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Author Topic:   overheating
Dirt Newbie

Total posts: 1
posted June 04, 2001 11:43 PM
I really need some partners and Street Stock at a local track in Lubbock, Texas......temps can be in the 90's during hot laps and first heats.....I can't keep my car is a 350 Chevy.....4 bolt main......decked 20 off the block and 26 off the heads.....ported heads.....Howe aluminum racing radiator......22-24 pound radiator around 6,500 rpm on a quarter mile track.......have a stock water pump.....reduction pulley on the crank.....middle size washer in the water neck.......good shroud....etc.....but....still overheats.....will come into the pits at 240 after a 10 lap me please.....thanks......Charles Chambers......#69.....I-27 Speedworld...Lubbock, Texas.......

Dirt Forum Racer

Total posts: 93
posted June 05, 2001 10:47 AM
There could be several reasons why or a combination of them. First you have to make sure you are getting adequate air flow throught the radiator, the first way to check is to remove any aftermarket nose or covering in front of radiator, proper ductwork directing airflow to the radiator is neccessary and you have to use a dam under the radiator making air rise instead of go under car. Don't forget fin maintenance. If your gonna run a stock pump, you better have the washer riveted to the back of the impellar, I have ran a heavy truck pump this way with great success. You also need to make sure the radiator is tilted back a few degrees, like 10 or 15 parrallel with the fan blades. Also make sure you are running the proper fan, I have had great success with the old 4 blade truck fans. Also check your plugs, a lean condition can cause heat as well, a nice dose of cold gas can cool alot. I am sure their are more like detonation due to cam overlap etc. but these are usually the basics. And if all else fails, water wetter can sometimes work miracles.

[This message has been edited by Racer4 (edited June 05, 2001).]

Dirt Administrator

Total posts: 3279
posted June 05, 2001 02:22 PM UIN: 16262997
Get rid of the reduction pulley and put at least a 1 to 1 ratio set of pulleys on it...

It will pull more air thru the radiator which will cool better, turn the pump a little faster to help your block pressure. It will probably fix you up.


Dirt Roller

Total posts: 6
posted June 05, 2001 05:19 PM
Charles, sounds like your having a common problem that we have all experienced. To be real honest with you the stock water pump is not going to work because of stamped steel impellers. Even some of the aluminum high flow racing pumps ($50.00 to $60.00 dollar range) still have the stock type impeller in them so if you buy one take the back off and see what you got. The pump that I have used for the past several years is an aluminum Moroso with a vane type impeller. Jammin is right on driving the pump one to one. Your kidding yourself if you try to underdrive the system.In these dirt cars running on gas you need all the air flow and water flow you can get. If it helps I run the Moroso 5.40 crank pulley and a upper 5.5 pulley off like a 78 chevy pickup. This is a double pulley so you have drill the spot welds and knock off the bigger outer pulley. I use a Dayco top-cog belt #15300 and a one inch washer in the outlet. I also run the 19 inch fan. Just as soon sacrifice a few horses to keep the engine cool. Hope this helps

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