# Recommend a list of smoke resistor values?



## Norton (Nov 5, 2015)

I suspect GRJ is best qualified to answer this but anyone feel free to make suggestions. I have a few different values of resistors mainly for use in Lionel engines. They include 28, 24, 22, and 8 ohm resistors. One of my Legacy engines uses a 6 ohm resistor. Now I find a bad 10 ohm resistor in a TAS turbo smoke unit. This is the first TAS unit I have had to repair. In addition I think MTH uses dual 16 ohm resistors.
Since I have to order a 10 ohm resistor for this TAS unit I figured I would make a list and order all the other values I don't have that I might need someday. 

Pete


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## Jeff T (Dec 27, 2011)

A number of years ago when I got back in the hobby I had a TMCC loco and found the Lionel video on removing the sock and carefully opening up the input hole in the smoke unit to allow more air.

Yes, there was an improvement, but I wanted more. I found a thread on another forum where Rod had put a few MTH resistors in TMCC engines.

I don't recall exactly how many ohms, either 16 or 18, but I installed it and it made a huge difference.

I remember GRJ saying it might be more than the engine could handle, but in three years I ran the daylights out of it and never had a problem.


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## gunrunnerjohn (Nov 10, 2010)

Lionel smoke units with the regulators use either 6 or 8 ohm resistors, I don't have any idea why they have two different values. For those, you must use the same value as that's how the regulator is "tuned". TAS has several styles of smoke units, their "turbo" smoke with the regulator uses a 10 ohm, don't know what the others use.

MTH uses two 16 ohm resistors, and of course, Lionel uses the 27 ohm in their standard fan driven units that run from the TMCC electronics.

I personally keep the stock the following:

Lionel 6, 8, and 27 ohm resistors.
MTH 16 ohm resistors.

Then, for custom mods, I have a selection of wirewound resistors from 18 ohm through 24 ohms that I use for upgrades.

The 16 ohm resistor that is used for MTH will work in a Lionel conventional fan driven unit to replace the 27 ohm resistor, and you see Jeff's result. The issue I have is that when you check the smoke triac on the R2LC, you'll find it's running pretty hot, typically 70-80C. That's way too close to it's maximums for me, so I don't use that as a long term configuration.

One thing I've taken to doing with my smoke upgrades is adding a "turbo" switch when I use an MTH smoke unit in an upgrade. I keep the 16 ohm resistor, and I add a few diode pairs to drop the smoke power in the "non-turbo" setting. I use three 1.2A bridge rectifiers wired as diode pairs for my low smoke setting, and I use a single bridge rectifier in addition directly in line with the smoke unit. This gives me prodigious smoke in the "turbo" setting, and very good smoke in the "non-turbo" setting. Of course, when you run the smoke on high, you have to stop quite often to add fluid, it runs a lot longer in the non-turbo mode.


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## HarborBelt1970 (Sep 24, 2015)

I tried what you want to do and found that essentially I had to get the resistors from Lionel itself or the late and much missed Boxcar Bill. The problem is that wire wound resistors without a ceramic coating are not that easy to find from ordinary electronics supply sources. (If you want to try to take the coating off yourself you'll find that suppliers like Digi-Key have a vast assortment.)

The values I got were all the ones you name including the MTH ones. Most late model Legacy smoke units use 8 or 6 Ohm resistors but these are coupled with one or another of the AC regulators that Lionel use and in fact these are a lot more prone to fail than the resistors themselves. For one of my favorite engines, the Legacy FEF Northern, I got in all of the smoke unit components including the right ACREG after the original one somehow toasted itself and the resistor with it.

TMCC engines from about 2005 use one or the other of the higher rated resistors you name, I think in particular 27 Ohm, but these were often encased in the fiber sleeve that it's now recommended be removed. I got in a stock of these too because I was not confident how long Lionel will maintain a supply of them.


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## Patrick1544 (Apr 27, 2013)

Is there an outside source for the 27 ohm wire wounds, besides Lionel, for bulk purchase?


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## gunrunnerjohn (Nov 10, 2010)

You can buy 3W wirewound resistors from places like Digikey and just use a Dremel wire wheel to knock the powdered ceramic coating off them. That's what I do with all the resistors.

I suspect Lionel will have smoke resistors for a long time in all their common values.

Yes, I take the fiber sleeve off the resistor if I ever find one. When doing upgrades, I also drill out the intake hole for better airflow.


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## L0stS0ul (Feb 6, 2015)

I did a smoke unit upgrade to an older lionel engine and used the 8057 smoke unit. I found that opening up the hole and using an 18 ohm wirewound resistor worked great in it. The 18 ohm one I ended up using was a lionel replacement for the old lionel puffer units I had on hand from a previous fix. Still very happy with how it turned out. The 27ohm resistor the unit came with was worthless and I tried a bunch of different options in this upgrade but none gave me the effect I was looking for until I got the 18 ohm one in there. Been running about 6 months now very well still.


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## Patrick1544 (Apr 27, 2013)

Thank you .


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## Patrick1544 (Apr 27, 2013)

John,
I found a vitreous enameled 3W 27 wire wound . Can that enamel be removed as easily as the ceramic coating you mentioned, without damage to the wire wraps?


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## gunrunnerjohn (Nov 10, 2010)

The vitreous is much harder to "knock off" with the wire wheel, it usually kills the resistive windings. I recommend the powdered ceramic, that comes off really easy.


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## Patrick1544 (Apr 27, 2013)

Ok. I'll look for the ceramic coatings.


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## gunrunnerjohn (Nov 10, 2010)

Digikey is your friend.


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## Norton (Nov 5, 2015)

OK, thanks guys. I will likely order some 6, 10, and, 16 ohm resistors to fill in the gaps. I have a pair of identical Legacy GP7s. One has a 6 ohm resistor and the other an 8. The 6 ohm engine definitely puts out more smoke when both are set to max. 
If they are available I prefer the square ceramic power resistors. They cost a bit more but easily break apart in a vise are easy to clean up. Still cheaper than buying from Lionel.

This is the style I prefer.

http://www.digikey.com/product-detail/en/SQP500JB-10R/10W-5-ND/18655

Pete


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## gunrunnerjohn (Nov 10, 2010)

The square ones will typically be far too high powered to work in this application. In the 3 watt range, I didn't find anything in the square resistors, they typically start at 5 watts.


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