Hello, Zspoiler. My name is Brian and I am from Loveland, CO. My neighbor has a 79 Camaro with a slightly massaged 350. He is overheating if not driving (moving). It runs a good temp when heading down the highway. He currently has a stock radiator (now with a broken drain **** - don't ask me why haha) and a very small electric fan that hardly blows any air, and no fan shroud of any kind to direct the air flow. After some investigation we decided we will replace the radiator with a nice fully aluminum 3 core, get a stock fan shroud and proper fan blades. We found on Classic Industries the fan shroud (#748623, if my memory serves me well), but they couldn't tell us the recommended fan to use or what size opening it is. We would like to know the fan diameter and number of blades you would recommend. Classic Industries had a 5 or 7 blade that was 17" diameter but in the description it said it does not recommend a fan clutch. Would you recommend a fan clutch or just run a spacer? I think I prefer to run a fan clutch. Which blade set up would have came with it (79 Camaro Berlinetta 5.7 with A/C (HD Cooling) so it has the wider radiator. Any help would be much appreciated. We are hoping to order parts today because Classic Industries is running a special deal right now that will really help my neighbor. My neighbor is a great guy. And he lost his leg a couple years ago and has a hard time with it so I wanted to get him back up on the road so he can drive his baby. Any help would be greatly appreciated.

I am editing this as I am not seeing a way to message you directly, so I hope I am not ruining this thread. I am happy to private message you or something else.

 

Mine is a 68 Camaro 427 with 5 speed. It has an electric fan and no other fan. The car runs at around 200-220. I'm thinking about going back to a clutch fan.
so...
1. Is 220 ok or too hot?
2. Is my idea to go back to a clutch fan good?
Thanks!
Scott

 

Unless its a high $ Spahl, ideally dual fan, most EL fans just don't draw enough air.

200-220 is MAX I would consistently run a car unless it was a Gen 2 LT1 which was a reverse cooling (went to heads first) SBC

Guys running more performance motors, especially in Vegas heat, run both mechanical fan/shroud and dual pusher, Spahl, fans to keep temps in the 180's

 

I sure would run a stock HD fan clutch and 7 blade fan
and
I would also run an electric fan as a pusher in front of the radiator
The two fans combined should cool it well enough to run what fuel you want, time it where you want, and run the AC when you want

 

QUICK UPDATE - I moved the electric fan to the bumper side of the radiator and switched its direction. It has an over ride switch. I also installed a mechanical clutch fan and shroud. Today was the maiden voyage at 95 degrees. It ran at 220 or so and blew its nose when I got home. I like the electric water pump idea.
It does have ac so the air has to pass through the radiator and condenser.
I will switch the thermostat also.
Thanks for your ideas especially about timing.

 

I cannot really add any direct things to try. On the race car we used a thermo camera to look for hot spots. If we had a flow issue the heat would concentrate or is a couple of cylinders where running lean that could cause hot spots. Back then thremo cameras where very pricey. Now you can find them for $100 ish. I have no idea how good they are. There is also the cheap thermo scanners at harbor freight. You can search around for hot spots.

Knowing the base timing you have at idle and the fuel mixture (o2 sensor) would also help running down what is wrong. I had one friend that chased over heating for a year or two on a 396 only to have it go away when he switch to EFI.

 

Great idea using the temp sensor gun. Here is what I did and the results. I installed a mechanical temp gauge under the hood, tied it down with a zip tie. Then I drove it all over town and on the freeway. It took longer for the gage to hit 210 but it did get there. No blowing out coolant after stopping! Both gauges read the same. The sensor read 120 at the top of the radiator and slightly hotter down lower, 180 at the thermostat housing, 200 further back along the intake manifold, 210 or so at the top of the valve covers.

 

Interesting, that is not what I expected. I am use to seeing the top of the radiator hotter then the bottom. . The coolant in your engine should flow from the top of the engine (thermostat housing) to the top of the radiator. Theoretically of course. With side tanks the coolant flows side to side with upper hose tank and the cooler lower hose tank. Maybe take a look at you rad and see if you have the side tanks and remeasure the tanks themselves.

During this test if you should see slightly low temps going in the the radiator then what you gage is reading (the coolant is not perfect). During this test you can verify if the coolant is cool enough going into the engine and hot coming out you may need to speed up the flow. (Pully size change.) If the coolant would be coming out of the engine much cooler then the engine is you may need to slow the coolant flow down. That give the coolant more chance to soak up the heat.

If you motor runs cool on the highway and only heats up in stop and go traffic you can have an issue with hot air getting out of the engine bay. Pulling heat out of an engine and putting around the engine is not very efficient. This is why a lot of older race cars would have their hoods up in the back to let the fan push the heat out of the engine bay. A good test for this is just to drive the car with no hood. It will run cooler but if you go from 210 to 170 degs then air flow is the issue and a bigger fan may not fix the issue.

I am not a big block expert. My history is keeping SB 400 and GM SB stroker motors cool on a dirt circle track. But after saying that I know the history of the Camaro and the first gen was not designed for a big block and as you add HP you add heat. The rule of thumb is 1/3 of the power in a gallon of gas goes to the back tires 1/3 goes out the tail pipe and 1/3 creates heat. Stop and go driving uses a lot of gas. This is a very basic theory but if you could measure gallons per hour you could estimate heat per hour. Anything above what the factory did HP wise needs upgrades and will run into limits. Take a look at the size of the hole in the radiator support for the radiator in a first gen camaro. I remember doing a radiator in a 454 camper special C20. that radiator had to be 36" long. I remember fighting to get that thing in. Your camaro can burn way more gas then that.

The reason I say rule of thumb is the 1/3 rule is kind BS but it is easy to remember. In the 60s most engine ran 20-23% efficient even today hitting 27 to 28% is considered good. Some things like advancing the timing or running lean can cause the engine to have more power but be less efficient which means more heat to do the same work. Larger Cams or any increase in air flow will mean more gas (More gas= more heat)

The point of this long post is to just show that bigger fans and bigger radiators are not always the fix. Like with most hot-rodding figuring out where you limits are and improving those until you run into a another limit is the trail and error method most guys use.

 

Thank you for this. I can try a few more things. Solving the puzzle is part of the fun...most of the time!

 

A bit more info -
I have a 67 with a 396 and it has a stock radiator. clutch fan and shroud. It runs cool - normal. No E fan
Here are the measurements of the 68 - 427 which has a Champion radiator, E fan and clutch fan. Photos too
2.75 thick 27.5 wide and 19 tall