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Author Topic:   Temp / h.p.
turnleft43
Dirt Full Roller

Total posts: 38
posted June 07, 2004 05:22 PM  
During the course of the races that ive been running the motor has been over heating. It takes about 6 to 10 laps before it reaches about 230 and i need to pull off. As the temp goes up does it take away from the h.p. in the motor ? The car seems to be pretty fast in the beginning then not so good before i pull off or is this just my imagination ?

19J
Dirt Freak

Total posts: 370
posted June 07, 2004 05:34 PM  
My car is the same way. No motor likes to run hot but then again you will get an exception here and there. Some guys like to run 220 but over that is gettin up there.

hughes
Dirt Maniac

Total posts: 194
posted June 07, 2004 07:26 PM  
Had the same problem. I was running the fancy reduction pulleys and the Day Motorsports fan. Chunk the upper pulley for a stock pulley and chunk that six blade junk from Day, and get a four blade fan from the Pontiac/ oldsmobile dealer. The fan is off of a olds diesel motor, (not the 6 cylinder 4-blade version it doesn't have that pitch, $36.00.)I think it was a late 80's model. It has alot of pitch and will pull some serious air. My car would get hot sittin at idle in the yard or during the race the heat would go up, then a caution would come out bump up 10- 15 degrees and never go back down after the race restarted. Then yep, another yellow. Bend over. I can find out the exact year, if you need it.

monteregal7
Dirt Maniac

Total posts: 126
posted June 07, 2004 07:31 PM  
Most will say that 220-225 is max HP for water temp. The problem is you need fresh air the the carb.

TxHobby3
Dirt Roller

Total posts: 9
posted June 07, 2004 10:10 PM  
We run the stock fan blade and alum. pulleys (standard, not reduction). I assume you are running a big radiator, if not, get one. We run a four core radiator out of a chevy pickup. The big thing is a fan shroud. We took a the stock shroud and added to it with sheet metal to help seal it off. When we broke in the cam, we ran it at 3000 RMP for 20 min. inside the shop. It was over 100 degrees in the shop and the water temp never got over 195. Does great on the track too.

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Gas on it!

slater00
Dirt Maniac

Total posts: 147
posted June 08, 2004 10:58 AM  
The best fan blade I ever seen was a plastic one, I believe you can get @ Speedway or Day.

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http://www.freewebs.com/redneckracingteam00/index.htm

WesternAuto17
Dirt Forum Champ
Total posts: 569
posted June 08, 2004 11:48 AM  
Most poeple with overheating trouble don't have proper shrouds, its all about the air flow.

I, along with a lot of other poeple, run reduction pullies and I have no trouble. I don't even need the fans on under green.

You have to get the shroud right before monkeying (sp?) with anything else.

redneck racing
Dirt Forum Champ
Total posts: 860
posted June 08, 2004 11:59 AM  
Were running distilled water with Hyper-lube in it, keeps the temp down was using the plastic fan but was breaking 1 a weekend due to rocks am thinking about using an electric fan but aint decided on it yet. Eddie

turnleft43
Dirt Full Roller

Total posts: 38
posted June 08, 2004 05:37 PM  
Thanks much for all the input.

eenfield
Dirt Maniac

Total posts: 116
posted June 08, 2004 06:46 PM  
When running a particular fan and shroud combo, remenber that the fan should be about 1/2 in and 1/2 out of the shroud, no more then 3/4 in. It should be sealed tight against the rad. Most any aggressive flex fan will do, though I like the plastic ones from Flexalite. Try running a 160deg Robertshaw style balanced thermostat and if you dont have the money for the good aluminum radiators, buy a parts store piece with extra capacity....usually reasonible in price.

wrenchturner10
Dirt Forum Racer

Total posts: 80
posted June 08, 2004 08:24 PM  
The problem we had sounds very simalar to yours. It had nothing to do with the rad, fan, or waterpump but had to do with the timing advancing to far. We pinned the distributor and set the timing at 34 degrees at 3000 RPM it fixed our problem and we run around 190 now, so don't overlook the timing as the source of your problem. Check all the little things that you might overlook.

o5racer
Dirt Freak

Total posts: 402
posted June 13, 2004 10:36 AM  
I had always heard that the ideal temp for a race engine was 200-210.

mavrik82
Dirt Forum Racer

Total posts: 93
posted June 13, 2004 03:17 PM  
The most commonly overlooked overheat problem on dirt track cars is DIRT!!! You may wash out the fins of your radiator but never get it all out. Take your radiator out, hold it up to a light. Garden hoses don't break up the clay. With the mod we pull the radiator every couple weeks and take it to the carwash.It can take a few dollars worth of quarters to get clean water to flow out the other side. Stay back with the wand and spray straight so you don't fold over the fins. Had a friend tried everything to stop overheating, lost a motor and beat up another because he was washing the radiator every week with a garden hose and assumed it was clear.Even if your not running hot, try it and you will see better cooling.

mavrik82
Dirt Forum Racer

Total posts: 93
posted June 13, 2004 03:20 PM  
By the way, your power loose when hot is due to the pistons getting tight from the heat.You very well may have some cylinder scoring, especially if you are using hypereutectic pistons. An engine will make good power hot, but cylinder clearances must be opened up to do it.

wermm
Dirt Maniac

Total posts: 107
posted June 13, 2004 07:46 PM  
on the cleaning the rad., I ruined one at the car wash. The best way that I have found is to get hold of a plastic 55 gal. barrel, drop the rad. down in it and fill with water. Let it sit for a couple of days then rinse with a hose. Works great, gets that old black Iowa dirt right out.

J3
Dirt Maniac

Total posts: 188
posted June 14, 2004 08:31 PM  
The best way I have found to clean a radiator, is to keep the dirt from getting in there in the first place. Go to Wal-mart and spend 5 bucks on the blue fiber home air conditioner filter. It does not have the hard cardboard sides. You can cut it to fit your radiator size, and it keeps all the dirt from getting in your radiator but doesn't hinder air flow. You can remove it and wash it extremly easy or even take it off at the track and clean it. Worked wonders for us and have not run hot since.

[This message has been edited by J3 (edited June 14, 2004).]

turnleft43
Dirt Full Roller

Total posts: 38
posted June 15, 2004 08:33 AM  
Yesterday we took off the 500 cfm holley and put on a 650 holley. In the garage the temp acted alot different. The temp got up too 188 idling then we opened up the carb for a few trying to see if the temp would rise like before. The temp was droping to 180 and staying there. After letting it idle again the temp went back to 188 and held.

Ego Racing
Dirt Forum Champ
Total posts: 724
posted June 15, 2004 03:06 PM  
Have you checked your Plugs? Sounds like the 500 is running lean and the 650 is running rich. This would explain the large temp difference.

turnleft43
Dirt Full Roller

Total posts: 38
posted June 19, 2004 07:40 AM  
A bigger carb didnt make a cooling difference but i could sure tell it helped the HP. So back to the basics and figure out the over heating. Thanks to all who replied.

    

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