More Fan Blades = Cooler Running?

[David B.]

This is probably one of those "Duh!" questions.

I have a '58 270 Duntov that runs up to 20 degrees hot (200 degrees) in slow traffic. Would moving up to a six-blade fan help?

Is it even possible to install a six-blade fan on this engine?

Thanks, guys.

Dave

[Duke W.]

Re: More Fan Blades = Cooler Running?

That's not abnormal.

When was the last time the radiator was rodded out or recored? Over time deposits build up that act as thermal insulators, which reduce heat transfer. I don't think most owners have any idea when their radiator was last serviced and they don't last forever.

If it pushes up to 220 that's what you should consider. If you put a 15 psi cap on it with a 50-50 glycol water mix the boilover temperature is 265F. In this case operating up to 230F is within the normal range - like modern Corvettes.

Set the idle at no less than 900 to maintain reasonable fan speed with the non-VAC distributor. The OE centrifugal maxes out at 28 @ 3700, so you should run the initial in the 8-12 range, and it should still run okay on regular, but if you get any detonation use mid-grade or premium.

The OE advertised CR is only 9.5:1, which is probably closer to 9:1 true, so it likely does not need premium even with the initial timing at 10 deg.

Duke

[David B.]

Re: More Fan Blades = Cooler Running?

Thanks, Duke. I don't know the history of my radiator, but even during extended idle, it's never gone beyond 200. Your comment makes me feel better about seeing 200.

[John F.]

Re: More Fan Blades = Cooler Running?

Also check your engine with an IR gun to see if the gauge is correct.