1gary

First and foremost you still have to establish you don't have any issues due to the number of times you have heated this up.Any bubbles???.

Reddeath210

iTrader: (1)

I didnt see anything, you said to take the rad cap off and start the car and let her idle, and if i see bubbles i got bad news :S correct?

1gary

If you allowed it to get to operating temp's and saw nothing that is a good sign.

bwiencek

Correct - Gasoline engines are about 35% efficent in converting the fuel into motion - the remaining 65% goes off as heat (or unburned hydrocarbons) So given that say you were producing 190hp (stock '86 TA with the 'good' engine) and you're producing "X" amount of heat... Now say you built a 383 and you're producing 380hp or twice that of the 'stock' engine - you're now producing twice the waste heat also - which means that now your cooling system has to get rid of twice the amount of heat then the engineers designed it for (there is a lot more too it with VE, thermal transfer rates if you're running aluminum heads vs the iron heads, etc. but you get the picture)

BUT - if you think about it - you shouldn't be overheating at idle and at a regular cruise speed you shouldn't be overheating because the cooling system was designed to handle those loads - it's just when 'getting on it' and creating more waste heat then can be pulled out that you'll start to run warm/hot.

I'm assuming that you've covered the basics - made sure the radiator wasn't clogged with junk in the cooling fins, that the inner tubes are clean and clear and flow well (no blockages) he hoses are in good shape and that you're running the minimum amount of coolant for the area you're in (more water = better heat transfer) - if you've checked all the basics and you're still having problems only under a heavy load then I'd look at upgrades.

Reddeath210

iTrader: (1)

Today i started the car, and i ran her for about 10 minutes. No bubbles, no overheating

The only time temp changes is when i drive her, the coolant levels looked fine, when she starts her idle temp is around 180ish. My thermostat doesn't look like it opens until around 210ish could be wrong but thats what i am seeing

1gary

Your theories sound like it's coming from someone with limited practical experience.Fact of the matter is 383's don't create anymore cooling issues than 350.I'm calling it for what it is.

bwiencek

Try again... theoretical and practical... Did you ever race a vehicle for more than a few hundred feet? 99% of the people won't push their engine hard enough for a long enough period to expierence major problems (which it doesn't sound like what we're dealing with here)

Did you READ and COMPREHEND everything?

It's real simple the More HP you produce the more heat that will be produced. end of story.


Let me break it down another way....

Idling - little HP produced and thus low amount of heat (BTU's) generated - stock is fine.

cruise - low HP required to maintain speed - should be close to stock heat generated for the same speed and thus stock is still fine.

mild acceleration (not faster than stock engine did) - more BTU's generated and since you're not using more HP than stock it should be just fine.

Heavy acceleration (WAY more than stock engine produced)/constant HIGH HP demand - this is where there will be MORE BTU's produced than the stock engine did and thus there is MORE than stock demand on the cooling system - now most cooling systems can handle more HP to a point - what that point is - when you find it you'll know - the temps will start creeping up under acceleration and will come back down during the lower demands (i.e cruise or idle)

Heck drag racers use old 4-banger VW radiators on 700-900 hp dragsters... how do they get away with it? They get the engine and coolant cold, then make their run down the strip - the temps spike in the system because of the load, but when they get back to the pits they turn the engine off, keep the fans on and keep the water pump on to circulate the coolant until it cools off enough. The cooling system can't handle the constant heat production and they're just raising the temp of the coolant the whole time - keep it under load for longer than 1/4 mile and it'll overheat in no time. Just ask one of those guys if he wants to hot lap it and make 5 or 6 back to back passes without a cooldown period then tell me that cooling system which can handle idling and driving around the pits all day long is adequate for a 900hp big block...

Sooooo - since I keep reading it idles fine with no overheating (and I'm assuming the fans cycle on and off properly and the thermostat opens/closes initially to regulate temp and then opens once the system is up to temp), AND it cruises without overheating, AND it ONLY overheats/runs HOT when doing HARD ACCELERATION then it's a cooling capacity issue - could be low flow, clogged radiator or cooling passages in the engine, etc. the 'system' (have to look at all the parts) has a weak link somewhere.... Either a BAD part not doing it's job or an undersized part not able to "carry the load"

1gary

Horse hockey.33 cubic inches more does not,never did,produce any more stress on the cooling system.Nothing significance that is.....................

bwiencek

it's 78ci... (stock was 305, he's got 383 now)

SO - you're saying that I can take out a smog era 350 that did maybe 180hp with a stock cooling system and then put in a fully built Gen III 5.7L (that's 350ci for us cid guys) with an all forged low compression bottom end and twin turbos producing over 800 hp and be just fine running a road course under load since there is no displacement change from the stock 350? Great - I'll quit buying the nice radiators for my big turbo builds then

redneckjoe

those airdams are very important on trans am's as there is basically no grille area for air to enter. are all the other plastics in place for the cooling system?

i personally dont see a 383 making much more heat then any other 350 etc. ive built a few with no problems.

i dont really agree with the theory of more horsepower making that much more heat. so if a 200 hp motor runs at 200 degress, a 400 hp runs at 400 degrees,...a 600 hp at 600 degrees?
nascar seems to be able to keep a 700+ hp motor cool enough at full throttle for hours. and they put tape on the grille to go faster.

gotta make sure the whole coolant system is working.

ASE doc

My 355 makes about double the power of the stock 350(430hp vs 225hp) and I run the stock radiator with stock dual fans. I do run a high flow water pump, a 160 degree thermostat, and I have the fans set up to operate as a pair at a much lower temp than stock. I have never had any issues with engine temp on this motor. As gary1 suggested, In all of the high performance motors that I have built, I have never had any issue keeping them cool. I run the higher horsepower motors cooler to begin with in order to help prevent detonation. That helps somwhat in keeping temps down, but your theory that double the power produces double the heat has not proven out in my experience.

Reddeath210

iTrader: (1)

Something weird happened today, i was sitting at a red light and a lot of whitish smoke came out of my dash. At the moment i don't have a dash pad on. Keep in mind my heat is disconnected, so is my AC, and the car wasn't overheating my gauge read about 190ish. I didn't smell anything.

I also don't have cats on the exhaust as well. There is a small exhaust leak on the car as well.

1gary

Whitish smoke??.Hummm.Defroster vents huh Have you checked the oil yet?.But no heater core hooked up.Maybe a wire loom giving up which could have been your problem all along.

Reddeath210

iTrader: (1)

The oil is fine from what i have seen, what do you mean by a wire loom giving up

Reddeath210

iTrader: (1)

anyone else got some input on why there would be whitish smoke coming out.

t-top havoc

iTrader: (3)

No smell is odd.
Elaborate a bit-- heater hoses on the heater core but no HVAC controlls?
No heater hoses to the core?
Be diligent- look over all the wire harnesses. Look for expansion // freeze plugs cracked.
Look over the exhaust system from heads to cat converter-- see if something got spilled or stuck to the exhaust somewhere.
Make sure no plug wires are against the exhaust manifolds // headers.