Clicking Sound When PS2 Steamer with Pittman Motor Operates in Forward

Sure!

Look at the assembly for wear and tear. Make sure it has grease.

Any chance it's a side linkage?

Try to determine if the clicking sound is internal or external. Generally, clicking sounds externally will happen with every revolution of the wheels if for say it’s a rod or linkage  as Joe points out. Internally, a clicking noise from the motor or drive shaft, would be a faster clicking noise as the motor rotates more revolutions than one revolution of the drivers ( wheels ) ….just a generalization, and not 100% typical, but usually that’s how it goes…..

Pat

Thanks for the recommendations. I've had roller click (piece of debris on a roller) and even side rod click in the past but this is definitely inside the engine and tied to the motor. Also, I added grease but that didn't change things. I had tried to run the engine with the shell off but had to disconnect a plug that went to electronics in the shell. After that, speed control went out the window! So I need to find a way to elevate the shell so I can see/listen to the motor and gearbox. Was hoping it was something simple. It's actually not an alarming sound and as the engine speeds up the chuffing sound kind of drowns it out.

@Scott J posted:

Thanks for the recommendations. I've had roller click (piece of debris on a roller) and even side rod click in the past but this is definitely inside the engine and tied to the motor. Also, I added grease but that didn't change things. I had tried to run the engine with the shell off but had to disconnect a plug that went to electronics in the shell. After that, speed control went out the window! So I need to find a way to elevate the shell so I can see/listen to the motor and gearbox. Was hoping it was something simple. It's actually not an alarming sound and as the engine speeds up the chuffing sound kind of drowns it out.

If you’re sure it’s coming from the motor try rotating the flywheel by hand to see if you can spot the condition. ,or,  do as I suggested, & temporarily disconnect the motor leads, solder in a temporary pair and hook them up to a DC transformer. You could just hold the chassis in your hands and run it to observe the condition. Just be mindful of getting your fingers in the way of the rotational mass….

Pat

I just had this exact same problem with a PS3 N&W J class, although no guarantee it's your problem of course.

Ticking/vibration I could hear and feel holding the boiler in forward, so bad at slow speeds the engine would studder and stall at speed steps below 5 or 6.  I knew it had to be drivetrain because it was proportional to the speed of the motor spinning and much faster than the wheels turning.  Went away almost entirely in reverse.

I disassembled the gearbox and inspected and greased everything to no avail.  Spinning the motor with the dogbone joint removed and everything seemed fine.  Finally, I very lightly greased the teeth/ears on the plastic dogbone joint and the problem has gone away entirely and has not come back in hours of running.  I can only assume it was binding somehow without any lube.

Thanks Pat and Woody. When I had the shell off I did turn the flywheel by hand but just briefly and didn't hear or feel anything. BUT, did not try to run the engine off of the track in any way (Pat's suggestion) or look at the drive shaft linkage per Woody. I've attached a photo of the motor/drive train with the worm gear exposed. The silver things on either end of the worm gear are what I thought would be thrust bearings.

it appears that the motor and the driveline are not aligned.

I'm with Joe, maybe try to bend the motor mount up to align the motor with the driveline?

Thanks! Sounds like you're referring to the white cylinder coming out of the motor flywheel and the black cylinder connected to the worm gear.

Yes, the tiny space between them means there is a very short dogbone in there, any misalignment will create noise.  The axis of the motor should align as close as possible to the driveshaft going to the gearbox for best operation.

The white flywheel contains an integral "cup" or female receptacle for the horned ball driveshaft.  It looks like the horns of the ball on the flywheel side have dug a notch into the slot on the side of the cup.  What you may be hearing, is the driveshaft toggling fore-and-aft as the motor turns, the horns may be jumping in and out of that notch.

If that's what's really causing the noise, improving the motor-driveshaft alignment may quiet it down.  You might also put some thick grease in the cup.  The risk here is that it will get slung around as the motor turns at high rpm.  The best fix would be to get a brand-new exact replacement flywheel, including the stripes and cup for the dogbone shaft, just like your original.  The flywheel is held on by a set screw so no pulling or pressing is required.

While you're in there, you should make sure that the thrust bearings are indeed lubricated, and snug in the chassis "gearbox" with almost no fore-aft movement.  These MTH Mikados were a good mechanical design, and this should give you more years of trouble-free service.

@Ted S posted:

The white flywheel contains an integral "cup" or female receptacle for the horned ball driveshaft.  It looks like the horns of the ball on the flywheel side have dug a notch into the slot on the side of the cup.

It's hard to imagine that plastic dogbone has eroded the steel flywheel slot.

I see what Ted is talking about and will examine the assembly carefully after I get the shell off. It has 1652 scale miles on it and I knew that when I bought it. The sound is more pronounced now than when I got it so I'm anxious to find the root cause and fix it. I also noticed that even though the bearings look snug there is a bit of fore/aft play in the motor. What I really need is a good set of test rollers. The engine itself is awesome.

Thanks for all the good feedback.

LOL. God I love this hobby! I spent a few hours yesterday building a test track. I bought the PROSES brand test blocks. Put the blocks on the test track, put the engine on the blocks and it all worked! Except no clicking sound . . . sigh. I just need to run it until it starts clicking again. But still, I'm all set to trouble shoot and repair and brag about my successful repair and I get a CND (cannot duplicate). Figures. Will post again when I can isolate the problem.

Maybe the clicking you heard was the center rail pickup rollers going over track joints?  Although, I can't imagine why they also wouldn't make a clicking sound in reverse.  Regardless, being able to SEE your loco mechanism turning slowly on rollers will greatly aid troubleshooting this, and any issues that arise with your other locos in the future.

@Scott J posted:

LOL. God I love this hobby! I spent a few hours yesterday building a test track. I bought the PROSES brand test blocks. Put the blocks on the test track, put the engine on the blocks and it all worked! Except no clicking sound . . . sigh. I just need to run it until it starts clicking again. But still, I'm all set to trouble shoot and repair and brag about my successful repair and I get a CND (cannot duplicate). Figures. Will post again when I can isolate the problem.

Did you run it on your new test rig with the shell off? ……if the condition existed when the shell is on, perhaps something in the shell is pushing on the motor causing your condition, and when you removed the shell, the problem went away,……I wish I had a nickel for every time that happened…..

Pat

I had the shell off over the weekend and ran on test blocks. Everything is lined up properly. It looks crooked in the photo above because I have the top of the gear housing off. The sound is almost certainly coming from the back end of the Pittman motor. It's quieter with the shell off. When the shell is on it amplifies the sound. There's an old thread with photos that shows a Pittman taken apart and there are two big screws on the back end of the motor that I imagine I could remove. If I did though, I would have no idea what I was looking at or what to do to fix it. I assume that it is repairable. Need advice on the next step. I'm guessing repair is the only option. A replacement comes up on the MTH website at $60 (a bargain) but of course "not in stock".

Thanks!

@harmonyards posted:

Did you run it on your new test rig with the shell off? ……if the condition existed when the shell is on, perhaps something in the shell is pushing on the motor causing your condition, and when you removed the shell, the problem went away,……I wish I had a nickel for every time that happened…..

Pat

Pat is your man!

Talk to Pat @harmonyards about your Pittman, he's the expert.  FWIW, they are indeed repairable, they come apart quite easily.  I've opened a few of them up, but not like Pat who changes the bearings, etc.

FWIW, without hearing the click and the frequency, it's very difficult to hazard a guess as to the source.  However, I have my doubts that a "click" is coming from the Pittman, even at slow speed it would be more of a "buzz" I'd guess.

Have you tried the old mechanic's trick?  A long screwdriver, touch the end of the blade to the hub of the motor (not the rotating part), and place the other end pressed against the front of your ear opening, right on that flap of skin next to the eardrum.  That will amplify the sound and you move the tip of the screwdriver around to see where the click is the loudest.

Removing the motor and running it without the dogbone will indicate if the motor is actually making the noise or maybe that's just what it appears.

Hi John. I did in fact use the screwdriver method and the back end of the motor seemed to give the loudest response. I also checked the gear train and of course you can hear it there as well but not as loud. I agree though that the logical next step is to run the motor by itself. I'm guessing the screws for the motor mounts are under the chassis. Thanks to you and Pat for weighing in! If it is the motor can he repair it?

@Scott J posted:

Hi John. I did in fact use the screwdriver method and the back end of the motor seemed to give the loudest response. I also checked the gear train and of course you can hear it there as well but not as loud. I agree though that the logical next step is to run the motor by itself. I'm guessing the screws for the motor mounts are under the chassis. Thanks to you and Pat for weighing in! If it is the motor can he repair it?

I can fix it. I keep the parts in stock for such repairs. However, if you’re unsure of the source, and it’s getting beyond your diagnostics, just pack up the whole locomotive & tender and send the whole thing to me. I’ll straighten out the noise, and I’ll report back on here as to the source…….nothing would be more aggravating if you sent the motor only, and I send it back, you install it, only to discover the issue hasn’t been remedied….

Pat

Whew. Thanks Pat! I'm going to do one more check where I will remove the motor if I can and feel confident I can put it back together afterwords. If my experience tells me "don't do that Scott" I will contact you about sending the entire engine. Thanks again for all the help and advice.