Is that WITH or WITHOUT a shroud? I'm guessing "without". With a shroud, I bet the fan placement in the shroud is FAR more important that the fan placement relative to the radiator. A first-gen Monte Carlo with a small-block had a 30-gallon drum for a shroud. I bet the fan was a foot away from the radiator. Here's an eBay pic I shamelessly stole (so it won't be available for long.)
(Lol, extreme shroud) Correct, I didn’t have the shroud on. But I do now: Radiator – Fan clutch = 1.574803 in Radiator – Fan blade = 1.811024 in Fan blade outside shroud = 0.5511811 in Fan blade pitch = 2-3/4" (Mopar 20 in 7 blade #3462186) Clutch = Hayden 2747HD Overall Height 3.34375 in Just worried that the radiator distance makes the clutch run engaged all the time.
1. Fan is way too deep in the shroud. 2. Fan is way too small for that shroud. 3. A "heavy-duty" fan is going to act like it's engaged because they have more drag than a "regular duty" clutch when not engaged. Yup, that's going to pull a lot of air. The fan may move a lot of air, but given 1 and 2, it's not going to do it effectively.
But, it’s the same shroud they had from factory (TA2040C), and this fan blade is 20” like original. It should match factory setup. My goal was just to move more air when disengaged so it doesn’t need to engage as often as standard duty clutch. buickperformanceclub.com/runhot.htm recommend to avoid the 5 blade and use 7 blade, and HD clutch is required. So, everything is wrong. I can’t move the fan out. And original 5 blade fan would not do any difference in depth. Should I search for another shroud or remove some material from this one?
Could shim the fan rearward with some washers but youre only talking about fractions of an inch. Do you have the long or short water pump?
I didn’t know it existed. I will search for it now. (I haven’t had thermal clutch before.) Short, high performance TA1537BHP
Nobody else gets “pucker factor”from spacing a fan back from the clutch? Without the lip on the clutch to center things up it seems like you could end up with a water pump killing out of balance situation really easily. Maybe I’m just paranoid...
The distance is fine. There was a gm tech article posted here a year or so ago. It tested the effectiveness of the fan vs. Blade depth in the shroud. There was barely a measurable difference with the fan in the perfect spot vs. Way too deep in the shroud or way to shallow. I went through this with my car. Ordered the hd clutch and it never disengaged. I ran it for a few weeks, even went down the highway at 3k for 30 minutes or so. I ordered the standard duty clutch and it works as it should. I'll try to find the part number..
Just noticed that Hayden have made a shorter version of 2747 called 2947. 2747 (HD) = 3.34375" total.... fan mount 1.625" 2947 (HD) = 2.707" total...... fan mount 1.09" 2765 (S) = 2.671875" total.... fan mount 1.09375" Which pulls back the fan blade 0.535" compared to the 2747. (Theoretically making my fan blade be: 1.0861811 outside shroud, 1.6638189" inside.) https://www.rockauto.com/en/moreinfo.php?pk=7669832 http://www.haydenauto.com/upload/HaydenAuto/Documents/Hayden_Low Profile Fan Clutch Flyer.pdf
