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#22846 04/09/2003 4:35 AM | Joined: Aug 2001 Posts: 44 New Guy | | New Guy Joined: Aug 2001 Posts: 44 | I hope some one out there may have the answer to this dilemma.
I have a 59-261 I am putting in a 51 1/2 ton. I replicated the shaft length from a short shaft water pump at 4 1/2 inches from the tip of the shaft to the base of the pump at the block mating surface. The front of the fan mounting hub is 4 1/8 from the base of the pump. I have a 2 1/8 deep 6.25 inch diameter pulley that locates the belt 2 inches from the block - exactly the same dimensions as the original long shaft pump and pulley. The clearance from the pump shaft to the radiator is 7/8 inch.
The problem is that the fan I though was the original fan (18 inch diameter), hits the harmonic balancer (7.25 inch diameter). The distance from the center of the pump shaft to the center of the crank balancer is 7.75 inches. Can some one tell me if they have a similar set up, what size fan will work?
Are the dimensions for the short shaft pump correct as above?
Are the electric pusher fans mentioned in some of the past threads an alternative to no fan at all?
41 Chev 2dr coupe
51 3100 w/a 261
11 Camaro RS ragtop
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#22847 04/09/2003 4:47 AM | Joined: Feb 2003 Posts: 1,377 'Bolter | | 'Bolter Joined: Feb 2003 Posts: 1,377 | You will have to get a smaller diameter fan as the original for the 216 and your 261 will be too big. When the pump was longer, the original fan for the 261 would clear the balancer. Its time to hit the junkyard or parts store. I ran into the same problem when installing a 57 235 in my 37,I installed a electric pusher and so far no problems. Jeff | | |
#22848 04/09/2003 10:43 AM | Joined: Jan 2000 Posts: 1,586 Extreme Gabster | | Extreme Gabster Joined: Jan 2000 Posts: 1,586 | I have short shaft water pumps on a 51 and 37, both with 261 engines.Both have the stock fans,using a spacer between the fan and pump pulley.About an inch or so clearance between the fan and radiator and the blades clear the pulley by a hair.I also modified both radiators, moved the mounting flanges a little to get the radiator foward as possible.The lower water pump and fan position leaves something to be desired when using a 55 and later block in a original 216 truck. | | |
#22849 04/09/2003 2:53 PM | Joined: May 2002 Posts: 44 'Bolter | | 'Bolter Joined: May 2002 Posts: 44 | The other option is to notch the fan blades so that they will clear the balancer. It is quite common to see notched fan blades. Make a template with a nice radius for the corner of the cutout and trace the shape on each blade. Then, use a die-grinder or snips to cut. Smooth the edges and paint to match......Done
"The Operation of GMC trucks is normally smooth and steady, with no loud rattling, knocking or unusual noises. A good driver will quickly become accustomed to driving a GMC truck and will get the feel of his vehicle regardless of his engineering knowledge."-TM10-1563
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#22850 04/10/2003 3:10 PM | Joined: Dec 2000 Posts: 506 Shop Shark | | Shop Shark Joined: Dec 2000 Posts: 506 | Pusher electric fan placed at the top of radiator is a nice add on. 16" is what I used. Not much room as you say. Eliminating the waterpump fan will give you a little extra hp also.
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