Tach tape-Pulmor

Hi RJR,

With many drives lacking a flywheel it is possible to put a tach strip on the back side of a wheel or the side of a large gear.  You have to print a different type of tach strip in such instances that looks like a sun burst.  This is how many G-gauge conversions are handled.

The bigger problem with a pulmor is insulating it from the locomotive frame.  Any drive motor running off a PS2 or PS3 board must be electrically isolated from AC track power.  Otherwise, you will short out the board.

I just don't see the reason to even attempt it. Change out the motor to a can then it's easy plus it will run much , much better.

I'd contact Frank Timko about a DC motor conversion, they're pretty reasonable and the problem is solved.

I don't know if this will work, but perhaps it's worth exploring.

You may be able to find a split (2 piece) plastic or metal collar that could be mounted on the driveshaft with a allen wrench or screwdriver.  Then you could apply the tack tape to the outside diameter (aka O.D.) of the collar. 

This is a possible fix, but probably not an easy one. There are a lot of issues to consider.  You would have to:

1) Measure the driveshaft OD and then either find or bore a split (2 piece) collar with a matching internal diameter (I.D.).  A solid collar could also work, however you would have to remove the driveshaft to install it.  Given a choice between plastic or metal, I would go with a metal collar because it has more weight.  A heavier flywheel has more inertia which will help the engine run smoother over the dead spots in switches.

2) Determine the collar OD.  The collar OD size would be limited by the available clearance. Clearance can be determined by measuring the distance between the centerline of the driveshaft and the closest obstruction such as the frame, sides, or roof of the engine shell.  I would take that number, multiply by 2 to get the max collar OD and then subtract maybe 1/8" to 3/16" from the max OD to insure the collar doesn't rub the frame or the shell after the tach tape has been installed. 

3) Determine the correct tach tape to install.  In a perfect world you might be able to find a collar OD that closely matches one of the standard MTH flywheels.  Then you apply the appropriate MTH tach tape.   If not, you will have to make a custom tach tape.  I think Dave Hinkel on this forum has instructions on how to do this.

You'll have to do some research to find a collar.  I would start by looking on-line at suppliers of small chain or belt drive componets.  Another possible place might be a hobby store or website specializing in radio controlled cars. 

Heck, you might get lucky and even find one at Lowes or Home Depot in the hardware department.

Good luck.

Many thanks for all the comments & suggestions.  As you may have guessed, I have a stable of old (pre-1955) Lionel locos that are never used since I got DCS.

Dave Hikel:  The two locos I have in mind have worm gears--no spur gears-- and I don't know if it's feasible to place a sunburst on a driver and expect to get a reading suitable for DCS.  On one of the locos, I've separated the field coil wire that connects to the frame, since I have the motor running on DC, the rectifier and filter being on board.

David1 & GRJohn:  I agree it would run much better.  But it would irrevesibly alter these 60+ year old antiques (a 1950 736 and a 1954 624).  My recollection from a post someone made years ago is that Frank Timko charges around $600.  That's more than I'm willing to spend.  But I will send a note to him to ask what's available.

DVBull:  Your idea has promise.  If I recall, there is a short stub shaft on the commutator end of the armature, and a hole could be enlarged in the end cap between the brushes.  Question would be whether the stub would provide a good anchor.

General: I wonder if a tach tape could wrap around the 3 poles of the armature and whether the sensor could function between the poles of the field electromagnet.

I also have several side frame motor locos but I don't deem them worthy of effort.  I have 1946 726, made for one year only, that has two worms on a long shaft, which is driven by spur gears off an "Atomic" motor.  A real dog, & noisy.

Hi RJR,

That might work quite well.  The sensor is optical and is highly resistant to electromagnetic fields.  The real trick would be shimming the tach tape between the windings to make something close enough to a circle.  The sensor only functions in a narrow range.  If you can make some styrene wedges that fit between the windings it might be possible.

As you go along with this project please take photos and post your results.  A "reversible" conversion would be very attractive to many others who have original equipment they want to run without giving up all collector value.

I have just been in contact with Mr. Timko, and he quoted reasonable prices for can motors that (supposedly) easily replace the Pulmors.  I'm going to go ahead and tackle the 624.  The problem of course will be getting PS2 upgrade kits out of MTH.

Dave Hikel:  I'm going to put off wrapping the tach tape around the poles, since mounting the sensor could get tricky, and it is possible that under certain conditions the Pulmor would draw more current than a PS-2 board could handle, plus a 3-pole motor is inherently not smooth.  FYI, my plan was to convert the Pulmor to a DC series-wound reversible motor by using a full-wave rectified to assure that, regardless of polarity, current would only flow through armnature or field in one direction.

I hope you have better luck than I do getting the steam conversion kit, still waiting for one.

I also think any alterations you make with the DC motor are reversible if you decide to go back to the original configuration.  OTOH, I buy trains to run, not to "remain original", so if a conversion will make it better, I'll jump on it.

GRJ, I also buy them to run, not collect, but when a loco is an antique and you've had it since new, flexibility is a good idea.

With many drives lacking a flywheel it is possible to put a tach strip on the back side of a wheel or the side of a large gear.  You have to print a different type of tach strip in such instances that looks like a sun burst.  This is how many G-gauge conversions are handled.

That doesn't work very well as the stripes are then on the low side of the gearing..I've never been able to get the smph readings anywheres near right that way as simply can't add enough stripes. I always flywheel all my installs..and that's now over 65 in G Gauge

And yes I have my own machine shop

Well, I believe the DC motor mod is reversible, at least that's my understanding.

I have obtained from Frank Timko motors for the 624 C&O switcher and the 1950 736 Berkshire.  He does a neat job and his prices are reasonable.  I have the PS2 steam upgrade kit, and will tackle this as soon as I get a chance.  Don't think I'll bother with a smoke unit, at least for now.  I also have an old die-cast tender (#2426W) from the 1946 Berkshire, which I'll use rather than the 1950 plastic tender (#2671W).

Looks like a bolt-in option, that's pretty neat.  I've toyed with the idea of getting my Phantom locomotive converted to DC so I could use a Cruise Commander in it.  I think I can transplant the sounds from the RS 2.5 board to a RS4 board, so I could just upgrade the electronics have have a lot smoother running set.

I started the project, and promptly hit a major snag.  The existing coil coupler has 23.4 ohms, is 2-1/2" long, is centered by a bar which presses against 2 springs, and is mounted on a bracket that come straight out from the top of the coupler..  The MTH coupler has 2.3 ohms, is 2--3/4" long, is mounted on a T-bar, and is designed to mount on a depresed bracket.  I could mount it with a bolt, but would lose the centering action and the coupler would protrude an extra 1/4" from the tender.  Any ideas?

Do the rest of the project first and see how you like the way the loco runs. While you run the loco, you can still be researching the couplers. Usually the postwar coil couplers need to be rewound. They are grounded on the inside of the coil and create a ground loop and fire intermittently. This info is from TMCC conversions, rather than DCS, though, so your mileage may vary.

Or, you could just hook the coupler up and see if it works. It might!

The other thing you could do is leave your 624 alone and buy a Williams repop. That loco already has two can motors in it.

No question it would have made more sense to buy the Williamns reproduction & then convert that to PS2.  If I had sense, would I spend money on trains?

The PS2 upgrade kits come with appropriate couplers, 2 in diesel kit, one in steam, so it's not worth rewinding the 66-year old Lionels.  My best bet might be to buy a pair of 6-wheel trucks as used on new MTH PS2 tenders.

As an aside, you mention the Lionel coil couplers fire intermittently.  I assume you mean by this that they kill their power when they open. The older Lionel couplers were continuous:  as long as power was being fed to the pick up shoe, the electromagnets remained energized.

Do any of you techs out there have in stock 6-wheel trucks as used on a tender with 3-volt PS2?  I have a 5-volt SOU 4-8-2 "Mohawk" that has 6-wheel trucks that look like they can be used.

As far as the couplers sticking out too far, you can buy the shorter ones that will solve that problem.

That is true, but the sticking point is that I can see no way of reasonably attaching couplers to the 1946 six-wheel Lionel trucks.

I have several ideas but I don't know if they are workable. The first would be if the coupler output from the PS2 board was able to drive a coupler with one side connected to ground. Then you could drive the coupler directly. The next possibility would be to obtain a small relay of suitable voltage and drive that with the coupler output. Then use the contacts on the relay to operate the coupler. I am sorry I cannot be more specific but I am not familiure with the outputs and voltages around the PS2 board. The coupler itself could be run off the track power directly.

Al

I'd consider trying to rewind them with less turns but larger wire.

Al, a board is too expensive to risk.  I had thought of a relay, and that might be the cheapest way to go; I'd have to determine votlage and ampacity of the board circuit before buying a relay.  I'm awaiting a price from MTH on new 6-wheel trucks.

John, again giving the value of the board, plus labor to have a coil rewound, with questionable result, I'm loath to try that route.

BTW, I see the steam upgrade kit was manufactured in Thailand.  I don't recall where they used to be buit--China?  Could be the Thai floods are the cause of the kit shortage.

The MTH couplers are designed to handle more current than the original coil couplers, so I really doubt you'll damage the PS2 board by wiring to the existing coil couplers.  It may not work, but it's worth a shot.

As far as the relay, that's a viable option if the couplers don't work connected directly.

RJR, can you please email me the contact info for Frank Timko?  You can email it to cando614 "at" aol dot com.

Also: For the Berkshire installation, the can motor appears to be quite a bit longer than the original pullmor.  How much does it stick out of the cab?  When you get it installed, can you please post or email me a pic?  

Thanks, and good luck with your project!

Just go to the home page, all the info is there.

Timko Repair Depot

Ted, GRJohn gave you the link.  It was 84 here and I spent the day on the boat, just getting back.

I haven't turned to the loco yet--been concentrating on the tender & boating.  I will post a picture as soon as I can.  Soon as I have a chance, I'll remove the shell and check motor size.  The diameter is so much less I wonder if it will have enough power for decent life.

In my basement I somewhere have some old Little Jewel relays, and the Lafayette look-alike, the Little Gem.  Since Lafayette has been out of business for some 50 years, these are old.  5000 ohms, pull in at about 1.5 ma.  I'm going to try these for PS2, to trigger the Lionel coil.  With 5k ohms, overloading the PS2 board shouldn't be an issue.

One thing about using the 2426 tender is that there is a great deal of space--it's longet than the 1950 tender.

Like I said, overloading the PS/2 board with those coils is certainly not an issue, they're much higher resistance than the PS/2 supplied couplers.

Ted, the can motor w/ flywheel protrudes is about 3/4" longer than the Pulmor, but is much lower.  Pix attached.

The PS2 coupler is 2.3 ohms.  The old Lionel is about 22 ohms.  So a PS2 board MAY not be able to supply sufficient voltage to cause enough amperage to fire it.

FWIW, the ERR boards open those fine.  The Lionel couplers are also higher resistance, so they may be outputting more voltage.

Ted, I put the motor in place and have included a few pictures:  the original installtion, side & top; the tender in progress (a lot of space), and the remotored 736 from the side.  Haven't figured where to mount the socket.  I must say I'm not ecstatic about the striped flywheel protruding & visible.  I'm keeping everything in such form that loco can be converted back if I'm not satisfied.

I hooked up a 6-volt battery to the motor directly to see how it would run.  It went at a decent speed, maybe like 10 volts with the old AC motor.  The flywheel doesn't do a think to keep it coasting.

RJR, thanks again for posting the pics.  The last batch is what I was thinking of.  If you've ever seen a Williams Golden Memories Berkshire, that loco has a black flywheel visible in the cab.  The appearance is similar to your converted 736.

Regarding coasting--have you adjusted the mesh between the worm gear and the worm wheel on the 4th driving axle?  The original Lionel 3:25 ratio gears were "back drivable" (the wheels could turn the motor) Do you know whether Mr. Timko used a standard 3-start Lionel worm on the tail shaft?

I would love to know whether the converted loco runs more smoothly than the Williams 726, which was born with a can motor but otherwise looks the same.  I have a lot of fond memories of my postwar steam, but the operation doesn't always measure up. Thanks for pioneering this effort and sharing with others who are considering an upgrade!  -Ted

I don't think the lack of coasting is caused by drag.  The flywheel is small & light, enough for a tach tape.  And of course DCS provides the coasting.

I assume that the Timko worm gear is the samne as the Lionel, since the spur gear on the 4th axle is not changed.  I'll probably get to the job again in a few days, when Sandy keeps me inside.

FWIW, I've never seen any flywheel equipped locomotive that coasts more than about an inch with no power.

I changed the sound file to one for a Berkshire, which has a great whistle, but speed is way off.  To illustrate:  to get 4 chuffs per revolution, I have to set chuff rate to ten.  Hard to believe that MTH steamer gear ratios are 2.5 times what Lionel used.  Would appreictae any input from persons having the facts of gear ratios.  Wheel circumference is certainly not that much different, if any.

After using loco awhile, a new issue is that when I press the uncouple button, engine loses its identity.  Checked wires to the relay, and no shorts.  I wonder if the coil coupler puts a surge on the track???