420C Speedo/Tach

General help and support for your Lindeman through 2010 John Deere crawler
skymoco
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420C Speedo/Tach

Post by skymoco » Fri Dec 24, 2010 4:29 am

Since my 420 has street tracks and there's snow on the ground I figured I would pull it into the shop for a little TLC. I've had this tach for a 420c sitting around a long time and I have a couple questions for you all. First, where does the drive cable go on the engine. I've looked all over and I cannot find where it might go. The parts book just shows the drive gear, not where it goes onto the engine. I'm missing the drive gear as well, so if anyone has one of those....
Secondly, the tach itself needs some help. I need some new paint for the needle and there is some rust. And the simple fact that the drive will not turn. Per the photo, the inner brass drive is frozen, but the outer brass collar moves. I think I just need to keep soaking, tapping and turning and hopefully it frees up. Any suggestions?

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Stan Disbrow
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Post by Stan Disbrow » Fri Dec 24, 2010 8:52 am

Hi,

The tach drive is just under the distributor. Most engines don't have it installed unless the tach were put onto the machine as an option when new. Usually, all you see is the metal plug in the hole to keep the oil in.

So, I think you need to find a tach drive unit to put in place of the plug.

The tach is rather useless on a crawler in my opinion. They were meant for the ag tractors to figure out the ground speed when using certain implements that require specific ground speeds to operate properly. Who does that kind of work with a crawler?

Later!

Stan
There's No Such Thing As A Cheap Crawler!

Useta Have: '58 JD 420c 5-roller w/62 inside blade
Useta Have: '78 JD350C w/6310 outside blade
Useta Have: '68 JD350, '51 Terratrac GT-25
Have: 1950 M, 2005 x495, 2008 5103 (now known as 5045D)

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Willyr
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Post by Willyr » Fri Dec 24, 2010 9:12 am

Image

as you can see in this picture. it is as stan says.
former owner of a 1956 420c
All help is greatly appreciated.

Proud owner of a project 1952 JD 60

http://www.youtube.com/watch?v=nFehqXVd9z4

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JD440ICD2006
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Post by JD440ICD2006 » Fri Dec 24, 2010 9:16 am

Stan,

I concur about a tach on a crawler for ground speed calculations. I do wish JD had offered up a tach option on the 440ICD though. It only came with an hour meter option. It is pretty critical to run the Detroits at the spec RPM's, hard to do that with an hour meter. :lol:
Some of the industrial 2-53's have tachs, so there is no question it could have been done, but I guess it would have added too much cost?


Merry Christmas!!

Chuck
1959 JD 440ICD w/64 Power Angle Tilt Blade
1959 JD 440ICD w/63 Manual Angle Blade
1959 JD 440IC w/602 Manual Angle Blade
1959 JD 730D W SE (many options)
1950 JD M S w/M-20 Mower
1952 JD M W
1955 FORD 640 (burns the most fuel)

skymoco
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Post by skymoco » Fri Dec 24, 2010 11:33 am

I agree with it's usefulness (or lack thereof) but I have the tach and this big hole in the dash.... And if I am gonna install it, I want it to work.

Are you sure you don't have a tach drive around there Lavoy?

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JD440ICD2006
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Post by JD440ICD2006 » Fri Dec 24, 2010 11:58 am

If Lavoy cannot come up with one, I would start calling bone yards with 420 tractors and crawlers. Not sure if the JD 40 had this option, but 430's did.
1959 JD 440ICD w/64 Power Angle Tilt Blade
1959 JD 440ICD w/63 Manual Angle Blade
1959 JD 440IC w/602 Manual Angle Blade
1959 JD 730D W SE (many options)
1950 JD M S w/M-20 Mower
1952 JD M W
1955 FORD 640 (burns the most fuel)

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Lavoy
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Post by Lavoy » Fri Dec 24, 2010 12:54 pm

I think I have one left.
Lavoy

skymoco
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Post by skymoco » Fri Dec 24, 2010 2:14 pm

Well, put my name on it. :)

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Stan Disbrow
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Post by Stan Disbrow » Fri Dec 24, 2010 6:35 pm

Hi,

Well, at least you have a tach for a crawler and it looks like you've found a drive unit. So, it looks like you're all set to know exactly how slow you're crawling! ;)

Later!

Stan
There's No Such Thing As A Cheap Crawler!

Useta Have: '58 JD 420c 5-roller w/62 inside blade
Useta Have: '78 JD350C w/6310 outside blade
Useta Have: '68 JD350, '51 Terratrac GT-25
Have: 1950 M, 2005 x495, 2008 5103 (now known as 5045D)

Ray III
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Post by Ray III » Tue Feb 08, 2011 10:42 pm

I see you figured out how to get the thing apart.

The mechanism that drives the hourmeter is likely what's frozen up. I don't remember how to get it apart, but I can look at it for you, since I have not put it back together in 2 years! Reason being that I want to calibrate it against a digital tach (adjusting spring tension on the needle) before I put it together, and I can't do that until I get a new tach drive too.

May be useless on a crawler, but it sure does look cool.

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notmeu
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Post by notmeu » Mon Feb 25, 2013 8:36 pm

Can you fellas offer any advice on setting up the spring setting behind the faceplate? I cannot seem to get mine to read correctly, the rpm is all over the place and there is little spring pressure that returns it to 0 rpm. I moved the spring but where I think it should be it cannot go because of the hour meter.
1956 JD420, gearmatic 8a winch, custom 6 way blade and FOPS.

gus
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Post by gus » Tue Feb 26, 2013 7:00 pm

Can't help on spring pressure. I had mine apart and loosened everything up. After I got it loose, I put the end of the broken cable in a drill and ran it up. I continued running and lubing it for several minutes. After that it ran very easily and I put it back together and so far it's working good.

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notmeu
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Post by notmeu » Tue Feb 26, 2013 7:09 pm

If you manually moved the gauge up the rpm scale did your indicator move back to zero fast and hit hard or does it come back slow. That would help me out with the spring tension. Thanks.
1956 JD420, gearmatic 8a winch, custom 6 way blade and FOPS.

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440 iron popper
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Post by 440 iron popper » Tue Feb 26, 2013 8:11 pm

Personnally I bought new parts for this. I didn't have nothing for a tach/hour meter. Lavoy had a couple tach kits in stock not long ago. Good for 420 to 440 with 5 speeds transmission. Very nice looking and fair price. So I bought Gauge and cable from Lavoy. I found out the drive gear on a 2010. We compared the part # in the books and from 420 to 2010 they use the same drive. That gives you better chances of finding one :) .

Not that I need a tach but after the rebuild it would be nice to have a completed dash with something in this empty space. I needed an hour meter too. I guess it is a good helper to set rated speed and idle as well.


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If your tach gives up, check with Lavoy. Good luck with the project.
440IC 1958 #443712, 602 blade, Gearmatic winch project in the back
440IC, serial tag gone, Blade with tilt
-------------------------------------------------------

gus
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Post by gus » Wed Feb 27, 2013 2:12 pm

notmeu wrote:If you manually moved the gauge up the rpm scale did your indicator move back to zero fast and hit hard or does it come back slow. That would help me out with the spring tension. Thanks.
I have no way of answering your question since I didn't quickly disconnect the drill. It does follow the rpm up and down as I ran the drill and there was no lag. If you just spin it by hand it should float up and right back down (not snap down).

Grind a small bolt to fit the square, chuck it up in a drill and run it up. Don't over rev it. I don't know what the gear ratios are from the engine to the tach.

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