Gang,
In the endless quest to have my cars run 180°-200°F in slow traffic on a hot day, I have a question. Subject car is a '66 Starfire with a stock-rebuilt 455, A/C equipped with 4 core copper/brass radiator. Nothing exotic.

My clutch activated fan blade is buried almost completely in my shroud. Right against the radiator rear with 1/2" of clearance against the rear fins.

I believe conventional wisdom is to have the fan blades half-in/half out. I'm not even close to that, but I can get there by getting longer fan bolts and shimming the fan backwards by a washer or 3.

Do you all have thoughts on whether moving the fan blade backward will make much difference? I thought I'd poll you all before burning half a day fooling with washers and skinned knuckles.

Opinions?

Thanks in advance
Chris

 

Maybe you can use the lower profile fan clutch?
You will need to check if the bolt pattern will match up with your water pump and fan blade.

Check out the Hayden part number 2947

 

I like the kick-in temp and depth of the current clutch, but you're right, I could use a shorter length fan.

Key question is how much difference moving the fan rearward by 3/8" - 1/2" makes. I've never seen information on that. Subjective or otherwise.

Hayden has wide variety of clutches that fit and I've tested a bunch of 'em. At this stage I'm at "Quiet, but hotter" vs. "Loud as a 747, but cooler"

So I'm looking for a reliable middle ground without getting exotic...

Cheers
Chris

 

Maybe you have a long waterpump om your 455 and it calls for the shorter one for a 425 Starfire?

 

Why? What does it run at now on a hot day? Your quest may be quixotic.

 

I think you should burn half a day. There was a reason the factory produced cars with half-in-half-out configuration.

 

if 200 degrees is as hot as it gets in traffic, relax. Don’t fix what ain’t broke!!

what’s the temp while driving on the highway?

Before doing anything, I’d call Hayden and discuss your concerns with them. Take some detailed measurements of your existing clutch. Maybe they could recommend a part number that will do exactly what you’re hoping to accomplish.

 

Gang,
Many thanks for your comments. My nervousness may be PTSD from overheating events in the past. I’ve had ‘66 Olds big cars since the early ‘80’s and been on many adventures, good & bad with them. Broken A-arms, snapped rear trailing arms, an engine fire or 2, and a few hot engine events…

In my ‘66 Starfire (455 with stock Freon A/C),l with the A/C on, in traffic, or at speeds averaging < 20mph, the temperature gauge gets past 210° which is when I start to worry. I’m happiest at 180-190°F, but near SF, we’re getting more & more hot days now in Summer. In a given year we get 14-21 days >95°F. When I was young, we had 2-5 days at those temperatures per year.

On those hot days, if I have the Starfire out & running, A/C is a natural choice, but then the engine temps creep up and I get nervous not knowing when the traffic will end (and I can speed up…) and knowing the temps will not go down until past sunset.

So I’m casually digging around for inexpensive tests to run since this car runs mostly in Winter (much cooler then here in SF — 40-65°F), but wondering if there’s a technical combination of radiator, fan, fan clutch which might keep my temps <200°F with the A/C running on a hot day.

My mechanic believes copper/brass 4 row with high fin density is the best you can get. I’ve never tried Aluminum radiators, but I’m open. What are your views on that.

And if we’re going Aluminum, well who makes good ones (probably USA made) in ‘66 big cars sizes? Tweaky request to be sure. But it’s not like I can just get ‘66 big cars stuff out of a catalog, so recommendations are most welcome.

I pulled a spare fan and clutch from storage today and will note bolt length to run the test. The spare unit has a Hayden clutch fan and 7 blade fan which I tested 10 years back, but it was loud as hell, so I yanked it in favor of “quieter, but hotter” 6 blade solution at the time. Looks like I have a half day or so of testing ahead of me.

Many thanks for your thoughts & experiences

Chris

 

Chris, I can speak to the technical diferences between copper/brass and aluminum radiators.

1) the heat transfer capacity of the copper/brass alloy is 120 W/m K
2) that of solder is 34 W/m K
3) overall, as built, a copper/brass radiator with solder has heat transfer of about 90 W/m K
4) aluminum alloy has heat transfer rate of about 180 W/m K and there is no solder to lower the effective rate
5) aluminum radiators have wider tubes and about a third more layers, giving more area to shed heat

Overall, aluminum radiators transfer more heat than copper/brass radiators.

 

Gary
That's exactly the kind of information I'm looking for. Many thanks. Now to get on the hunt for a domestic aluminum radiator manufacturer who builds things for 66 Big Oldsmobiles.

I think I've been down this road before and always wind up envious of the A-body crowd. I can get stuff made, but hoping there's something out there for us, maybe branded for Caddy or something.

Many thanks again.
Chris