Hi All,
My Universal M35BC diesel came with a crankcase blow-by vent tube routed to the air intake. I understand that this arrangement is ideal for capturing smelly crankcase fumes and routing them thru the engine and thus out the exhaust. I’ve heard of some concerns regarding run-away engines using oil infused blow-by gasses but my understanding and experience with my own engine suggests that, for what ever reason, that does not happen.
My only issue with my current set-up is that my engine blow-by has sufficient oil mist infused in the gas that it saturates the foam air filter and drips into the bilge. My bilge is always an oily mess. I use oil absorbent mats below the engine which float in the bilge water but this oil gets everywhere. I’m also concerned about the degree to which the oil saturated foam air filter is impeding air flow into the combustion chamber. It seems to me that this is not an ideal arrangement.
And so, I’m exploring the option of installing an oil catch can along the length of the crankcase blow-by vent tube. Amazon has a number of these for sale for around $30 bucks. Many of these have an air intake air filter mounted on top whose purpose I don’t understand. Perhaps in a sealed system this allows for air pressure equalization. Mine, of course, is not sealed and is open to atmospheric pressure at the air filter and so this small air filter would be unnecessary, I think. Do any of you have any thoughts or recommendations on this general topic?
Thanks,
John
John, that's a pretty fancy catch can! I have the original M35 with a blow-by tube that merely emptied into the bilge below the engine. I looked at buying a fitting and directing it into the air intake, even considered trying to install the fitting INSIDE of the circular foam to ensure more of the mist would get sucked into the engine, but in the end I figured that there would be a lot of black oil pooling inside. I went for the el-cheapo option, strapping a glass 'mickey' whiskey bottle to the forward port engine mount wrapped in duct tape and held in place with a small bungee cord. The tube goes inside and very little oil ends up in there. I suspect that a lot of the oil we see in the filter is actually coming OUT of the engine through that port. To further improve on the situation I tossed out the foam and replaced it with NAPA GOLD air filter #2032. I change it out once a year along with the fuel and oil filters and rotate it a couple of times during the season to spread out the misty oil that comes OUT of the port.
Kevin Lenard
"Firefly"
'91 C-36 Mk. "1.5" Tall Rig, Fin Keel, Hull #1120, Universal M-35 original (not "A" or "B")
CBYC, Scarborough, Lake Ontario, Canada
NOTE: the US part number might bring up a square filter. Be sure you're ordering the round one.
Kevin Lenard
"Firefly"
'91 C-36 Mk. "1.5" Tall Rig, Fin Keel, Hull #1120, Universal M-35 original (not "A" or "B")
CBYC, Scarborough, Lake Ontario, Canada
HI Keven,
Thanks for responding because your response is exactly why I asked the forum about this. I never considered the oil's source as being from the air intake port itself. I can picture myself a year from now scratching my head while holding an empty oil catch can and still oily bilge. I'll have to snoop around now and find out where that oil is really coming from.
Thanks again for your input,
John
Just a thought, but in automotive and motorcycle and airplane uses foam air filters are supposed to be oil soaked. There is such a thing as foam filter oil. I have a K&N filter in my jeep that gets oiled regularly, and my cessna uses a foam filter that has nasty sticky oil on it. My old dirt bikes used to need the filters cleane dand re-oiled regularly.
Its possible the oil isn't coming from where you think it is. I had a similar issue with oil in the bilge. It turned out the seat for the oil filter was so corroded that the oil was slipping past the seal. It wasn't till I addressed that problem that I stopped getting oil into the bilge.
It's interesting that our 2005 M35 BC has no hose venting the oil vapors into the air cleaner. We have an aluminum honeycomb mesh that acts as the filter element in the air cleaner housing. Our air filter s the same as what appears on the Catalina Direct Web Site for Universal Engines. I wonder if a metal mesh element would be less likely to become saturated compared to a paper filter?
Paul & Wendy Keyser
"First Light"
Rye NH
2005 C36 MKII #2257
Wing, M35B
This has worked for me
2003 Catalina 36