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Clunking Shay

2462 Views 10 Replies 6 Participants Last post by  DB
Help! I bought a Accucraft Shay at the end of last summer and ran it around a temporary track on the driveway for about a month without any percieved problems. Today I was invited to a steam up and noticed that my Shay was making a "clunking" sound under power on a elevated track. I disconnected both trucks and both are free to turn. I also noticed that there seems to be some binding to go along with the clunking. Has anyone else had a similar problem and any thoughts on a fix. Thanks.
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My 2 cylinder Mich Cal did that once and I found that one truck had distorted itself into a parallelogram instead of a perfect rectangle. A couple of bolts had loosened. That caused a gear to jump teeth. I aligned the truck with perfectly square corners and made sure the bolts in both trucks were snug, lubricated the gears and shaft journals and the problem went away. It's hard to diagnose your problem with out seeing or hearing it. But, perhaps my idea will help. Good luck.

Check to make sure the drive-line universal joints are in phase !! Just like the universal joints on the drive shaft of your car, the Shay drive line has to be in phase too. If they are out of phase , it can cause a strange noise and problems with going around curves on the track. I have owned 13 Shay locomotives from N scale to G scale and it applies to all of them.

Charles M SA#74
Charles, please clarify 'in phase'. I occationally remove my shay trucks for cleaning and don't want to encounter a problem in the future. Nick Jr.
DB I had a similar problem with a two cyclinder about a year after I first steamed it. The problem was only in forward. Reverse was ok. The problem turned out to be the johnson bar adjustment to the piston valve reverser. I can't remember which direction but there is a mark on the piston valve rod that has to line up with the piston valve block. This is an easy adjustment to make and it straightened out my problem. Good luck

Take a look at the line shaft , that is the coupling shaft between the engine and the trucks. At the end of this square shaft is a " Y " shaped piece which is fastened into the coupling ring , there is one at each of the shaft . The shafts slide back and forth as the locomotive goes throught the curves. These " Y " shaped ends on the shafts should be aligned in the same plane to each other. If they are out of phase by 90 degrees , the shaft doesn't transmit rotary motion smoothly to the trucks. The good news is they can only be 90 degrees out , so just move the truck and try realigning them by rotating one quarter turn of the shaft . I have seen a Shay with them out of phase walk off of the track in a tight curve. Hope this helps.

Charles M SA# 74
Charles, thank you, sounds easy enough to do. Nick Jr
That's very odd. I've got one of each of the Accucraft Shays, and I've never heard of or seen any evidence of 'out of phase-ness' in all the time I've had them.:confused:

They are called Hooke joints, BTW.

Besp from yUK

tac the Griper

The line shafts can get out of phase when they come disconnected . When I place my Shay in the box to transport it to the running site, sometime the drive lines will come apart. When they are reconnected is when the mis-alignment can occur. If you try running a Shay through an R1 radius curve with the Hooke Joints out of phase it becomes very apparent there is a problem. You can see the Hooke joints " kick " back as they rotate . The greater the angular displacement the more apparent it becomes. Thanks for the correct name for these by the way.

Glad to hear from you Tac. Cheers

Charles M SA # 74
R1 curves. Ah, right./DesktopModules/NTForums/themes/mls/emoticons/blink.gif

Don't got none R1 curves, us. Only 12 foot radius.;)

tac the Griper
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Thanks for the information and I will be looking into the solutions all of you have suggested. I did take a look at the phase of the nooky joints and one was out of phase. This could be the problem but it had a clunking sound even on straight sections of the track.I'll let everyone know the final remedy once its figured out (but keep going with suggestions).
Dennis Baran
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