Chopped 18" fan down to 17".

[john.thompson068]

So the 18" fan was too big. It was slightly larger than the 18" MP fan I replaced. I should have been smart and measured the opening and ordered a 1817 17" Flex a lite fan. So instead I first messaged the opening in my box to give me 19" from the previous maybe 18.50". Needless to say I had to re-drill some holes, reposition and add a couple extra brackets, but it is nothing that is noticeable when you look at the outside. I posted a picture just showing how I had to modify the side of the shroud just to accommodate even a 17" fan. The radiator is 25x20 four core aluminum.

I also cut a half inch off of all my fan blades. So now I won't have to struggle with any more fan clearance issues. I also built a piece for the bottom of the box like I mentioned in the earlier thread which will keep any air from being able to fill the low pressure zone through that opening in the bottom front of the radiator. Now all the air that will be getting sucked in to fill the low pressure zone behind the fan must all come through the radiator. So even though I feel kinda bad about having to chop up my brand new fan, I feel very confident that this fan will keep things running cooler. Even with the half inch removed, the blades are still bigger than the MP fan, and there are seven blades. You can see that all of the material I cut of the ends of the blades is only equal to 2.25" of fan blade. In the pictures it looks like it has way more than enough clearance, but there is only 1/2" between the end of the fan blade and the head of the machine screw which holds the shroud in place.

When I get enough money to repaint the car and put her together new again, I will buy another radiator, fan shroud kit, and proper size fan. This stuff is cheap any way. The rad is only a few hundred, the fan is only 50, and the shroud kit is only 50. I will use the lessons learned from this fan and do everything perfect next time.

 

[john.thompson068]

And I didn't cut off any fingers or parts of them!!! That is always good considering all I have to work with is a clamp and my kitchen counter top, or my foot holding the metal on the floor on top of my drill case.

 

[greenmonsta79]

I don't think I would have done that, you just threw the balance of the fan off and it will wear the front bearing in the water pump out.

 

[5.7 hemi]

If all the blades were cut the same, then balance should be there, kinda like drilling rotors, gotta do both sides the exact same or you'll be in trouble.

 

[john.thompson068]

I don't know either. The variance is a difference of about 9 thousands of an inch on each blade and also from blade to blade. I am beginning to think Green might be right. At 6000 rpm that could make a difference. Also, the slight differences in shape and weight at the end of the blades would create different forces on the blades. I'll just bite the bullet and order a new one. Lessons learned. Looks like I can work on wiring everything up for the electric fans and maybe spend some time at the pool this weekend. Then next week put an 1817 fan and the radiator in and not have to worry about anything. That is the most important thing anyway; not having to wonder if I am harming my bearings.

 

[john.thompson068]

If all the blades were cut the same, then balance should be there, kinda like drilling rotors, gotta do both sides the exact same or you'll be in trouble.

Unfortunately, I wasn't able to be exact, especially with my crude cutting method.

 

[john.thompson068]

Since I will have the correct fan for it in a few days anyway, I think I will retain the entire set up for the life of the car. It suddenly seems like it would be a waste to recycle that glorious set up over such small little issues. Actually, I think these fans are great value at less than 50$.

 

[john.thompson068]

Okay never mind. The fans were the same size. I am just an idiot. I can now see that it was a miracle I ever got the other fan to eventually clear everything and not make contact as the engine twisted. At first it actually was hitting a little under full throttle and I can see where the fan blades had been slightly ground down and bent in certain spots. But after a couple slight adjustments I was able to make it work. But I am not willing to damage a brand new fan again. I am not going through that again. I am not going to be an idiot anymore starting today!!!

 

[greenmonsta79]

Live and learn, I have done plenty of stupid stuff myself! nobody is exempt we are all human!! :icon_mrgreen: