How to overhaul a Lionel fan-driven smoke unit....
Updated 11-11-02.
These are a few things I have done to keep my early Lionel fan driven units alive, with some easy mods to boost output at the same time. These mods do not cover piston-driven puffers or the newer fan driven units that are showing up lately in locos like the 0-8-0, etc.
Click here to see how these units operate in both conventional and command mode.
The image above shows the top board of a typical Lionel fan driven smoker after a few weeks of use - and some smoke boost abuse! Although this one isn't as bad as others I've seen, you will notice that the sleeve over the element in the top image is almost completely scorched. In this condition, it will not wick smoke fluid up out of the reservoir efficiently. Remove that sleeve and toss it.
The top of the board also shows some evidence of overheating. In the worst case scenario, the solder joints themselves melt and the traces will lift off the board. After heating up to this point during operation, the solder melts and the smoke output decreases dramatically because the element loses contact with the traces and the element no longer receives power. I have a simple fix for this which I'll show you after this....
Here is the reservoir and fan housing in a typical TMCC diesel. Take this opportunity to change out the yellow wadding Lionel uses in the reservoir. The stuff tends to dry up too quickly and there usually isn't enough in there in the first place. I have been using white fiberglass insulation with good results - plus it's cheap! I simply stuff it in there up to the bottom of the notch between the fan housing and the reservoir. This will ensure good airflow across the element. Keep in mind, even with normal use this stuff degrades over time and should be checked whenever you are performing maintenance on your loco.
Here is what the bottom of the top board looks like after my little mod. This is my fix for the scorching problem. I applied some metal repair tape to the bottom of the board, carefully cutting out the holes for the element, the intake, the screws, and the output. This material is typically sold in the automotive section of any hardware store and is very inexpensive. The brand I used here is 3M. This stuff really does the trick by keeping the heat generated by the element inside the reservoir and letting it go to work on the fluid instead of the top board. It also sinks enough heat to keep the solder joints from melting.
As for the element, I go with different types depending on if the loco has Odyssey or not. Why? Well, with Lionel's RS4.0 locos, the non-Odyssey versions had a little-known speed-related smoke boost function that applied full track voltage across the element after a certain speed step. For these locos, I keep the stock element which seems to be designed to handle full voltage across it for extended periods. This stock element is roughly 27 ohms, seems to have a fairly thick ceramic core, and is pretty durable. If you're real curious as to what I mean by the 'speed-related boost' feature, check out the link at the top of the page and see the relationship between TMCC commands and smoke unit behavior.
For Odyssey locos, there is no speed-related boost function so I go with a hotter element like the one shown above. The one shown is a Lionel part I get from my dealer. I believe these are replacements for their mechanical puffers and the part number may or may not be 600-8141-055. I say may or may not because I've never gotten them directly from Lionel and the number could be incorrect. These heat up quicker at lower voltages but will burn out quickly at boost levels. Their resistance value is roughly 24 ohms. They work so well at normal levels that the boost isn't needed. I generally get a couple months out of them before they quit and by the time they do, the unit needs to be restuffed anyway. HIINT: When an element fails in a Lionel unit, the fan won't even run (due to the way the TMCC electronics work - this is normal), so if you're not getting any smoke, listen to hear if the fan is running. This may be a sign the element is done.
Lately, I've tried some MTH smoke elements with some decent results. I picked up a few at their York parts bin but I don't know the part number. I think these are used for both the PS-1 and PS-2 smokers and from what I can tell they only sell this style. They seem to have a glass(?) core and their resistance is about 18 ohms. A word of warning - they run very hot and should only be used in TMCC steamers or locos with a straight stack! Locos like the LionMaster Challenger, with its S-bend funnel, will simply run too hot due to restricted air flow and will give you a cauldron-like effect at the stack. Yuck! I wouldn't recommend these for diesels either, especially diesels like the Dash 9, the C 420, or the U Boats since they all have some form of offset funnel to connect the smoke unit to the loco's stack. That being said, I have these elements in my K4 and my J (they both have straight stacks) along with TAS Puff n Chuff boards and the smoke output is impressive. These elements also seem to be very durable. Their life span is yet to be determined though as I need to run them more. As with all the elements I mentioned, I highly recommend insulating the unit like I've shown above to avoid destroying the top board.
In any case, I do not replace that sleeve shown in the first picture over the element. I'd rather replace scorched stuffing, since you'll have to do it no matter what after a while. In some cases, the sleeve scorches so badly that it fuses itself to the element, and when you go to remove it, you end up breaking the wires on it.
The final step is the reassembly. Be sure to replace the gasket shown above to ensure that it doesn't leak smoke out the sides. The insulation is thin enough that it won't interfere with this step. Plug everything back in and fire it up. In some situations, this step may have to be done outside of the loco while connected to a small AC transformer at about 9-10 volts. In either case, you will want to run it and observe its output. The 'toothpick down the stack' trick shown above is simply to push the wadding around a bit to maximize airflow and smoke output. It is important to get the best airflow at this point. Efficient airflow will help produce more smoke and extend the life of the element.
One more thing to keep in mind is that these modifications may void your warranty and will be performed at your own risk!