CHB 44' / Ford Lehman 120s Question

[Dave L]

Hi All,
I'm the proud new owner of a CHB 44' with two Ford Lehman 120s. Yeehaa!
Whilst the PO has taken fantastic care of the boat, there are a few things I am not clear on - and neither was he.
On both engines there is a breather hose that comes down from the top of the crankcase, on the opposite side to the injectors, and terminates in a cylindrical structure with multiple, small perforations on the curved surface. Rather than blowing the crankcase blow-by straight into this open can, it looks to me like it should have something in or around it to collect the oil.
Neither the previous owner or the previous engineers were aware of what might be missing.
My apologies for a lack of a photo, but I am currently at home, 1,700km away from where the boat currently lives!

Any thoughts on what might be missing? I can't seem to find a reference to it or pictures.

Thanks!
Dave

 

[SteveK]

Hi All,
I'm the proud new owner of a CHB 44' with two Ford Lehman 120s. Yeehaa!
Whilst the PO has taken fantastic care of the boat, there are a few things I am not clear on - and neither was he.
On both engines there is a breather hose that comes down from the top of the crankcase, on the opposite side to the injectors, and terminates in a cylindrical structure with multiple, small perforations on the curved surface. Rather than blowing the crankcase blow-by straight into this open can, it looks to me like it should have something in or around it to collect the oil.
Neither the previous owner or the previous engineers were aware of what might be missing.
My apologies for a lack of a photo, but I am currently at home, 1,700km away from where the boat currently lives!

Any thoughts on what might be missing? I can't seem to find a reference to it or pictures.

Thanks!
Dave

Are you describing the air filter intake?

 

[Dave L]

I don't think so. Not that I can clearly see where the air filter intake is. But the perforated can at the end of the 1cm diameter hose certainly looks as if it is designed around some sort of filter which isn't there.
I thought it is a rocker-cover/crank case breather, as it appears to come off the top of the rocker cover, from where the flange where the oil filler cap is. I would also have thought the hose is way too narrow for an efficient air intake hose.
I could be wrong.

 

[hytedin]

Some sort of airsep?

 

[hytedin]

Some sort of airsep?

Have you tried to open it up?

 

[SteveK]

I don't think so. Not that I can clearly see where the air filter intake is. But the perforated can at the end of the 1cm diameter hose certainly looks as if it is designed around some sort of filter which isn't there.
I thought it is a rocker-cover/crank case breather, as it appears to come off the top of the rocker cover, from where the flange where the oil filler cap is. I would also have thought the hose is way too narrow for an efficient air intake hose.
I could be wrong.

post a picture

 

[warfdog]

The black can in this picture is the air intake filter and normally has a foam filter slid over it. If your engines don’t have the foam filter you can get replacements from American Diesel .

The hose attached to the top of the can goes to the crankcase ventilation valve (a metal kind-of PCV valve) on the valve cover. I’m not sure what the purpose of the valve is, but maybe it reduces oil in the crankcase gases that go down the pipe into the intake.

If a lot of oil goes down that vent hose it will accumulate in the filter “can” and eventually just run over into the bilge. You can pull the whole can off the manifold the clean it.

There is another crankcase ventilation port on the lower part of the block under the alternator which does not have any recirculation attached.

 

[Dave L]

Thanks, everyone! You've collectively answered my question.
I now believe it is the air intake, without the foam filter. I was a bit focused on the narrow oil breather hose dropping in to it. Funny, the PO couldn't tell me what it was and said it had always been like that.
I suppose the problem with oil-soaked foam filters is if they deteriorate foam could be sucked into the engine. However, they've obviously had a long usage history.
Apologies for not being able to send a photo, but unfortunately I live nearly 2,000km from the boat and have to commute!

 

[SteveK]

In case you are interested
I recently upgraded my air intake with K&N RC-4570

 

[Comodave]

Welcome aboard and congrats on your new boat. Brian at American Diesel is a tremendous resource.

 

[koliver]

Your description is very much like the crankcase breather setup on the Volvo TMD40 and similar older style engines. My newer TAMD41s put the breather hose directly into the air intake, so all of that dirty air goes back inside the engine, keeping the outside cleaner.

Yours can be modernized to bring the Crankcase breather into the air intake, as suggested by Soo Valley. Left to itself that old style breather allows a lot of oily deposits to accumulate on that part of the engine.