Mixing 201 Connecting Rods and Caps

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   I've been struggling with new con rod bearing clearances in the WD engine I'm rebuilding. Crank was ground .030 under and is right on the money, but a couple of the rods give me .001-.002 INTERFERENCE when I torque them down and measure with a dial bore indicator set to a micrometer for the corresponding journal on the crankshaft. Swapped in several new sets of bearings with no change.
For kicks I grabbed a random cap off of a junk set of rods I have, and voila, the bearing clearance is spot on. I'm thinking there's something up with my engine's original caps.

It looks like my options are to either have a machine shop resize the connecting rods, or swap the caps from the bad rods onto these rods. Is mixing and matching caps acceptable or not?

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wjohn Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Joined: 19 Jan 2010 Location: KS Points: 1911	Post Options Post Reply Quote wjohn Report Post Thanks(0) Quote Reply Topic: Mixing 201 Connecting Rods and Caps Posted: 3 hours 57 minutes ago at 7:29pm
	I've been struggling with new con rod bearing clearances in the WD engine I'm rebuilding. Crank was ground .030 under and is right on the money, but a couple of the rods give me .001-.002 INTERFERENCE when I torque them down and measure with a dial bore indicator set to a micrometer for the corresponding journal on the crankshaft. Swapped in several new sets of bearings with no change. For kicks I grabbed a random cap off of a junk set of rods I have, and voila, the bearing clearance is spot on. I'm thinking there's something up with my engine's original caps. It looks like my options are to either have a machine shop resize the connecting rods, or swap the caps from the bad rods onto these rods. Is mixing and matching caps acceptable or not?
	1939 B, 1940 B, 1941 WC, 1951 WD, 1952 CA, 1956 WD-45

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Les Kerf Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Joined: 08 May 2020 Location: Idaho Points: 748	Post Options Post Reply Quote Les Kerf Report Post Thanks(0) Quote Reply Posted: 1 hour 42 minutes ago at 9:44pm
	This is not normally considered to be good practice but if the parting lines match and the bore is round (within reasonable tolerance) it should work just fine