8MM Pulley Question

I am switching from 14MM pulleys to 8MM pulleys and have found the hub bolts won't go in with the 8MM pulleys. I have tried PSI and RCD brands and neither bolts up. Went back to the 14MM pulley and it bolts right up. Am I crazy or what? Thanks, Jim

 

Blower pulley line up

Hay Jim,

Some of the snouts have one bolt offset and some of the pulleys have a slot for it and some don't. Find where the 5 bolts line up and slot the pulley for the other. Chuck

 

^^^^^^^^^^^^^^^^^^^^^^^^^
Chuck is right ! I just had to slot the one odd hole in one of my pulleys ...
A small burr bit on a diegrinder works good but be carefull to not let it catch

 

I've always wondered, how did that slot ever get started. What's its history? Who was the first to put it in?

 

I heard that it dates back to the crank hub bolt pattern on early Hemi? (could have been another make engine) - one bolt hole was offset for balance reasons and one of the blower manufacturers used that pattern for their blower drive hub....anyone care to elaborate?

 

The early Hemi crank hub had one bolt hole offset for timming mark, so you couldnt get it wrong, I talked to Steve Leach at RCD and he said he couldn't bring himself to build the pulleys with tat pattern. He may have been th one to fix the problem.

 

Yeah Keith - I knew that the offset bolt was to install the hub or pulley to index it for a timing mark or engine balance issue....sounds like most pulley manufacturers have got all of the bolt holes spaced evenly now....but some of the used pulleys that I have bought recently have the slot in em....