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

[wm3798]

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

They LIST for those prices, they don't sell.  I've been following three, the lowest being $569, the highest $799.  All three have been eternally listed for at least the last 3 years.  I bought mine for under $350, obviously with the caveat that it's a bit of a fixer upper.

I suspect that actual market is around $400.  While they're lovely to look at, they aren't the latest tech, so they aren't really comparable to new release steam, highly specialized or not.  I wasn't uncomfortable with what I paid for it (although that was not the majority opinion here at the ranch )
and I'm not uncomfortable taking it apart and putting it back together.  But that's probably just me.

I'm sure if I put a fancy decoder and sound box in it, and added lighting etc, I might get back what I paid, maybe a bit more.  But I'm not here as an investor.  I like playing with trains!

Lee

[peteski]

Yes, due to the current fee structure for eBay listings, eBay is full of sellers listing their items for ridiculous prices hoping to sell them to somebody. As Lee mentioned, they just get perpetually relisted (sometimes for years).  Best way to look for actual prices is searching for ended listings which sold.

[u18b]

They LIST for those prices, they don't sell.  I've been following three, the lowest being $569, the highest $799.  All three have been eternally listed for at least the last 3 years.  I bought mine for under $350, obviously with the caveat that it's a bit of a fixer upper.

I suspect that actual market is around $400.  While they're lovely to look at, they aren't the latest tech, so they aren't really comparable to new release steam, highly specialized or not.  I wasn't uncomfortable with what I paid for it (although that was not the majority opinion here at the ranch )
and I'm not uncomfortable taking it apart and putting it back together.  But that's probably just me.

I'm sure if I put a fancy decoder and sound box in it, and added lighting etc, I might get back what I paid, maybe a bit more.  But I'm not here as an investor.  I like playing with trains!

Lee

Actually Lee.   I was referring to the passenger cars which someone asked about.

But you are correct, the loco is worth about 400 (Aaron said he would shoot for 350 with patience).   But the cars go for much more.

[u18b]

OK Lee.   @wm3798


 Here you go.
Aaron brought his over tonight.   Almost mint.  Very little run time.






Now, his grease was all dried up so I had to disassemble and clean and re-lube.

When I put power to the chassis with a 9 volt battery, it locked up.   The place it locked up is orange.



Here is what I noticed.  The hanger is very floppy.   It pivots on it's post (blue).   So if you can press in at the top of the hanger (red) that will make the bottom pull away from the side rods.

And the way you keep that top inward is with the shell.   The hanger goes INSIDE the shell.   




Aaron reminded me that when he got it years ago, someone had placed the shell on with a hanger on the outside.  We had to correct it.

Aaron's runs great now.

[u18b]

One other note.   Aarons gear was REALLY tight on the screw for the geartower.

I took the brass gear and reamed it out by a TINY amount.

[chessie system fan]

You're welcome, everyone.    One reason I volunteered is if this  gear is a weak spot in the model's design, I might as well  piggyback on Lee's order and get a spare gear now while we're troubleshooting.

[peteski]

Aaron's gearbox is different than the one in my S-1 model, but it looks like an exact match for Lee's (where mine is not identical).

I also noticed that the worm in Aaron's gearbox appears to be steel with the worm wheel being brass. That is a good combination which should not cause excessive wear.

[u18b]

One more piece of information.

Aaron and I played with pulling his passenger cars and mixed a few couplers (1025, 1015).

Conclusions:

The Cincinnatian cars really need 19" curves because of the skirting.  Anything less and they will derail.

We confirm what someone else said, that the locomotive is anemic.   We are running it without the traction tire (and didn't feel like installing the traction tire wheel) and as such it will only pull 3 of the 5 cars (my Model Power Pacific will pull 4 of them).    But there's another issue with the P7d.   I think it is too light in the nose.    There is a nose weight, but it is not enough.   The weight does not fill the nose- and it needs to.  What I was observing was that the loco would do a slight tiny wheely.   The nose would lift (which makes the drawbar to the tender dip).  When the nose came back down and thus lifted the drawbar, then the loco drawbar would lift the tender front end- and thus the tender would derail at the front truck.

So if I had one of these sets and it was going to be a runner.....

--I would drill the nose for a light
--then fill the nose with hot liquid alloy (like Cerrobend) and completely fill the nose (after doing tests with water to make sure there are no surprises) to add more weight up front.   I would add weight from the middle driver forward.
--run it on 19" curves.

[u18b]

Aaron reminded me I needed to mention something for clarity.

I said the gearbox screw was tight, but did not go into further detail.

So here goes.

--- The screw was so tight, I almost could not break it loose.  It was really torqued combined with dried out lube.

--- And when I did get the screw loose, I had a hard time getting the screw itself out of the gear.

--- When giving you measurements for the gear center hole... I couldn't measure the hole directly.   So I thought I would measure the screw.

I was surprised to measure that the screw was not uniform thickness all the way across.   It was thinner right near the head (which is where the gearbox is) and fatter near the threads- which is where the gear spins.   Combined with the fact that I could not easily get the screw threads through the gear hole, I concluded this was too tight and would add friction.  So I used my reamers and opened up the gear hole just a tiny amount.   I estimated that I opened it up 1/100 of a millimeter- which was just what it needed.

This is interesting because Aaron's P7d is almost new.   It made me wonder -- assuming your gear might be similar-- if it was a contributing factor to the destruction of Lee's gear, because of this higher level of friction.

[ATSF_Ron]

Lee, I'm in the camp of "never again" when tearing into brass locos in N scale.  I've had to work on several, the worst being a Key AC6, which I ended up returning.  It was a bit of a dog to disassemble and reassemble.  My hat is off to ya!  Good luck with this one.

[learmoia]

Similar example, although not as severe as Lee's example.  But all those brass shavings (occurring even when lubricated) tell the story.

Ooo it looks like my transmission pan when I change the fluid

[wm3798]

I finally opened her up again to inspect the worm gear.  It appears to be fine.


Then I got all excited about finding a repository of more gears, and I had one that looked pretty close.  I was wrong.  The diameter was a hair off, probably 6.0 mm as opposed to the 5.98 mm that Ron measured.  The gear count was also sufficiently off to be problematic (18 teeth as opposed to the prescribed 22).  I tried testing it with a few revolutions of the worm using a low speed drill.  There was enough torque to overcome the friction, but it ended just chewing the plastic gear up.  It never would have worked with the stock motor. 



So after another bout of "close but no cigar" I've resolved to pursue the Polish Gear Works.

Hopefully the replacement bits will get this charming shelf queen back on the rails.

Lee

[peteski]

Yes, the modulus of teeth (their spacing or pitch) was off.  Similar to trying to thread wrong size bolt into mismatched (but similar diameter) nut.  like 5/16"-18 and 5/16"-24. You can force them together, but the threads will be damaged.

[mmagliaro]

I'm sure the diameter was fine.  .02mm isn't even .001".    It was the count of the teeth.  At that diameter, it HAS to be 22 teeth or the mesh will be wrong.   You could get a .25 mod gear that is 21 or 23 teeth, and as long as it isn't too big or too small for the teeth to engage properly, it would still work.  But the mod is the mod.  Can't get away with that one.

[wm3798]

I finally pulled the trigger and ordered the replacement gears. I went with the size closest to the specs provided, 1mm thick, 1.5 hole, 6mm diameter, m22/25.  I ordered a couple of brass ones and a couple of plastic.  Fingers crossed that these will be the cure.

Another modeler has asked me to piggyback one for him as well, which will help defray the overseas shipping.

I have no idea how long it will take to get here, so don't hold your breath waiting for an update!

I'm hoping it arrives in time to take the engine to N Scale Weekend to show it off.

Thanks again for the guidance.
Lee