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Hello, I am one screw short of a full deck, eh, engine rather.  I got an auction diesel disassembled which is not so much an issue as it needs some wire repair, but it only has three of the four screws.  Below is a picture of the engine (Ajin) and screw.  Any suggestions of what this is and more important where I could order some?

Thanks

RobbinEnginescrews

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Last edited by Robbin
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Not to be overly nitpicky, but this is a phase II E7.  The spotting features are the roof vents in lieu of fans, the lack of a continuous filter grille along the side, the vent compartment behind the door, and specific to a late phase E7 are replacement of paired windows with vents.  Much like the F3 built during the same period, the E7 was an evolution of design specifications that changed quickly from the E5/6 prewar locomotives to the E8s of late 1949.

As for the screw, have you tried looking at the brass screw section at Ace Hardware?  I have found more than one good match going through the miscellaneous bins of brass screws.  I believe Overland imported a lot of Ajin product.  The trainphone antenna gives it away as a PRR prototype.

A great find!  Enjoy!

Last edited by GG1 4877

Robbin, get your hands on a SAE/METRIC screw checker, …..nice ones around 10 bucks on popular shopping venues, ……Working with brass models, the need for screw identification will be almost commonplace……save yourself a big headache and look into one!…So while you’re shopping for Pete’s recommendation, stick a screw checker in the cart too…….😉

Pat

Thanks GG1!  When I was writing I was struggling to figure out what I had bid on (and won).  E7 is great!

And yes this was sold with a huge number of Overland models but this one had no box, so it makes sense (and I assumed, hoped) it was an overland model.

And right again on the PRR as there was a ton of PRR engines.  All brass.  I tried to get a few but this was my only success.  My first diesel two rail to go with the steam fleet!

Should be fun to get this running.  Looks like it has been quite some time since it ran so need to lube and such.

@Robbin posted:

Thanks GG1!  When I was writing I was struggling to figure out what I had bid on (and won).  E7 is great!

And yes this was sold with a huge number of Overland models but this one had no box, so it makes sense (and I assumed, hoped) it was an overland model.

And right again on the PRR as there was a ton of PRR engines.  All brass.  I tried to get a few but this was my only success.  My first diesel two rail to go with the steam fleet!

Should be fun to get this running.  Looks like it has been quite some time since it ran so need to lube and such.

I like the E7, especially for PRR as they lasted in some cases into the Conrail era with NJDOT.  They pulled the great limiteds all across the PRR system into the PC years and closed out their days in the more mundane duty of commuter service.  There are even a few photos of PC E7s in early Amtrak service.  E8s and E9s often get all the glory, but the E7 more than proved its value and is indicated in the numbers produced with 428 A units and 82 B units compared to 450 E8As and 46 E8Bs.  The E9 while the most powerful and modern of the E units only had 100 As and 44 Bs built.  Just evidence that both passenger service was starting to decline, and the cab unit era was nearly its end.

While many E8s/E9s exist, the only surviving E7 is the PRR one in Strasburg.   



Does your model have the nose mounted lift rings?

Brass trains have historically been almost exclusively imported since the 1950's staring with Japan, Korea in the early 1980's, and then to China near the turn of the century.  It makes complete sense that all the screws would be metric.

Japan adopted the Metric system in 1868, so they have had a little more experience than us here in the world of nonsensical imperial units.

Yes it has the PRR standard nose left rings.

I have another question though.  In the gear lube effort they have a gear box on each axle.  Anyone have experience opening these up or a video somewhere?  I did the gear tower last night.  Would have been easier if I was willing to replace the tubing in the drive.  Any ideas on what to order to replace the tubing (is it rubber?)?  I would think this is pretty standard in working on these engines from the look of the drive system.

This model may have never run.  It looks like couplers were never installed.  I ran it and it is doing okay but I would like to add new lubricant everywhere as I have read they did not come lubricated from the factory.  The tower however did have oil inside or some kind of lubricant that I cleaned out before putting in some Labelle (102 I think?) gear lube.

I'm not sure what the tubing is, but the one time I had to deal with one of those coffee grinder drives, I figured out the parts to convert it from the vertical gearbox to a toothed belt drive. The axle boxes come apart in halves, there will be some fiber or plastic shim washers keep track of the count and the location. Its best to service one axle box then move to the next.  If you clean out the old grease, you can replace it with new, reassemble and spin test the input shafts to make sure they run free. Note the position of each gearbox as there is an inner, middle and outer axle box for each truck. The trucks also benefit from adding pickup wipers in order to get 12 wheel pickup, instead of relying on the truck sideframes to pass power.

Thanks on the suggestions!  I will proceed with the truck axle gearboxes carefully.

And thanks for the suggestion on the wipers.  I may have been seeing some issues already but had assumed I needed to clean the wheels or test track.

Yes the surgical tubing looks like it would replace what is there.  I will take the calipers and figure out what ID is required.

My father at 82 does all my mechanical work for me because he enjoys it a lot more than I do.  On an Overland P5a, he replaced the tubing with fish tank tubing much like he's done with HO brass with similar drives.  He did not take the gear boxes apart though because they had signs of cracking and didn't want them to break.  Thankfully it runs, but best practice is to take out the old grease and use modern lithium greases and then these less than stellar drives do run much better.

More than any other class of PRR passenger diesels the E7's appearance changed noticeably over their long service lives. The wire steps up the right side of the nose on your model date it to 1960 or later.  An earlier prototype detail change relates to number boards.   As built PRR E7 A units featured somewhat small "streamline" number boards.  For reason of visibility in the mid 1950's PRR shops began retrofitting distinctive large rectangular stand-off number boards to the E7's.  Overland E7's came with a parts bag that included number board castings to model various eras. To detail, paint, and letter your model in a prototype fashion you'll need to do some research.  IMO the best source for info and dated photos on PRR E7's is PENNSYLVANIA RAILROAD Diesel Locomotive Pictorial Volume 7 - EMD E Units and Alco PA's by Paul K. Withers.

Thank you all for the great information!  
I finished the removal of the old grease and was test running.  There seems to be a bind and it seems like it is in the vertical gear box.  I’m going to disassemble it tomorrow and clean more thoroughly.

i looked briefly at replacing the vertical gearbox like boiler maker mentioned.  Any thoughts on where to find toothed gears and belts? I looked at 3d rail site but they didn’t list parts.

Thanks Ed!

my model came without a box and so no parts like number boards either.  I will see about making modifications before painting (not that I have painted anything but I do have some spray guns).  The model needs at the least windows and headlight lens (and headlight I think) to finish it off.  Oh and couplers!

Quite the adventure.  I will be more careful about what I get myself into but you dont know what you dont know.

Thanks again!

a couple comments on the drive train: Toyota #0 tubing has worked well as a replacement tube. it has a fairly thick wall section. I used it on an Overland P5a boxcab engine as replacements.

To convert to a cog and belt drive, try 'Stock Drive Components-Sterling Instruments' (SPD/SI). I've used them for rebuilding Weaver drives and have sourced cog and belt parts from them. They have a utility that helps figure correct sized belts for their cogs.

There are other robotic parts suppliers that will also have the components needed.

Great!  Thank you so much for the recommendations Chris!

I worked more on the vertical drive train (pictured below) and the axle worm gear (transfer?) cases.  I found that the old grease was really stuck on the gears and what I had done was not sufficient.  And one of the axle gears was binding which I am in the process of trying to fix.

So working it.

AxleCase1AxleCase2AxleCase3AxleCase4FirstCleaningDriveSystemVerticalDrive1VerticalDrive2

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@PRR Man posted:

a couple comments on the drive train: Toyota #0 tubing has worked well as a replacement tube. it has a fairly thick wall section. I used it on an Overland P5a boxcab engine as replacements.

To convert to a cog and belt drive, try 'Stock Drive Components-Sterling Instruments' (SPD/SI). I've used them for rebuilding Weaver drives and have sourced cog and belt parts from them. They have a utility that helps figure correct sized belts for their cogs.

There are other robotic parts suppliers that will also have the components needed.

Hi Chris

could you point me at robotic suppliers?  I am interested in upgrading the drive train.  I have worked over the holidays at freeing up all the gears but the main tube connecting the motor to the vertical drive still slips occasionally.  The SPD/SI site is fabulous!  I just dont know where to look for similar U joint drive components (like the ones below the chassis) that would direct connect the motor to the gear tower.  North West Short Line offers some drive connectors but I would need to add a screw, which I can do, and move the motor, which I can also do.  But I dont know any other suppliers so it would be great to see what the robotics suppliers have.

Thanks!

@Robbin posted:

I worked more on the vertical drive train (pictured below) and the axle worm gear (transfer?) cases.  I found that the old grease was really stuck on the gears and what I had done was not sufficient.  And one of the axle gears was binding which I am in the process of trying to fix.



AxleCase2AxleCase4

I have found that Deoxit D5 does an excellent job cleaning out old hardened grease.   Spray it right out of the can with the tube attached.  No scrubbing or wiping required.  Everything will come out quite clean

Last edited by John Sethian

Quick update, I was still having the drive train bind and the motor coupling just spin.  I narrowed the issue down to the center truck gear box.  I had just kind of taken it apart previously but with this issue I took off the couplings (the silicon tubes) and completely disassembled the gear box.  What I found was that the worm gear that drives the axle (gear) had old grease just glued on the bottom of the gear.  I had to take a tooth pick and a decent amount of force to dislodge it.  So with that finding I will go back and make sure the other axle gear boxes are cleaned out.  I did order the deoxit (liquid) so if it gets here soon I will see if it helps.

@swrr posted:

Thank you for showing the disassembled gear tower.  Very useful photo.   If this were my project I would just get rid of the gear tower and modify the chassis to allow for placement of a Pittman 82xx to be placed in the fuel tank with direct drive. Just my two cents.

Except that it appears that the vertical gear tower effects some speed reduction (because the second gear in the stack is a compound gear.)  If you really want to replace it with a belt and two pulleys, you should make note of the gear ratio, so you can recreate it by using a larger pulley on the bottom.  I'm curious to know the overall gear ratio from the motor to the wheels, which takes into account the drop-down tower AND the axle gearboxes.

IMO the original Ajin design is sound.  "Tank drives" like this are probably the most common arrangement used in 2-rail O scale diesels.  None of the gears in the vertical tower appear to be cracked, so the bind you mentioned is possibly a split axle gear (which is a little surprising because they appear to be metal gears.)  You could test this theory by separating each gearbox from the lower shaft, and twirling the input shaft with your fingers for one complete revolution of the driving wheel.  Please post back again when you find the cause.

Hi Robbin. First suggestion would be to replace all the screws with blackened metal metric of the proper size. They are magnet friendly unlike brass a make working on the engine 100 times easier with a magnetic screwdrivers. I have a number of older Ajin and NJCB engines all switched.

My second suggestion is to replace the innards of the gear tower with sprocket and chain. I did this on a friends Oriental SW1. This resulted in a quiet and smooth drive at normal switcher speeds! He loves the speed and quiet. Follow the pictures and listen/watch the videos for the difference  

https://youtu.be/_--SYkDbQQU?si=3FGkKNLqnGaJvMAh

https://youtu.be/WUe1Q59vUwo?si=z6b_PMn4ZRpfY0zj



Peter

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I forgot I had these but did not upload them to YouTube. This is an iCloud link that should allow you to see them. It will "go away" in 30 days.  I think you can copy them if you need them for some reason.  


https://share.icloud.com/photo...whne7zGP1giy5G_hXE9Q


My friend is a DC guy. I’m pretty sure I could get a smother dead slow speed with a decoder.  The gearbox is now quiet enough to be inaudible with sound. Also, in that one where I did top speed you should realize it’s track glued directly to plywood causing the noise.

Oh, if you spend a lot of time working with older brass and especially with DCC do yourself a favor and use an S shaped test track.  I spent many hours working on an engine using rollers and my short straight test track to get it perfect, only to have it short out on the first curve it reached on the layout!



Peter

Last edited by Peter E B

Not really, George. You’ll note the Oriental tower is made in three pieces, the center one lucite.  This made removing a little material to make room for the chain easier.  Th Ajin one pictured here is only 2 piece and would need machining and maybe a small spacer piece in the center to add width for the chain, not a project for anyone without a milling machine and experience.

Peter

Thank you Peter!  I would love to do a replacement of the tower like that with chain drive.  In general it would be valuable (and honestly fun) to get the machinery to do all this.  Chris posted a site that has belt and gear components (and a lot of good info).  Is that where you get your parts?

It would be great to change the gearing a bit from the current ratio as I tend to like to run super slow crawl and not really go at a scale top speed (dont need to make time over my small ovals ).

I have put the model away for the moment but would gladly bring it back to the bench.  It took quite a bit of time but I worked out all the binds and it is running pretty well.  But it does not crawl like I would like.  Since I seem to be buying used KTM and Overland brass remotoring and gearing and drive train work is of a lot of value.  I just bought a little book titled Upgrading The Running Performance of Your Brass Steam Locomotives from NWSL.  So I am looking for information like what you have posted here.  Thank you again for sharing that and taking the time to document it.  For me, this group is just such a great thing!

Thanks on the screws, yes I have been replacing with black and my screwdriver set has a magnetizing magnet that makes working the screws so much easier.  Great tip that I just stumbled on.

Also thank you for the test track idea.  I have only a 36" gargraves wired for two rail or three rail (as I am still running both) but it is straight.  Will look to expand to curved as well.

Cheers!

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