[SEL] Couple questions please

[Elden DuRand]

Rick:

For a low speed splash lubed engine, I'd set 2" main and rod journals at about 0.001" or so.  If the crank is out of round a little, that should be the clearance at the tightest spot.

As to the piston fit on the engine, it'd depend on how much noise from piston slap you can stand.  Knurling the skirt is an option but doesn't work well on iron pistons.  Don't expect the knurling to last long.  I think it was mostly used during WWII and at used car lots to silence the noise of a loose engine.

My ZC52 (3-3/4" bore) had about 60 mils of skirt clearance at the most worn part of the bore and the piston slap was easily heard.  I'd guess at about 0.020" or so to be the max without the noise disturbing your nap.

Take care - Elden
edurand at iglou.com
http://www.oldengine.org/members/durand 

> -----Original Message-----
> From: sel-bounces at lists.stationary-engine.com
> [mailto:sel-bounces at lists.stationary-engine.com]On
>  Behalf Of Richard
> Strobel
> Sent: Tuesday, January 09, 2007 08:45 AM
> To: stationary-engine-request at oldengine.org; sel
> Subject: [SEL] Couple questions please
> 
> 
> 
>   Howdy all;
> 
>    What would be the proper clearance for 2" rod 
> and main babbitt bearings? 
> I would swag 1500 rpm max., splash lubed.
> 
>    How far could I bore out a  4.125" cylinder 
> and still not need an 
> oversized piston?  Is knurling the skirt an option?
> 
>   That's enuf for now :-)
> 
>   TIA,
> RickinMt.