How to check a crankshaft stroke

[David Lee]

Good day,

I was asked by a machine shop that is going to do my offset grind on my crankshaft to check what the stroke is before we do the offset. How would I do this in the block?

Thanks

[Tom Turner]

If your crankshaft grinder does not have a stroke checker, request that he gets one or find a grinder that does. You can check it yourself in the block with a long travel (at least as long as your stroke) dial indicator and a bridge (at least as wide a your bore spacing) Run the piston to BDC and zero the dial. Run the piston up to TDC and read the travel. You can do this with a dial caliper (like NHRA does) but a dial indicator is more accurate. Crank grinders tend to setup on existing crank pins and disregard actual stroke. Make sure your guy understands the concept of "grinding on index" and the importance of the stroke being the same on all throws. Another thing.....only take .014.

[David Lee]

Thanks Tom, I will ask him if he does. But I would also like to know so I can make sure that the grind was correct. Time to get a long travel dial indicator

[kansas stocker]

I use a depth mic and a dial caliper as a back-up.
I shoot for .013.
Pete