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]

Ok, Box, that brought back many memories (Photobucket). . . and reminded me why I cut my cableTV cable. . . but, now I believe I can show you exactly how the O-ring looks mounted on the distributor housing. It might be helpful for you to see a picture. Maybe I installed an incorrect O-ring. Who knows?



Measured the OD of the O-ring and it is > 0.5 mm larger than the nose of the housing. Seems to me when the nose is inserted into the orifice of the head, the O-ring will be pushed to the rear of the channel and be squeezed by the narrow orifice. When squeezed, I can imagine it would compress somewhat inward (toward the right in this photo), but I cannot see it completely filling that channel. You might be able to see a bit of scarring on the O-ring from my first attempt at assembling the IIA to the head without lubricant.

My concern here is that it is supposed to seal oil flowing past the O-ring, to the left, and without the O-ring completely filling the channel, there could potentially be oil covering a fair amount of the surface of the O-ring, as it filled in whatever empty space there might be in the channel. Maybe I should purchase another O-ring that I know was made for the distributor housing and compare them? Or, I could simply stop obsessing, and wait until I find an oil leak at the distributor end of the head after the engine has been reassembled?