1949 Farmall Cub - Oil Around Spark Plugs

[Hobo,NC]

Looks to me like some slobber from incomplete combustion and under torqued spark plugs. I'm not fan of Champion, Bosch or Autolite plugs. I used to use AC Delco with good results but for the past 20 years I have used mostly NGK and sometimes Denso, depending on application. I think I'd throw in a set of NGKs, torque them properly and work the tractor a bit.
And as mentioned, adjusting the valves might be in order.

Incomplete combustion was the issue I had once valve adjustment was in spec the issue "mostly" cleared up. I have had a spark plug issue with it since. I had thoughts of doing a edit to my post you beat me to it.

Autolite and their chinna connection DIY folks will never understand the pain a professional went through 15/17 years ago. I think every Autolite spark plug set I put in around 2010/2011 at least one spark plug failed. Up to that point 30 plus years I had exclusively used Autolite plugs I may have had one bad plug in that time. 2010 vehicles started returning with misfires I had one I towed in for engine noise a spark plug came apart and was jumping around inside the cylinder. I probably had 40 vehicles I replaced the plugs in that two year period.

Autolite admitted to this issue they claimed to move production back to Mexico which they did on premium plugs but not the plain standard plug you use in your tractors. Autoilite can go to ell!!!.

When will DIY learn a a professional does not us Autolite why should YOU?

Do not buy autolite spark plugs

 

[GaDog]

Looks to me like some slobber from incomplete combustion and under torqued spark plugs. I'm not fan of Champion, Bosch or Autolite plugs. I used to use AC Delco with good results but for the past 20 years I have used mostly NGK and sometimes Denso, depending on application. I think I'd throw in a set of NGKs, torque them properly and work the tractor a bit.
And as mentioned, adjusting the valves might be in order.

thanks. I would appreciate some insight on how to adjust the valves.

 

[NDIHC]

thanks. I would appreciate some insight on how to adjust the valves.

A Cub is a very rare tractor in my area. I remember seeing exactly 2 within 50 miles of where I live so other than knowing they are a valve in block engine with valve clearance adjustable with 2 wrenches, I have no personal experience working on a Cub. When it comes to Farmalls of that era you will find at least 100 Ms for every Cub on the prairie of ND. They are way more common in the southeast USA. Someone will pop on with more info than I can give.

 

[used red MN]

thanks. I would appreciate some insight on how to adjust the valves.

To adjust the valves on that engine you will remove the intake and exhaust manifold. Then remove the valve access cover on the side of the engine. The back valve closest to the driver is #4 exhaust, turn the engine and watch it’s lifter. (take all the spark plugs out and the engine will turn easily by the fan) When it raises up and comes back down as it is nearly all the way down the 2nd valve from the back which is the intake for that cylinder will start to raise up to open. When the two are at an even height you will be at Top Dead Center(TDC) of compression for number one cylinder and the timing mark at the front pulley should be close to lining up with the pointer. At this point adjust the 4 valves as shown in the attached photo. When finished turn the engine one revolution this will set it on TDC compression of #4 cylinder. Then adjust the 4 valves remaining on the photo instructions.
Here is a link to a guy adjuster valves during a Cub engine overhaul, the valve adjustment is at 27 minutes. Cub engine overhaul
Edit: I should add the technique I gave you to locate the correct location of the engine is called the valve overlap or “rock” method. I instruct you to look at #4 cylinder valves to locate the position for #1 piston compression stroke. This is correct, #4 cylinder and #1 are “running mate” pistons. This means they raise up and fall down simultaneously, but fire on opposite strokes. Their valve actions are opposite of each other, you will just have to trust me that this process is correct.

 

[Powered By IH]

thanks. I would appreciate some insight on how to adjust the valves.

To adjust valves, undo the assorted linkages and pull the carburetor off. The manifold does not need to be removed.

Carefully loosen the bolts and wiggle the cover off. If you get lucky, you probably can reuse the cork gasket if you clean the gasket surfaces off, otherwise it might leak.

Turn the engine over until cylinder #4 valves are rocking back and forth, or the timing pointer is lined up with the notch in the front pulley. Adjust valves 1, 2, 3, and 5 to .015. (1 being at the front of the tractor)

Then turn the engine over 1 revolution until cylinder #1 valves are rocking back and forth or the timing pointer lines up again. Adjust valves 4, 6, 7, and 8 to .015.
Reinstall the valve cover and carburetor and you are good to go.

Couple things to note:
Removing the spark plugs can make the engine easier to turn over.

The tappets you screw in and out to adjust are a locking type thread, meaning that they probably will be hard to turn. This is normal, and it's so that the adjustment doesn't come loose when the engine is running.

The attatched picture might help also if you prefer visuals.

Good luck and keep us posted!