Cooling thoughts.......

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Cooling thoughts.......

Postby cjbiagi » Sun Jul 01, 2018 10:55 am

I posted this on Monza Madness Facebook page but thought I would share here too as I know not everyone is on FB.

Well with the recent intense heat (upper 90's) I thought I would just mention how happy I am with the way my 350 Monza is running. While I know there are often cooling issues with these cars it seems with all the little things I have done over the years it is really paying off. In stop and go driving it never went over about 180-185 degrees. Yes, my auxiliary electric pusher fan did occasionally cycle on and off but other than that I noticed practically no difference in the gauge. I have posted most of what I have done over the years but here is a short synopsis. First, a good radiator, I use a Griffin "drop in" 400hp version. I use the factory 7 blade fan and added the optional plastic fan shroud. I also have a auxiliary electric pusher that is temperature controlled. I have also added some sheetmetal baffles between the grille and the radiator, this forces all the air entering the front of the car through the radiator. I have a high flow chrome water pump with factory pulleys, a couple bottles of Redline WaterWetter along with a high flow 180 degree thermostat. I have my vacuum advance connected to full time vacuum source with about 14 degrees initial timing. I use molded radiator hoses for better flow, not those universal ribbed ones and make sure you have a spring in the lower hose so it doesn't collapse. I made sure I have a good radiator cap and functioning overflow recovery system. This assures that the system is 100% full of coolant. Coolant should be no more than 50% coolant to water ratio, a higher water ratio is best for cooling but you probably want at least 40% coolant for corrosion and freeze protection. Other heat related things I do is have a phonelic heat insulator under the carb, all fuel lines insulated in the engine compartment, added a recirculating fuel system so fuel does not dead-head at the carb, it is constantly recirculating a small amount back to the tank. (This was easy to do with my dual inlet Edelbrock carb, one for inlet, the other side for return back to tank, feeds through a small orfice so it doesn't affect fuel pressure) I should add that I also have ceramic coated Hooker 2135's. Supposedly the ceramic coating reduces the heat output from the pipes. Every little thing helps, don't overlook things that seem trivial. For example the radiator fan shroud should be designed so there is about 1" clearance from the blades and half the blade should be in the shroud and half the blade out. You need air flow through the radiator and coolant flow through the engine. This along with proper tuning, timing and fuel ratio, will provide the best results. These are the highlights of what I have done. As I mentioned the results are awesome even driving in 90 - 97 degree heat. Hope someone can benefit from some of these tips.
Clyde.........75 Monza 2+2
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Re: Cooling thoughts.......

Postby Smiley » Sun Jul 01, 2018 4:52 pm

Nice write up!
When you say "Factory pulleys" a lot of people do not know V8 Monza's and Corvettes used special factory pulleys to overdrive the fan and waterpump faster than the crankshaft.
Stock pulleys from other Chevy cars are 1:1 and the cheap chrome pulleys are copies of those.
1:1 pulleys are fine on larger cars as they have a lot more radiator surface area.
For the same reason avoid underdrive pulleys on a street driven H-body, a few HP is not worth overheating the engine.
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Re: Cooling thoughts.......

Postby cjbiagi » Sun Jul 01, 2018 8:19 pm

Funny thing is I always knew about the overdrive pulley for V8 water pumps but I just recently changed my water pump and looked at the water pump pulley and it appears to be the same size as the crank pulley. It's possible that 75 V8 Monza's did not have the overdrive pulley. Either way, it is the stock pulley that I had chromed many years ago and it works great along with the high flow pump.
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Re: Cooling thoughts.......

Postby Bullet » Tue Jul 03, 2018 9:20 am

Thanks for the insights Clyde. Do you have a link to pics of the ducting you installed? I would be interested in seeing how you did that. Also I would add my 2 cents on radiators, there are cheap radiators out there, cheaper than Griffins, but no one should think because they look like they should cool well that they will. I've had my share of wasted money on cheap Ebay radiators. Things like tube size and fin spacing are critical to keeping a V8 H-body cool and Griffin has done the research to make sure what they sell works. That's why they put a horsepower rating on them, they've done the testing.
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Re: Cooling thoughts.......

Postby cjbiagi » Wed Jul 04, 2018 12:15 pm

No, I do not have any pics of the baffles. Basically they just go on the sides from the radiator core support toward the grille area. I agree about the radiators, I think it is a mistake to assume all aluminum radiators are the same in terms of quality or cooling ability. I immediately noticed the Griffin had a lot more tubes than my recored 3 row stock radiator. If I remember correctly it went from about 27 to 35 tubes. Now multiply that by 2 ( Griffin is two 1" rows) and that is approximately 14 more tubes than stock. That is significant..... Yes, the Griffin is expensive but I never regretted it. I can honestly say I have no cooling issues with my 350 V8 Monza.
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