SL Loco Tune Up a how to

johnreid · SL Loco Tune Up a how to

No, I am not an expert on this, but since I have been doing all of this recently and found that each step has made a significant difference in the operation and performance of my SL3 Loco, I thought that I should share what and how I have done.

First off, for American Mamod Railway Enthusiasts, track is an important item. For 32mm Locos, O Gauge for us Yanks, Lionel track is abundant. IT can be found inexpensively on Ebay or at Yard Sales. However, there are two basic varieties of Lionel track, O27 which was for tintype toys, and Standard O Gauge track. The height of the rail is different and makes a big difference, go for the Standard and avoid the O27 if you can as I have found O27 to be problematic for several Cars and some Locomotives.

Note the difference, O27 is on the Left

Now, before the Loco can perform pn the track, it has to operate without leaking Steam and Priming like mad. There are two things that need to be addressed, the Cylinder/Port Face surfaces and the Reverser Block surfaces. Both are areas where Metal to Metal contact is made and a seal has to exist. If those surfaces are not perfectly smooth, they will leak.

Notice that the Cylinders are held on with four screws, the two front screws are threaded into the Reverser Block and the rear two are threaded into Nuts. You need to remove all four, but take care to hold the nuts as the screws are removed, I used Needle Nosed Pliers, but I suppose a spanner wrench could be found that would fit into the tight space inside the Loco Frame.

The Cylinder removed, note the Gasket on the frame, the idea is not to damage it.

Remove the trunion screw and the cylinder comes apart from the Port Face

Now for the Lapping/Polishing step. I use a piece of 1/2" Plate Glass that is perfectly flat, it is imperative that whatever you use be PERFECTLY FLAT, wood will not do, maybe a piece of machined metal might do. I lay a piece of Wet and Dry Sandpaper on it, I first use 600 grit, then 1200 grit then finish off with 2000 grit ( sandpaper this fine is sold at Auto Body Suppliers ) I then use a Sharpie Pen and blacken the surface to be lapped, this way I can see the progress I am making, I do the Sharpie trick for each grade of sandpaper and often I redo the Sharpie while still in the same grade of paper. You can see the progess you make this way.

Then while holding the sandpaper perfectly flat on the glass I move the item to be polished on it FLAT in a CIRCLE or FIGURE EIGHT pattern, do not just go back and forth like you are sanding a piece of wood.

This is repeated for both Cylinders and Port Faces. When done they will have a mirror finish.

Next is the Reverser Block, the screws holding it in place are already removed as you have not replaced the cylinders yet.

Here it is before the second cylinder has been removed ( I did not remove the second cylinder as the surfaces were already polished on this engine so why take it further apart than needed )

You also need to remove the trunion screw for it also and once removed the Reverse block both comes apart and is easily removed from the Loco Frame. Behind the Reverse Block is a round piece of metal that retains the O Rings that seal the Steam Line and the Exhaust Line. The trunion screw presses the circular piece of metal against the Reverser Block and compresses the O Rings, sealing the Steam Line and Exhaust.

I then repeat the Lapping and Sharpie process on the parts of the Reverser block

Reassemble the Reverser Block and the Cylinders to the Loco and then proceed to do a test run, you will notice a considerable improvement over the leaky Loco you had before. Note that I use one hand to hold the sandpaper flat on the glass and the other hand to handle the parts to be lapped, When taking these pictures I did not have use of both hands as one hand was holding the camera.

I also have found that the three wick burner as sold by Dream Steam or Forrest Classics is essential.

image taken from Dream Steams Page http://www.dream-steam.com/upgrade_parts.html

I have not added a Regulator to mine or the uprated Safety Valve or Top Off valve, maybe someone else can show how to install them.

rangerssteamtoys

Very nice step by step process John.

I would think that a uprated safety valve would be easy to install, just screw it in ( or is there something that I missed). Maybe modify the existing safety valve.

johnreid

The Safety Valve wold be an easy job, mentioned as most people do that, if ordering a 3 wick burner, get the SV at the same time.

I believe the Regulator is a bigger but not overly difficult task.

Graham-Jilly

John that was a great description with pictures

I agree with you on the figure 8 polishing motion as that is how I was taught to polish when I did my course in polishing fiber optic connectors but we used finer paper than that tho measured in microns

my only concern is with the addition of the uprated SV is that I found that the increase in pressure came an increase in temperature for making the steam and I lost many sight glasses so be careful going down that path.
any way great work John Im glad you are sorting it out

johnreid

Thanks for the information. I have not pulled any trains with it yet, but it seems to run well by itself with the factory SV.

Mamodman123

Can I just add that there is another surface on these locos that leak like crazy and thats between where the reversing/regulator block meets the chassis frames, there is no gasket there and its just metal to metal contact.

That is an often overlooked area on these locos and one that often leaks more than any other.

CuriousSteam

Thanks for that John, I did lap the faces of all metal to metal contacts. It helped alot!!! I see my issue now. The track!!! I have the 027 and it just keeps wanting to derail. I made a burner for it and it works well for now.

johnreid

That would be a difficult area to lap too, any tips MM?

paul_c

The only way to keep it on the track is to dump the standard wheels. A set of cast steel wheels is a must, if you do no other mods to the loco this is the best one. Derailment problems all solved due to deeper flanges on the wheels and extra weight down low.

metalhead100

Nice work John.......Like the sharpie idea! beats that damn blue layout dye any day....

As for all the leaks and problems...... did Wilesco make these engines?

See they are all the same....they all need tinkering....

Jim

rangerssteamtoys

johnreid

Deeper flanges on the wheels would make O27 even worse, so avoid O27 track. The only derailment problems I have are with the two O27 turnouts. One of which I have spent too much time trying to modify to enable it to work.

Graham-Jilly

CuriousSteam

I am seeking some o gauge track at the moment. I hope this solves my derail issues. If that don't work I'll have to look into different wheels.

johnreid

Some Ebay Auctions will say O42 or O72 as an indication of what the curve radius is. For some reason the Lionel people do not know the difference between Radius and Diameter so they will say 42" diameter is 42" radius. For the Mamod, the 43 works really nice and one could still run a Bowman 234, however the 72" sure looks the best

Stitch

Great thread John

I have been meaning to get around to lapping some poorly performing engines but didn't have the confidence. After reading your great outline above, I will now give it a go.

kk

Hi John,