Over the past few months, I've been working on mechanical and electrical problems, beginning with the leaky head gasket that ended the first road trip. The pressure relief in the radiator was puking a nasty-looking creamy substance, obvious evidence of combustion gases and angtifreeze getting together. Now, parts for a 503 cubic inch GMC inline six are about as scarce as a chicken with lips, and that includes head gaskets! I finally located an original-equipment GMC valve grind gasket set up in Canada, the one and only one of an inventory of 40,000 obsolete gaskets the supplier had in stock! Ed had the gasket set shipped to me quickly. Since the compression leak seemed to be fairly small, I decided to try an "old school" fix before doing a full teardown. Some of you other oldtimers might recall a product known as "water glass"- - - -Sodium Silicate. It's a clear, viscous liquid that was used as radiator stop leak half a century ago. It works by seeping through head gasket leaks and hardening into "glass" with an 800-something degree melting point when it encounters the heat of the combustion chamber. It's used buy doing a thorough flush of the cooling system, and using straight water as a coolant, with a heavy dose of the silicate added as the sealer. Warm up the engine, shut it down, put a few pounds (3-5 PSI) of air pressure to the cooling system, and wait a few hours. Repeat as necessary. In this situation, it took 3 warmup/pressurize/cool down cycles before the radiator quit bubbling. OK, the leaky head gasket is fixed (maybe) and the gasket set is still unused!
Next problem- - - -the fan belt is rotten, and it's 1 inch wide! Ebay to the rescue- - - -I found a belt that was a pretty close fit, but the alternator mount and belt tensioner bracket had to be modified a little to get enough adjustment. The belt is on and tight- - - -nope, still no charge from the alternator! The 100 amp Leece-Neville alternator has a bad regulator, and it's set up for positive ground! Back to Ebay- - - -found a regulator! I also switched the ground polarity to negative by swapping some wires on the alternator so a Garmin GPS could be used as a speedometer. Next problem- - - -the add-on electric fuel pump is wired to a manual switch, which can be left on accidentally with the engine stopped and run the battery down. This gets replaced by an oil pressure switch to assure the pump stops every time the engine does, wit a push button bypass switch to fill the carburetor after a long shut down if necessary. On to other concerns- - - -the original-equipment coolant temp gauge doesn't work- - - -replace it with a direct-reading gauge and do a little temporary reconfiguring of the dash instruments so no permanent holes are added!
No parking brake- - - -fabricate a pieced of linkage from the brake handle beside the shifter to the HUGE disc brake at the back of the transmission!
Time for a trest drive, with only two weeks before the KC reunion. Ed and I have made plans to meet there and he will drive the truck the rest of the way to Denver- - - - -more to come!
