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Author Topic:   40 LAP FEATURES
posted February 08, 2003 11:26 PM
Our track just posted its schedule for the 2003 season, which includes 2 40 lap - double point features in the mid summer. My car runs hot during a 20 lap feature. Looking for ideas to keep it alive for a 40 lapper. 383, 12.5 to 1, .535 lift solid cam, 2bbl, headers, 3spd, 6.00 gears, 3400 lb car (GM metric)on a 3/8 - 8 deg track in southern New Mexico. car has an aluminum radiator and a sprayer bar.

posted February 09, 2003 12:01 AM
make sure you have a good screen in front of the rad 'good shroud,bigger water pump pulley, jets,timing and get rid of the spin out bar never did see the point of spraying the track down in front of me

posted February 09, 2003 12:18 AM
buy a new radiator......don't tell me your old one is good........if it's good keep it for a spare then.....don't throw it out...LOL

Buy a new radiator that is as big as you can fit.....then put BOTH hoses in the right side tank...........and the filler neck on the left side.........then half way down on the right side tank there needs to be a baffle.......this will force the water across the fins to the left tank then water drops down and across the fins again to get out the bottom hose.........the flows the water across the cooling area twice.....and will cool about 30 percent better then conventional radiators.........

You can order one built this way from AFCO or you can build your own if you are handy. The AFCO one does NOT cost but about $10 EXTRA compared to the standard radiator....

This is what they use in BIG BLOCK east coast mods that run 14 to 1 compression on gas...................

posted February 09, 2003 05:11 AM
I had a heat problem in the stock car. The water temp comming out of the engine was 260, but leaving the raditor it was 180. I needed to get the water out of the engine sooner. By taking off the gear reduction setup and running the waterpump at crankshaft speed the problem went away, and the engine ran 180-200. Jeff's idea on the crossflow raditor is good, but your problem might be as mine was.

rico 08
posted February 09, 2003 09:12 AM
I used to run a spray bar only use it on cautions though,i quit using one after i got the combo to run cooler,also try maybe jetting a little richer and less timing 'cause the track will be slick anyway.

posted February 09, 2003 10:08 AM
Gene, I agree a gas motor needs to have 1 to 1 pullies.......NOT reduction pullies.

I would say this you move the water faster through the motor you are also moving it through the radiator faster.....if you temp was 180 out the bottom hose, that SHOULD have went up a little.....say to 190...because it's not sitting in the cool air taking heat away..........and at 190 in and then what out now???? I'm sure you understand where this is going......

Like I said, I AGREE on 1 to 1 on a gas motor............But the water temp out the bottom SHOULD be in the area of 150-160.....I know that is HARD to achieve, most people will end up around 165-175 out the bottom to get a SAFE margin........that will make the temp gauge show around 195-200 out the top............

Your gauge must show 210 -215 out the top of the motor NOW.......close???? Do the radiator deal and you will see 185-190, now when you got problems you got 1/2 lap to shut it off before you start hurting the motor.


posted February 09, 2003 10:25 AM
what do you set your timing at??
what plugs are you running??
these two things and jetting may be all you need to address.

one to one pulleys would be better.

or run no restrictor whatsoever with reduction pulleys.

a DOUBLE PASS radiator is great, been useing one for years. it did not change my temps whatsoever when i changed to it though. but i went with the smallest i could 16x26.

i use elect fans that are 16 in dia, thats why i use that size radiator, no sense having uncooled water passing thru the system.

posted February 09, 2003 11:31 AM
Most of these things are things I already use or have tried, except the Afco radiator. Checked their web site - decided to get one. I run a reduction pulley and restictor, I may try a different combo there. As for 66jj's questions: 32 degrees btc, AC R45TS, Holley 4412 with 77 jets (a little on the rich side already). If you can suggest a better plug, I would appreciate it.

posted February 09, 2003 12:24 PM
thats a hot plug for a stock gm hei motor.

with your compression you need a colder plug.

without all my parts books, all i can give you is a autolite #. you can use it to interchange if you hate autolites.

autolite plugs you should consider for sure.
these are non projected tip, and with your compression im assuming you have domes, and straight plug heads. 135,134,133,132 lower # is colder. id start 133 and if they foul which they shouldnt you can go up.

also 123 is a colder projected tip plug, that you can use with domed pistons if you have angle plug heads. thats the # i used you can start there if you have clearance.

32 degrees is conservative enough on timing, id stay there if your allready getting hot.

as for red. pulley and restrictors easy way to see if you need to speed up water is pull out the restrictor and try it.


if you have a infared pyrometer you can also check your water temp, at top and bottom of radiator, versus block temp, right of the track, if its really cool at the bottom going into the water pump. you need to move more water, which will get the hot water out of the motor sooner.

i wouldnt go buying radiators just yet.

its hard to fix this stuff in the winter but id write it all down, in a order your going to try it and stick to it... dont change too much like the radiator, or youll never know what was not working.

on a side note i went from a stock oem water pump, long with a plate i riveted on the back of the impellers to a alum one from speedway for 70 bucks and instantly had heating problems. just food for thought, it had curved vanes and should have moved way more water, but when i took it off the problem was solved.


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