PS2 Steam Upgrade to MTH Greenbrier

Not that specific model, but it seems to be a large engine.  I would check wire routing, smoke unit alignment, anything else you removed from engine.  Does it seat at one end and not the other?  G

Agreed. Any wiring/misalignment can  keep a shell from aligning. I'd pop the shell and "commune" with it, for a while. You will see the problem. it took me days to get my diesel shell to sit right. I hope never to open it again!

The shell fits at the front end but it will not seat at the rear.  I have rerouted the red and black wires under the Pittman motor which leaves the six leads for the headlight, fan and smoke unit resistor.  I fear that the tach reader support might be the problem since it sits higher than the motor.  I hate the thought of grinding the inside of the shell that is why I posted the question on the forum.  Any suggestions?

you can put a small amount of clay on the tach reader and see if it is compressed when trying to put shell on.  what about the harness pcb on the engine, is that clearing the shell?  G

 or if it is the motor terminals hitting the shell

You certainly don't want that. I sometimes line the boiler with electrical tape just incase something touches the boiler. This is probably going to make it worse in this case.

 Once you get things straighten out, and reach the testing part, don't be in a big rush to raise the throttle on the transformer. You'll be able to tell if somethings not quite right and can back off.  hopefully get a second chance to fix it. .

GGG....That is a good suggestion to use the clay.  I will have to give that a try.

Gregg....I agree with you.  I did line the inside of the boiler with 3M electrical tape.

Now the new problem:  I just stripped the head out of the set screw holding on the fly wheel.  I'll have to see if I can purchase a small easy out and drill bit or a new flywheel and set screw. 

I put the PS/2 upgrade into the MTH General, the tach bracket wouldn't clear the top of the shell.  I ended up bonding the tach reader down under one side with a home-made block to do the proper spacing. 

If the tach bracket is what is hitting, I'd consider that method, some of those shells don't offer much clearance.

gunrunnerjohn.... I will give that a try.  First, I"ll use the clay to see if that is the problem.

If it's like my conversion, the top of the bracket sticks up right into the top of the shell.  When they designed these things, they didn't plan on the decoder sitting up there.