67 Cuda Cooling

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67commando

67commando

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2.5 years later and I haven't done a thing with my 67' Cuda FB, other than start it and drive it rarely and confirm it is still running hot in summer and running ragged in the 30-40mph range. I was considering buying a 3-row Champion radiator to replace the non-original 68 318 high altitude radiator.

Anyone out there wish to chime in on Champion? If I go with it, should I buy the shroud too? I have that original 4-blade non-clutch fan so I guess I could replace it too...suggestions on where to buy that?

Thanks!
67 Cuda, 273 Commando, Auto, All Stock (exc paint, radiator and dual exhaust)
 
For sure it is hot at idle - worst situation by far is stop and go traffic on a 80+ day. On highway, I can keep the flow going enough that it doesn't happen as often, but the second I slow down, it starts to climb again.
 
This sounds more like a pump problem, or lack of airflow. If it will cool at any speed, then you likely have enough radiator.

Do you have a heater? Does and how good does it work, IE really hot, or "lukewarm?"

I'm in Coeur d Alene, by the way
 
Others addressed a possible pump problem in 2012 when I first brought it up. Never considered it but it sat not running in a barn/shop shortly after an engine rebuild in 1992 until I had it restored in 2010/11. I suppose the pump could be an issue. It never used to overheat before it sat and now it does often at idle. Heater works average I would say.

So near by in Idaho? Are you part of a MOPAR club?
 
The water pump impeller could have slipped on the shaft so that it is freewheeling. That means no cooling at low speeds.
 
Many years ago I had one that did similar. Another problem was how well it sounded from cold to warm. Even when maintaining a round town travel it would run hot enough to spark knock under load. Everything except a new radiator was tried. Well except a shroud I should say.
New radiator cured it without a shroud. Then I added aftermarket under dash a/c unit and it still wouldn't run hot when stuck in traffic without a shroud. Keep in mind I had previously installed a 7 blade fixed fan, etc...
The original radiator was clogged with barnacles, bottom of the core mostly. Simply not enough gallons per minute passing through it.
 
Thanks for the ideas thus far. I am beginning to think I ought to just replace the fan, radiator and pump and rule out all areas of weakness...
 
My 67 Commando has never had overheating problems. It has a factory 68 340 radiator (due to an accident, but that's basically the same as the 273 3-row), and a 7 blade fan, with no shroud. I have taken it to track days and run mountain rallies. So you seem to have something else going on. Start with the fan and water pump, I think.
 
67commando said:
Thanks for the ideas thus far. I am beginning to think I ought to just replace the fan, radiator and pump and rule out all areas of weakness...
Click to expand...

I would start with the fan, a 4 blade? That could be part of the problem, not pulling enough air through.
 
I agree with above and stick to my guns. I don't believe this is a rad. issue.
 
67commando said:
Thanks for the ideas thus far. I am beginning to think I ought to just replace the fan, radiator and pump and rule out all areas of weakness...
Click to expand...

I think you're on the right track, but maybe the wrong order. I would look at fan, pump and then radiator. You know your four blade fan isn't enough. I'd replace it with a five blade and a MP viscous fan clutch. If that doesn't solve your problem, look at replacing the water pump. I used a HD for police and taxi applications. If you make it to the radiator step, take your's to a local radiator shop and have them check it out. If your car is mostly stock, it should be fine after it is cleaned out or maybe recored. I bought a four core Champion w/dual electric fans for my 67, but it is a cut up hot rod, not a mostly original car. That's just my opinion.
 
I cant argue will the " try all the less expensive stuff first" approach. I took the same approach. I had spent my wad in the whole blown slant to rebuilt 318 and drive line so... In the end I had replaced everything from radiator cap to tail pipes.
 
Thanks for all the advice from everyone. If a 4 blade worked for 35 years, why wouldn't it work now; I keep asking myself that. But I will replace it first. Then the pump. As for the radiator, it was completely gone through during the restoration in 2011, but maybe they didn't really do much to it.
 
This might be an issue with 'pump design' or to put it another way, "pump not meeting spec." Somwhere on the vast www is an article where someone did experiments to increase flow with "modern" pumps. Part of this had to do with adding a back plate on the rotor do decrease rotor - to - timing cover clearance.

It also occurs, that wear and erosion in this area might be a concern.

I don't like "throwing parts" at a problem, but it might be worthwhile to try a different T stat and try and get the best one you can find.

Last, are you using different pulley sizes?
 
67commando said:
Thanks for all the advice from everyone. If a 4 blade worked for 35 years, why wouldn't it work now; I keep asking myself that. But I will replace it first. Then the pump. As for the radiator, it was completely gone through during the restoration in 2011, but maybe they didn't really do much to it.
Click to expand...

Did those cars not come with a shroud? I'm not well versed on the early A's so I'm not sure. If most of your issues are at idle and low speed a shroud and different fan might indeed help.

Also there was a thread a few weeks ago where someone was chasing overheating issues and it turned out to be the impeller on the water pump shaft was spinning on the shaft and not providing sufficient flow.
 
67commando said:
Thanks for all the advice from everyone. If a 4 blade worked for 35 years, why wouldn't it work now; I keep asking myself that. But I will replace it first. Then the pump. As for the radiator, it was completely gone through during the restoration in 2011, but maybe they didn't really do much to it.
Click to expand...

So it started get hot after you rebuilt the motor? Did they put in a new cam when they rebuilt it?

No replacement cam is 100% identical to your a factory cam. So things have changed.

Also, gas is not like the gas you had 25 years ago. More ethanol, more epa changes.
 
Bad Sport said:
Did those cars not come with a shroud? I'm not well versed on the early A's so I'm not sure. If most of your issues are at idle and low speed a shroud and different fan might indeed help.

Also there was a thread a few weeks ago where someone was chasing overheating issues and it turned out to be the impeller on the water pump shaft was spinning on the shaft and not providing sufficient flow.
Click to expand...

per factory manual

273-4bbl with auto or 4speed get 4 blade 17" fan, 2" wide blades, 2.38" fan spacer.

Now for C.A.P. (California Emissions) w/o A/C, cars with A/C... got 7 blade fan, 1.75" wide, with fan shroud, and 2.0" spacer.

CAP car with A/C got got 7 blade fan, 2.25" wide, with fan shroud, and viscous fan clutch.
 
Again great ideas by all... Thanks for the help. Not sure about the replacement parts as the work was done when my grandma owned it, but I think the guys threw high performance parts in it to increase prices. When the restoration was done in 2010/11 the engine guy said the parts were all high quality HP parts and looked to be in outstanding condition still. The discussion about gas is an issue I never thought of and then there is definitely a problem tuning the original Carter vacuum carb so it either starts great and runs rough at low speeds or it takes forever to start but runs good at all speeds. I ought to replace the carb but since the car was my grandma's, purchased by grandad, I am sentimental about replacing anything. I did change out the bright blue for dark blue though...
 
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