Lehman Mushroom

[Mike GB32]

I don't want to bother Brian at Am. Diesel with this one because I'm sure there's an easy answer.
Can someone please tell me what the mushroom looking thing is coming out of the side of the oil pan on my FL 2714E ?
I looks like it would be a breather but when I pull the top off there is an o-ring seal. It's on the front left side of the engine.
Thanks
.View attachment picA.pdf

View attachment picB.pdf

 

[hytedin]

Crankcase breather?

 

[Eli27]

not sure what your talking about but i did find a pic and i think i know what youre talking about,,, dipstick tube? so you can place the stick on either side for twins? Maybe

Eli

 

[High Wire]

Sure looks like a crankcase breather flame arrestor.

 

[Mike GB32]

I see the pictures in my original post as "picA.pdf" and "picB.pdf" is there a way to insert actual pictures?
Crankcase breather makes sense but there is breather fabric or vent.

 

[warfdog]

It's a crankcase sump breather. Lower left in this picture.

 

[kchace]

Yup, it forms part of the breather system.

 

[Comodave]

I see the pictures in my original post as "picA.pdf" and "picB.pdf" is there a way to insert actual pictures?
Crankcase breather makes sense but there is breather fabric or vent.

Go to the forum home page and there is a section on How to use the forum. In that section there is a sticky thread on How to post photos.

 

[Mike GB32]

I guess I’m going have to call Brian about this.
It makes sense that it should be a breather and maybe there’s a fabric missing on the underside of the ‘mushroom’ but there is an o-ring seal that would prevent it from acting as a breather.
I don’t get it.

 

[Mike GB32]

Ok. I did a google search and was brought back to a forum thread that explains it.
Apparently, what I have is a cap to block off the old style breather. Below is from a post by member 'Oil Gypsy' from two years ago.

I spoke to Brian at American Diesel this morning, the breather was only fitted to the early models of the Leham engine that were marinised in Asia in the early 1970's. The "well" is supposed to be full of oil so that the wire mesh is immersed in a bath of oil.

Apparently it was found that this style of breather could cause back pressure in the crankcase and the breather wasn't installed on later models, also as mentioned fumes from the crankcase could vent to the engine space and bilges which is far from ideal. There is an alternate system in the engine to vent the crankcase to the foam covered air inlet on the engine where the fumes are fed to the pistons and emitted through the exhaust after combustion.

The recommendation is that the unit be removed and the hole be plugged.

Thanks all

 

[Mambo42]

I have asked the same question to the company that overhauled my engines and they told me it is to fill oil in case you cannot fill it from the top. I have not tried it, but have no reason not to believe them.

 

[Comodave]

I have asked the same question to the company that overhauled my engines and they told me it is to fill oil in case you cannot fill it from the top. I have not tried it, but have no reason not to believe them.

Maybe time for a new mechanic???

 

[kchace]

You CAN put oil in from there, but that’s not what it’s there for. The reason it has an oring in it is to seal to the tube so oil won’t splash out while running. The cap has a labyrinth to allow air through but keep oil from splashing out. Gotta love mechanics that just make stuff up as they go along. I’d wonder where he was trained.

 

[Eli27]

You CAN put oil in from there, but that’s not what it’s there for. The reason it has an oring in it is to seal to the tube so oil won’t splash out while running. The cap has a labyrinth to allow air through but keep oil from splashing out. Gotta love mechanics that just make stuff up as they go along. I’d wonder where he was trained.

That mechanic was trained in that class that shows you how to install the blinka fluid and test Cadillac converters.


Eli

 

[Mobcat]

You can also put a vacuum on it from your air intake and it will stop your main seal leak, saves pulling the engine to fix .

 

[steve marcus]

sump vacuum fix

You can also put a vacuum on it from your air intake and it will stop your main seal leak, saves pulling the engine to fix .

That is very interesting to read as I have a problem with the rear main leaking after a rebuild (done by myself so no one else to blame) and I suspected that reducing crankcase air pressure would help so i have inserted a hose that fitted tightly into that pipe where the mushroom was and ducted it high just so any "splash" couldn't escape but it didn't make a lot of difference to the oil leakage. I will try you suggestion ,should I run a hose from there to just above the air filter on the inlet manifold ?

 

[Mobcat]

I remember on a workboat we had that had a SP 135 in her, she leaked oil like a pig on her out of the main seal enough so it came out of the starter motor, and we thought why not put a vacuum on the sump pan and take all positive pressure of the main seal and it worked a treat, absolutely no leak after vacuum applied to sump vent through air filter intake, certainly saved pulling the motor out and down for a $5 seal also people tend to over fill with oil which will pressure main seal as well …..SP135 13 litres oil is plenty and remark dip stick

 

[koliver]

I remember on a workboat we had that had a SP 135 in her, she leaked oil like a pig on her out of the main seal enough so it came out of the starter motor, and we thought why not put a vacuum on the sump pan and take all positive pressure of the main seal and it worked a treat, absolutely no leak after vacuum applied to sump vent through air filter intake, certainly saved pulling the motor out and down for a $5 seal also people tend to over fill with oil which will pressure main seal as well …..SP135 13 litres oil is plenty and remark dip stick

I am pretty sure that vacuum would have eliminated a main seal leak that I spend angst and money fixing years ago. Surely this solution is not restricted to Lehman engines.

 

[Lepke]

Crankshafts operating at high rpm have a lot of air mixed with oil rotating around them. Pan breathers usually have a tube rising above the pan top. The farther the better. Otherwise some of that oil comes out of the breather. Vacuum helps reduce the pressure. Racing engines and some big diesels use a dry sump system where all the oil is pumped to a tank and the usual pressure pump draws from the tank. The pump that scavenges the sump creates a high vacuum in the crankcase and eliminates the air rotating with the crank. It also gives the engines more hp because the pistons aren't pushing air when they come down the cylinder. I've seen it make 10-25 hp more for a 900 hp engine on a dyno.