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I am in the process of upgrading a MTH Premier 20-3007-1 pacific to PS2. This was made in 1994 and came with a Suethe smoke unit. It also has a small 21mm flywheel on a Pittman motor. I can machine a new flywheel or make a sleeve to make the OD the same size used on newer steam with Pittman motors. The smallest tach tape is 27mm but I assume the ideal OD is what will work best with the tach sensor.

What is the more common flywheel diameter used today?

Also what would be a good MTH smoke unit to use with this USRA Pacific? 

TIA

Pete

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Last edited by Norton
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Is what I think is happening, is getting ready to happen, based on your previous thread with the brass pacific shell?.......I don’t have the flywheel Pete, but I do have the tach mount, tach sensor and harnesses for a PS 2 premeir pacific if that helps.....I’m going ERR on the pacific I’m building...you can have all the related guts I have out of this PS2 unit....Pat

Pat, I have PS2 kits so I have the tach sensor mount and tapes. I could use the smoke unit though.

My plan to mount the Sunset shell on the MTH frame came to a dead end yesterday. One measurement I forgot to make is the smokebox diameter. The K5 is much larger than the USRA. I could machine out the MTH steam chest but would loose the flanges. I have a Williams masterpiece Hudson frame but that steam chest is also a different diameter. Driver spacing and size is the same though.

I think the only way I will be able to three rail the Sunset model is machine new driver tires as another forum member is doing now. In the meantime the K-5 still needs a lot of repair work as it was beat up when I got it. Only way I could afford one.

What are you going to use for a K5? I always thought a Blue Comet would be close.

Pete

Last edited by Norton

Ok Pete, shoot me your adress, emails in my profile......your more than welcome to the parts, I have more PS2 smoke units than I’ll ever use.....in the meantime, if there’s anything else PS2 wise you need out of that pup, let me know and I’ll harvest what you need......then I’ll send it all at once....Merry Christmas.........Pat PS , I’ll send the PS2 smoke unit bracket, it’s boiler mounted, but may come in handy for your build.....

It's quite possible to use that flywheel as is for a PS/2 upgrade, just did one recently with a small flywheel.  You just have to devise your own tach sensor bracket.  I do them with styrene strips.  I curve the first one and glue it to the motor, then cantilever them down to get the proper spacing for the tach sensor. 

Here's a link to Custom Tach Tape Images that you can print any tach tape spacing you need to make the speeds work out with your flywheel.

Norton posted:

Pat, I have PS2 kits so I have the tach sensor mount and tapes. I could use the smoke unit though.

My plan to mount the Sunset shell on the MTH frame came to a dead end yesterday. One measurement I forgot to make is the smokebox diameter. The K5 is much larger than the USRA. I could machine out the MTH steam chest but would loose the flanges. I have a Williams masterpiece Hudson frame but that steam chest is also a different diameter. Driver spacing and size is the same though.

I think the only way I will be able to three rail the Sunset model is machine new driver tires as another forum member is doing now. In the meantime the K-5 still needs a lot of repair work as it was beat up when I got it. Only way I could afford one.

What are you going to use for a K5? I always thought a Blue Comet would be close.

Pete

I’m not sure what route I’m going with my Pacific......mine is a USRA heavy, my initial thoughts were I could make a very convincing K3G out of this...but yes, I’ve been staring at Comet shells and thinking the same thing....either way, I’m in to this heavy pacific so cheap, it won’t hurt my feelings either way....just got to hunt down a comet shell.....and a smaller tender.............Pat

gunrunnerjohn posted:

It's quite possible to use that flywheel as is for a PS/2 upgrade, just did one recently with a small flywheel.  You just have to devise your own tach sensor bracket.  I do them with styrene strips.  I curve the first one and glue it to the motor, then cantilever them down to get the proper spacing for the tach sensor. 

Here's a link to Custom Tach Tape Images that you can print any tach tape spacing you need to make the speeds work out with your flywheel.

I would agree with this. Why change the flywheel diameter just to use a given tape? I have used custom tapes on smaller flywheels in G scale.

I didn't do this exact engine upgrade. I did do a first edition MTH Allegheny. I don't remember the flywheel being that much smaller?

 Some of the old stuff had different gears and you must make a custom tape to get it right anyways. I did a Williams Challenger and although the speed matches my other MTH engines ( I think?), it screams at high speeds from what I think is low gears? Sounds like it's doing 150MPH! So I set the max speed at 50 MPH and try to keep it slower. I just don't like how it sounds. I wanted it to be at the correct speed to match the read out. I am surprised that the board doesn't shut down from the gearing difference. The custom tape must make the board happy? …. or I just didn't get that one right! 

 

Last edited by Engineer-Joe

Thanks John for the link. I will see about a different sensor holder. Joe, for me to machine a new ring is actually easier than making a new holder. I'm all for easy. Different gearing may be an issue though. I had to open up the gearbox to be able to get to the screws that hold the motor mount. The worm gear didn't appear to have many teeth.

Pete

Last edited by Norton

After seeing the modifications to the boiler required to accommodate a larger flywheel I opted to make an adapter for the sensor to be able to read the 21mm flywheel.

Meeting critical dimensions required time and care to make this little bracket. This plus the mod to the motor mount represents almost two hours time. The gap to the test strip is .035" not far from the ideal .030" and well within tolerances.

 

 

Now to sort out a correct tach tape.

Pete 

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Last edited by Norton

From John's link I found this.

It seems to require data from an engine I would be using for a sound file. How does one get this info if you don't have the engine in hand? I can probably assume driver diameter is the same but don't think I can assume gear ratio or flywheel diameter is the same. 

I am upgrading a USRA Pacific. Data for this is Driver Diameter= 1.535", Flywheel Diameter= .827", gear ratio = 16:1

Pete

A bit of thread drift, if no one minds.  I am not real familiar with MTH trains.  I have bought and sold the few I had.  I was looking at an AEM-7 w/PS1, which is the oldest version, I believe.  What's the difference in the PS levels ?   Is there any reason to stay away from a PS1 loco ?   I would be running it on a conventional layout with a post-war ZW transformer.  I do have fast acting circuit breakers wired to each post.  I know the modern electronics need to be protected.  

Dan Padova posted:

A bit of thread drift, if no one minds.  I am not real familiar with MTH trains.  I have bought and sold the few I had.  I was looking at an AEM-7 w/PS1, which is the oldest version, I believe.  What's the difference in the PS levels ?   Is there any reason to stay away from a PS1 loco ?   I would be running it on a conventional layout with a post-war ZW transformer.  I do have fast acting circuit breakers wired to each post.  I know the modern electronics need to be protected.  

Dan, I agree with Norton. If all you want to do is run conventional, you will be fine.  The battery is crucial.  Avoid battery worries and buy a J&W Electronics BCR to replace it. You can get them from many vendors.

Have Fun!

Ron

 

Just a followup here. First off thank you to GRJ, Pat, and Joe for helping me out here. I ended up using the existing flywheel and using one of John's custom tapes. Worked fine with PS2 file for this engine. 

This engine required many mods to get everything to fit. The tunnel in the engine had to be milled wider to fit the tach sensor holder. The smoke unit from a PS2 USRA Pacific had to also be cut down to fit in this smokebox. MTH must have made the later ones larger diameter.  The motor barely fit in the firebox. I couldn't even use a tie wrap around the motor to hold the wires but had to use tape instead.

I straightened the tether as shown in earlier threads and added a cab apron. Also made a shorter drawbar. Air hoses were added to the pilot. Still few more details to add before I am done. 

Here it is on its maiden run.

Pete

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Dan I personally wouldn't buy a PS1.  The circuit boards are prone to scrambling if powered up with a low battery.  AND they don't have speed control.  IMO, PS1 diesels and electrics don't run as well as a Postwar 2330 GG1.  Or at least they slowed down more on the sharp curves of my old layout (maybe thank rubber tires on both wheels of the same axle for not allowing the wheels to skid.) 

Even though I feel that speed control is a giant band-aid, it was a game-changer.  For that and better sound it's PS2 or later for me.

Ted S posted:

Dan I personally wouldn't buy a PS1.  The circuit boards are prone to scrambling if powered up with a low battery.  AND they don't have speed control.  IMO, PS1 diesels and electrics don't run as well as a Postwar 2330 GG1.  Or at least they slowed down more on the sharp curves of my old layout (maybe thank rubber tires on both wheels of the same axle for not allowing the wheels to skid.) 

Even though I feel that speed control is a giant band-aid, it was a game-changer.  For that and better sound it's PS2 or later for me.

                  They do that so the tires will wear out faster.     j

Ted S posted:

Dan I personally wouldn't buy a PS1.  The circuit boards are prone to scrambling if powered up with a low battery.  AND they don't have speed control.  IMO, PS1 diesels and electrics don't run as well as a Postwar 2330 GG1.  Or at least they slowed down more on the sharp curves of my old layout (maybe thank rubber tires on both wheels of the same axle for not allowing the wheels to skid.) 

Even though I feel that speed control is a giant band-aid, it was a game-changer.  For that and better sound it's PS2 or later for me.

PS1 can be a great value if you can upgrade it yourself. They are well built and the Premier steamers come with a big Pittman motor. This engine cost me 170 bucks delivered. I picked up a NOB PS2 kit at York for 120 bucks. With a little help from my friends and about 15 hours sweat equity I have this. Compare to the latest MTH and Lionel USRA Pacifics.

Pete

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