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Author Topic:   Fans, Shrouds & Pulleys
Dirt Forum Racer

Total posts: 81
posted April 21, 2003 12:00 PM  
Another "Low-Buck Racing For Dummies" question (and I'm full of 'em):

We've got a stock 350 in a metric Monte. Re-fabbed a pretty serious and good shroud from the boneyard, the fan will be well within the shroud and probably around 4+ inches from the radiator (hence the shroud). I've got the top ducted and plan to do the same w/the sides and bottom (probably w/some old discarded LM nose plastic cut down).

Right now we have a 1-to-1 pulley setup, but will most likely get some reduction before the end of the year (or sooner depending on how the pump works while spinning like a mo-fo).

I guess my question is: I'm probably going to go w/a 6-blade metal fan from Summit (the $20 variety). I haven't heard too many good things about the flex fans, and I don't think I want to run a clutch fan even though it's a bomber.

Are we in the ballpark here? Is it gonna slush the water as opposed to moving it with 1-to-1 pulleys? Will it move enough air? (Front belt circles pump & crank; back belt grabs both plus power steering pump; got the top 2-groove pulley off an old Camaro and re-drilled to fit -- I believe the bottom is stock.)

Also, what's a good boneyard combo to get a little low-buck reduction while running two-groove pulleys?

Any ideas are greatly appreciated as always; this is one heckuva forum.

After that, I'm gonna have to figure out how to properly mount a Metric Rectabular Excrusion Bracket onto my Pneumatic Catalytic Inverter sytstem. I saved all the bearing grease from the stock woofers before stripping the interior ....

[This message has been edited by Deak-Jr (edited April 21, 2003).]

rico 08
Dirt Forum Champ
Total posts: 1139
posted April 21, 2003 12:15 PM  
The older two groove pulley that's 6 7/8 inch dia part #3956666 and the upper 7 1/8 inch part #3989305 are the ones that underdrive the accessories slightly,good luck finding them,they are very hard to find anymore.You're setup sounds good but you didn't mention any type of thermostat or any restrictor,i myself use a restrictor i've had the best results with one.If you run without one better keep an eye on the piston return springs.

Dirt Forum Racer

Total posts: 81
posted April 21, 2003 01:37 PM  
We've got a thermostat (not gutted) in right now ....

... and we ditched the piston return springs. Found out from a Bazooka Joe gum wrapper that Ziploc baggies filled with hydraulic fluid was the way to go. Of course, we had to wrap the bags in NASA heat-wrap ....

[This message has been edited by Deak-Jr (edited April 21, 2003).]

Dirt Forum Champ
Total posts: 5390
posted April 21, 2003 07:35 PM  
I got a fan out of an old bus and it works well. I get good airflow and never overheat.

Dirt Maniac

Total posts: 132
posted May 25, 2003 12:26 AM  
I got a new 4 core rad with a 17" 6 blade racin fan and I run a 160 thermostate... and my car runs at 180... thats been for two races this season... so, so far so good..... and Ia m runnin a 357 with 10.8/1 compresion

Dirt Forum Champ
Total posts: 823
posted May 25, 2003 08:16 AM  
i allways run a stat so my motor warms up BEFORE i race it. 180 high flow from mr gasket or moroso etc its all brass and opens with the flow of water. once your racing it stays open and is just a restrictor. but on cautions etc it will cool down to the stat rating.

1-1 pulleys is what you want.


Dirt Newbie

Total posts: 4
posted June 06, 2003 06:36 PM  
I just started racing this year and I first had a problem with overheating (230 degrees).
We tried different stuff and came up with this setup. now running (180 degrees)

2 core aluminum radiator
4 blade fan
gutted thermostat (make sure it is in right way)
fan blades 1/2 in 1/2 out of shroud
shroud or pannles going from radiator to nose (sides and top) holes in performance bodies nose.
reduction pullies ( 1:1 spin stuff way to fast)

on gas and running strait water one bottle of redline water wetter.

Dirt Maniac

Total posts: 132
posted June 07, 2003 02:34 AM  
one of my buddies tryied that exact setup except for the water wetter and well he had no luck....

[This message has been edited by dtd_93 (edited June 07, 2003).]

rico 08
Dirt Forum Champ
Total posts: 1139
posted June 07, 2003 09:51 AM  
A boneyard item for reduction is a top pulley off an old inline six i've heard.

Dirt Freak

Total posts: 370
posted June 08, 2003 10:14 PM  
Ive heard alot of contraversy about reduction pullies and burning gas I turn my 355s and 360s at 7800 rpm and I cant get by without my 30% crank reduction ps pumps new wouldnt last a month until I slowed them down as usual just my opinion Towman

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