Excessive Fan Noise due to fan speed

[Kern Dog]

I do have video but would need to load it to my computer THEN to YouTube. I’ll gladly do that later.
While at the repair shop today getting the A/C done, I asked the man about fan noise. He agreed that some they have installed have been really loud.

 

[Kern Dog]

Jigsaw is my ratty Charger…

Something I just noticed…

Six blade fan. Look at the edge of the blades.

They have a notch on the trailing edge.

Now Lookie here.

OEM 7 blade.

The notch is on the leading edge as the fan spins. Does this reduce noise?

Here is the blade fan from Jigsaw.

I could use any of these three.
The pitch of the blades looks similar. The 7 blade fan is 1 pound lighter. That seems odd but using this gauge…

The 6 blade is 14 gauge and the 7 blade is 16.

 

[68 Sport Satellite]

For those arriving late to the party or forgot to read the earlier details:
I’m the OP. The fan clutch is brand new. So is the fan - a 6 blade from Bouchillon. KD is helping me since I hired him to do my AC install.
Previously i had no AC and an OEM 7 blade fixed steel fan. No excessive noise. Cooled great.
Adding the AC required using a smaller size water pump pulley to make room for the 4 groove crank pulley. Running the OEM fan made really loud noise above 2000 rpm due to higher fan speed. I asked yuu fellow mopar friends and many told me they had the same issue and swapping to a clutch fan solved the issue. KD recently installed for me my new Bouchillon 6 blade steel fan with low profile HD fan clutch 2947. The fan noise due to excessive fan speed is even worse than before. Early assessment seems to show the fan clutch is not releasing at all. Online searches show many using the HD fan clutches after brand new swaps are having the same issue.
KD has the same 2947 low profile fan clutch as I in his ratty Charger he calls Jigsaw but it is not excessively loud. The plan is to swap this into my car as a test. I may have a new fan clutch from Hayden that they wound too tight.

 

[68 Sport Satellite]

I already have a proper shroud. This is not a case of worn parts as it’s all new.

 

[Kern Dog]

S U C C E S S !!

I used the OEM 7 blade fan and the clutch from my own car. Fan noise is still there but about half as much. This is MUCH better than before and in my opinion, quite tolerable. I did record video but am out in the shop posting from my phone. I sent before and after videos to Dwayne.
You will be pleased.

 

[68 Sport Satellite]

Nice. So we have an option.
Does the 7 blade OEM with your old 2947 clutch sound louder than when you ran that in your car with the 5 blade? (I hope not) Is it quieter than when I had the fixed blade fan with the smaller AC pulley? (I hope so)

 

[Kern Dog]

It is hard to compare levels of noise without equipment. I do know that as it is now, it seems about the same as it was when the car got here when sitting inside the shop idling and revving up. I have not driven it yet.
To recap: It now has a factory 18" 7 blade fan mounted on my very low mile Hayden 2947 clutch. Putting my hand in front of the radiator, I can feel the pull even at idle. It holds a sheet of paper against the condenser at idle.
It is hard to compare how it feels compared to Jigsaw. That car has a different cam, headers, exhaust system, no carpet, holes in the firewall and a fan shroud with a different shape to it and I had a 5 blade fan on it.
Both 2947 clutches had similar amounts of resistance to turn so maybe the clutch wasn't the problem.
I have a similar fan in my red car:

This car has never overheated even in 110 degree weather here. I do run up to 205-210 but since the boiling point of a 50-50 mix of anti freeze and water is.....

267 degrees with a 16 lb radiator cap, I'm waaaay within the safety range.

 

[Kern Dog]

Fan noise with the 6 blade fan:



Fan noise with the 7 blade fan:



Pay close attention to the noise change as the engine is revved up a bit. The 6 blade was horrendous!

 

[68 Sport Satellite]

thanks. Tough to tell from the video sound, but I recall being there in person and hearing the original fixed blade fan after the AC pulley swap as I drove the car and it was intolerable. If the 6 blade clutch fan was just as bad or worse, getting back to where I was before with this OEM clutch fan is a welcome relief. Plus it's nice that the OEM 7 blade fan is lighter weight.
Thanks for resolving this so quickly!

 

[Kern Dog]

Tough to tell from the video sound.

I have admitted to having hearing deficiencies so I sometimes miss higher frequencies but this car, whoa.....
Maybe my ears were "looking" for it but it is as obvious as night and day for me. I can assure you it wasn't wishful thinking that the 7 blade fan was quieter.

 

[68 Sport Satellite]

I talked with Greg and after he installed the OEM 7 blade fan in my car with his lightly used 2947 shorty clutch, which gave us much lowered fan noise, he then took the new 2947 clutch that had been in my car and combined it with his on the shelf 5 blade fan. No loud noise from this. It appears that the new 6-blade Bouchillon fan combined with my smaller A/C pulley was primarily to blame for the excessive fan noise issue and not the new 2947 fan clutch. All is good now. Thanks for everyone's comments and thanks to Greg for having an available OEM fan for me to try.