D7 17A pony problems

farmerfred

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Have a neighbor who acquired a 17A C model with a dead pony. We took the pony apart and the bearings are out and the crankshaft has already been turned - 20 on the mains and 30 on the rods. He got another pony for nothing and of unknown condition but the guy said it would fit. We took it apart and it has a rod out, but in the process we discovered the one on the tractor has a big counter weight and both rod throws are on the same side. The freebie one has opposed rod throws. If he has to fix one, which would be the best or is there any difference? He'd like to go electric start, but he has a 6 volt gear driven generator and one guy told him it would be over a grand to go electric. How does the opposed pony fire compared to the one with the throws on the same side?

We're just looking for input as we're just a couple of farm boys that are a little out of our league. Thanks.

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Mon, Apr 9, 2007 7:50 AM

Al Letts

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Hi

I'm unsure of the answer to your question as my experience is limited to D2, but there is a lot of knowlegable folks on here that I'm sure will chime in. "Old Magnet" on the list here has compiled alot of data on direct electric starting. I'll enclose the website below. Dollars sound about right though. But pony motor repairs can be pricey as well. "Kid Nevada" on the list has a good source page for parts suppliers in the FAQ section.

OldMagnet's Electric Starter Mode

good luck

AL
D2-5U-10614
other small excavating pieces as well.

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Mon, Apr 9, 2007 8:28 AM

Old Magnet

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Reply to Al Letts:

Hi

I'm unsure of the answer to your question as my experience is limited to D2, but there is a lot of knowlegable folks on here that I'm sure will chime in. "Old Magnet" on the list here has compiled alot of data on direct electric starting. I'll enclose the website below. Dollars sound about right though. But pony motor repairs can be pricey as well. "Kid Nevada" on the list has a good source page for parts suppliers in the FAQ section.

OldMagnet's Electric Starter Mode

good luck

The counter weight pony was used up until sr. no. 11667 then was changed along with the magneto change from vertical mount to a low horizontal mount.
Yes, they will interchange but unless you have all the pieces to convert you will go nuts getting it mounted.
I would think the later opposed rod journal version would be the one to rebuild.
I would suggest you get hold of the parts books covering the early and later models so that you can assess what all is involved.
The direct electric start is not the easiest conversion either as there is no flange for mounting and installation starts with getting an adapter plate mounted to the bell housing. There are direct electric start conversions available ready to go but a complete installation including batteries, battery box, switches, etc. plus a generator/alternator to keep it charged will more than likely exceed that $1,000 estimate.

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Mon, Apr 9, 2007 9:28 AM

Stretch

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Reply to Old Magnet:

The counter weight pony was used up until sr. no. 11667 then was changed along with the magneto change from vertical mount to a low horizontal mount.
Yes, they will interchange but unless you have all the pieces to convert you will go nuts getting it mounted.
I would think the later opposed rod journal version would be the one to rebuild.
I would suggest you get hold of the parts books covering the early and later models so that you can assess what all is involved.
The direct electric start is not the easiest conversion either as there is no flange for mounting and installation starts with getting an adapter plate mounted to the bell housing. There are direct electric start conversions available ready to go but a complete installation including batteries, battery box, switches, etc. plus a generator/alternator to keep it charged will more than likely exceed that $1,000 estimate.

OM,
Its strange that you mentioned that ser.#.
I have 11668. I posted several picks on the old board during resto.

I finished the pond I was working on and she's still running good.

See attached.....

Farmerfred,
Good luck with the pony work. I have been lucky with mine. It just takes a clean dist. cap and sandpaper thru the points every now and then....
Attachment

Stretch

Cat D7 17A11668
John Deere 1010 (gas)
other less desirable junk.....

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Tue, Apr 10, 2007 12:59 AM

Stretch

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Reply to Stretch:

OM,
Its strange that you mentioned that ser.#.
I have 11668. I posted several picks on the old board during resto.

I finished the pond I was working on and she's still running good.

See attached.....

Farmerfred,
Good luck with the pony work. I have been lucky with mine. It just takes a clean dist. cap and sandpaper thru the points every now and then....

By the way,
Here are a couple before pics. The Cat and the pond.....
Attachment

Stretch

Cat D7 17A11668
John Deere 1010 (gas)
other less desirable junk.....

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Tue, Apr 10, 2007 1:21 AM

Stretch

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Reply to Stretch:

By the way,
Here are a couple before pics. The Cat and the pond.....

One more with the rake.....
I was also trying to get the signature option to work.
Attachment

Stretch

Cat D7 17A11668
John Deere 1010 (gas)
other less desirable junk.....

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Tue, Apr 10, 2007 1:34 AM

ccjersey

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Looks like to me the counterweight type with the rod throws on the same side would be an even fire, with 1 cylinder firing each time the pistons came to TDC (360* apart). The other crank could only have the cylinders fire 180* apart and then would have a 1 1/2 turn lag before the next cylinder fires.

Not sure what the practical effect of this would be. I believe the mags would have to be different.

I used to run a JD 420 that had the 2 spark plug wires next to each other on the 4 position cap instead of opposite and if you pulled off the leading plug wire with it idling, the engine would almost stall, while if you pulled off the following wire, it made almost no difference. I suspect the leading cylinder was getting most of the mixture because of the long common runner into the intake ports of the two cylinders.

You didn't say anything about the cylinder bores and pistons. That may make a difference which one you want to rebuild.

Jim

D2-5J's, D6-9U's, D318 and D333 power units, 12E-99E grader, 922B & 944A wheel loaders, D330C generator set, DW20 water tanker and a bunch of Jersey cows to take care of in my spare time😄

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Tue, Apr 10, 2007 2:58 AM

Old Magnet

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Reply to Stretch:

One more with the rake.....
I was also trying to get the signature option to work.

Hello Stretch,
Great pictures and nice setting. Tractor looks a lot better than when it had the thrown track (if I remember correctly).
Really like that HD root rake.😄 😄
By parts manuals sr. no. 11668 was the first to get the pony motor changes that included the opposed rod journal crankshaft and the low mounted (Wico) mag. Is that what you have on your unit??

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Tue, Apr 10, 2007 3:03 AM

SJ

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CC those two style engines were known as the odd firing engine & the other one an even firing engine so that way you knowed which one you had.I,m not sure anymore been away from them too long but there was so much that was different between the two that I,m not sure if one could be installed in place of the other one & if so there could be some cutting & fitting to install it.

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Tue, Apr 10, 2007 3:23 AM

Stretch

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Reply to SJ:

CC those two style engines were known as the odd firing engine & the other one an even firing engine so that way you knowed which one you had.I,m not sure anymore been away from them too long but there was so much that was different between the two that I,m not sure if one could be installed in place of the other one & if so there could be some cutting & fitting to install it.

OM,
Thanks for the mention of the setting. It's been a lot of hard work!

I have half as much in the rake as I do the Cat..... The thrown track took me about a day and a half to get back on. (I'm always alone when the real work starts) The problem was the seals in the adjusters. Both sides were 50+ yrs old and had to be replaced.
My pony has the low horizontal Wico mag but I'm not sure what you mean by opposed rod journal.....

I'll take a pic tonight if I make it home before dark......

Stretch

Cat D7 17A11668
John Deere 1010 (gas)
other less desirable junk.....

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Wed, Apr 11, 2007 2:00 AM

SJ

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Reply to Stretch:

OM,
Thanks for the mention of the setting. It's been a lot of hard work!

I have half as much in the rake as I do the Cat..... The thrown track took me about a day and a half to get back on. (I'm always alone when the real work starts) The problem was the seals in the adjusters. Both sides were 50+ yrs old and had to be replaced.
My pony has the low horizontal Wico mag but I'm not sure what you mean by opposed rod journal.....

I'll take a pic tonight if I make it home before dark......

If your mag. is down front then it is the later starting engine & the throws on the crank are opposite or 180 D. apart where with the early engine both throws are on the same side & have a counter weight as part of it.The mag. on this early one has it on top of the front cover standing up & the cap & wires pointed up in the air.

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Wed, Apr 11, 2007 2:18 AM

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