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My knowledge is that manufacturers wen't to alloy because of electrolysis with engine metals and the fact it's a lot cheaper and nothing to do with thermal conductivity.

cheaper, space saving/weigh reasons as well. Better thermals allows a smaller and cheaper rad. Back in the day alloy was prohibitively expensive once it was the same or cheaper the other benefits were a no brainer.


if you compare 80s cars with 90s and onward you will see all rads were typically 40-50mm thick in copper and then the same motors in the 90s got 20-25mm thick alloy ones and also the incidence of over heating also was less with the smaller rads.

Copper rad although copper itself has a conductivity of nearly 400 w-mk it is limited to about 60ish because of the solder joints and brass. All alloy is about 200 so about double as good as copper rad's worst points. Also coincides of their aprox double thickness.

I am trying to find a 6 cylinder CL/CM valiant 26” aluminium radiator in Australia but it’s really difficult. It seems they sourced the Mopar B body big block radiators as they are pretty much the same configuration including the mounting brackets and auto trans cooler inlet/outlet. Unfortunately it is very expensive to ship to Australia considering the exchange rate and would be near $450.

Charlescrown wrote:I don't think there's much between alloy and copper. Yes copper is better but is it that much better. Where did you get that fan. It doesn't look like a Valiant one to me. Why not put a couple of thermo fans on and set the temp to say 85 deg.

Good idea Charles, I put in the larger CL radiator with one of the ford thermo fans which I needed to grind down a section for clearance and set the temp to 85 degrees. It didn’t exceed 91 degrees in the shed at idle but I need to test it out with some heat in the turbo.

I don’t have room for both the Ford thermo fans but I reckon a couple of these would do the trick and should be able to fit two side by side. Also slimline so won’t need to grind any clearance

https://daviescraig.com.au/product/10-s ... n-12v-0147

The late model falcon single fan works just as good as the dual fans of not better and is low profile

delcowizzid wrote:The late model falcon single fan works just as good as the dual fans of not better and is low profile

Thanks I will keep that in mind if this doesn’t work. I just purchased a slimline 10” fan that will fit alongside the Ford fan.

I took it out for a run today in 33 degree heat with the 26” radiator and single thermo fan and it sat on around 93 degrees but soon reached 100 after idling for a minute or two. However I still need to modify and enlarge the radiator support panel opening another 50mm which I have started doing now.

Hopefully the combination of the second fan and larger opening will help bring the temps down.

Well you gotta think that the turbo heat is only happening for seconds. Most (I say most) people don't drive around under boost all day. I find my old Lancer gets hot only if it idles too long. It never overheats but hit's 90 when the fan is set to 85. I am only running a 2L Sigma radiator and a cheap electric fan. Driving hard under boost never causes a problem.

From the outside looking in, this just looks to be air flow through the radiator. When you’re moving, it doesn’t overheat, when you’re stopped and idling, it gets hot.
As Delcowizzard suggested, those Falcon fans are the go. Slim line and flow a lot of air. Whack one of those on and get some air flow through the radiator when the car is stationary and see what happens. You’d probably get away without opening up the radiator support panel as well.

Yeah I wish I knew about the single Ford fan earlier but anyway need to push on with what I have.


Bit of an update before going back to work tomorrow.

I am increasing the VK radiator hole to take the larger CL radiator.
Starts with drilling out lots of welds.
Cut out the old existing panel.
Cut down and reposition

Continued

Radiator bottom panel will get repaired
Both sides need trimming to get the desired opening size.
Resized panel on the left is temporarily held in place.
I assume bigger hole means more airflow