Distributor O-ring lubricant? Options

[Langing]

1994 Celica ST, 1.8L, Manual

Rebuilding the engine after 300,000 miles and an overheat incident. Need information that isn't in the BGB.

Trying to reassemble the IIA (distributor) into/on a 'remanufactured' head. The part of the assembly that goes into the head goes through a largish circular hole, and there is a large O-ring (distributor O-ring?) riding in a square cross-section groove cut into the IIA that supposedly seals the hole so oil does not escape from the head.

Some places I have read that the O-ring should be 'lubricated', but there is nothing about that in the Repair Manual (the big Green books). I had an unpleasant experience when I rebuilt the disk brakes a couple of years ago. Because of the 'lubricant' I used on the slider pins, the rubber ring absorbed something from the grease and made it swell such that the pins stopped sliding. Am I about to do something stupid again if I 'lubricate' this O-ring? And, what 'lubricant' or grease should be used to make that O-ring create a proper seal?

TIA

[Langing]

Thank you for the help, box and bitter. I continued looking on-line yesterday and found a handbook on o-rings and seals that I found overwhelming, considering that I got the O-ring in an engine rebuild kit so have no idea what material it is. It is called 'The Seal Man's O-Ring Handbook - Harvard Physics' and is packed with information that depends on knowing its material.

But I found it interesting that this source cross-references the compatibility of O-ring material type with thousands of different chemicals. Silicone seems not to effect O-rings of almost any material.

This handbook also is useful for explaining the various failure modes of O-rings, and how o deal with them.

Thanks again for your useful advice. It really helps to be able to turn to experts as I move from one uncertainty to another that I have never dealt with before, while rebuilding this engine. This is a FIRST for me!