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Denny
05-14-2010, 10:29 AM
We run a 383 chevy motor in my son`s mod. But it always overheats, usually no less than 250, and up to 270. But when we tear it down, bearings and everything looks brand new. We use same carb, radiator, distributor, ect. on other motors and they are fine. We also had the block pressure checked and it come out ok. Anyone have any ideas on why or what is making this do that. Any imfo would be appreciated. Thanks

LFMotorsports
05-15-2010, 12:26 PM
Gas or Alky?? Guessing gas. How close is the fan to the radiator? What I've read is ~2" away from the radiator is a good location. Also, AFCO 4-blade fan pulls air better than the other fans with more blades. Lastly, some people put a larger diameter water pump pulley on to slow down the water "resinance" time in the radiator. Longer cooling time.

Just some thoughts and suggestions.

nikk
05-15-2010, 01:40 PM
Is anybody running fan shrouds on modifieds?

2138d_Racing
05-15-2010, 03:27 PM
Water pump moving water? Too much body sheetmetal in front of radiator blocking airflow? Thermostat stuck?

Erichofer77
05-16-2010, 01:14 AM
I had lots of overheating problems last year and now I have too cool problems!! Sounds odd huh??

After talking to kinder racing team I took some ideas they gave me on how they did it with gas and well like I said I put cardboard in front of my grill to warm it up!

1. Create a duct from front of nose to the radiator preventing air from going out the sides!

2. I run 25% reduction pullies but 1:1 works good too
3. I use a 5/8 radiator restrictor in bottom of radiator outlet! Available at speedway motors 4.99 I think
4 no thermostat
5. Good shroud covering atleast 95% of rad
6 . Single pass radiator creates less friction in rad causing less heat!
7. Good water pump
8. Keep 4 blade high pitch fan half in half out of shroud!


This may not be the typical setup for all cars but I will tell u that this is a great setup for gas! I can't get over 180* if I tried!

U may not need all this but u xan take these nessesary measures to make it happen

p.s since u don't have a grill in front u can make your bottom duct aim down a tad to give u a low pressure draft!

I hope thus helps u!

Other than that recheck timing and jetting
7.

buckmaster
05-16-2010, 03:40 PM
Had Over Heating Problems In Our Mod Also Running On Gas.we Found The Problem To Be Areverse Rotation Water Pump.we Installed Water Pump From Allstar Part#all31105.car Runs At 200 Deg.hope This Helps

dirtpartsdirect
05-27-2010, 09:44 PM
Cam shafts and gear your heads may be different on the steam holes as well it sounds crazy but i bet that is where your trouble is its cam or heads

Dirt Parts Direct
317-213-2975

lucknoluck
06-03-2010, 05:10 AM
We run a 383 chevy motor in my son`s mod. But it always overheats, usually no less than 250, and up to 270. But when we tear it down, bearings and everything looks brand new. We use same carb, radiator, distributor, ect. on other motors and they are fine. We also had the block pressure checked and it come out ok. Anyone have any ideas on why or what is making this do that. Any imfo would be appreciated. Thanks

If you run gas you have to run a fan shroud that is sealed against the radiator core and at least 1 inch past the fan blade.

Egoracing
06-03-2010, 06:51 AM
www.stewartcomponents.com
There is great info on the stewarts site.
What pressure radiator cap are you running and how old is it?
How old it the radiator and when was it cleaned last? About every few weeks it should be soaked for best results. Get a kiddie pool at Wal Mart and out the rad in it tubes up and fill with water to cover the fins and not the tubes and a few 3-4 drops of dawn liquid soap. Some soaps will attack aluminum and dawn will not. Every 30-45 minutes gently lift the rad and let it back down. You may need to replace the water and do not add soap after the first time. When the water stays clean check the tubes in the radiator and make sure they have not swollen up and closed off air flow. A dusty dry track will plug a radiator as fast as a sloppy muddy track.

hpontap
06-03-2010, 07:34 AM
Verify that the balancer ring has not slipped and the timing is way off.