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View Full Version : fan to radiator distance issues??



dirty white boy
06-01-2011, 01:33 PM
small block chevy,..with short pump,..got 11 1/2 inches between water pump snout an radiator,....not wanting a real long spacer on fan,....can move radiator mounts back a lil an maybe get distance down to 8 1/2,..how much longer is a long pump verses a short one?? an whats the longest fan spacer that is safe to run??tryin to get fan lest a inch from radiator,....thanks for any wisdom an for thought!

carowner73
06-02-2011, 01:08 AM
WHY?

wouldnt go over 3 inches on spacer, but as long as you build a good shroud, the distance from fan to radiator is almost irrelevant.

Egoracing
06-02-2011, 07:20 AM
A fan against the radiator is only going to pull air through the radiator in the area covered by the fan. If you use a shroud think of it as a funnel, the fan pulls air from the small end from the complete area at the top of the funnel. This will allow it to pull air through more of the radiator.

bushracing67
06-02-2011, 07:31 AM
i run a 4" spacer with a 17" allstar nylon fan and my shroud is about 6-7" the nylon fan is super light, which makes me more comfortable running a longer spacer

stock car driver
06-02-2011, 09:16 AM
Wow on busch 4 inch. I think your LUCKY..

Just run a 2 inch spacer and like ego said run a nice shroud.

Heres a picture of the shrouds I make and run. You can probably copy it?


http://www.jnjfab.com/gallery/gallerylarge.asp?picid=323

dirty white boy
06-02-2011, 01:29 PM
Wow on busch 4 inch. I think your LUCKY..

Just run a 2 inch spacer and like ego said run a nice shroud.

Heres a picture of the shrouds I make and run. You can probably copy it?


http://www.jnjfab.com/gallery/gallerylarge.asp?picid=323wow you an ego agree'in,..lol,....thanks for replying,..........how come all the "over heating" threads on here some body always posting to get fan 1 inch from radiator? nice shroud,..sure i can fab one up no problum,...just tryin to get it right the first time,...learnin as i go!

Egoracing
06-02-2011, 09:59 PM
Wow on busch 4 inch. I think your LUCKY..

Just run a 2 inch spacer and like ego said run a nice shroud.

Heres a picture of the shrouds I make and run. You can probably copy it?


http://www.jnjfab.com/gallery/gallerylarge.asp?picid=323

Nice work, that is what one should look like. I have seen WAY to many boxes with a tube connected for the fan.

bushracing67
06-02-2011, 10:29 PM
why am i lucky ?

stock car driver
06-03-2011, 01:35 PM
Ive never seen anyone say 1" from the radiator. But I skip most over heat threads because too much stupid stuff gets posted.

like add water weter, detergent, any old shroud will do, no restrictor, you need a restrictor, plastic fan, flex fan. etc. not into argueing.

I stay cool with what you see in the picture and I have 15-1 or more compression 400 block motors. I run water out of my hose.

Busch 4" spacer and you dont think thats lucky? Most cant keep a flex fan on a 3 inch spacer on a 4000 rpm street car.

merc123
06-06-2011, 09:15 PM
My engine builder said 3/4" from radiator is the best they have found for pulling air. With no shroud or holes in the nose we ran 210* on a 90* evening. We have a 3/4" hole water restrictor and that's it. Also it's only a 22" radiator.

bushracing67
06-06-2011, 10:01 PM
My engine builder said 3/4" from radiator is the best they have found for pulling air. With no shroud or holes in the nose we ran 210* on a 90* evening. We have a 3/4" hole water restrictor and that's it. Also it's only a 22" radiator.

on gas ? or alcohol ?


4" spacer, canton v-belt pulleys, victor jr water pump... never had a belt failure, or pump failure... all parts have at least 60 races on them.. last failure was my chineese wieand aluminum water pump housing busted, replaced with the victor in 2006 and never had another issue since... raced it last night, was on the track for almost an hour long feature (demo derby is more accurate) and never went over 180

Graff Spee
06-06-2011, 10:13 PM
I have had fans eat radiator at anything less than 2 inches. I run a DLM at 7 to 8 rpm. No shroud and I cut down my spacer on lathe to 3/4 inch off of w/ pump. Just so fan clears pulleys. I try to move that radiator weight as far back as possible. 4 blade GM style ridged fan.

bushracing67
06-06-2011, 10:15 PM
cant really do that in a street stock... radiator has to stay in front of steering box, unless you run a really narrow rad

dirty white boy
06-06-2011, 11:16 PM
cant really do that in a street stock... radiator has to stay in front of steering box, unless you run a really narrow rad
yup,..8 an 1/2 inches from radiator to short pump