Crankcase breather oil separator.

[Roger Long]

Mainsail,

I don't have the details with me up here in Nova Scotia but you have got to tell people about the oil separator you had me buy for my crankcase vent line. It's only collected a couple teaspoons of oil but, if you think of that misted all over a hot engine, you get the idea. My boat smells a lot less "engineey" since I put it in. Best under ten dollar item I ever put on a boat and better than a lot of the $100 plus items.

Highest recommendation.

 

[Maine Sail]

Mainsail,

I don't have the details with me up here in Nova Scotia but you have got to tell people about the oil separator you had me buy for my crankcase vent line. It's only collected a couple teaspoons of oil but, if you think of that misted all over a hot engine, you get the idea. My boat smells a lot less "engineey" since I put it in. Best under ten dollar item I ever put on a boat and better than a lot of the $100 plus items.

Highest recommendation.

Is this the factory made one from JEGS or did you do my home made version?

If it is the pre-made factory oil separator it is here:

http://www.jegs.com/i/JEGS/555/52205/10002/-1

Image Courtesy JEGS

 

[bobtigar]

What is the purpose of this item? Where is it installed? Bob

 

[Roger Long]

Is this the factory made one from JEGS ?

That's the one.

 

[Roger Long]

What is the purpose of this item? Where is it installed? Bob

The crankcase has a vent, usually connected to a hose led near the air intake so that vapors will be sucked back into the engine. In my case, this put it right over the starter and alternator which were found oil soaked when I had them overhauled last winter. A little oil sometimes is expelled or condensed out the breather line.

Installation is simple, cut the breather line and plug it i. I had to add a piece of hose to reach a convenient mounting point but that was cheap and easy.

 

[jviss]

...connected to a hose led near the air intake...

O.K., you got my attention. I have been meaning for years to get a hose barb and connect it directly to the air filter housing so the vent fumes get sucked right into the intake. Why wouldn't this be just as effective as the $50 separator?

 

[Maine Sail]

O.K., you got my attention. I have been meaning for years to get a hose barb and connect it directly to the air filter housing so the vent fumes get sucked right into the intake. Why wouldn't this be just as effective as the $50 separator?

Because you can set up the potential for a run away diesel. You really want to "filter" out any potential for oil getting directly into the intake.

 

[jviss]

Because you can set up the potential for a run away diesel. You really want to "filter" out any potential for oil getting directly into the intake.

Got it, thanks. I always thought the fuel path on a runaway, when the fuel was the lubricating oil, if not a broken turbo, was crankcase oil entering the combustion chamber past the worn rings on the intake stroke.

I'm sure many, many boat owners have the vent line connected to the air filter housing without the oil trap. Is this a big risk?

 

[Donnybrook]

The breather hose on my M-18 runs to the top of the air cleaner snorkel and is held there by a small metal clip. There is plenty of suction to pull fumes back into the snorkel. Small amount of oil would collect in the hose and on shut down I would get a drop out of the hose. Simple fix. I got a longer breather hose and run it as high as possible in the engine bay. I used a wire bundle tie with a screw hole to attach the hose to the bottom of the cockpit floor. The other end goes back to the snorkel. Now the oil that collects in the hose runs back into the engine on shutdown. No oil smell, no mess.