Reducing blades to two on cooling fan - Page 2 - Alfa Romeo Bulletin Board & Forums
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post #16 of 21 (permalink) Old 10-20-2017, 07:11 PM
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Originally Posted by PSk View Post

Its a lovely original car, why are you chasing tiny amounts of hp on a stunningly original car? ... leave the fan on and enjoy your beautiful car
Originally Posted by Gordon Raymond View Post
Plastic fans become brittle with age. They are actually a type of nylon, I believe. They are a replacement item. The support ring in front of the hub MUST be used, the bolts NOT tightened terribly tight. If you fear they will loosen with use, put a dab of silicone sealant on the threads before tightening.
If you examine blown up fans, they will fail with a blade breaking off from a nick in the edge, or come apart at the hub, from over tightened bolts. It's not a bad plan to replace the fan every 5 or 6 years, buying new from one of our good sources.
Years ago in racing, we used to boil them in a large pot of water for 15 minutes before initial installation. The thought was it stabilized stresses in the material. This came from radio controled model airplane builders that did the same with thier nylon propellers.
All the short blade GTA fans were boiled, and many are still around. Maybe boiling had a benefit.
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post #17 of 21 (permalink) Old 10-25-2017, 06:21 AM Thread Starter
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Thank you all for your comments. I decided to remove the fan and take the car for a drive. I was surprised at how much quieter the engine was, eliminating the roar of the fan. Acceleration above 3000 was very significant and a pleasant improvement.

Based upon your comments about plastic fans coming apart, I’ve decided to install an electric fan. But which one?

1. Centerline’s fan (they don’t mention the manufacturer)
3. Flex-a-lite fan which has a controller/relay allowing slow starts and less amperage draw.

Your thoughts?... Thanking you all in advance.
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post #18 of 21 (permalink) Old 10-25-2017, 06:33 AM
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SPAL are good. Wes Ingram sells an aluminum cross flow radiator and he specifies a SPAL pusher fan. The one on my Spider is model # 30101505 and it moves a lot of air. Also mounting the fan as a pusher will free up some space in front of the engine and that will make some maintenance jobs easier.

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post #19 of 21 (permalink) Old 10-25-2017, 07:02 AM
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I agree with Ed, though others that use 'letrik fans may have other opinions. With vintage 101 or 750 1300 cars, these conversions are easily reversable, and offer a nice alternative for those that regularly drive these cars.

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post #20 of 21 (permalink) Old 10-25-2017, 08:43 AM
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SPAL over Centerline for me - I have used both on Alfas. With an oil cooler and 3 row high efficiency radiator core I have found a 9" SPAL pusher to be sufficient. YMMV.
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post #21 of 21 (permalink) Old 10-26-2017, 11:56 AM
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Originally Posted by Alleggerita View Post
I used to run without a fan all the time ... wouldn't consider it in current traffic.

Have an Autodelta fan in one car with all blades cut down to about 1.5". It won't cool enough even with a three row high efficiency core in standing traffic ... putting on the heater in hot weather almost does the trick. It's still in the car for looks but an electric SPAL pusher now sits in front of the radiator.

With a modern high efficiency radiator core a small electric pusher is all you need.

If you don't want to go electric, the smaller 1300, 1600 fan will use a bit less power.

I wouldn't consider taking out all blades but two in current traffic - never mind the potential hassle of having to balance the thing afterwards.

u need a full length blades for traffic ever with a extra capacity rad core. this is especially true if your motor is hopped up.

the fan shrouding make a huge difference also drawing more are through the rad. you can break the shroud and fan if you drive spiritedly without reinforced motor mounts due to excessive motor movement and the poor old school location of the drive-train mounts. dont ask how i know this... :-)
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