Overheating issue - Ever heard of a "heat reducer"?

ONE MORE TIME

Water is H2O two gasses One of the major jobs of cooling liquid is taking heat away from the exhaust valve seats.

If you heat a pan of water air bubbles form Before it really begins to boil
The same thing happens inside the head.AND this air doesn't transmit heat as well as liquid so more heat more bubbles and so on

If you restrict the water flow out to the rad everything between the pump and the restriction has more pressure MORE PRESSURE HIGHER BOILING POINT ..... LESS BUBBLES! Better heat transmission!!!

It's really simple if you think about it

 

Remove the restrictor, build a shroud that's fits correctly, drill a 1/16" hole in the edge of the thermostat, make sure you didn't use underdriven water pump pulley (aftermarket are usually underdrive or 1:1 - stock is like 20% over-driven - this is real important on keeping cool at low rpm's (i.e. idle)), set the timing and check the advance. Run as low of a concentration of coolant as needed to prevent freezing in your area (more water the better) Now here's where the small hole comes in play.... drive the car so that the radiator is way higher than the engine block (i.e. ramps, steep drive, etc.). Let cool, remove radiator cap, start engine, set heater on hot (if equipped) and then fill the coolant as the engine runs - the hole will allow any air bubbles to bleed off quickly, let warm up, keep filling, then cap it.

If you do all that it should run cool enough at idle and HWY speeds - sounds like you're really close/marginal on the cooling capacity of the radiator, so everything has to be 'spot on' to make it run cool.

 

Is timing a cooling problem when it's too advanced, too retarded, or just too far off either way?

 

Get the timing right and install a recovery tank.


My touring would heat to 218 then the t stat would open up and the guage would drop. I had air in the system. I finally installed my recovery tank a couple weeks later. it allowed the air to be burped outta the system and the guage stayed normal afterwards.