Diesel engine blow-by

[WillieC]

Our recently refreshed Volvo Penta MD17C engine is producing a bit more blow-by than expected and I am researching aftermarket solutions and have come across Racor's CCV4500 and Mann Provent 200. These are both described as Closed Crankcase Ventilation (CCV) using coalescing type filters. Most, if not all, of the installations I am finding are incorporated into turbo assisted engines, though Racor Tech Support said the 4500 model would work fine in my Ancient VP.

The more I read, the more common I see the issue of blow-by is. On the road, the old school solution was to dump the excess coalesced oil on the road via a tube. Notice the black stripe on our interstates. The new, improved method is to recirculate that collected oil into the crankcase. On our recent trip, I collected what didn't make it back into the engine in a plastic jug; about half a pint in 130 engine hours. This was using the original designed system: the hose off the oil fill cap routed to one of the three air intake horns. No interim filter, so the runoff out the end of the air filter was pretty cruddy, sooty, bilious, vile and not welcome in my nice newly painted engine box. (Many auto forums addressing this issue simply catch that oil and dump it periodically.)

So, anybody out there familiar with either the Racor or Mann Provent in use on smaller, non-turbo engines like mine? Thanks for your input.

[Tree]

Do Walker Engineering do an Airsep for your engine - that will solve all your issues.

I’ve recently bought the air filter for my 6lp albeit without the Airsep as I can no longer see it listed for that engine.

[WillieC]

Thanks, Tree. I looked at Walker Engineering's website and went over all their technical info and FAQs. Their products, though they say they work on naturally aspirated engines, don't appear to apply to my ancient engine. For example, the MD17C uses three individual air filters, not a common airbox/intake manifold. Neither does their list of applications for VolvoPenta go far enough back, nor appear to apply to any 36HP engines. The space in my engine box is also pretty limited for that monster filter they advertise.

[RobS]

I think your initial post says it all ... why would you want to do anything with the "puke" other than collect it and dump it. Having to dump 8 ounces in 130 engine hours seems doable. Adding any "system" is just going to become another thing requiring maintenance. Why not mount a "permanent puke bottle" of a size that will limit the emptying intervals and make sure it's see through. And be sure it's at the lowest point in the tubing so there is no "trap" in the line.

The zero maintenance and puke bottle setup is the basis of Tony Athen's EnviroVent setup (link attached) which is what I have on my 6BTA's (pic attached) and it is super simple.

Here's the link:

https://www.sbmar.com/articles/envirove ... e-diesels/

Click on my picture you can see the puke bottle just ahead of my fuel filters.

Starboard EnviroVent and SMX DD.jpg

[jleonard]

I second the puke bottle plan. I had one and it worked perfectly. I even made one for my VW tdi. Put a piece of oil diaper in to absorb the yuck and you've got it made

[Tree]

Without wanting to hijack the thread - would this work for the 6lp? I’ve thought about installing a crankcase breather filter from the likes of K&N but would rather have a catch can if possible?

[WillieC]

My only problem with the vomitus erectus bottleus is that the spew is coming OUT the inlet horn of my air filter. I am already catching that but it is the fine mist that is spreading its love juice all over the place.

Currently, the hose from the top of the oil fill cap runs directly to the closest inlet horn to be sucked back into that cylinder. I am guessing the bulk of it leaves the crankcase via the oil fill hose in a mostly mist state. Then it condenses when it hits the air filter, some gets sucked back into the combustion chamber of that cylinder, the rest drips down the innards of the intake horn to my catch bottle, a Costco 10 pound M&M jar.

This pic shows the hose going to the air filter. It may be 4" long. The oil fill cap is just out of the bottom of this picture. (Not shown is the M&M jar. It still had M&Ms in it at the time of this picture.)

IMG_0669.JPG

Is your suggestion to interrupt that stubby hose with a tee and collection jar, forcing the air to make a 90 degree turn and hopefully causing the oil droplets to fall into the collection jar? That I can do, and the price is right.

[WillieC]

Rob, I read with great interest the Seaboard link. I sent an inquiry. I am small potatoes for sure and not their go-to brand. I am about to just get the Mann Pro-vent 200, it is cheap enough, and slap it in and NOT re-route the puke back to the engine and see what happens. I do like the little plastic bottle that Seaboard provides but I should be able to come up with something suitable. I think I need more than a simple tee to drop the oil out of the mist and am hoping the filter will do that.
Apparently this blow-by issue is pretty common on marine diesels. Thanks for the lead.

[RobS]

Tree, with the breather setup the way it is on the 6LP I don't see you'd have the room to simply put a puke bottle in line with current setup but I'm sure anything is possible with some creative hose routing and mounting. You'd of course still want the breather hose ending up at the air intake for the negative pressure.

[kerrye]

Yes interrupt that line with a bottle as you describe. I’ve known people to do that on old Mercedes. Perfectly acceptable. My 6.5 GMC diesel has a similar system that most people call a ‘tuna can’ to separate oil from fumes

[WillieC]

Thanks, Kerry. Simple is very good, now just to come up with an easy bottle attachment for quick removal.

[kerrye]

https://www.google.com/url?sa=t&source= ... _73zAvnZmx

[kerrye]

Blowby can be measured. People use a water manometer. I've never used one but on the Mercedes forum I belong to where the topic comes up frequently an attempt at assessing relative blowby conditions was attempted. People would attach a 30 gallon garbage bag to the PCV hose and measure how long it took to inflate it.

[WillieC]

Unfortunately, there is room for only one gasbag on the WillieC.

[DougSea]

Unfortunately, there is room for only one gasbag on the WillieC.