you know, our BJ diesels uses "fuel-shut-off" to stop them and not "air shut-off".

 

[amaurer]

Be aware of the risk you run if you follow through with this idea Drew.

I believe a rollover can result in your engine self-destructing by burning the oil that it is being fed into it via that breather hose and leaving you with NO WAY in which you can shut it down or even limit its revvs.



PS As you know, our BJ diesels uses "fuel-shut-off" to stop them and not "air shut-off".

This is a popular thing to say, and while I have no doubt it can and has happened, I think people have blown it way out of proportion. Heres why:

a) Roll over is not a factor for breather-induced runaway. Oil spillage during a roll over will be a pool rather than a spray, and an oil pool won't burn (hell, a diesel pool won't even burn - injectors atomize the fuel for a reason!)

b) If true runaway occurred because of the atomized oil content of normal (while upright) blow-by, one can always drag the clutch in 4th to stop the engine. At least one source says the clutch may just slip, but I simply don't believe that - the engine timing is all wrong when running on intake gas, I'm pretty sure it will be producing far less power when running away than under normal operation.

c) I'd put some money down that a significant portion of the "omg diesel runaway" stories on the web were caused by governor failures, or at best turbo seal failures, rather than running on the oil content of breather gases.

d) I'm also willing to bet (ha, obviously, as I'm going to do this to my truck!) that if you had blowby bad enough where runaway was a risk that you'd have correspondingly bad compression to match. I've got 390s so I don't think I'm in that zone.

e) The handful of stories I found which I consider reliable seem to be regarding 2-stroke Detroits. My guess is that a 4-stroke IDI diesel is going to have comparatively more trouble running on intake gas.

We'll find out if I'm right in time...

 

[lostmarbles]

Here's some good reading:

Diesel run away? - Page 2 - Dodge Diesel - Diesel Truck Resource Forums

Read ALL the pages.

But you could be right Drew.

... We'll find out if I'm right in time...

You planning on rolling over?

 

[amaurer]

Here's some good reading:

Diesel run away? - Page 2 - Dodge Diesel - Diesel Truck Resource Forums

Read ALL the pages.

But you could be right Drew.

You planning on rolling over?

That thread illustrates my point pretty well. The anecdotes offered don't seem to have anything to do with blowby-induced runaway.

Post #20
-One runaway after overdoing it with ether
-Two from blown turbo seals

Post #24
-Incorrectly installed fuel rack

Post #25
-Runaway from nearby paint fumes

Post #28
-Runaway allegedly from oil getting past the rings. How this was verified would be really interesting to know.

Post #30
-Runaway from unstated causes, although considering that the operator allegedly tried to stop it with his ass I'm going to assume this had more to do with owner idiocy than any blowby phenomenon.

Post #33
-Claims runaway with the intake and fuel pump removed and assumes it was due to worn rings. Cannot be blowby recirculation, however, without the intake installed.

Post #42
-Runaway from a gasoline spill in the area.

Post #49
-Runaway, no cause or info.

Post #54
-The Ether Bunny strikes again.

Post #64
-Runaway from nearby gasoline vapors.

Post #66
-Not a runaway story, but a good post supporting my assumption that 2-strokes are more susceptible. It points out that rollovers can be a problem if you have an oil bath filter, which makes some sense, the filter element is probably a good evaporator.

Post #67
-Two runaways from turbo failure.

Post #72
-This might be a real one, although its saying that the engine was configured such that the breather would actually become submerged in oil resulting in some serious oil drinkage. I'll admit this may affect my theory that pools of oil are nothing to worry about, but I suspect that if the diesel fuel was shut off it wouldn't have been able to burn the oil. However, I do wonder how the author verified that the mechanism he proposes was, in fact, to blame.

But I think my point is intact, namely that most of the runaway stories that are out there often have some extra issues at play.

Also, it stands to reason, IMO, that if your oil consumption rate is significantly less than your gas mileage then your blowby probably isn't bad enough to run the engine on

 

[crushers]

as been stated, oil resistant hose would be good, heater line is not.

nice read on runaway, i have heard (never experienced) that bad turbo seals could cause runaway but it would have to be very bad seals...

i thought Bruce knew of a runaway diesel experience...?

 

[lostmarbles]

...Roll over is not a factor for breather-induced runaway. ...an oil pool won't burn ..

I think the thread (that I provided the link to) has a number of "reasonably credible posts" that suggest liquid oil will indeed fuel a diesel engine simply by entering via the intake valves while the engine is hot and revving.

...one can always drag the clutch in 4th to stop the engine. ......

"Wheels in the air" after a rollover make this option impossible.

....I'm also willing to bet ...... that if you had blowby bad enough where runaway was a risk that you'd have correspondingly bad compression to match. I've got 390s so I don't think I'm in that zone....

I think your risk is from liquid oil FLOWING through the engine breather after a rollover. (Nothing to do with blowby.)




PS. While I see that the majority of posts in that thread do relate to motors ingesting "combustible vapours", I think there are sufficient credible posts relating to "ingestion of liquid engine oil" to cause me some concern.

(Actually thanks for making me do an "Internet Search" on this topic because I like the way that thread looks at the dangers of ether-usage too.)

 

[cruiser_guy]

Use of a hose that is not oil resistant will eventually result in a gooey hose and leakage.

 

[Ron R]

Never happened to me, but I can remember (back in the 80-thies of the previous century ) that shortly after I bought a VW Golf Diesel (I know -but at that time I didn't know better than that but at least it was diesel!) a modification was made because there were numerous stories about runaway engines. I cannot remember exactly but I think the position at which the vent entered into the air intake was changed from close to the engine to a position at the airfilter, but I might be completely wrong there.

 

[crushers]

makes sense but then your air filter becomes an oil bath unit and will be needing replacing more often....

 

[amaurer]

Well, in any case, I got the message, heater hose won't cut it. As for our hand-waving out my engine running away, we shall see...................

thanks fellas.

 

[Ron R]

Oh boy, almost thirty years ago....maybe just after the filter? Before it would have the problem you mention.
All I now for sure is it was initiated by the VW company after several engines desintegrated because they were hardly stoppable. Only if you reacted very quickly (put it in gear and stalling the engine) you might have succes.
However this was only happening with the very first version of the VW Golf. At that time the only small passenger car with a small diesel (1.4 litre) that VW had (if my mind is serving me well )

 

[Chang-kuao-lo]

My old 1L ran off on me twice. Both times it shut down with the key. I think the rings were bad in one cylinder so it was just enough oil getting by to run away, but not enough so that it wouldn't shut off. Freaky though, it must have gone up to 5,000 or 6,000 rpm, it sounded like a heli throttling up for take off.

 

[lostmarbles]

..."Wheels in the air" after a rollover make this option impossible.....

Errrrrrrrr.

Flatulence of the brain?

Of course the brakes should still work (on the first pump at least) if your wheels are in the air. But there are further reasons why I think you would be unlikely to use the brake pedal to stop a "runaway engine" after a rollover.

Unless the rollover was both "mild" and "expected" (like on a trail where you're following other vehicles and have already observed some coming close to rollover - and even then, provided you roll no more than 90-120 degrees) then I believe you would suffer "shock" with its associated "disorientation". In such circumstances I believe you won't know where your pedals are or even whether or not your vehicle is still in gear. And fear/shock will mean that your entire brain will be devoted to "getting you out of there". And you will have "zero control" over what you do in the process.




PS. I wouldn't have posted again here - except that I happen to be having "restless sleeps" lately and somehow my mind turned to this subject and I realised what nonsense I had written.

And you're probably like me (with my pride-and-joy BJ40) in that you would "turn-around rather than risk rollover" and with your driving experience/maturity coupled with your "desire to keep your bodywork straight" means a rollover is extremely unlikely for you. In which case, piping your blowby into your air intake (coupled with your lack of "positive-air-shut-off") is unlikely to pose a significant risk. -

 

[amaurer]

Well, I took the plunge. No runaway on my first drive, anyway. I had to use the heater hose because I hacked up my stink tube already, but I'll swap it out ASAP.

Pics:
https://forum.ih8mud.com/diesel-tech-24-volts-systems/269425-3b-intake-breather-mod.html