Can I fix it? Brass B&O P7 Pacific by Key

[wm3798]

This is the stuff of nightmares for me.

I've been able to do repairs on my Blackstone running gear and I've torn N scale Bachmann and MDC engines down to rebuild like this, but brass... You're a braver man than I, Lee.

I just take the advice of an old carpenter I used to work with.  If someone put something together, someone else can take it apart. 

The keys to success are:
Figure out which ghost you're chasing, be it electrical (is the juice going where it's supposed to), mechanical (is something binding or in the wrong place), or elemental (is the motor shot or a part missing).  In this case it's a mechanical and elemental... there was a bind in the valve gear that caused the main gear to get ground off thus needing replacement.

The next key is make sure you keep your eyes on all the bits as you disassemble.  I work over a shallow cardboard box, in this case it was the lid of the engine packaging, which had a nice yellow foam insert.  Keeps everything from bouncing too far and visible.  I also have a shallow cat food box with a piece of felt in it that I put on the workbench.  Plenty of light is also essential.

Separate the subassemblies into groups so you have at least some idea how the damn thing goes back together.  I'm pretty pleased that each subassembly I've come across here has different size and style screws.  Very easy to identify what goes where.  This is especially important with springs, because the spring that floats the motor housing is not the same size or tension as the spring that keeps the pilot truck on the rails.

and finally, even if you're not done-done, if there is an extended break in the action, such as dinner or turning in for the night, it's a good idea to put the engine back together before you step away.  You might not get back to it as quickly as you thought, and your recall of which bit goes where can rust faster than a sawblade left out in the rain.  There's also the off chance that Mr. Cat will decide that something on your workbench needs to be pounced on, and it's best if all those fiddledy bits don't get scattered across the room while you slumber.

It also helps to be a little fearless.  Keep in mind that you're not walking a tightrope here, and even though the task seems daunting (cost of the engine, difficulty finding replacement parts if you launch something, etc.) it's really just a little puzzle that needs to be worked.  Oh, and also take a moment to marvel at the folks in those Korean sweat shops that put these things together.  They deserve our respect.  They are the equivalent of the clockmakers of old, assembling dozens of tiny precision parts into something that is not only beautiful, but functional.

Back to work now!
Lee

[chessie system fan]

I got all excited because last night while I was rooting through the last boxes of stuff from the storage unit, I came across a bag full of brass engine bits... looks to be frames and parts from two USRA Mikes, I think.  Sadly, there were no gears.  I believe these came to me from the DKS collection, and I think he had scavenged them to use in a scrap yard scene.  There's not enough there to complete a working model, and the drive train bits there are not the same as the bits I need.  Oh well, back in the bag until the right diorama or module comes along.

Those actually came from me.  The Key mikes had been submerged in salt water during Katrina. I had bought them at a train show a few years later for $15.  I still regret not getting the HO Bachmann connie and the RR 2-10-2 the guy was selling for $5 each.  Someone on the Atlas board (I forget now who) kindly ran them in his ultrasonic cleaner, which made a big difference.  I sent them to you when you were soliciting victims for a scrap yard scene for one of your articles.   

[wm3798]

Ah yes.  I remember that now.
Well, they're still waiting for their moment in the sun.  Thanks for that reminder.
Lee

[mmagliaro]

By your measurements, yes, that would be a module 0.25 (not 2.5). gear.    But like Peteski, I am extremely doubtful
that it is that fine.  It sure doesn't look that fine from its appearance.   Can you possibly measure the outside diameter of the DRIVER gear, with calipers, and count its teeth?  At least that will tell us for sure if you got the mod right.

If that turns out to be correct...
Mikroantriebe does appear to have it...
https://shop.kkpmo.com/product_info.php?info=p474_gearwheel-pinion-m0-25---22teeth-od-6mm.html

Make sure you choose the correct width (thickness) and bore (1.5mm).  They have it in acetal white (delrin) or brass.  I would go with the plastic.  Maybe also get one in 23 teeth and see which is the better fit.  As long as the module is correct, it does not
matter how many teeth it has (there will be no gear ratio change).  You just want the gear that fits best between the worm and the axle gear.

And yeah, I'd also bite the bullet and get a few of each size, just in case there are other problems and it jams or somehow damages the new gear.

About 4 Euro each , $4.29 US.  Plus shipping.  Expect that to be somewhere between $5-$10... it's not bad even though it's all the way fron Poland.

The also have a full custom gear option for more like $7.68 EUR
https://shop.kkpmo.com/product_info.php?info=p21680_spur-gear---customized-gearwheel.html

That lets you choose black acetal if you want it.

[u18b]

Chessie System Fan is coming over this weekend.  He has a P7d in almost new condition.
We plan to take it apart and get some photos and measurements for you if they could still be helpful.

[wm3798]

That would be terrific.
As you can see, I can only estimate the diameter of the gear.  Having a good one to measure will be ideal.

When I put together the order, I'm planning to get the plastic gear for durability.  Shall I order a couple of spares?

Lee

[mmagliaro]

That would be terrific.
As you can see, I can only estimate the diameter of the gear.  Having a good one to measure will be ideal.

When I put together the order, I'm planning to get the plastic gear for durability.  Shall I order a couple of spares?

Lee

YES....   If you have any sort of mechanical "accident" while you are fixing this thing and the plastic gear is somehow damaged, it would be really nice to have spares.   Also, if you have anything else that you need a gear for, this would be the time to measure it and get them all in the same order.

[peteski]

Ok, in the name of  friendship I took apart my Key Imports PRR S-1 loco.





Looks like they realized that material other than brass should be used. Look like nylon.  Notice that there are no shavings in there, and this is a well used model.

That gear (and the gear on the driver's axle) have skewed teeth (matching the worm's angle).
The gear is 5.98mm in diameter, and 1.80mm thick.  It has a 2.0mm bore and 22 teeth.

[wm3798]

Thanks, Pete!

[spookshow]

That makes me wonder if somebody replaced the gear in one of those two. It's not like there were multiple production runs of these things.

-Mark

[Jimbo]

That makes me wonder if somebody replaced the gear in one of those two. It's not like there were multiple production runs of these things.

-Mark

To which model are you referring - Lee’s P7D or Pete’s PRR S1?

[spookshow]

To which model are you referring - Lee’s P7D or Pete’s PRR S1?

Oops, my mistake. I missed the fine print and thought they were both P7D's.

-Mark

[brokemoto]

I have been driven to try things in this hobby simply because the alternative, doing nothing, guaranteed me that I would have nothing.  If I at least tried the daunting task, if I succeeded, I had something.  If I failed, I was in the same place as I was when I started:  I had nothing.  I had nothing to lose by trying and everything to gain.  Aside from that, several hundred bananas is too much to spend for a Yard Queen.

Bravo for going for it, Lee!

Whi-i-i-i-i-i-i-le you have the thing in pieces................................................

Many years  past, a guy who had a hobby store, had one of these.  Many of the posters here will be acquainted with him. He was (and still is, assuming that he still is alive) a straight-up, honest guy.   I had the money for it.  Said dealer warned me away from it.  He told me that it would barely get out of its own way, never mind that it would not pull the cars that Key sold for it (which he did not, at the time, have).  If you can get the gears, you might want to figure out a way to improve its pulling power, be it acquire a tired driver set or re-distribute the weight.

Mind you, I have no experience with this item.  I only pass on what the previously referenced hobby store owner told me. .  Never have I seen one of those things run.  I have seen several offered for sale. I did not buy any because of the dealer's warning.  Only once have I seen the cars for it.  Some guy was running them on an N-TRAK layout at some show somewhere.  He had a pair of Kato F-3s that were pulling them.

[u18b]

I have been driven to try things in this hobby simply because the alternative, doing nothing, guaranteed me that I would have nothing.  If I at least tried the daunting task, if I succeeded, I had something.  If I failed, I was in the same place as I was when I started:  I had nothing.  I had nothing to lose by trying and everything to gain.  Aside from that, several hundred bananas is too much to spend for a Yard Queen.

Bravo for going for it, Lee!

Whi-i-i-i-i-i-i-le you have the thing in pieces................................................

Many years  past, a guy who had a hobby store, had one of these.  Many of the posters here will be acquainted with him. He was (and still is, assuming that he still is alive) a straight-up, honest guy.   I had the money for it.  Said dealer warned me away from it.  He told me that it would barely get out of its own way, never mind that it would not pull the cars that Key sold for it (which he did not, at the time, have).  If you can get the gears, you might want to figure out a way to improve its pulling power, be it acquire a tired driver set or re-distribute the weight.

Mind you, I have no experience with this item.  I only pass on what the previously referenced hobby store owner told me. .  Never have I seen one of those things run.  I have seen several offered for sale. I did not buy any because of the dealer's warning.  Only once have I seen the cars for it.  Some guy was running them on an N-TRAK layout at some show somewhere.  He had a pair of Kato F-3s that were pulling them.

They are expensive, but they appear fairly regularly on ebay.  They tend to go for 500-700.
Like now.

https://www.ebay.com/itm/335439751145

[peteski]

Oops, my mistake. I missed the fine print and thought they were both P7D's.

-Mark

I received my S-1 as a gift from a friend who I'm sure bought it new from a dealer (many years ago).  I doubt the white colored gears are replacements.  I suspect that Samhongsa eventually realized that they needed to make the gear from a different material than the worm.