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Message started by old dirt racer on 12/19/11 at 6:35pm

Title: spark plugs
Post by old dirt racer on 12/19/11 at 6:35pm

how cold of plug can you run with msd ? looking for lower cylinder temps.

Title: Re: spark plugs
Post by RACEGLASS on 12/20/11 at 7:08am

You always want to run the coldest plug you can without it fouling. This will generate you the most horsepower as it slows the burn down and gives you a more thorough burn and not an explosion (detination) within the cylinder.

Title: Re: spark plugs
Post by sj_valley_dave on 12/20/11 at 10:39am

Running gas or alky, and what type of cylinder head will all play a part in the suggested heat range...

Title: Re: spark plugs
Post by old dirt racer on 12/20/11 at 4:27pm

running race gas 112 octane ,4412 ,76 jets ,67 cc 194 stock heads .last season car couldnt make it 25 lapes with out reaching 250 couple times 280 . , motor only turns around 6500. changed fan, triple pass rad, 3/4 restrictor dominater schroud ,40 below ,

Title: Re: spark plugs
Post by chevy68pickup on 12/20/11 at 6:37pm

I never used restrictors on any of my race motors, i always used a 190 thermostat with 2 1/4 inch holes driled across from each other and my cars ran 210 at 8500rpm. I no alot of people dont like to run thremostats but i proved to alot of people that had the problem you are having it works. and i use water wetter.

Title: Re: spark plugs
Post by old dirt racer on 12/20/11 at 6:51pm

thanks worth a try.

Title: Re: spark plugs
Post by Bap33 on 12/20/11 at 8:40pm

I run race gas, in the hot valley, in high compression engines. I am happy with 240 under yellow, 220 at speed.
1) Double pass, as big as will fit. Tripple pass is not a good idea ( I read an article that said it)
2) 1:1 pulleys
3) 5/8 restrictor in termo-housing
4) A good Howe steel fan
5) Good shroud covering at least the top and sides
6) 25psi cap or higher. A good race cap. And leave it loose all week. Only have it down tight on race-day.
7) A good water pump. I like the Weiand with the twisted neck and the 5/8 shaft.
8) If rules allow, tap into the water jackets at the back of the heads, through the intake, and pull that water to the thermo-housing with 1/2 line.
9) If rules allow, tap into water pump where the block entry ports are and bring that water to the block between the middle cylinders on each side, about 2" below the deck. Or (second choice) plumb into the heads where the sending unit bore is already there.
10) Wash out the radiator each week. I remove mine, bounce it face down on a soft wood surface until there is no more rocks and dirt, then I wash is out until the water flows clear, then I bang it face down somemore, and I put it back in .. takes about 20 mins and results in fresh water each week in the system. I use some cooling aid things that are not legal to use in racecars in California, but it lubes the water pump and keeps the alluminum radiator from getting all chocky.

That is what I do to run on gas. I keep the advance below 35* too. A lower compression 355 runs very cool with my current radiator, while a 406 with high compression gets warm. I have a larger radiator that cools even the big monsters, but does not fit a D&M nose.

Title: Re: spark plugs
Post by over4t on 12/21/11 at 9:11am

Fought the same problem of running 230-260 degrees with good high compression engines for a couple of years up here, where it's often 95 degrees or better. Tried lots of fans, radiators, restrictors, shrouds, etc. with little success. Talked to Griffin Radiators last year and followed most of their recommendations and now barely see 200 on a long hot night. Here's what worked for us.
Dirt style single pass Griffin radiator with 1-1/4" tubes. Ninety % of radiators sold have 1" tubes. Not cheap, around $290. They also make one with 1-1/2 " tubes. They don't recommend the 2 or 3 pass ones. 25 lb. cap.
Got a 4 blade fan with 32 degree blades from CV Products. Bout $35. Can also get one from GM but a few more bucks.
Made another shroud with fan about half in, half out. Try to keep the fan 2-4" from the radiator. Closest we can get is 4-1/2"..
Absolutely no restrictors.
Thirty % pulley reduction. They recommended 1-1 but wasn't easily doable on our car.
Clean the radiator from the back with low pressure hose weekly. Don't flatten the fins with a lot of pressure. I've always screened the front to keep the big chunks out.
Good water pump. Tried lots of them but the aluminum Summit one for about $80 works fine.
And the big thing they told me was to run only distilled water. no crap out of the hose as they said the crud in tap water will clog the tubes up in only a couple of nights and you'll never get it out. Add water wetter or the green stuff from NAPA that's the same thing.
We run 32-34 timing. And like Raceglass said run the coldest plug possible. This has been the best combo we've found. Hope this helps.

Title: Re: spark plugs
Post by old dirt racer on 12/21/11 at 7:13pm

thanks for all the info guys .

Title: Re: spark plugs
Post by dirt33 on 01/01/12 at 12:09pm

What is everyone's thoughts on running antifreeze? I've heard it both ways.... Some guys say run a gallon of antifreeze due to its ability to raise the boiling point of the water in the system, while other guys say don't run any antifreeze at all.

I have been fighting overheating problems for the better part of 2 years. Going to try a new radiator and fan to start this next season.

Title: Re: spark plugs
Post by sj_valley_dave on 01/01/12 at 1:24pm

Never have ran it...all pavement short tracks will not allow it because if you loose a lot of it on the track, it's really tough to clean up...If you get your cooling system set up correctly, you will not need it...

Title: Re: spark plugs
Post by bb49mod on 01/01/12 at 9:53pm

Basically, your engine is 10.5-1. 112 octane is too much. You are not compressing the air and fuel tight enough to get all the fuel to burn. Blend your fuel to get it to around 100-103. This should help the engine run cooler, and make more power. One of my friends was doing the same thing as you, he put 5 gallons of 89 octane with 10 gallons of 110, ran 20 degrees cooler and made more power. Don't run antifreeze. It allows the cooling system to run hotter, but also makes the cooling system run hotter. Most rules don't allow it either. Use a good high pressure cap instead.

Title: Re: spark plugs
Post by THROCKS11 on 01/03/12 at 11:34am

The heavy pressure cap deal is really not a good thing. Oh ya it allows to run longer at a higher temperature before spitting out 260 degree water. But all your doing is damaging internal parts like head gaskets etc. The systems are designed to run a 18 to maybe 22 lb cap which will let you run plenty hot before it spews. If it does start pukin at 230 240 its a better deal & pull in & fix your cooling system & save money in the long run on high dollar engine repairs. If your cooling system, fuel system, fan & shrouding are right an 18lb cap should be plenty. :P