Ok people, the white stuff I found on the threads of the screws holding the cylinder into the crankcase on my 65 (first trime strip) was analysised as part corrosion part "locking compound". This was done by the lab doing the spectro analysis of our engine oils (P&W JT8D). Like one of the correspondents I lube all the treads with ATF prior to installation on a rebuild. I use either SQ32 (Hylomar, "Rolls Royce Blue Glue" its other names) where sealing gaskets are required in fuel "systems" and RTV 105 (orange) for oil gasket seals. The SQ 32 also works there. ATF has been used as a preservative in my modelling circles since time immemorial, good stuff and handy. It is a smoother blend of MIL H 5056 (red hydraulic oil, mineral type). On torque wrenches, I have seen the "cone heads" (avionic techs) use them to torque up screws on LRU's (black boxes that drive modern a/c) in particular the mounting bolts on boards on the inside. I have one of these that reads as low as 2 inch/ pounds, however I generally use a calibrated right arm during model engine assembly. On the locktite thing they have a very good set of date on application of their various fastening liquids and they also have a number of release agents for this stuff. I use 742 with its appropriate release agent (forgot the number) as appropriate in my shed. I have also found that nail polish works as a locking agent and nail polish removes the need for excess force when one is trying to undo the bolt / screw.