Oil clearance

[sgkent]

I used to size connecting rods for a living. When the rod halves are sanded, the edges also come in closer. If you think of a clock, think of the pairs 8 and 2, and also 10 and 4. If the rod is not 100 percent centered when it was honed at the factory, 8-2 or 10-4 can be closer. Example, 10-4 might be a shorter distance than 8-2 if the rod and cap were slightly off center when honed but it could be within an acceptable distance at that time. If you start bringing the 12-6 dimension together to make the hole smaller then that 10-4 example distance can change enough to pinch the crankshaft so the rod seizes. That measurement could have been fine but you changed it after the factory honed the big end of the rod. We used to measure 360 degrees of the big end as we resized it to not get caught in that rabbit trap.

 

[Stryped]

I used to size connecting rods for a living. When the rod halves are sanded, the edges also come in closer. If you think of a clock, think of the pairs 8 and 2, and also 10 and 4. If the rod is not 100 percent centered when it was honed at the factory, 8-2 or 10-4 can be closer. Example, 10-4 might be a shorter distance than 8-2 if the rod and cap were slightly off center when honed but it could be within an acceptable distance at that time. If you start bringing the 12-6 dimension together to make the hole smaller then that 10-4 example distance can change enough to pinch the crankshaft so the rod seizes. That measurement could have been fine but you changed it after the factory honed the big end of the rod. We used to measure 360 degrees of the big end as we resized it to not get caught in that rabbit trap.

Makes sense. But what if you took equal number of “strokes” on sandpaper on both halves of the rod?

 

[sgkent]

Makes sense. But what if you took equal number of “strokes” on sandpaper on both halves of the rod?

you missed the point. It isn't just the top to bottom clearance you are changing but also side to side ESPECIALLY if the cap is offset, which you can't measure without very expensive devices like one of these