Well, I finished my restomod of my 76 a couple months ago. Now for driving and working out the bugs. The first bug in the system is my electric fan set-up. Dont rush to conclusions, It runs at a steady 180 degrees at any speed and the temperature was up over 90 today. well to make a long story short, I charged the A/C this week and while charging the system I noticed the air temp under the hood was extreme. Having 4 shows/cruise-ins to go to from Thursday to today, I put over 80 miles on the Vette in 3 days. Heres the rub. While the water temp was great, the temp under the hood was enough to set off my fan circuit breakers shutting my fans down for a few minutes. Coming off the interstate today on the way to the last show, I got stopped at a light coming off the interstate. When I got to a low speed, the air flow under the hood decreased to a point where the air super heated and shut down my fans circuit breaker. It still didnt get over 195 degrees but, when I started moving and the air flow picked up, the breaker came back on. I noticed that even with the fans on, thay push the air down and under the engine, instead of across the engine as the stock fan does and doesnt give the cooling effect to the engine compartment. I have Hooker side exit headers as well so that just makes the problem worse, especially at highway speeds. I dont have this problem around town where the headers dont heat up so much, yet. So, for those running electric fans with headers, what have you to say? Maybe just use fuses instead? I like the idea of a breaker protection instead of a fuse that wont click back on. Put a air diverter to direct the air over the engine? I am open to anything right now, even the stock fan set-up is better than the present circumstance.

 

the electric fans will tend to push the air under the block. my radiator is mounted about 3" lower than stock also. what i am doing is mounting two 8" 2100 cfm cooling fans near the side vents to exhaust the engine and header heat out of the compartment. my engine compartment is completly custom so the fans will be hidden and ducted but i still think you could still go this route even with a near stock set up. this is one of the fans i am going with and this shows the compartment as it sits now. the sides will be cut for intakes and ducts are going to be run to the fans and from the fans to the outer side vents. this should move pleanty of air. i have tested them next to the side vents with no ducting and they still blow quite a bit of air out the side vents. this should also help cool the side exhaust tubes too. hope this helps

 

To a location outside the engine compartment. I have my contoller located on the forward side of the passenger-side wheelwell; to the right of the headlight.

 

Thats probably what I am going to have to do. What about heat and the alternator though? My 10si suffered from heat soak and I attributed it to being upgraded to 100amps, so I replaced it with a 12si and the turbo fan. Seems to be working so far but, I might have the same problem with it later on, getting nothing but superheated air from the headers. I really dont want to run a duct into the engine compartment.

 

I find it strange that there isnt anyone who has done the electric fan conversion noticing the excess heat in the engine compartment. Maybe I did something wrong.

 

Nope I have the same problem. But working on it.

 

What ideas have you come up with so far? I have had many but only going to the engine fan with an electric back-up seems to solve them all. I am not sure I like that idea as I have gotten real used to how it looks without all that under the hood. Since I have never seen it any other way on my car.

 

 

I converted my 79 L-82 to dual electric fans and don't have a problem with engine compartment heat; however, I don't have headers. Do you think your headers could be a contributing factor?

 

I think the headers are the biggest part of the problem. I'm not getting rid of my hookers though and a bunch of heat shielding cluttering up the engine bay isnt appealing to me so there has to be another solution. Either more air flow into the engine bay or components that can handle the heat.

 

thermal wrap or coat the headers or both

 

Mine are ceramic coated hookers from JetHot.

 

Been watching this thread as it applies to what I am doing as well

Will wrapping a ceramic coated set of headers ruin/damage the thermal coating?

No sense paying extra for that just to wrap it if that damages it.

I plan on wrapping for my headers to control both engine compartment and floorboard heat

thanks

 

Why are you using thermal breakers for the fans?

 

Having an electronics/avionics background, it seemed prudent to run a redundancy in the system. Therefore, each fan is run on its own switch set at different temperatures and seperate relays. This way, if one goes the other can allow time to get the car off the road and out of harms way, which is my main concern. This is also why I run a breaker instead of fuses. If a fuse goes, there is no way to recover power to the fans, if a breaker trips it will cool and restore power in cycles to get the car out of traffic and is rated below that of the wiring keeping the wiring from going up in smoke.
Keep in mind the problem is radiant heat that is not being moved by airflow from a fan as the engine fan and shroud would do in a stock set-up. There is no problem with the electric fan set-up as far as cooling the engine coolant. It runs a steady 180deg at any outside temp or condition, UNTIL the ambient heat in the engine bay raises too high and then the problems start. Not just with the breaker but also with the alternator. So, to that end, moving the relay/breaker board to a cooler place will only solve the fan problem. The heat under the hood will still be there. So, I have to find a way to move the air across the engine like the stock set-up does to keep everything else happy.
One side note, I do not have the seals on top of the radiator to the hood. While driving at a higher steady speed, the engine temps stay a steady 180 AND the compartment temps stay down due to the air getting in at the top of the engine compartment and pushing the heat out. It is when I stop after getting off the highway and the airflow stops that the heat from the headers floods the engine bay and causes the problems. The coolant temp is still a steady 180 deg while this is happening.

 

Seems this would solve your problems quite nicely.

Or dump you electric fans and go back to an engine driven fan.

 

You can open up the rise back of hood to let hot air out when stopped, air flow in at speed.



Guys w/ 1 el. fan could consider using the shroud.

 

Sound like your breakers are near the electical limit (heat) anyway and any extra heat just puts them over the top. Glad moving them helped.

I'm in S Florida, so it's probably consistantly slightly hotter here. Have long tube black headers, but with stock fan setup, and yes the engine compartment is very, very hot. Some things just won't last as long as they will in North Dakota.

This is summertime in Florida, get used to it.

 

Hey Noonie, where in south Florida are you? I am just south of Tampa, been here for most of my life. Anyway, My fans are pulling about 24amps total together and the breaker is a 40amp and two 30amp relays set to come on at different times, to keep from having overdraw on start-up. Every other car I've built for myself has had a verticle radiator so this has never been an issue.

 

Mine has the L88 hood with air box, so there is no way to open it up without going through the air box and that means alot of cutting and repainting. I have thought of going to a single fan and running the shroud though. Just cant seem to find a fan with the cfm rating I want that has a sealed motor.