All good input, thanks! I guess the question I should have asked....has anyone tried both a 6 blade flex fan and a 4 blade steel fan on the same engine/car and noticed any difference?
Thanks for that info and parts number. I wasn't bent on using that flex fan I posted in post 12 as that was an illustration to show that all flex fans are not created equal. https://www.amazon.com/Derale-17315...fa9272a1f&pd_rd_wg=0lPY3&ref_=pd_gw_ci_mcx_mi Sure look the same https://www.amazon.com/Mechanical-S...025fc1&pd_rd_wg=Jt2ga&pd_rd_i=B07N7RSQQ5&th=1 I've seen damage from fiber glass fans coming apart and have had at least one aluminum fan come apart. Luckily that one didn't cause any damage worth noting.
What car that was made within the last 25 years did not come factory-equipped with an electric fan? I never had one fail, but I've had to replace radiators that have plastic tanks.
While I'm not nearly as hard-core traditional as some here, I do draw the line some places. Electric fans is one of them. And I have owned a couple of cars with aftermarket electric fans and neither worked all that well.
I was planning a custom shroud and a light plastic flex fan on the Powergen pulley, extracted the proper depth fan mount from a bent 4 blade stocker. The shroud would have made distributor service damn near a coolant drain to get access. This is all behind the sexy deco grille/hood pieces on a 39 Std. The top tank, the grille opening up front, the closed forward hood sides, then the tunnels in the inner fenders. Dafuq I need a shroud for? The whole front end is already one. The only reason for plastic; light wt, black, it fits, low RPM stockish flatty. I have a stainless one just for fit but something bugs me about it. The weight on the nose of the Powergen is driving my choice of fan. In order, the fan hub shagged from the stock 4 blade, the pattern for an aluminum shroud, the temporary fan for fit.
While just as Steve I don't have a real thing against electric fans, to me they are a last resort just as they are on the transverse engine front wheel drive rig I have. On rods sometimes you don't have space for a fan between the water pump pulley and the radiator or as with my 48 the pulley is so damned low that the mechanical fan on the engine of choice misses over half of the radiator. I could have put an electric fan above my mechanical fan pretty easy or put a pusher on the top of the front side to cover the area that my mechanical fan didn't reach.
Had a vehicle that had only two blades on top. It made a fucking lot of noise when it was involved in certain aerodynamics....It would chop the air and go "CHOP...CHOP...CHOP". You could hear it coming from a distance if the air was tight. Other times we could sneak in to land or take off before anyone realized we were there...
I once traded my solid OEM fan for another guy's OEM clutch type. It was an 'even-up' trade except I had to also throw in a can of beer. That was back in my race-it-on-weekends days. I considered it a power upgrade.
Squirrel, Me having an engine test stand and swapping engines (SBC) often the unequally spaced fan blades make it so much easier and quicker to work. It has a larger gap for removing or tightening bolts, clamps, adjusting hoses etc as compared to the six or four blade fans. With a fan clutch you can clock that larger gap where you need it. I wonder if the design was to speed up the assembly line more than move more air.
I expect the easier servicing with uneven spaced blades is an unintended consequence. The designers generally went to a lot of trouble to make the customer happy, and didn't give a shit about the guy who had to work on it.
I'm replacing my 4-blade, fiberglass fan/w heavy-duty 6-blade, which seems to be a popular item for 55-57 Tbirds that are known to overheat. Whether noise will be a problem remains to be heard.
Same here, I'm going with the one posted by jmountainjr. An odd number of blades will be noisier, but cool better. Sadly, after re-locating the bolt holes in the Mopar 7 blade, Its 17.5" blades would be dangerously close to the top rad tank
I've been looking at fans off and on for about a week (trying to find a cheap used oem one). Chevy TF trucks (and I think the AD ones too) have an option for a "heavy duty" cooling fan of 6 blades vs the stock 4 blade (all fixed rigid), IF you can find one expect to pay $$$. Also from mid 60's down fixed rigid fans it looks like Ford has the uneven spacing more in 5 and 6 blades (GM has some 6 blades). I did notice that the Derale rigid fans are rated up to 8k rpm.
1oldtimer, see if Amazon has a Derale fan for your application. Had I known the part # for the fan I bought, I could have saved at least $30 + free shipping by buying it from Amazon.
Put a shroud kit on my coupe. Needed a 13” fan. Took my 15” Chevy six blade and cut an inch off each blade. Cleaned it up and used my bubble balancer to balance it up! Works great!
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