'66 Valiant Running Hotter than Expected

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This is not a carb-too-small-problem. You could put a single barrel carb on the engine...& tune it to run rich at cruise speed.
On YT, there was a bloke who put a lawn mower carb on a 289 Ford......& it ran surprisingly well...& didn't overheat.
 
It may well be something else. It was just an idea. Good luck!
 
30 degrees of total timing is not a lot for that engine. What octane fuel are you using? What kind of water pump are you using? Are you running vacuum advance (ported or manifold)? Retarded timing can cause heat buildup. Best to run max timing the engine will tolerate for both economy & performance.
 
After I loosened up the ring gaps, my Eddie-headed 367 has run at least;
> 3 different cams from [email protected] > 223> the current 230; and
>Compression ratios from 10.7 to 11.3, currently 11ish; and
> with accompanying Cylinder Pressures approaching 195psi; and
> five different carbs from 500> 600> 750s> the big Thermoquad; And
> three different intakes; and
> I learned a thing or two about tuning distributors and timing; which btw is now 14 idle/28Power@2800, slowing to 32/34@3400; with 22* in the can. This lets me run 87E10 full time.

> But none of those things budged the temp-gauge significantly, except fixing the tight ring-gaps; and,
BTW, I run an ancient 26" A/C rad in a 22" opening, off a 73 Swinger 318 auto, at 7psi. Even the patches on that 50 year old rad, have patches.
From memory, it's a 2 row.

NONE of this is bragging.
I'm just relating to you, what worked for me.

Here's the thing; my engine runs the KB107hypers, and
The catalog suggests;
a skirt clearance of .0015> .0020, and a ring-gap factor of .0065
which on a 4.04 bore, works out to .0263.
When I picked up the block from the machine shop, the builder had already set the skirt to .003, which really pissed me off and I told him so too; cuz the whole reason I chose the Hypers was for the advertised tight-skirt running.
Well that didn't work out so good for me, even with the "loose" pistons.
When I freshened it up at the end of the First summer, after fighting overheat the whole time, I added another half a thou skirt clearance, so it ended at .0035skirt. And at the same time, I readjusted the rind gaps to KBs "towing" ring factor of .0080 which comes to .032/topring. Now I was really pissed.
Well, that finally did the trick! No more hot running.
And I was able to undo some of the tricks I had to do over the previous summer, to keep the engine alive.
and it turns out, that it was really good for fuel mileage too,
and a few years later, with the 230/110 cam, the car went 93mph in the Eighth. So .... I had to go back to the builder and eat crow; I hate that.

So bottom line; with the KB107s, what worked for me was;
skirt of .0035, and
gaps of; .032 top, and I think I did the Seconds at .029
which was half way in between the two gap-factors.
I'm pretty sure that, I couldda left the skirts at .003. It might even have been ok with less, I'll never know. and Yes, it does rattle on cold mornings, just a bit, for only a few seconds, but I have to almost listen for it.
Happy Hot-Rodding.
 
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.
 
30 degrees of total timing is not a lot for that engine. What octane fuel are you using? What kind of water pump are you using? Are you running vacuum advance (ported or manifold)? Retarded timing can cause heat buildup. Best to run max timing the engine will tolerate for both economy & performance.
@Jim Kueneman Since you didn't answer the questions, what did you disagree with?
 
Only thing I want say WRT timing is that based on the info Jim posted, it would seem that the cruise timing ought to tbe close enough that its not the cause of the problem.
 
Only thing I want say WRT timing is that based on the info Jim posted, it would seem that the cruise timing ought to tbe close enough that its not the cause of the problem.
He also posted that turning on the defrost helps a bit. That's an indicator that the radiator may need help.
 
He also posted that turning on the defrost helps a bit. That's an indicator that the radiator may need help.
Hah! I read his post that the heater did not help.
huh-gif.gif

So much for my reading comprehension.
 
30 degrees of total timing is not a lot for that engine. What octane fuel are you using? What kind of water pump are you using? Are you running vacuum advance (ported or manifold)? Retarded timing can cause heat buildup. Best to run max timing the engine will tolerate for both economy & performance.

Better do it now or I’ll forget.

Rebuilt (local friend) OEM factory pump with AC 6 vane impeller that was pressed on to the correct distance to the housing

Ported vacuum advance with NOS pot. Verified 52 degrees all, all in.

I have not seen a few degrees of timing make much difference based on the 318 experience in the Coronet years ago
 
Would be nice to see what the motor was "actually" running at, with a modern day temp gauge. The car could be running right where it should. Relying on a 40-50 year old gauge isn't always the best.

I would bump the timing to 34˙ all in.
 
He also posted that turning on the defrost helps a bit. That's an indicator that the radiator may need help.

It’s pretty much where I am to Rusty. The duster doesn’t have any problem but recall the duster I actually put a 73 and up radiator support and the big 26 inch radiator. That could be the main reason why that one doesn’t have a problem. This is just a narrow 22 inch radiator, that’s all they did in the early days even with air conditioning I was just hopeful that the aluminum heads and having Bob do a four core would make a difference, but seems like I’m wrong
 
It’s pretty much where I am to Rusty. The duster doesn’t have any problem but recall the duster I actually put a 73 and up radiator support and the big 26 inch radiator. That could be the main reason why that one doesn’t have a problem. This is just a narrow 22 inch radiator, that’s all they did in the early days even with air conditioning I was just hopeful that the aluminum heads and having Bob do a four core would make a difference, but seems like I’m wrong

In the Coronet had the same problem with the 26 inch radiator
 
I’m gonna backpedal on the 30° all in statement. That was for the slant six to be honest I don’t remember where I set it but I’m going to bet I said it more in the 32 to 34 range since I had the aluminum heads. I’ll have to go measure it again.

I do know that they’ve all in with vacuum will be between 52 and 54 cause that’s where I try to hit with all my cars
 
We have to get over 135 posts for this to be a valid thread, like the others .

I know! The only reason I posted this, as I’ve been down this road before, is how many bloody bugs there was on the bottom side of the hood! I have never seen that before. There was clearly more bugs, splattered on the bottom of the hood, then there was on the front of the car, it just didn’t seem normal to me

And I mean a lot more bugs
 
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I know! The only reason I posted this, as I’ve been down this road before, is how many bloody bugs there was on the bottom side of the hood! I have never seen that before. There was clearly more bugs, splattered on the bottom of the hood, then there was on the front of the car, it just didn’t seem normal to me
How far does the fan blades stick out of your shroud?
 
How far does the fan blades stick out of your shroud?

Whatever the factory intended everything’s original OEM air conditioning 66 parts. I think it’s about an inch or so.

And I doubt if the fan has a whole lot to do with anything at 80 miles an hour!
 
Just trying to get something substantive to start process of elimination.
Is it really hot, does the rad shed sufficient heat, is the rad plugged with bugs, does it have a partial plugged core, bottom hose sucks shut closed on high rpm, - stuff like that . lol

If the rad is shedding 100* and it's still getting hot, and your other car is only shedding 70* and stays cool, ? ?
 
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Just trying to get something substantive to start process of elimination.
Is it really hot, does the rad shed sufficient heat, is the rad plugged with bugs, does it have a partial plugged core, bottom hose sucks shut closed on high rpm, - stuff like that . lol

Haven’t followed my build threads I see! My cars are spotless show cars. Bugs are not allowed to remain after each drive. No expense spared restorations with as much OEM stuff I can find. The radiator hose thing I’m my opinion is a bit of a myth. They did that back in the day because they pulled a vacuum on the system in the factory to get air out. Hoses today are much stiffer as well (again I’m fussy and only use the best I can find in todays world. Dayco and Delco are the best most stiff hose I can find)

IMG_4708.jpeg
 
Haven’t followed my build threads I see! My cars are spotless show cars. Bugs are not allowed to remain after each drive. No expense spared restorations with as much OEM stuff I can find. The radiator hose thing I’m my opinion is a bit of a myth. They did that back in the day because they pulled a vacuum on the system in the factory to get air out. Hoses today are much stiffer as well (again I’m fussy and only use the best I can find in todays world. Dayco and Delco are the best most stiff hose I can find)

View attachment 1716159231

Very, very nice rides, I do beg to differ with the hoses sucking closed, as thru the decades of experience, I have actually seen it occur, but most folks don't look at the bottom rad hose, if it can be seen, and don't look at it when revving at hiway speed.
I've literally seen a few hoses suck flat at 3k rpm, especially older soft hoses without a spring.
The spring has a very valid use, especially when using higher capacity pumps, pulleys, and rpms way above factory "normal", and the rad is/isn't partially restricted .
Good luck
 
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Very, very nice rides, I do beg to differ with the hoses sucking closed, as thru the decades of experience, I have actually seen it occur, but most folks don't look at the bottom rad hose, if it can be seen, and don't look at it when revving at hiway speed.
I've literally seen a few hoses suck flat at 3k rpm, especially older soft hoses without a spring.
The spring has a very valid use, especially when using higher capacity pumps, pulleys, and rpms way above factory "normal", and the rad is/isn't partially restricted .
Good luck

Agree totally with high volume pumps and partially plugged systems. Much like a furnace with plugged filter and how it trys to collapse the duct work
 
It’s pretty much where I am to Rusty. The duster doesn’t have any problem but recall the duster I actually put a 73 and up radiator support and the big 26 inch radiator. That could be the main reason why that one doesn’t have a problem. This is just a narrow 22 inch radiator, that’s all they did in the early days even with air conditioning I was just hopeful that the aluminum heads and having Bob do a four core would make a difference, but seems like I’m wrong
There's been a lot of studies that show an efficient 2 row radiator with 1" or 1.25" tubes will out cool a four row. The theory is that once you start stacking so many rows in front of each other, they block air flow. I'm no thermodynamics guru, but that sounds very plausible to me.
 
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