5 blade vs 7 blade clutch fan

-
What are the differences in cooling capability between the MP 5 blade viscous fan and this one I have here, which is a 7 blade unit, but I don't know what it came off of? Big block? Motorhome? Max cool package?

I'd like to use either of these on my 408 stroker, but what is the max rpm for these, considering the clutch will be replaced with a new one. :) it sure seems like this 7 blade unit can move a huge amount of air.

View attachment 1715221830

View attachment 1715221831
I have both and used both I stuck with the seven blade it kept the car cooler than the five blade and there was no performance differences on the track at all
 
Can you tell me the aluminum 7-blade fan part #? I have an original fixed blade 7-blade steel fan cooling my big block with 180F stat and 2-row Griffin 26" radiator. it stays 185-190 almost all of the time. However, if I'm idling in traffic longer than 15 minutes, which does happen occasionally, the engine temp will start to rise past 200. What surprised me is that I was stuck in a complete traffic jam dead stopped for 25 minutes and the temp rose to 230. I'm wondering if the aluminum 7-blade clutch fan at idle would keep it cooler. Not sure if the pitch could be different or maybe aluminum spins more freely being lighter weight?

Just thought I’d update this thread since I started it.
I ended up using the 7 blade fan shown in my original post, with the MP viscous clutch, on my ‘74 W200, original radiator and shroud. It’s a rebuilt 360, 10.5:1 compression with a little baby cam not worth mentioning. I have a Stewart Components 180* thermostat and I tell ya, the sob does not get any hotter than 180.
I’m driving the truck right now in 90 degree weather all over town, it stays at 180.

View attachment 1715757155

View attachment 1715757158
 
Can you tell me the aluminum 7-blade fan part #? I have an original fixed blade 7-blade steel fan cooling my big block with 180F stat and 2-row Griffin 26" radiator. it stays 185-190 almost all of the time. However, if I'm idling in traffic longer than 15 minutes, which does happen occasionally, the engine temp will start to rise past 200. What surprised me is that I was stuck in a complete traffic jam dead stopped for 25 minutes and the temp rose to 230. I'm wondering if the aluminum 7-blade clutch fan at idle would keep it cooler. Not sure if the pitch could be different or maybe aluminum spins more freely being lighter weight?
Are you running a shroud? Is the fan centered in it? It sounds like you got your cooling system pretty well together...
 
Are you running a shroud? Is the fan centered in it? It sounds like you got your cooling system pretty well together...
Yes and Yes. The only difference is I recently installed an A/C condenser and trans cooler in front of the radiator on the grill side. Maybe now it's not pulling enough air at idle...
 
Can you tell me the aluminum 7-blade fan part #? I have an original fixed blade 7-blade steel fan cooling my big block with 180F stat and 2-row Griffin 26" radiator. it stays 185-190 almost all of the time. However, if I'm idling in traffic longer than 15 minutes, which does happen occasionally, the engine temp will start to rise past 200. What surprised me is that I was stuck in a complete traffic jam dead stopped for 25 minutes and the temp rose to 230. I'm wondering if the aluminum 7-blade clutch fan at idle would keep it cooler. Not sure if the pitch could be different or maybe aluminum spins more freely being lighter weight?
I was looking on there I don’t see a part number on it. Strange. It may be on the backside of it where the clutch bolts to. I’ll look when I have it apart next time.
 
The funny looking 5 blade setup was used on M body up thru 1989. Nothing special. Very common fan.
Also on a 90 W-150 318 with a/c (clutch fan) Have read elsewhere that the blades are offset in order to reduce noise.
 
-
Back
Top