Positive / Neg Ground 1949 Cub

Thu Jul 03, 2014 12:09 pm

Hi,
I bought a 1949 cub and it is wired with a negative ground from battery ... is this correct? Were there both positive and negative ground 6 volt versions?

Also, there is an oil seal behind the magneto ( a domed shaft with slot in it to drive magneto - on the tractor - not magneto itself). This seal is not installed correctly (since it is on a slant - not vertical) ... can anyone tell me which side of the drive housing the seal is installed from? After you take off magneto the drive housing would be next which contains this shaft. I don't know if I should try and drive the oil seal (like a large washer with rubber seals) in to straighten it or just leave well enough alone since it only leaks a tiny bit.

Also, do those electronic ignitions work well - I am upgrading to distributor from magneto?

Thanks in advance,
Gary

Re: Positive / Neg Ground 1949 Cub

Thu Jul 03, 2014 2:52 pm

Welcome to the forum!

Your Cub would be positive ground. Negative ground came along later with the 12 volt system.

Sorry, Can't help with the mag.

Re: Positive / Neg Ground 1949 Cub

Thu Jul 03, 2014 3:30 pm

The seal should be equal depth on all sides. See this topic for some help.
http://www.farmallcub.com/phpBB2/viewtopic.php?f=140&t=76420

Re: Positive / Neg Ground 1949 Cub

Thu Jul 03, 2014 4:20 pm

Cecil wrote:The seal should be equal depth on all sides. See this topic for some help.
http://www.farmallcub.com/phpBB2/viewtopic.php?f=140&t=76420

I hope to have an update with pics of the above "How To" within the next week or so...

Re: Positive / Neg Ground 1949 Cub

Thu Jul 03, 2014 4:25 pm

Welcome to the best forum on the Web, and congrats on your first Cub!

You can easily change the tractor back to positive ground, just swap the cables and re-polarize the generator.

Why do you want to switch from magneto to battery ignititon?

Re: Positive / Neg Ground 1949 Cub

Thu Jul 03, 2014 5:15 pm

A new magneto oil seal is driven in from the magneto side. You can make your own installation tool by following Raymond's instructions. Alternatively, Earl Fauble, a forum member, sells an installation tool, that makes it relatively easy to install a new steal at the proper depth and square in the bore. If the existing seal is leaking, it could over time have a negative impact on the ignition, because oil will eventually find its way to the points.

Re: Positive / Neg Ground 1949 Cub

Thu Jul 03, 2014 8:48 pm

WOW! Thanks for the reply's! Actually, to clear up a few things ...1) My dad has had the cub since the 1950's ... I have used it to help him mow with the sickle bar over the years. Now it's mine and I mow with it!
2) (Here's where I feel STUPID!) I had to rewire the battery system since the cables were shot. I don't remember if I didn't look at it when I took it apart and thought NEG ground was standard or what but it been running like that for about 8 years. It does not get used a lot because I mostly use it to sickle cut the fields. I will have to FIX THAT!!!! Would that cause the tractor to run hot? Or is that likely caused by crud in the bottom of the coolant lines like I read about?
3) The info on the mag oil seal was great too ( I knew it looked wrong) How do you get the seal out? It looks like I will need a new one since this one is probably damaged. Do you need to take off the Mag drive Assembly to replace it?
4) I was going to replace the Magneto with Regular Distributor because the parts to rebuild it cost $300 including points, condenser,rotor, gaskets, little gear drive, J4 coil and plug wires!!!! I can get a rebuilt Distributor for $179 with every thing but plug wires and next tune up is only $40. for points, condenser, rotor & cap. Also, you can put the electronic ignition on the distributor setup which should give much higher spark, horsepower & reliability! AM I WRONG ON THIS TOO?

Thanks Again,
Gary

Re: Positive / Neg Ground 1949 Cub

Thu Jul 03, 2014 9:12 pm

Gary:

Hey, welcome to the Forum. Long time cub family member now the Keeper of the Cub .. excellent. They guys have got you headed in the right direction as they always do ..

ismirk wrote:4) I was going to replace the Magneto with Regular Distributor because the parts to rebuild it cost $300 including points, condenser,rotor, gaskets, little gear drive, J4 coil and plug wires!!!! I can get a rebuilt Distributor for $179 with every thing but plug wires and next tune up is only $40. for points, condenser, rotor & cap. Also, you can put the electronic ignition on the distributor setup which should give much higher spark, horsepower & reliability! AM I WRONG ON THIS TOO?


To answwer those questions .. you can get a decent magneto on eBay anywhere from $25.00 to $250.00 depending on the seller. I have bought them for $25.00US a number of times but truthfully those ones are rare :-) Search eBay.com and eBay.ca for Cub parts..

I am not a fan of distributors. I have a 6 volt distributor and I now have a 12 volt Cub lo-boy that I am really becoming happy with. I prefer to leave them as they came from Louisville but that is only a personal preference. Many change them over to distributors and in the manuals on me server, you can find the IH upgrade installation guide specifically for that. See the links above and of course below.

Can you put electronic ignition? Yes you can. Search the archives and you will find a couple how to's as well as numerous threads on the subject.


Hopefully the following will be of help .. it is also the 1st time I get to post this in quite a while...

Image to Farmallcub.com :big smile: Forum Family. And you have come to the right place for all things Cub related. If you click on the Site Rules, Regulations, & Important Information, it will point you to :arrow: the Welcome Wagon wherein you will find links to many useful sites and topics. One of the most important resources are Owner's Manuals, Parts Catalogs and Service Manuals. The Cub Manual Server is the home of the jpg versions and the PDF Manuals -- well the pdf's of course :wink: Enjoy!.

Re: Positive / Neg Ground 1949 Cub

Thu Jul 03, 2014 9:37 pm

ismirk wrote:WOW! Thanks for the reply's!
3) The info on the mag oil seal was great too ( I knew it looked wrong) How do you get the seal out? It looks like I will need a new one since this one is probably damaged. Do you need to take off the Mag drive Assembly to replace it?

Thanks Again,
Gary


Gary,
To remove the old seal you will have to remove the magneto. I also prefer to remove the governor to pull the old seal out from the magneto side. I have heard that it is possible to remove the magneto oil seal without removing the governor, but I think it is too difficult. Just remember (before removing the governor) to position the engine at top dead center on the compression stroke and that will allow you to reinstall the governor and insure you have the governor gears meshed properly with the idler timing gear so they are timed correctly with the ignition. The governor and idler timing gears are both marked (punched) to insure they are timed properly after installation, and this is much easier to do before you install the new oil seal. After the governor is installed, you can install the new magneto oil seal.

Good Luck,
Bill