Options to route crankcase breather to air intake

[KWKloeber]

Just FYI



[attachthumb=#]


Ken

[KWKloeber]

Updated options (for B-series engines) to route the breather hose to the air intake:

https://c34.org/wiki/index.php?title=Diesel_Engine#Misc_Projects

[Stu Jackson]

I've added this to the 101 Topics links about this subject.  Thanks.

[Paulus]

You might also add to this project a fuel sediment bowl to collect the blow by in the breather hose on its way to the air intake.
Paul

[KWKloeber]

Ok, why?

There's no sediment trap on any auto Positive Crankcase Ventilation system.  I've never seen an explanation why this is necessary.

[Paulus]

To catch the small amount of oil that travels to the air intake. It is not necessary.  Now we have a lot of things on a  boat that we did not have 40 years ago.
Paul

[Stu Jackson]

I agree with Ken.  Indeed, I think putting ANY restriction in that line is the most incorrect thing to do.  I've read of some skippers even putting in oil traps.

Why?  Because it is an atmospheric vent design, not made to "push" against any resistance.  Why create any additional resistance at all?  And when the trap does its job and, uhm, traps, it is even more resistance.

Far better to drop the teeny tiny amount of oil already in that line back into the engine.  Without anything blocking it.

[glennd3]

Could be a way of monitoring blow bye.

[lazybone]

There's a sponge like piece of something under the valve cover at the hose exit that filters the oil and let's it settle back to the pan.  When it disintegrates you'll get a lot more oil out of the hose.

Checking it's condition also gives you a good excuse to check the valve clearances.

[KWKloeber]

My grandfather (who owned a "service station"** taught me that before wasteful throw-away air filters came to be, the old-fashioned "metal mesh" air cleaners (like the original coffee-can air cleaner on the M-25) were renewed by cleaning the mesh with kero and lightly OILING the mesh while reassembling the can.

See https://youtu.be/AKu4dKQUhvA?t=160

Directing the crankcase breather directly to my air cleaner saves me a step.

**(an ancient proprietorship where one could have a mechanic look at and fix an auto; opposed to a modern "filling station".)

Don't get me wrong, I'm open to learning why a trap is needed or desirable, but I haven't yet heard any reasonable explanation from a diesel mechanic why it's desirable (or that the alternative is detrimental.)  The only very remote detriment is the infinitely tiny chance of a run-on diesel (which could easily be counteracted by yanking off the greater hose from the air intake.)

BTW, if deteriorated the metal mesh can be renewed by visiting the dollar store:

[Paulus]

the "breather tube" topic was covered in August of 2013 and it might be worth re-reading. 
Paul

[glennd3]

I would be careful with scotch brite. The expensive SS pads are made with one continuous strand of steel. Cheap ones are made by smashing pieces together. I would not want that deteriorating into my intake. I am probably over playing this but I have learned not to get cheap at the wrong time, Like buying ####ty tires.

[Stu Jackson]

the "breather tube" topic was covered in August of 2013 and it might be worth re-reading. 
Paul

Where might that be? 'Cuz I looked in the Aug 2013 tech notes, not there.  Thx, from Mr. Link.

[KWKloeber]

the "breather tube" topic was covered in August of 2013 and it might be worth re-reading. 
Paul

https://c34.org/bbs/index.php/topic,7709.0.html

I hadn't seen that one. ( https://c34.org/bbs/index.php/topic,7709.0.html )

Why does one have to use an oil separator?  Couldn't one just let the oil get sucked into the intake and be burned in the cylinders?

Inquiring minds want to know that. Diesel is one of several fuel "oils" isn't it?

I suspect (of course don't know for sure know) that an oil trap wouldn't be detrimental if it caused no backpressure (like a drip-type) but any filter-type would cause some, if only minor, backpressure.  The hose direct to the manifold (vs. simply directing the hose to the coffee can) should receive more vacuum to counteract a filter type.   If it goes to the inside of a KN the vacuum loss across the filter should apply more vac to the breather hose but I'm clueless how much and whether it would counteract a filter-like trap. 

My baseline is kinda with Kubota's option that brings the breather directly to the manifold.  Endorsement by Kb that it's not detrimental to burn it would seem to be enough (I'm not sayin there ain't other options,) but heck what do they know?

[KWKloeber]

I would be careful with scotch brite. The expensive SS pads are made with one continuous strand of steel.

Sleep easy, SBrite is one continuous pc. of s/s.