Rivarossi motors test run - now closed - see new "For Sale"

[spookshow]

Hey Max, if you manage to turn this into a cottage industry I'll be happy to promote it on my website 

Cheers,
-Mark

[Cajonpassfan]

What an asset you are!  You never cease to amaze! 

+1 here!
Otto

[OldEastRR]

I do believe those engines used the same can motor, but I don't have any RR E-8's or C-Liners to confirm or test this.
Of course, once again, if somebody has a dead E8 or C-Liner they want a motor for, and can pull the motor and send it to me for the swap, we can find out for sure.  Just like for the 0-4-0 (which I have an order for now, so we'll know 100% for sure if it works in a week or two), all you risk is a little postage.  Anybody who isn't happy with their motor just sends it back and gets all their money back.

I believe there's a certain TRW member named Lee who has a veritable sea of ancient RR/Atlas locomotives of all types, a lot of them with dead motors that would be the candidates providing you with one of each kind of loco produced to test. You can find the guy on the Layout Engineering Reports board. 

[kiwi_al]

Hi Max,
Here's a picture of the Atlas / Rivarossi E8A mechanism where the motor fits.
The diameter of the hole is 14.75mm or 0.580 inches.
The outside diameter of the rivarossi motor is 14.44 mm or 0.568 inches.

I can fit the motor from the 4-6-2 into the E8,
The motor from the 4-6-2 O.D is 14.49 mm or 0.570 inches
There's a little bit of wriggle room with the motor size


Alister

[peteski]

One possible complication with the E-units is that the worm doesn't not have a hole in it to facilitate removal.  Instead, the endof the worm is reduced to a small nipple with a groove in it. That nipple is inserted through the bottom plate of the truck and it is the truck's pivot point.  The truck is retained by a clip which fits into the groove in the worm's nipple.  Also, the ride height is dependent on how far the worm is installed onto the motor shaft.

Alister, if you could, take a closeup photo of the worm, and also of the bottom of the truck (with the clip) when it is installed onto the worm.

[kiwi_al]

here you go. I had completely disassembled it - running out of finger power 

Close up of motor and worm


Close up of motor worm in truck no truck bottom:



close up of truck with plastic bottom on:



A bit fuzzy - using a cell phone sorry

[mmagliaro]

The truck cover puts pressure on the motor worm and armature shaft?  Man, that is a really bad design.  It
pretty much guarantees that the motor will never run as well as it should because something is always pressing
on the shaft.

Anyway...


So, unlike the steam locos, what keeps the motor together?  In the steam chassis, like the 4-6-2, the front edge of the can pushes up against the frame, and the rear plastic motor cover screws to the back of the frame, so the plastic cover cannot just pop off.

But it looks like the motor in the E8a just hangs there.  Even when truck cover plate is on, and it slightly presses on that little nipple at the end of the worm, that won't keep the metal can from separating from the plastic back.
Or is that worm pressed on so close that it actually rides against the nose bearing of the motor???

It is definitely the same basic motor.  I'm a little worried about one thing.  In some later versions of the motors I've been doing, I have started replacing that little protruding part of the can where the bearing is, and replacing it with a larger diameter brass insert.  This gives me more room to work with inside the can and makes it much easier to fit the armature in place.  It looks like this (below).  This fits fine in the 4-6-2, 2-8-2, and 0-8-0.  But if that motor and worm in the E8 work the way I think they do, I don't know if the brass insert scheme will fit.    I'll need to see the engine.

I could always make up a motor the original way, with the can's original front nipple.  But I'd really rather not.  The new scheme with the brass insert is easier to do, and it's easier to get the armature perfectly located inside the motor.



Here is that example motor in a 4-6-2:

[peteski]

My question is: how in the world would you remove that worm from the shaft?

[nickelplate759]

There are screw on the top of the chassis that hold the motor back in place.

[kiwi_al]

The little nub on the end of the worm is part of the worm. You'd need to use a different type of puller to get it off possibly.

[mmagliaro]

There are screw on the top of the chassis that hold the motor back in place.

Yes, I realize that.  But what keeps the front of the can from dropping down?  On the steam chassis, the front of the can presses up against the frame.  The E8 frame looks like it just has a big hole in it and the can hangs down in there.  The screws will keep the back firmly in place, but they don't keep the can from dropping.  And the worm/shaft goes THROUGH the front of the can, so pressure from the truck plate on the tip of the worm just pushes all the way through the motor  to the back.  I don't see what keeps the can from sliding down.

Peteski... yes, getting that worm off is going to be a nightmare.   I can envision all sorts of ways to do it if I don't care about saving the motor.  But even then, if I put that worm on a new motor, your stuck again and it can never be removed, which I don't like.

I guess I would drill out the tip of that worm to expose the shaft, and then use a regular wheel puller.   Assuming I'm replacing the motor, then:
-  leave the shaft a little long
-  put a bronze "hat" bushing in the truck plate hole and let the end of the armature shaft run in that,
-  The worm no longer has anything to do with the hole in the truck plate.   
It will probably work better that way anyway.

But I have a sneaky suspicion that there has to be pressure on the tip of the worm (or the armature shaft), because that's what holds the motor together.  In that case, use a CLOSED hat bearing in the truck plate, so the end of motor shaft is gently pushed on by the plate.  If I get one of these, I'll check it out.  I don't have a RR E8.

[kiwi_al]

I just noticed that I had missed posting a picture which should match up with what Max was saying.
The motor is held in place on the mechanism by 2 screws, the worm protrudes down into the truck and is locked to the truck by a brass or phosphor bronze locking plate which keeps pressure on the motor. The locking plate is screwed to the truck (screw is missing from the photo but you can see where it would go) Basically what Max was saying.

[mmagliaro]

Thanks, kiwi_al !

Well, there you go.  So  you drill out the end of the worm, and use a conventional puller to get it off.
When putting a new motor back in, my preference would  still be to put a "hat" bushing in that truck plate and let the end of the armature shaft run in it.

Now, the shaft is free from all those lateral pushing forces that were coming from that truck plate.

[kiwi_al]

No worries Max, Sorry it took so long to realise I had missed a photo.
I reckon you have it sussed !!

[mmagliaro]

No worries Max, Sorry it took so long to realise I had missed a photo.
I reckon you have it sussed !!

I just realized that in your first photo of the frame with the motor hole, at the bottom of the hole there are two metal "fingers" that protrude into the hole space.  I didn't see those before.  So THAT's what keeps the motor together.  Even better!  It makes me wonder why the tip of the worm has to run in that truck plate hole at all.  I guess the motor moved around too much or there was too much wiggle in the gear mesh.