Need Help installing Smoke Unit In 6-8100 "611" MPC #746 Reissue

My guess is the heater element is shorted out. When the heater has become overheated the core becomes conductive and glows cherry red, and makes lots of smoke, for a few seconds before the circuit breaker pops. Are you sure the smoke unit is really new? Does the unit have that stinky overheated smell? Could the headlight bulb be defective, or maybe the wires to the headlight be bad?

The Z-750 isn't powerful enough for that loco with the E-unit, motor, and smoke unit element... you are overloading it.

How many ohms is the new smoke element?

I don't know how many ohms the smoke unit is.It is similar tot the one in the original #746,but it is larger, and has tubes running out of the top to the sides, to produce the steam cylinder effect.  

Are you sure that 75 watts is not enough for a loco??  I have some 110 watt postwar transformers I could try it out with. I tried it with a CW-80 also, and it shorted it out ,once I added the smoke unit in the mix

It's pretty close to the limit on both of those, but trying a better, more powerful conventional transformer is a step in the right direction to troubleshoot.

I am very familiar with the 8100, but you will need to check the smoke unit impedance too, with an ohmmeter,  to determine if it's really shorted or it's just very low resistance. The headlamp is wired in parallel to the smoke unit, so remove the bulb before testing. You can also test the smoke unit alone by powering it from a transformer with alligator clips before connecting it to the locomotive. Be sure there is at least 12 drops of smoke fluid it before testing.

I would guess that anything below ~16-19 ohms, is too low for plastic bodied smoke units.

What happened to the original smoke unit?

Where would I put the alligator clips to test it? Obioulsly, one clip would go to the place where the wire running to the e-unit goes.Where would I put the ground?,or second clip?   The original unit still works,I just thought a fresh one would produce more smoke,,and it had a few leaks around the high temp cement . 

Ive never seen a plastic smoke unit except old Marx. But there are only two connections to a heating element 98% of the time, be it a space heater or smoke unit. They are just resistors in any form. That's why he suggested an ohm reading (you really should put aside a few bucks for a cheap harbor freight unit, or eBay special[$15-30] It's a valuable tool in the hobby)

You've found one lead, Jump it to the hot leg, (center). There is either another wire to be found, or a connection to the chassis somewhere to supply a "ground" to the common leg.(outer rails) that might just be a tab touching a mounting screw or something.???

  A fan unit might complicate it slightly with three or four wires. But it doesn't sound like it. Can you clue us incase Rob doesn't answer right away?

kennyb posted:

Where would I put the alligator clips to test it?

To the two light bulb / headlamp leads.

kennyb posted:

The original unit still works,I just thought a fresh one would produce more smoke,,and it had a few leaks around the high temp cement . 

Unless the specification of the element itself is changed, there is no improving it. They were not prolific smokers. I have sealed those leaks with Walthers Goo.

The usual issue with these is that the surgical tubing used for the steam chest emissions gets brittle & breaks.

For those unfamiliar with this unit, it is a modification of the first 909 smoke fluid equipped loco, the 746, introduced in 1957. On the 8100, there are fitting at the top of the bowl to allow for steam chest emissions tubes.

746:

8100/611:

kennyb posted:

...Then It shows a short.

Looking at the three views above, I would check your unit carefully to be sure that the two wires going to the headlamp bulb do not make contact with each other anywhere, including upstream to the e-unit and chassis/ground connection points.

Does this engine have an electronic e-unit and a railsounds tender?

Blue wire, hot comes from the motor terminal and other wire to chassis ground

Edit; I am not very good with the supplements - the 6-8100 in 1-9 has no wiring diagram.

Edit 2; added 6-8100 from S1-9 - no wiring, but does show a fuse for the smoke unit.

Moonman posted:

Does this engine have an electronic e-unit and a railsounds tender?

No... electronic whistle and Mighty Sound of Static.

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It works fine with the old smoke unit in it, but does not produce smoke like the replacement one that is shorting out.How/or Can I fix the new one?The new one gets HOT right away, and is producing smoke like crazy, but is shorting everything out after 3-4 seconds.There is nothing wrong with the old smoke unit, but I wish I could get the smoke coming out of the one that is shorting, it looks fabulous before it shorts out!!! 

Does anyone know the official Lionel part number for this smoke unit?I am not familiar with the new website, and I would like to know the official number of this engine as well.I thought it was 6-8100,but I was just taking a guess.

The resistor is shorted. Take apart (carefully) and replace the resistor. I would recommend resealing it with JB Weld. I have found Walthers Goo bubbles up and softens with the heat from the unit. New 8100 smoke units are hard to find and expensive.

Red hi-temp automotive silicone would be another GREAT heat proof glue and sealer. It can handle exhaust pipe heat on cars no problem. It would let you reopen the thing one day too. JB Weld is my buddy, but kinda permanent.

Was that unit from 57 plastic? Bakelight?  Must have been a good one, I don't recall ever seeing one sitting on Gramps bench.

Yes, it sounds like the resistor/element is out of spec - something that would show up very quickly by checking the resistance with a VOM.