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 Posted - March 30 2008 : 03:23:11 AM
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For reference, I present the following series of photos.
The Powertorque debuted in 1974, in the Spirit of 76 Alco 430. Tyco claimed it was the "result of years of development"... a specious claim given how quickly it was revised. Those first variants can also be found in the Phase II 630, and the first release plastic Sharknose (D&H, NYC).
The battle-worn Super Spirit of 76 C630 above is equipped with the "Mark I" Powertorque. These are easily spotted from underneath, as the truck caps are held in place with a single slot-head screw. The screw is actually unnecessary, since there are beveled tabs at the ends of the cap, to snap in place on the housing. Also note that the couplers are in separate draft-gear boxes which only fit this PT truck (and the Rivarossi-drive Phase I 630).
Mechanically speaking, the pinion gear is brass. I own over 60 PT locomotives built from 1974 through at least 1988, and the only brass pinions are on the MarkI PTs.
The reduction (large) and idler (smaller, twin) gears are a thin, brittle plastic that wears easily.
The armature cover is a solid thick piece of plastic, with riveted posts. This provides good sealed protection, but retains heat.
The pickup truck is a unique housing that resembles an empty motor truck, but it in fact is a unique piece. Because one side is hollowed out, the other side has more mass and as a result the truck could tend to lean.
These motors run very hot and are generally poor performers.
Tyco quickly revises their "developed for years" PT into this version, which makes a few improvements. The armature is the same, but the gears are thicker, tougher stuff. Notice the reinforcing ring on the reduction gear: this feature is not always present on later PT runs, but is common. The pinion (removed in this picture) is now an odd cast metal.
The big improvements are on the backside, on the cover plate. Ventilation holes are added, and instead of sealed riveted posts, removable brush retainer clips are used. This makes assembly and service a bit easier, and the vent holes address the heat issue, although not entirely.
The truck caps change to the common style, with 3 self-tapping screws. The taps for the screws are added to the casting.
Compared to the MkI, Mark II (and later) PT motor housings seem to be a weaker casting. It is possible to break the axle posts for the idler gears, if the gears bind too hard. While this may yet be possible on the MarkI (they are scarce enough that I haven't yet happened to break one), it "feels" tougher.
Mark II PTs do perform better, but only just so. They are quite common in all diesels across the line.
The Mark III PT is noticeably revised, and appears around 1979 or so. A cast ridge has been added around the reduction gear; the exact purpose is unknown but it may serve to keep oil and grease out of the enlarged vent holes. In addition to making the holes larger, a third one has been added at the 3-o-clock position. Finally, the round post for the suspension spring is recessed into the top of the casting.
Tyco simplifies the headlight mount on some diesels by attaching it directly to the block (this change does not seem to happen until the 80's).
The armature cover once again sees big changes, with enlarged and reinforced ventilation holes. The brush clips are also revised. Finally, a note about "oil" is embossed, but the novice may not be sure of where exactly it was supposed to go, as the embossing is some distance from the bearing.
The Mark IV PT does not entail any huge changes, but Tyco does attempt to idiot-proof it by now telling you where to put the oil.
Also, this particular example (from a GG1) has a felt pad under the pinion gear. Presumably this would absorb excess lubricant and protect the bearing. I have a reversing-light 630 with this pad as well.
The Mk II (left) and Mk III & IV (right) use the revised pickup trucks shown above. These are better balanced than the Mk I version. Strangely, the hollow version weighs just as much as the filled-in one. In reality the difference is negligible.
Mix and Match!
There were many odd, inexplicable, inconsistent, and ongoing modifications to the PT over the years. Looking at the pictures above, you may note the reduction gear changes each time. The MkII without a pinion gear, actually has a longer armature shaft that serves no purpose. The same white plastic used on that last reduction gear, was used for some MkIV armature covers. Then of course you have the headlight mounts, and pinion lubricant pads. None of these features directly affect the performance of the motor... but all of them may be seen in a dizzying array of combinations.
You can run any style motor truck, with any style pickup. You can swap the gears and armature from one to the other. The basic mechanics and gear ratio of the PT never did change, which makes this possible.
Edited by - GoingInCirclez on March 27 2009 10:33:50 PM
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Posted - March 30 2008 : 1:12:20 PM
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GIC,
Also note that the Mark IV (and perhaps the III) has felt bearing packing to hold extra oil, since keeping the meager bronze bearings lubricated was a major problem for these motors. That's probably why the oil arrows were added.
I also noticed that they changed the axle diameter from Mantua's standard .125" to what looks like 2mm on the third version.
I didn't know the brass pinion was from the first run. That would make the first Chattanooga's Mark II's, then.
The Tyco Depot
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Posted - March 30 2008 : 1:39:03 PM
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Great info.
This is very helpful.
Ray
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Posted - March 30 2008 : 3:36:19 PM
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quote:Also note that the Mark IV (and perhaps the III) has felt bearing packing to hold extra oil, since keeping the meager bronze bearings lubricated was a major problem for these motors. That's probably why the oil arrows were added.
I also noticed that they changed the axle diameter from Mantua's standard .125" to what looks like 2mm on the third version.
I didn't know the brass pinion was from the first run. That would make the first Chattanooga's Mark II's, then.
Originally posted by NickelPlate759 - March 30 2008 : 12:12:20 PM
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Yeah, I kind of figured the pad might hold excess oil but then how much good would it do? As soon as the hairs inevitably get sucked up there, you won't be able to tell the what the pad is anyway.
Out of all the engines I have, only TWO had that pad... and I have several more with the cast"oil" indicator.
The one that cracks me up is the armature cover. It says "Oil", but for the love of pete, WHERE? The axle? The big hole right next to it? [Oops!] If you notice though, they did cast a reservoir of sorts around the bearing there. I have found this does a good job of suspending a full drop of oil right over the bearing.
The casting for the 0-8-0 Tender Drive PT (Chattanooga, et al) is modified with two large posts, one on either end. The tender trucks clip to these with a snap-ring. These posts are in place of the round groove for the standard diesel swivel mount, so it IS a unique casting... but all the guts are standard just like the rest.
Early tender drives have a cast copper (at least it looks like copper?!) chassis weight to which the PT block is attached. Later tender drives use a plastic chassis.
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Posted - April 02 2008 : 3:07:35 PM
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quote:Yeah, I kind of figured the pad might hold excess oil but then how much good would it do? As soon as the hairs inevitably get sucked up there, you won't be able to tell the what the pad is anyway.
Out of all the engines I have, only TWO had that pad... and I have several more with the cast"oil" indicator.
Originally posted by GoingInCirclez - March 30 2008 : 8:36:19 PM
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The Mark IV truck I have doesn't only have bearing packing on the pinion side - it has packing in the brush holder plate as well. The plate looks like the Mark III, but there is a felt pad visible instead of the armature shaft.
The frame on the original deluxe Chat's were cast out of Zamac, just like the rest of the truck. Their blackening treatment looked coppery when worn a bit. I wonder if they had to plate the parts with copper in order to blacken them.
The Tyco Depot
Edited by - NickelPlate759 on December 08 2008 02:45:43 AM
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Posted - April 02 2008 : 6:53:44 PM
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I appreciate the effort that went into this post.
I have 6 MK-I PTs with the brass pinion and the one photographed at the top in the 630 is the only one that the cover screw on the top right is connected to the brush carrier contact on the right. Mine have a wire soldered but don't have a cover screw through it.
Alco Fan
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Posted - December 10 2008 : 09:11:14 AM
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GIC:
Wow, look at that halo of brass shavings surrounding the pinion of that Mk1. I wonder if they're from the pinion or the bearing? It trips a vague memory, and I think I've seen this pattern on other Tycos, although my Mk 1 Chessie Super 630 doesn't have it.
I never realized there were variants, but now that you post this, I wonder how I missed it.
Probably the single screw, and later the multiple screws, were added to the cover plate to keep the axles from migrating away from the idler under load and stripping the teeth.
You're not kidding about the Mk 1's thin gears. I wonder how much of the bad reputation came from those earlier models.
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Posted - January 31 2010 : 11:44:22 AM
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Can anyone see the images in GIC's posting here?
-Gareth
"A is A"
-Aristotle
Law of Identification
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Posted - January 31 2010 : 2:24:07 PM
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quote:Can anyone see the images in GIC's posting here?
-Gareth
Originally posted by romcat - January 31 2010 : 11:44:22 AM
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NO
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Posted - January 31 2010 : 4:45:52 PM
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nopes just Xs
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PowerTorque Variant photo reference
