Cooling fan upgrade

[NCArachnid]

I'm contemplating upgrading my cooling fan in my '72 spider when I have the radiator out for the timing belt change/ alternator upgrade/ electronic ignition conversion. It occurred to me that in order to upgrade I need to know the original spec. I'm also keeping in mind that I will eventually be installing a built 2L. Does anyone know the cfm output of the original fan? Also does the stock temp sensor/ fan switch keep these engines operating in an ideal range or is there room for improvement there with a different temp switch?

[zachmac]

I'm contemplating upgrading my cooling fan in my '72 spider when I have the radiator out for the timing belt change/ alternator upgrade/ electronic ignition conversion. It occurred to me that in order to upgrade I need to know the original spec. I'm also keeping in mind that I will eventually be installing a built 2L. Does anyone know the cfm output of the original fan? Also does the stock temp sensor/ fan switch keep these engines operating in an ideal range or is there room for improvement there with a different temp switch?

I don't know the OEM CFM but I have a perfectlyy good working OEM spare if you want to buy it (make any reasonable offer) it came out of my 80 2L FI car and maintianed it's temperature below 190 in SC summer heat.

[NCArachnid]

Thanks for the offer, Jeff. I have a working fan from my '83 pininfarina with A/C and the '72 fan works fine, too. But because a 12" aftermarket fan from Spal, Zirgo, or Flex-a-lite is lighter, quiet and will pump out over 1200 cfm and about $75, it seems like a good option. Also, these fans are less than 2.5" thick which gives more clearance for a 2L.

I guess you're right, the easy thing would be to just swap in the newer spider fan. I'm always thinking about how to improve the original design though. 2010's technology vs. early 1980's. Looking at the fans, I think I would have to mount the '83 fan in the '72 housing because they are in different locations relative to the center of the car. Does that sound right?

[mdrburchette]

They're basically the same fan, aren't they? The fan on my 72 rarely comes on, and when it does, it cools the engine in a few seconds. Is the 2L really going to get too hot for the stock fan to handle?
This is the fan I have on my Lemons racer. The radiator is from a Volvo 240 so we needed a thinner fan to make it all fit:

[courtenay]

That's interesting, Denise. How is the fan attached to the radiator?

[manoa matt]

What I like about the stock fan is that I know when its on because I can hear it, plus I have three spares.

The aftemarket fans are ususally secured directly to the radiatior core itself with plastic ties that that go through from the front. The good is that the fan is close to the rad, and pulls air through the radiatior. The bad is that the vibration from the fan and just general bumping around of the car can cause the securing brackets to cut into or damage the delicate core tubes.

A bracket that holds the fan close to the radiatior, like the stock fan housing, will be more durable and less harm to the radiator, but the farther away the fan is from the radiatior surface, means the fan will pull air in from the sides instead of through the core, making it less efficient.

[zachmac]

I guess you're right, the easy thing would be to just swap in the newer spider fan. I'm always thinking about how to improve the original design thought. 2000's technology vs. early 1980's. Looking at the fans, I think I would have to mount the '83 fan in the '72 housing because they are in different locations relative to the center of the car. Does that sound right?[/quote]

I think the later fan would fit but I also have mounted a modern unit. I didn't do it for CFM though as the stock unit really was quite adequate. I did it to 1) reduce weight and 2) to reduce the amperage drawn. the modern units draw a lot less current and we all know our systems were pretty maxed out to start so every amp saved helps the lights and wipers. As far as the weight, it isn't a "racy thing" so much as a reduction on the vibration / loading on the radiator itself. Even the stock unit mounted to the outer edges puts a flex on the radiator that adds to cyclic stress.

As Matt said, in a properly functioning system the fan shouldn't come into play all that often. My car only needs it at stop lights in 90+ heat here in Aiken. I think you are usually a degree or two cooler in Charlotte. Crusing at anything over a crawl it stays just below the 9 on the 190 with a stock radiator. BTW, I also run and highly recommend Red Line's "water wetter " product. I know it sounds like BS but that stuff works!

Matt, I know it's on because the temperature gauge goes the right direction. I don't miss the noise!

[NCArachnid]

So the consensus is that the stock system is adequate but there may be a weight and electrical advantage. I was concerned that a 2L with 10:1 compression may overwhelm the cooling system. The theory that one upgrade taxes other systems which then must be addressed is what I was thinking.
I also have never trusted those through the core mounts for fans. Spal has a nice metal rod system that would set the fan back about 1/4 to 3/8 in. from the core and would mount to the rad. mounts.
I guess I may be over thinking it a bit. The only time my spider ever got hot was in stop and go traffic shortly after I changed my water pump. I didn't get all the air burped out likely.

[NCArachnid]

While doing the timing belt change this past week, I decided to pull the radiator and clean it up. Then I decided to replace the old fan assembly with a new light-weight, high cfm, low amp fan. I built an assembly for the fan that bolts to the original mounting points on the radiator. It also keeps the fan within about 1/8-1/4" of the core. I'm not a fabricator so I apologize for the crude nature of the mount. At least it is sturdy, light and I can easily go back to stock.

Frame from radiator side...


Frame from back after paint....


Mounted to radiator...haven't cleaned and painted radiator yet.


The fan is a Jeg's 10"/1000cfm/7amp. I used the stock wiring clip.

Now I just need to get it all back together.

[mdrburchette]

Looking good! Are you planning to attend Fiat Freakout since it's being held in our state this year?

[NCArachnid]

I'd love to go, but am very bummed out that my car is in pieces in the shop. We have a family camping weekend planned with the kids as well but I may sneak up Thursday night or Friday morning just to take a peek. I looked at the schedule but didn't see a real time that everyone would be together with their cars (car show style) to get ideas, meet people, and drool. When would be the best time for that?

[mdrburchette]

Friday afternoon you'll probably see most everyone since we'll be autocrossing yard karts close by and many people will be washing their cars and getting ready for the show. Friday evening we'll all be together after the cookout for the Friday night drive-in movie that will be held in the back lawn of the hotel, then Saturday morning until 2 at the Biltmore will be the car show. Saturday evening after the banquet is the parking lot jam and everyone will be out having a good time getting reacquainted with old friends and making new ones. Sunday around noon, there will be a gathering in Hendersonville too.
It would be great if you could stop by just to get a feel for what Freakout is all about and hopefully, your car will be back together in time for Labor Day weekend for the Dixie Fiatfest in Winston-Salem.

[spiderrey]

my fan mod, not complete but working. Needs some cleaning up of the rough edges and paint'

[lanciahf]

Spiderrey,

Do you have a close up photos of how your throttle linkage hooks up to the carb? I would like to get rid of the cam mounted bell crank.

Thanks,
Ralph

[NCArachnid]

Spiderrey,

Nice fan housing. Looks stock. Did you have to cut and re-radius the stock housing or did you find a fan that fit sans modifications? Engine is a beauty too! My 1600 sometimes begs me to buy dual carbies. So far I've ignored her.