[SEL] O/T Steam main bearing babbitt

[Joe Prindle]

Hi Rick,
Is the knock when you are running the engine, or turning it over by hand.
Are you running it on air or steam? An engine needs to be timed so that it
goes into compression on each end of the stroke, to cushion it as
everything comes to a stop and reverses direction. An engine timed wrong
will really, really knock.
Another thing that can cause a knock is if the engine is running without
load and the governor has the steam throttled back so far that the
pressure in the steam chest is so low that when the engine goes into
compression, it lifts the slide valve off the seat, then as the piston
goes back down the cylinder, the valve slams back against its seat.
The bearings, as you describe them, don't sound all that bad. Are you sure
the knock isn't somewhere else? Steam engines are usually a lot more
forgiving than a gas engine, things have to be really worn to be a
problem.
Do you have a book with the details of setting a slide valve? A slide
valve is a lot harder to set than a poppet or corliss valve since you
can't get everything perfect, just a series of compromises. Ha, sounds
like being married.
Good Luck,
Joe



--- Richard Strobel <Richard_Strobel7 at msn.com> wrote:

> 
>   G'day all;
>     Friend Corky and I are at our wits end trying to find a very
> obnoxious 
> knock(s) on both dead centers of our vertical Wachs engine.  This list
> has 
> such great experience with main bearing babbitt, I wanted to ask here.
> 
>   Here's the engine and as you all probably know a "Single Simple"
> fires?? 
> on both sides of the piston;
> 
> http://home-and-garden.webshots.com/photo/2308067910039077051Ronfyj
> 
>   Dial indicator on end of cs shows .003 slop.  This may indicate a bend
> 
> crank or just out of round..I would think this would be tolerable.
> 
>   M/B babbitt looks new and shows no sign of ever being scrapped...one
> can 
> still see some ripples.  There is some side to side/axial slop in both
> main 
> bearings.  Yes, this would have showed up on the dial indicator had we 
> loaded one side.
> 
>   Now the big question as the crank is going to the crank doc and he can
> 
> flux weld and machine to any diameter.
> 
>   Do I have him flux weld and machine to a diameter so there is no side
> to 
> side/axial slop and if so, how do I determine what diameter to use?
> 
>   Also, the rod inserts show wear on one side towards the solid
> flywheel. 
> How do I assure this crank is level?  This has been mentioned
> before..eh, 
> Curt.. somewhile back.
> 
>   I really don't want to pour new babbitt.
> 
> 
>   Thanks much...after this endeavor, I'll be headed back to the 4.5hp
> New 
> Way in which I'm always looking for a mixer.
> 
> Best Regards,
> RickinMt. 
> 
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> 


Joe Prindle
Baraboo, WI USA
"All I ask is the chance to prove that money can't make me happy." Spike Milligan


       
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