Fan spacer size?

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68383GTS

68383GTS

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I have a 71 Duster and I am dropping in a 318 and a 26'' radiator.Does anyone know how long of a fan spacer I need? Trying to figure out the size before I install the engine.I am guessing maybe a 2 inch?
 
I think mines 3", I can go check.


EDIT: 2 1/4" that puts the fan a little better than 2 inches from the rad, blade half in half out of the shroud.

318, 26" radiator. Dart Sport, but it should be the same.
 
Not to complicate matters but if there is a shroud involved then the fan depth inside the shroud is going to be the measurement you want and not how far from the radiator the fan is, right?
 
All things being equal (same engine, same size rad, same size shroud etc), it should fall half in half out like it should be, no?

There would be one other consideration, are all water pump snouts the same length? :toothy10:
 
Bad Sport said:
All things being equal (same engine, same size rad, same size shroud etc), it should fall half in half out like it should be, no?

There would be one other consideration, are all water pump snouts the same length? :toothy10:
Click to expand...

Pretty sure there are two different lengths out there, but other than that they are probably the same.
 
Yeah, it seems like I read somewhere there are, I wonder if it's the difference between the early cast and the late aluminum.
 
Bad Sport said:
Yeah, it seems like I read somewhere there are, I wonder if it's the difference between the early cast and the late aluminum.
Click to expand...

Yep, the stupid looking aluminum one with tubes all around the snout. :)
 
My '70 Dart w/ 318 (not sure about original radiator size) has a spacer that measures 1 3/8"

The car has a '70 up alum water pump
 

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cast aluminum uses a 3" deep pulley and the iron uses a 2 11/16 pulley. I shoot for 1" away from the radiator. I have seen at least 4 or 5 different length spacers. it all depends on the application. those spacers were used all across the board for all car and truck lines. it will also depend on whether or not you use a clutch or solid mount fan
 
If I put the power pulley laid flat with the spacer on it, the measurement is 4 5/16"
 

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73AbodEE said:
cast aluminum uses a 3" deep pulley and the iron uses a 2 11/16 pulley. I shoot for 1" away from the radiator
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That's only 5/16" difference between the two spacers. We're talking about 3" vs 1 3/8" spacers. (That's 1 5/8" difference) I don't know if mine was changed at some point, or if it is the correct one.

My pulley is 3" (alum water pump)
 
73AbodEE said:
cast aluminum uses a 3" deep pulley and the iron uses a 2 11/16 pulley. I shoot for 1" away from the radiator. I have seen at least 4 or 5 different length spacers. it all depends on the application. those spacers were used all across the board for all car and truck lines
Click to expand...

Thanks for some numbers. :)
I thought I remembered correctly that there were differences, but I didn't remember how much.

Personally I wouldn't do anything with it till the fan was where it was going to live, but...
 
TrailBeast said:
Thanks for some numbers. :)
I thought I remembered correctly that there were differences, but I didn't remember how much.

Personally I wouldn't do anything with it till the fan was where it was going to live, but...
Click to expand...

.............I'd wait also..............Jim, I have about 20 different size spacers if u happen to need something different...........kim..............
 
A little tip, The further back the fan is from the radiator the more air flow you will get over more of the radiator and I know this because of previous heating issues in which this did the job with no further heating issues. ex: if you have a 26" rad with a 16" fan your air flow coming thru is pretty much contained in that small area leaving an overall of 10" (5" per side) of your rad without much flow where moving your fan further back will increase the air flow over more of the rad.. That is MO..
 
cant use a 24 " diameter fan with that 26 " radiator. Fan will be 18" at most. That's why a shroud helps. I would just wait until I can hold the fan in place half in half out of the shroud and measure twice, buy once.
 
Jim,

You have to go by what your car needs. The fan should overlap the shroud by about 50%. This means that half of the depth of the fan should be inside the shroud, and half outside. This will help ensure that the fan pulls the air through the radiator better.

Put your parts together and find out how much shim you need to get your fan to be half in and half out of the shroud that you are running.
 
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