Shay cylinders/chuff contacts: subtle problems, some conclusions

Started by DennisBT, January 09, 2019, 05:12:15 PM

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DennisBT

This is a followup from my recent post regarding early production/version 2-truck Shay chuff contact question.  Respondents suggested removal of the cylinder set.  Some before me had discovered the secret to removal were the two hour-glass lobes-on-posts visible inside the firebox.  Bachmann's concept was the lobe being hour-glass shape would fit through a mating keyed hole in firebox, and once inside the lobe could be turned 90-degrees or so, it's screw tightened and that became part of securing the cylinders to the locomotive.  With the screws loosened, ( and that requires an off-set Phillips and patience), MY lobe would not budge.  Worried I'd break it.  What was I missing?  Interestingly, I'd bought a brand new cylinder set from Bachmann months ago.  I grabbed that to see what it would reveal.  Yup, lobes-on-post were there.  Loosened screw, tried turning.  Not a chance!!  Felt like it was all welded in place.  Could not see any parting lines in moldings.  Also that is a long screw in there; part of what holds the cylinder base molding together.  So back to my project Shay.  Mind you, I've got 3 or 4 hours now fussing with this.  One lobe on my Shay was already positioned to exist the keyway.  Other nearly so.  Hmmm.  Wonder if someone's been in here?  (Used Shay)  So only one requires movement....and only a few thousandths of an inch.  Finally risked breaking it and turned harder with long-nose.  Got it to move just enough to get cylinders OFF the loco.  Whew.  The short story and answer here is that all of these on my two cylinder sets were so dry and tight, they were locked stuck.  I put a tiny drop of plastic compatible lube where each lobe-post met the rear of the cylinder base and waited a while.  Got brave and with parallel smooth jaw pliers, began working them.  Each produced a faint, "squawk, then came loose.  Worked them all free.  So some day, some of you will encounter this.  And since I've viewed every, "tips," and youtube helps I can find this week, None mentioned this.  Hope it will help one of you some day. 
Second, the reason for all my efforts is because in rebuilding my Shay toward DCC, I'd checked continuity with a VOM on every wire in this locomotive looking for the chuff contacts.  NEVER found a pair that revealed make-and-break continuity as I rotated the cylinder drive lines.  Never.  Now that I have everything out I see that my chuff contacts are not working at all.  Pulled cylinder heads off - and they work.  So I'll have to play with re-tensioning/bending springs until it becomes as reliable as I can make it.  PS:  my NEW cylinder set shows continuity ALL the time, so it will have to have attention some day too and be adjusted properly.