Working on a 2 cylinder Ford and have a knock that sounds like a loose rod. I took out two shims from the hinged bearing (It had opened up to 7 thou) and was able to lock it up with a strip of newsprint. Still have the knock. I've adjusted the mains, inspected timing gears etc. Have good even compression, good spark to each cylinder, valve timing is on the money, carburetion is good. Nothing is hitting inside the engine compartment so I think somehow its still that darn rod. I see there very little side to side clearance on the rod bearing and wonder if somehow the rod may be bottoming out on the radii. Anyone have any thoughts?
Check for excessive wrist pin clearance in the pistons.
Short each of the spark plugs to disable that cylinder. A major change in the knock will indicate the problem is in that cylinder. You may have to wind it up a bit before dropping half your cylinders.
Check the rod alignment for Twist, Bend, and off set.
Were you able to check the hinge pin in the rods for loose fit? The pin will wear and the holes in the rod and rod cap will wear causing excess clearance in the bearing. There are several ways to correct this issue. You might want to call Jeff Beaumont for further ideas.
Evan in Paso Robles
P.S. is this in the Model F? That is a very sweet ride!
We are in the process (well, Dean Yoder is) of putting in oversize pins in our Model K rods for this same reason. With a hinged bearing, the pin wear and then there will be "slap" or slop.
You can see part of the hinge on the back side of this pic of one of the rods, along with the oil hole on the hinge bolt side: