Timing a Cub with dial indicater

[Deere Oliver Farm]

I'm helping a friend time his Farmall Cub correctly. I always used a dial indicater to find exact TDC. Should the Cub spark exactly at top
dead center? Or should the spark occur a little before? How many degrees before? Last tractor I did was an Allis B and I set it to spark at
about 3 degrees BTDC and it ran good. Don't know if that was a lucky guess or was still off a little? Please advise. And thank you to my
respondents. Merry Christmas!

 

[wore out]

There you go!

 

[Jim Becker]

Wore out gave you all the right specs. Addressing the question of finding TDC, a dial indicator isn't required. The crankshaft pulley has a notch that you align with a pointer to get TDC. Even someone only half paying attention should get to within a fraction of a degree of TDC. Later Cubs had two notches in the pulley. The added one is at 16 degrees advance. If there are 2 notches, the second one to reach the pointer is TDC.

By the way, I have set timing on an Allis B. I completely understand why you want a dial indicator for that job!

 

[used red MN]

I am not that familiar with a Cub engine but I know they are a flat head, so curious can you access the top of the piston through the spark plug hole? Probably very likely, otherwise not sure how you would find TDC off the valve train? It could probably be done but you would need the cam degree specs. I agree with Jim, probably way over kill on that engine. Use the pulley mark and call it good.

 

[grandpa Love]

My goodness, we have set the timing on dozens of Cubs, magneto and distributor. Way too easy to do. Then fine tune by ear.

 

[GarryinNC]

I believe that the spark plug hole is over the valves, as stated below.
Garry