[SEL] O/T Steam main bearing babbitt

[Richard Strobel]

Joe, we've ran it on air and steam. With steam the knocks are very 
obnoxious.  To be honest, I don't recall it on air.
  Here's the deal on our timing.  Please keep in mind the eccentric is keyed 
to the crankshaft and eccentric has two keyways with setscrew.  I assume the 
two positions are for forward and reverse.  There is no reverser lever on 
this engine.

  So we centered the piston in it's throw and adjusted the slide "D" valve 
linkage so that the throw was equal on both centers.  This automatically set 
the lead/lag/cushion which in turn opens the ports when the crankshaft is 
past it's centers.  This is not right but we don't know how to change 
it...other than elimate the key on the eccentric and just use the setscrew 
so we get a "lead."

  We don't have a good book now on timing a stationary.  One is on order and 
the other we'll get at Rollag steam school next year.

  I find the governor feature you mentioned very interesting.  We have not 
loaded the engine yet nor "put it on the gov." so to speak.

  Gotta be something simple...hell, I might be turning the engine the wrong 
direction.

  Very soon the setup will be going into the shed as winter is arriving way 
too soon...and then back to the drawing board...."steam 101 fer dummies."

  Thanks much Joe...ya got me thinkin' which is a scary thought in itself.

  Many thanks also to Ken, Curt, Dave, and Peter.  I have re-read all your 
posts..hopefully it will sink in.

  Sorry to garbage up the SEL, the steam list is pretty dead nowdays.

  RickinMt.


Subject: Re: [SEL] O/T Steam main bearing babbitt


> 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