Lionel brass 6-51702 smoking caboose

So how big of an opening is there for air to enter?

Some of Lionel's recent steam engines, at their own suggestion, have been improved, in part , by enlarging the opening.  I should add these are not Seuthe units, but more traditional 25 ohm elements.

But it can't hurt to ask . . .

John

The newer smoking cabooses suffer from the same problem; no way for air to flow into the smoke unit.  I pulled mine apart and added a few holes under the smoke unit hoping that the heat would cause the smoke gently rise but the results were unsatisfactory.  Finally I removed the smoke unit and replaced it with a fan driven unit.  I added a rectifier and 2 miniature buck converters; one for the fan, the other for the heating element.  I tuned them to give just a wisp of smoke.

Thanks John and Dan for your replies.  I didn't want to do anything major so I just lowered the shell onto the frame of the caboose to see how low it went before the smoke stopped flowing.  I  decided to put a few card stock shims on each end of the caboose between the shell and the frame to allow more air to get inside the shell.  The caboose smokes better now.  It's not a heavy stream, but at least I can see it when the caboose is moving.  That'll do for the time being.

Lonnie

The real cure is a small fan driven smoke unit, no more smoke volume issues.

Gunrunnerjohn,

You're right, that would be the ultimate solution.   I have 12 smoking cabooses and none of them are fan driven.  I guess I've been reluctant to dive in to see what it would take to remove the present setup and mount a fan driven unit.  The electricals should be easy, it's the mounting of the fan driven smoke unit that I've only done once and that was in a Lionel F3 that was converted to an ERR DC Commander and I had to mount a new smoke unit.

GRJ is right.  He helped me find an LC smoke unit that could fit.  Because this was a die cast caboose I didn’t have to worry about melting the plastic.  I created a bracket and mounted the smoke unit to the roof and fit the buck converters inside the cupola.  I was pretty happy with the result.

The great thing about the fan driven smoke is the smoke unit doesn't get nearly as hot as the Lionel or K-Line stationary units in newer cabooses.  The Seuthe unit isn't likely to melt things, but the typical plastic "tub" smoke units in cabooses are infamous for that.  I've seen a couple of similar instances.

I have done a few with the MTH HO smoke unit.  The smaller O-scale single resistor MTH smoke unit is also a good candidate.

As mentioned, you can also use the LC+ or even Legacy smoke units, they're fairly small and do a good job.