Farmall Cub

I'm solicting ideas for an engine noise I'm having with the H. There is a loud tick that appears to come from the #4 cylinder. I pulled the plug wire while it was running and it becomes a loud knock. Pulling other cylinder wires changes nothing. Checked valve rockers and they all good as is the lash. No noise is coming from the valves with the cover off either.
Most of what I know about true rod knock is its worse with increasing RPM and load. This worsens with decreasing RPM and load.
Other than this noise all engine parameters are normal and it runs nicely.

Fire away!!

I would suggest using pump gas

Seriously, it sounds like a rod bearing to me.

Was raised on Hs, and I agree with donny, sounds like a rod beairng to me.

I would take it down and check. Continuing to run it may score up the crankshaft if it is not already so.

Bill