340 Main Bearing Clearance

1969GTS340 said
I appreciate your feedback on this. I did meet up with an old machinist buddy of mine who. along with FABO members, schooled me on the proper method for using the snap gauges. I re-measured ( .002, .004, .004 .005, .004, .004 ) yielding better numbers but no cigar. The issue this time was partially due me to not tightening the snap gauges enough, but at risk of marking the bearings with this method, I chose not to go any tighter. With that experience, I purchased a Fowler dial bore gauge that should be delivered tomorrow. At $108 shipped, I'll have peace of mind and if it gets dusty enough from laying on the shelf after this motor is finished, I may offer it up for sale on here and recoup some of the cost.

The dial bore gauge will leave marks on the bearing much more noticeable than the snap gauges. Just be careful and don’t move it around more than necessary.

Setting up the dial bore gauge may feel like a puzzle the first time. If you can gently mount the frame of your micrometer in a vise with soft jaws to support it you will have an easier time setting up. If you hold the frame of the micrometer in your hand long enough during setup or journal measurement, the micrometer will expand a little and your measurements will be off a tiny bit.