Bearing clearance

I should be able to measure crankshaft then measure the inner diameter of the connecting rod n with those two measurements I can decide on what bearing thickness to order I assume. Then recheck clearance once bearing are in correct?

To find your rod bearing clearances you'd perform these steps:

1. Use an outside mic to measure the outside diameter of the rod's respective crank journal

2. Use the micrometer now set to the outside diameter of the rod journal to zero out your dial-bore gauge (inside mic)

3. Put the rod in question into a vice (with soft jaws so as to not mar the rod) and torque the cap bolts to the proper torque spec (or to the proper bolt stretch depending on preference) with the old bearings in place or a new set of bearings

4. Use your inside mic to measure the inside of the rod bearing, the measurement you get here with be your rod bearing clearance

5. Determine if the clearance you currently have is in spec and/or acceptable for your application. If it is, you're good to go on that clearance. If it is not you then would use a thicker or thinner bearing set as required and measure again to see if you now have the clearance that you want.

With most late model engines you are able to purchase graded bearing sets from the manufacturer to achieve a specific oil clearance. The process is to measure the inside diameter of the rod journal and the outside diameter of the crank pin. In the workshop manual you can then compare these to the spec range to find a 'number' for both the rod and the crank pin (in stock form these are often stamped on the front of the crankshaft and the block (for main bearings). You then use a grid of numbers in the workshop manual to decide which grade of bearing shell to order for that location in the engine.

Of course you also can use a 'trial and error' method where you fit bearings and check the clearance so you can make an assessment on what you need to change.