Another Radiator Dilemma

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llih said:
I used the stock rad, shroud and a flex fan for years. I live in the Mohave desert. I used to drive up and down the Cajon pass everyday with no overheating problems. That being said, I wonder how much the placement of the Chevy with relationship to the firewall affects the heating issue? I remember way back reading something about not getting enough airflow over the v8 when it was too close to the firewall. I also question how accurate some of our temp gauges are.
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I am not sure about engine placement, but I do have some first hand experience about gauges reading wrong.

One thing I used to always hear from the old guy at the Speed Shop was that you can't make more power with out making more heat. He used to say this because guys would drop in a warmed over motor back into the same car it came out of and the motor would overheat and or run hot. Add a hundred HP and it's going to run hotter. The same radiator that worked before, was no longer good enough. GM used to have trouble with Corvettes overheating brand new, they were the LT1 versions that probably did not get a special radiator where as the stock 200 HP version would never over heat. It's not just F/2F running cold and V8's running hot. Souped up V8's run hot.

Having said that, I can totally see how one guy can run a mild stock V8 with the stock radiator no problem with good air flow due to engine placement and a very good stock radiator that flows well (not clogged or scaled up).

On the other hand, some other guy has a warmed over V8, too far back from the radiator and an old stock radiator that's full of scale or even a good stock radiator with too much HP in the small block for the stock radiator and in both cases it runs too hot.

It's not a black art; it's science. Too much HP = too much heat for that radiator to deal with. The back art part of it is taking engine placement and or airflow into consideration. Even then, it's not that hard.

If there is any one thing that amazes me is how many people have small leaks in their coolant systems that cause overheating. No matter how much radiator you have, if you a leak, it's not going to build up pressure. A leak at the thermostat housing or fill cap is not even going to loose much fluid but will loose pressure and not let the system work.
 
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FJ40_owner said:
Could you please provide me the exact part number and dimensions of the rad you bought? I am not a super fabber but am able to weld and cut metal.
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Nothing bolts right in. I liked the way the CJ/Wrangler SBC conversion radiators mounted. I fab'd vertical supports that attach the integral mounting flanges on the sides of these radiators. I paid more for this than a generic Summit ($300 vs $200) but it greatly simplified the mounting issues, at least for me. Re-read my links in the earlier email. All of this has been discussed in great detail before.

As fas as the job and no money...been there too. If you got more time than money I would walk through a couple junk yards, looking around and getting ideas/looking for bargains. Look for a rad that will physically fit, enables you to mount it in your truck and has a V8. The core should be somewhere around 19X20-21-22-...The rule of thumb I was told was a stock SBC in a passenger vehicle (no excessive loads IE towing ) needs approx the same square inches of radiator core area as cubic inches. More obviously for higher HP. I have approx 275HP with a 350 and my core is 20X20 or 400 sq in.
 
Update on my Cooling issues.

I removed the efan and put the mech 6 blade back in. Shroud, no clutch, 180 stat. The rad shop guy said to have the fan be located half in and half out of the shroud. Some lousy welding and cutting later that is what I did.

Took the Cruiser out on a hard run in 95 degree heat. Drove the same roaads that the efan had me at 230 and climbing. The mech fan kept me under 200 the entire time. Idled back to 180.

What still amazes me is the "apparent" amount of airflow the efan put out versus what the mech does. The efan would have caused my car to seize up had I not stopped and let it cool.

$280 wasted. (expensive garage fan.)
 
If you have a v8 with a small or stock camshaft it will generally run warmer than a motor with a longer duration cam because, the larger cam bleeds off more cylinder pressure, because of valve overlap which relieves a good amount of heat once combustion happens.

My brother and i have basically the same compression SBC's but he has a much larger cam and he has no problem keeping his cool, mine on the other hand is very difficult to keep cool. Both have Taurus fans and 4 core radiators.;p
 
I have an "RV cam" I am informed it is for more torque. Cannot confirm. I also have bare pipe headers. My hood gets so hot you cannot touch it!.

Thanks all

JB
 
I wraped my exhuast pipes trying to keep heat out of the engine compartment
 
mminter1973 said:
If you have a v8 with a small or stock camshaft it will generally run warmer than a motor with a longer duration cam because, the larger cam bleeds off more cylinder pressure, because of valve overlap which relieves a good amount of heat once combustion happens.

My brother and i have basically the same compression SBC's but he has a much larger cam and he has no problem keeping his cool, mine on the other hand is very difficult to keep cool. Both have Taurus fans and 4 core radiators.;p
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Saw whaaaaat? How about an English translation on this.
 
FJ40_owner said:
Update on my Cooling issues.

I removed the efan and put the mech 6 blade back in. Shroud, no clutch, 180 stat. The rad shop guy said to have the fan be located half in and half out of the shroud. Some lousy welding and cutting later that is what I did.

Took the Cruiser out on a hard run in 95 degree heat. Drove the same roaads that the efan had me at 230 and climbing. The mech fan kept me under 200 the entire time. Idled back to 180.

What still amazes me is the "apparent" amount of airflow the efan put out versus what the mech does. The efan would have caused my car to seize up had I not stopped and let it cool.

$280 wasted. (expensive garage fan.)
Click to expand...

For $280 you could have had a new generic Summit aluminum or the generic copper/brass CJ/SBC I linked to before with some $$ left over. Bad choice IMO but it's your $$.
 
Sometimes it is cheaper to bite the bullet, spend some $$ and do it right.
Go with a large aluminum radiator, build a fan shroud, and run a factory fan with a clutch.
 
A early 90's Taurus fan and a 4 row steel radiator are as good a cooling system as you can buy. I had a aluminum radiator and it was no better than the steel one i replaced. If that still wont keep it cool step up to a cam with between 218-226 degreees duration at .050 lift, still PLENTY of torque to drive off road, and is a pavement ripper on road.
 
projektdotnet said:
this is why i dont run an SBC
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Some of us with SBC engines do not have cooling issues. It is a non-issue if you build it correctly.
 
dgangle said:
Nothing bolts right in. I liked the way the CJ/Wrangler SBC conversion radiators mounted. I fab'd vertical supports that attach the integral mounting flanges on the sides of these radiators. I paid more for this than a generic Summit ($300 vs $200) but it greatly simplified the mounting issues, at least for me. Re-read my links in the earlier email. All of this has been discussed in great detail before.

As fas as the job and no money...been there too. If you got more time than money I would walk through a couple junk yards, looking around and getting ideas/looking for bargains. Look for a rad that will physically fit, enables you to mount it in your truck and has a V8. The core should be somewhere around 19X20-21-22-...The rule of thumb I was told was a stock SBC in a passenger vehicle (no excessive loads IE towing ) needs approx the same square inches of radiator core area as cubic inches. More obviously for higher HP. I have approx 275HP with a 350 and my core is 20X20 or 400 sq in.
Click to expand...


yo, you got this all put together yet, i have yet to buy mine. let me know and send me some more pics
 
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