"Charlie" has Overheating probs- Here are my Clues and please chime in with opinions!

This is a post also happening over on Slant Six....


It didn't help after all. Got her buttoned up, timing set, valve lash reset, idling smooth- and took her out yesterday and same deal. Runs nice, but after a 10-15 minute highway run it starts to creep up in temperature from 1/3rd of the gauge (160 'stat). Once it starts up past the halfway mark it continues to heat even if you slow down to 20-30 mph. Nice afternoon/evening about 83 degrees F. I let her get nearly to the last tick this time- and once shut off, steam and water out the outflow, temperature of the outside of the radiator about 180+ with another thermometer I have that goes to 220 degrees.

Moved the timing more advanced- up to 15 degrees BTDC- it controls the temperature better- actually will stay at 1/3rd to 1/2 temp gauge and more importantly, it will cool back down from a speed run like it ought to. . .unfortunately it won't idle without a miss and is hard to start cold. I can't hear detonation- but I'm not sure that it isn't occuring silently. No indication of detonation on the plugs either- nice clean light brown, no overheated ceramic or welded looking electrodes. . .Ran her at 44 degrees total advance (preset, mechanical, vacuum) for 8 months and she did great- got that idea from Mopar Action Mag and Erhenberg article from last year. . .dunno, could be the timing mark is slipped around on the vibration dampener too and all my calculations are squat! Looked close when comparing the distributor position though. . .

Now, what about a crack in the head? I wish I had taken it to be Magnafluxed while I had it off. Did closely inspect the thing, but. . .sigh. Look at previous pics- no obvious signs there.

Before I go to the time and expense of disassembly (again!), will try to see if combustion gases are getting into the radiator water a 'la TopHat's (/6) suggestion and procedure. Right now, going back to re-check the simplest stuff- good pump flow, clear water, clear radiator, flush and fill, etc.

Quick answer to a few other suggestions: no, no A/C so no condenser (one day!); exhaust is 1 7/8 short stack welded to 2.5 from the outlet point all the way back and new, not crushed; there Was crud inside the block when I replaced the freeze plugs, but we dug all we could out and then flushed- and the damned thing did run cool for over 8 months. . .? Radiator is a new (1 year installed) 3 row made for a V-8 and fills the hole in the front firewall completely like on my other one. Kept the little fan since it was cooling fine before late May, drat it!

I had friends with this problem in cars before and felt sorry for them having a "problem child" that overheated. . .what goes around. . .

Keep those thoughts and suggestions coming! Appreciate the help.

As far as the head gasket and the pistons being aftermarket are concerned, maybe it Has been overhauled- my first Slant dissection(?), as it were. Wish the previous owner was savvy and concerned enough to "pickle" the darned thing properly for storage!

Thanks to everyone with a thought!

Mike