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Discussion Starter · #1 ·
My Garratt was acting a little sluggish so I looked it over and found that the eccentrics were worn
The eccentrics and valves are from Rubys. One was from an an old Ruby I had and another from a kit.
I guess I must have run them in an abrasive dust situation because I think I had lubricated them well enough
In any event they needed work.
Accucraft valves should have a 4 mm of travel and one engine was at 3.5 and the other at 3.0 - OUCH !
I had used ball bearing eccentrics on my scratch built stuff but wasn't sure how they would work with the small Ruby wheels so I had the goal to match the size of the original eccentrics
I had some 12 x 18 x 4 skate board bearings I got on eBay

The first step is to mark the wheel position and then remove one wheel


Here are the components of the stock setup. After the snap ring and link are removed, you will find that the bearing fits right over the 12 mm shoulder

Accucraft has two styles of links, one is stainless and the other has a brass bushing if you look at the right side of the lower one the wear is apparent

The outside race of the bearing is 18 mm or about .706". I took 3/4" round and bored it out for the new link end

I got to within a thou or two and then cut 1/2 thou at a time to get a press fit with the bearing

The sleeve is now too thin to part off so I turned a wood dowel to a press fit and inserted it in the sleeve for support

Here are the new bearings and the link rings

The bearing is set on the bottom link and the cut off line is drawn. the upper link shows where the cut will be


I cut just shy of the line and then grind the curve to the curved line

The ring is silver soldered to the link stem and the bearing pressed on the ring

Here they are in action. The size was so close to the original that only minimal valve adjustments were necessary

The second engine was a little more challenging. This was equipped with a single eccentric and a non-bushed link
The single eccentric has a cover screwed on to either side into holes that are 90 degrees offset.
The covers allow for the narrow factory link but needs to be opened up for the bearing
also, without the bushing, the step diameter is 13.5 mm which needs to be turned down to 12 mm

I took .050 off of each side of the eccentric and made these spacers to go between the cover and eccentric
You can see that the holes in the spacer are a little bigger than on the cover for clearance
You can see where I turned the step on the cover down to 12 mm (shiny part)


Here is the finished project

If you really feel ambitious, you can tighten up the linkage
If you look at the small hole on this crank, you can see it is worn and elongated
The play is only a few thou but while it's apart.....

The pivot pin is 2 mm and is drilled out with a bit which is a few thou under 2 mm
The worn hole is drilled out with a bit slightly larger than the widest measurement of the existing hole

A new pin is turned on the lathe out of 1/8" stock for a press fit into the link and a slip fit into the crank
Note that the stem of the link has a slight countersink to aid the peening process
Note the dimple in the top of the pin for this purpose.

A blunt punch is used to peen the pin in place
 

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O.K., now that is impressive! My C-16 eccentrics are so worn and I've biased the timing so much towards forward, to take up the slack, that it won't run in reverse. I'm giving this a shot. Thanks Bill, Great job!
 

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Posted By seadawg on 14 Aug 2013 05:58 AM
O.K., now that is impressive! My C-16 eccentrics are so worn and I've biased the timing so much towards forward, to take up the slack, that it won't run in reverse. I'm giving this a shot. Thanks Bill, Great job!

That's cause your C16 drinks too much booze!
 

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Neat idea Bill.

I had replaced those pins on a friends loco also as they too sloppy. I ended up with a press fit on the rocker so it was more stable. The original one was too small for both holes and would wobble on both wearing them to a much smaller diameter.
 

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Discussion Starter · #7 ·
Jason
My pins on the rockers were ok but that is another fix for sloppy valve gear.
There are plenty of bearings on eBay. I think I paid about $2 each but I saw this on sale last night
http://www.ebay.com/itm/10pcs-12-x-...Control_Parts_Accessories&hash=item5659559ec3
$5 for ten - WOW
Saturday we are going to see if this will work on Eric's Shay which Henner is rebuilding with the same problem - bad eccentrics
 

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Awesome! I would imagine all the clearances would be sufficient around the eccentrics on the Shay. But, like you said we'll have to see. When Henner started the rebuild I seemed to remember that you had done ball bearing eccentrics before. Nice to see this write up.

Regards,
 

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Thanks for the tutorial--my Accucraft 3-cyl. Shay suffers from the same situation.

Those replacement parts should be inexpensive for a quick repair, but Cliff has told me they are not available.

Larry
 

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Larry, I would imagine this is a common problem. My 2 cylinder Mich Cal Shay is one of the earliest examples around (serial number 13). It always ran very smoothly. Finally the wear seemed to reach a tipping point and it began running very roughly. An examination of the engine revealed the incredible amount of slop in the eccentrics. There is wear and slop in other areas but the eccentrics seem to be the worst. I consider the Shay and C-16 to be some of Accucraft's greatest achievements. It's a shame that they do not have parts support for these great engines. At this point there is an aging population of these locomotives so perhaps we could gather enough voices to have them add the parts to the E Store. Regards,
 

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How many hours of running does it take to wear these eccentrics like that?
 

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Discussion Starter · #13 ·
jim
I don't think there is an answer to that
Mine wore out much faster than I had expected.
I think it depends on the lubrication and dirt/dust in the moving parts
The speed you run at makes a difference also
 

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I agree with Bill. I've found the biggest issue with wear is grit getting mixed with the oil. I used to run exclusively on ground level track and would clear the track with sparkies pulling a home made cleaning block to clear mulch and the battery loco wheels would cut any sedum or ajuga or what have you that crept over the track. What I have discovered is that any plant or weed that will brush on the loco will transfer grit that has bounced upon it from the rain or wind. I now trim back ANYTHING that comes close to touching locos and rolling stock with a string trimmer or scissors before running live steam. And I now steam clean my valve gear and drive rods after every session or two on elevated track or EVERY session on gound level track! (Lesson learned the hard way with my C-16 and Frank S)

I've considered building a horizontal dual string trimmer to push in front of the sparky, but that's rather low on the project list.

To answer you question directly Jim, the more clean, the longer it will last. If you ever "put it on the ground", discontinue use until a thorough cleaning has been done.
 

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Discussion Starter · #15 ·
Dave
When you say that you steam clean your engine on an elevated track, is that with a regular steam cleaner or do you have some way to use the boiler's steam for this?
 

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I have seen people use the loco's boiler that they would keep pressure up after their run specifically for use to clean the engine. But actually have a REGNER vertical boiler that I use to test chassis assemblies before continuing a kit build. It's much easier to troubleshoot and binding issues before attaching the loco's boiler and associated fittings. I've found that most binding issues that are revealed by running on steam as opposed to air are usually related to crosshead guides. I test on air first, then test with steam which reveals any issues caused by metal expansion caused by heat.

My vertical boiler has two taps; one is hard piping with a couple of union joints that includes a inline hydrostatic oiler, the other is about two feet of silicone with a stainless steel wand that I chucked in my lathe and necked down while heating it cherry red with a torch. Made a nice little nozzle.

You can see the test setup at the beginning and end of this challenger chassis test video:
 

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Posted By Eric M. on 14 Aug 2013 09:40 AM
I consider the Shay and C-16 to be some of Accucraft's greatest achievements. It's a shame that they do not have parts support for these great engines. At this point there is an aging population of these locomotives so perhaps we could gather enough voices to have them add the parts to the E Store. Regards,


I do too, Eric. I wish they had a better parts inventory also. I recently had to replace the rod pins on the drivers on my C16. The main one was worn very badly. Cliff actually had a set of these he sent me. My K27 also wore out the main rod pin. When you run on the ground as I do, this stuff wears out.
 

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Posted By bille1906 on 15 Aug 2013 07:56 AM
Dave
When you say that you steam clean your engine on an elevated track, is that with a regular steam cleaner or do you have some way to use the boiler's steam for this?
Bill
Appreciate you notes on the eccentrics and upgrades...

Cleaning a steam locomotive can be done via trapping the locomotive steam pressure (most can be step up to do so):

Clean engine
 

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Well thanks to a nice donation, and the handiwork of Bill, my lucky number 13 Shay has ball-bearing eccentrics. Henner promises that I should have a nice and tight running engine soon!!! Thanks Bill!!!
 

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Well, here is the disassembled engine from Eric's Shay:



I marked wear on the different parts with red/yellow/green arrows. The eccentrics are already the replaced ones made by Bill (It took him about 20min to upgrade them...). Surprisingly the O-ring looks almost like new, as does the piston rod, "crosshead", valves/pin, cylinder/valve bores, crosshead guides, crankshaft and crankshaft bearing. Wear on all these parts is either not detectable or negligible. The worst wear was on the eccentrics (the eccentrics proper looked good, only the strap was worn) and the connecting rod big end. In both cases the wear was in the order of 0.02" (0.5mm). Especially the wear on the eccentrics affects timing. The deterioration in slow running was the main reason for this repair. Another weak point is the wrist pin in the "crosshead". The full force of the piston stroke is transferred by a tiny M1.6 screw (about 1/16" diameter). The thread is visibly worn. I will replace these screws with a shoulder screw (waiting for the M1.6 die).
Regards
 
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