Lister 12/2

[Samo]

Hey all,

Long time since I've been on the forum but finally had time to complete my 12/2 lister rebuild. Everything has been done (it was seized) - pistons, valves, bearings, gaskets etc...  It's running ok but there are a few issues. Non too serious but the most annoying is oil seeping from the crank... copious amounts. I thought the crank case ran at a slight vacuum to help stop oil leaks? At least that was the case in the 6/1 I have.

Both sides are leaking at quite a rate. I installed the felt washers and set everything up by the book.

Appreciate advice on what I should look at.

thanks,

John

[sinna42]

Hi John,

I'm nearing the completion of my 12/2 rebuild & looking forward to getting her running again !

The only thing I can suggest is that the drain hole in the bearing housing isn't allowing any oil that flows to the outboard end of the bearing back into the crankcase.
So the space in between the bearing & the felt seal, sitting in its groove, is just filling up with oil.
Can't think of any other reason for oil escaping !

Cheers,
Jim

[mike90045]

Is the crankcase flapper valve actually working (that's what creates the vacuum) and the paper thin steel not rusted thru ?

[Samo]

Thanks for the good ideas. I'll check both during the week and will let you know how I get on.

[mikenash]

Am I right in thinking I have seen 40/50mm plumbing non-return-valve units used on crankcase covers?  The brass-body type with the spring-&-seat arrangement?

What is the thinking?  The valve opens to allow crankcase pressure to escape as the piston descends?  Or do I have that ass-about-face?

Cheers

[mike90045]

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What is the thinking?  The valve opens to allow crankcase pressure to escape as the piston descends?  Or do I have that ass-about-face?   

Yep, the valve allows air to be blown out, and then builds a vacuum as the piston goes up (as I understand it)

[Samo]

Actually I'm surprised there would be much crank pressure (positive or neg) on a 2 cylinder... unlike a single cylinder the volume would remain fairly constant due to the opposed cylinders.  On my perkins diesel they connect the crank breather to the intake manifold. Wonder if that would be a good idea on the 12/2?