Another smoke question, Polar Express...

The ball bearings are supposed to be a one-way valve to allow the downstroke of the piston to suck less air backwards through the smoke unit.  I don't see a solid one doing better, but I've never tried it.

My postwars don't have smoke coming out the bottom, but the new one does? I guess everything new isn't a definite improvement!

Some of the old PW locomotives have pretty close fitting pistons.  I just put a 675 back together, the piston in that is a pretty close fit, much closer than the plastic ones we have now.

 

I tried fabbing up a nylon washer to tighten it, no better...

Are the balls loose?  If they're sticking, they may be making the situation worse if they aren't closing off the passage of air on the way up.

 

Yes, they're loose...

Don't have one to look at, but the one at Henning's Trains I was running the other day didn't have smoke coming out below.  It might be cool if it did, but it just came out the stack.

 

Mine smokes out the bottom. Always did since new. It is a cool effect though

At least I'm not the only one! 

Not just the PE engines, but the Baby Mikados too!

 

Jon 

Thanks Jon, maybe we should start a club! 

Just a thought, but if the piston was installed upside down the ball valve could not work properly and the smoke would go out the bottom.

Can you flip the piston over and connect it?

I had smoke out the bottom of my P.E. loco the first time I replaced the wicking.  Subsequent re-examination revealed that I had fully blocked the air holes with the replacement wick.  When I re-arranged it so that the holes were clear the loco smoked normally, through the stack only.  I performed the entire operation in situ without disassembling the loco any further than removing the shell.  I didn't know until I read this thread that there were ball check valves in the smoke unit.  Sometimes ignorance is bliss, eh.

Pete

Good point on the smoke vent Pete, that would sure cause issues with the smoke unit.

I wish the solution was so simple! I have a new smoke unit in it where Lionel cuts the wadding around the air holes...

I have a Pennsylvania and Eire Jr. Berkshires and both of them have smoke out the bottom also.

How loose are these pistons?  The older PW style and even the modern era metal versions have a smooth but close fit.  No ball bearings either.  Interesting to add the additional cost for starter sets.  I would think it must be a tolerance issue if the pot air port is clear.  G

The old metal piston cup has a much tighter tolerance than these new units. Probably not today or tomorrow, but I will try to find some time to measure up the new one.

I've replaced the resistor in my PE already and installed the packing with the hole clear. Still smoked out the bottom.