Lube on the backside on the thrustwasher

I notice it has been common practice on honda b-series engines to use a slight amount of moly lube on the backside of the thrust washer to hold it against the block during installation is this recommended or should the backside remain dry and clean during installation?

It's not something I personally do but in operation it'll have no negative consequences. The only thing I would say is that it can make it harder to get an accurate measurement on the thrust clearance.

Can't remember the last time I did an engine with a three piece thrust washer assembly, but do recall using a SMALL dab of plain old grease to hold the thrust washers in place. Remember, in service the oil will naturally make it's way behind them.

As Andre points out, if you leave it that late to check the thrust, there will probable be a false reading. Depending on the specific engine, I'd probably have done a 'dry' (lightly oiled) check before final assembly

As an apprentice, I'd seen more than one senior mechanic (AKA butchers) using loctite(!), even on the bearing shells where they fit in the block and rods! NOT recommended, on so many levels and, as you may expect, even in such low stress engines (it was a LONG time ago) there were bearing failures.