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Hi there-my 2nd post-I have been doing some restorations and mods of Marx locos. My most recent project is installing a 666 motor and smoke unit in a Commodore Vanderbilt. I bought the 666 mainly for the double reduction motor. When I got it I didn't think it smoked very much so I did some research and somewhere read that a lower ohm element would smoke more than a higher one. So I bought a Lionel 16 ohm element (I think the standard one is about 28 ohm.) I got the mod done and running and am not impressed with the smoke output. The more I think about it, the more it seems like more resistance would lead to more heat and more smoke. Anyone know for sure about this? I have a very, very small "layout" so can't run it very fast or with a lot of cars in the consist, which I understand would put the motor under more load and thus more heat. Please see photos.

TIA, CBIMG_0117-smallIMG_0465-smallIMG_0466-smallIMG_0467-small


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Actually, the 16 ohm resistor should yield MUCH more smoke at the same voltage as the 28 ohm resistor!

At 12 volts on the track, the 28 ohm resistor would result in 5 watts of power dissipation in the smoke resistor.  For the same track voltage, the 16 ohm resistor would result in 9 watts of power dissipation in the smoke resistor.  Hotter doesn't even begin to cover it, that's more heat than almost any modern locomotive pumps into the smoke unit, the resistance isn't your problem!

I did the same modification on a Marx 666 smoke unit using a 20 OHM resistor with a small amount of wicking in the bottom of the bowl to about a third of the way up the resistor.

My results are very good.  Using a 16 OHM resistor as you have should result in good smoke.  Personally I found the 16 OHM ran too hot.

Are you certain that you have one end of the resistor (the positive side) isolated completely?

Thanks to both of you for the replies! You can't imagine how much I appreciate it. This has been bugging me for quite some time.

IIRC, the original unit had a wire wrapped around some wicking and either it was broken or I broke it taking the unit apart. I couldn't find a source for that type of setup but saw that Parts4Marx were listing a replacement more like the Lionel one. I think I ordered that one from them but then in the meantime came across the mention of the 16 Ohm one and ordered it. I did put a bit of house fiberglass insulation in the bottom of the opening as I read about somewhere. Since I did the mod I have seen a video on converting Lionel units from pellets to fluid, and saw that the element is designed to lay horizontally on and in contact with a bed of wicking. I did put the wick sleeve over the element and I do have insulation on the positive wire going through the unit, and not wanting to rely on ground being made by the other wire, I lengthened it and attached it to the frame. So, I am now wondering if maybe the wick sleeve is not in contact with the fiberglass insulation on the bottom.

John-Do you think it is getting too hot?

Soo Line-I didn't know that one end of the resistor is supposed to be the positive side.I didn't see any designation of that so just picked one end and put the tubing over it. The first time I ran it, it was working intermittently, and I realized the other end wasn't making good contact going through the side of the unit, so added a piece of wire to it and attached it to the frame for ground. So, is it possible, I have it in backward?

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