'66 Valiant Running Hotter than Expected
It is a 360 that has aluminum Edelbrock heads and a 4 core radiator by Bob at Glenray.. factory shroud, correct factory direct drive 7 blade fan, all lower factory grill area filler panels, and hood seal. It ran right in the middle (NOS gauge and sender) of the temp gauge till it hit 90F. After that I could modulate the temp by how fast I went.. the faster I cruised the hotter it got. Cruising around 80 MPH it got up in the 75% of the gauge. The car has AC but I have a leak to fix so I was not using it. From what I experienced I would not have been able to use it anyway.
I stopped to get gas and it hit the upper normal line at the red light (about 95F outside). I was disappointed, I was sure the aluminum heads and radiator would be fine.
When turnin an engine off, its normal for the coolant temperature to rise. This part is normal.
Now the interesting thing. On the way home at dusk through farm land there were a lot of bugs. The next morning I got them off the front of the car but when I opened the hood the BOTTOM of the hood around the fan was almost black from bug guts. The where thrown everywhere around the fan... I am scratching my head about if there is some weird aerodynamic of the '66 that causes a vacuum to first suck that many bugs up from.... ??? under the car????? and second if that is part of the cooling problem...
Yes I see fans toss all sorts of stuff from bugs to oil up at the hood. So you're thinking the bugs could not have come through the radiator and A/C condensor ? maybe, maybe not. But even if not there is air pressure under the chassis. Go fast enough and there is some lift on the front (hence the use of air dams at high speed). I don't think this (the bug splatter) is a big clue.
Put a spring in the lower radiator hose to keep the water pump from sucking and collapsing the hose.
Most people think with the modern hoses that they are not needed........but the factory thought they were needed....must've been a reason and this sounds exactly like what the reason might very well have been.
Carrol Smith stopped with the springs because he found the material used to make the hoses much better (and this was in the 1990s). That said, it can't hurt and I've done it myself as a belt and suspenders measure.
It is running around just a bit richer than ideal 14.7 (high 13's) at cruise and 11's at WOT (I think... I have slept since then). Oh and the last time it was at WOY was when I tuned it. :).
Closer to 14.7 will be hotter in the combustion than where it is now. I didn't look at the cam specs but high 13s is not surprising with a hot rod running at fairly closed throttle (cruising).
The gauge was right at the max normal range when I was at the off ramp red light after cruising for 80 miles an hour three hours. Once I hit the highway it would come down to about 3/4 to seven eights of the way to the max normal range.
OK. That is not surprising based on the temperature gage while running 80 mph, but certainly would make anyone uncomfortable.
I agree. That's entirely possible. I would be verifying with an IR temp gun.
IR Gun. Compare top tank to bottom tank temperatures after a drive. You could also do hoses. Flat black should provide a pretty decent hose temperature reading.
The question your trying to answer here is whether the radiator is working.
Yes, I was running the defroster experiment and it would bring it down quite a bit, but it brought me up quite a bit ha ha
If this didn't help (additional cooling capacity) then one possibility is the problem relates to coolant flow.
So I would focus on the following.
Is the pump and thermostat working at all ?
Test: From cold, remove radiator cap and start engine.
a. The pump should pull the fluid level down.
b. When the thermostat opens coolant will flow into the top tank.
Is the pump impeller matched to the pulley ratios? In other words is the pump turning too slow ? A/C pumps got a different pulley ratio.
