Masfel74

Goodmorning everyone!
I have a 1969 BB L36 Corvette, considering that the fan is really very heavy , I'm thinking to replace it with a plastic or aluminum ine, in other words lighter. Obviously the problem is to find a compatible fan to mount on the original clutch.
Does anyone have experience on this? Do not tell me to put an electric fan because I think it's not good as a solution
Thank you!

MelWff

here is a list of 5 fans but I would stick with the factory fan.
https://www.summitracing.com/search/...-block-mark-iv

cv67

You dont need a clutch with those, Ive been using them on/off since the late 80s they are awesome. Less wear on the water pump bearing and will never break. They look like cheap crap but cool well without the noise of the metal ones. We used to use them on the cars we ran at Saugus Speedway, turning a lot of rpm season after season, I still have one.
Ive ben using strictly electric on mine in search of that last few hp and dont like it. Putting the plastic one on at some point and will use the electric as a secondary run off a sender.
If I wasnt so ignorant Id use a controller but too lazy to learn about it.

IMO a nice electric only setup would be an OEM truck or V8 luxury car (or MB), with a controller but wiring upgrades arent my thing. Keep it simple, use the flex a lite plastic and if need be stick an electric on as a secondary. Now you can sit in 100 deg traffic all day with the AC on and never gauge watch.

Big2Bird

Wanna bet? I sent that same $54 Flexilite thru the hood of my dually.

Masfel74

Thanks a lot for the useful informations!

OldCarBum

I know you were asking about plastic fans, but did you consider Hayden aluminum flex fans.
I've installed them on many vehicles.
They are light weight, you can get rid of the heavy fan clutch they assist with cooling, are top quality and I have never heard anything negative about them.
I've also seen many used by forum members in photos.

cv67

Put these through a few hoods, stock clutch fans also.

https://www.summitracing.com/parts/flx-1317/overview/

Plastic ones I dont see how that can happen? They weigh a few oz

7T1vette

Do you remember why the Space Shuttle failed? Piece of FOAM blew a hole in the leading edge of one wing as it was gaining speed after launch. It doesn't matter how "light" something is, if it's going really fast. Turn a flex-fan 6000 revs and have one blade crack and fail? Shrapnel for the hood, etc. Not for me!!!

aussiejohn

Masfel, I won't tell you to put an electric fan on, but consider this. Every OEM auto manufacturer in the world fits electric fans to their cars and they would not do this if they were not as good as a belt driven one. I have electric fans on most of my classic cars and would never go back to a belt driven one. I have a single 16" fan on my '74 coupe and the engine is so much quieter when I'm driving, because the fan doesn't run at normal road speeds. It only comes on when I'm in slow moving traffic, etc. My '64 Caddy and '67 GMC are both fitted with a twin electric fan set up off an Australian Ford Falcon with thermostatic controllers. Fabulous!!!

Regards from Down Under.

aussiejohn

Dynra Rockets

I mounted an aluminum blade fan on the existing clutch. It was a Flex-a-lite 5717. While not super light but it was about 2.5 lbs lighter than the stock steel blade fan.

R

cv67

x2 on factory fans. Id bet they are way better quality than any aftermarket stuff we can buy. Think about it they have to last how many thousands of test cycles and continuous running?
The 16 in spal I have is Ok but think its way underpowered to most, noise I dont care about its gaige watching that bugs me. Temp up......then slowly back down. Then up...ugh. Steadier would be nice.
Esp with lash and lots of lift .

Big2Bird

I have dual spals on the 81, which is NO beast. The set up loses weight, and I am using the painless speed controller. It has trim pots so you can set it at any temp, and vary the on-off set points.It is connected to the A/C, so it comes on full when idling with the A/C in traffic, and I have it tied into the speedo sensor, so it goes off on the highway at any speed you choose. I set this at 35mph. Mechanical fans put out the least when you need them, and use the most HP when they do nothing. An electric fan set up the way I have it, I can get the most when you need it, and turns it off when it's not needed. 2 years and 8,000 miles later, I have yet to touch it again. Having the stock shroud and fan out of the way sure opens up the front of the engine compartment. You do need to upgrade the alternator, but my new unit is also lighter than stock.

lars

Before using one of those plastic fans, watch the Engine Masters dyno testing of the plastic fan....:
https://www.motortrendondemand.com/d...ut/0_olymz420/

Lars

Edit:
I'm being told that my link to the Engine Fan Test does not work... not sure what's going on, since it works every time I click on it... If the link does not work, Google "Engine Masters Cooling Fan Test" and open up the "Engine Masters: Season 2, Episode 20 Cooling Fan Shootout". It shows up as:

https://www.motortrendondemand.com/d...ut/0_olymz420/

cv67

Got a link to the painless piece Big 2 bird? I have a sender on my T56, if it stayed in a narrower range of temps or say automatically shut off over 35 mph Id be happy

Buccaneer

I've seen this before and was rather eye opening to say the least. Save your money and some HP and don't put a plastic fan on your motor. Go either electric or fan clutch style.

Big2Bird

I just looked. It appears they no longer produce it. Shame really, it's pretty slick. When/if it croaks, I'll have to go to plan B.

7T1vette

I was interested to see the video testing Lars suggested....but I couldn't stand to 'wade' thru all the commercials before I could get to the "bottom line". WOW! Is there any way to kill all that dead time?

Anyway, it was no surprise to see a high load loss for a fixed fan; nor was it unexpected to see a significant loss with the flex fan, but lower losses as the rpm flattened the blades out.

But what I wasn't able to find was how much loss there was with the stock thermo fan. That thing freewheels at a much lower rpm, if the temp doesn't engage it. I would suspect MUCH lower losses from it when fan not engaged. True? False? Was that even tested in this video?

MelWff

without a fan the engine generated 407 ft/lbs and 349 HP, with the stock thermo fan it generated 400 ft/lbs and 335 HP a loss of 14 HP.

lars

Results and numbers on that comparison at 6:20 into the video... Clutch fan consumed the least amount of torque and power with 7 ft/lbs and 14 hp.

Lars

Big2Bird

On a stock '81 that's 10% improvement without a fan.
I'll take it.