Actually, I ran hoodless, for much of the Summer! I had broke a corner off the hood, when it was off the car and it took awhile to fix it. I never had that being 'Baked Alive, while you Drive" feeling until I put it back on.

As far as factory changes, to help cool the engine, could you elaborate? Because I think the factory cooling system is fine, and add points if you have an aluminum radiator. Open the hood on your C3 and take a long, careful look. Check out how tightly the entire hood seals off the whole top of the engine compartment. Look at all four sides of the tiny box, that your BB or SBC lives in and see if there's any provision, designed by the factory, to let the heat out. Except for the spaces, in front of, and behind the A-arms at the bottom, I see nothing.

That engine develops an enormous amount of heat and it has nowhere to go. At about the 45 minute mark or hour, your entire engine compartment is heat soaked, including the entire firewall. Heat travels, through conductance as well as radiation and that heat, comes right on through the firewall, to you.

I don't mind modding my hood either. I've been doing a lot of work, these last three we with mixed results and I'm ok, with reporting that.

 

Went for about a 50 minute ride today it's a nice mid 80's day, when I got back I got my IR heat gun out, with the motor still running I measured 120* right behind the gas pedal, up further on the firewall I measured 130 on the factory insulation, I measured 109 on the shifter, 106 on the e-brake. I went to the engine side of firewall and measured a whooping 180* just under the brake booster by the #7 header and 176 just a little inboard of that. These firewalls do get a lot of heat soak! I just for the heck of it checked the valve cover just after I shut it off and it was only 169*...

 

Wow! Thanks for your input! That verifies what I think we're looking at! Good one!

 

Drove my 73 on the street without the hood and had no issues with heat. Put the hood on and my feet baked!

 

Like everyone else my '77 is a sweatbox after just a 1/2 hour drive. When I redid my interior I put down as much insulation as I could. It did help a little but not enough to claim any kind of success. The one reason for so much heat on my feet is the rear of my L/88 hood is opened up, I haven't put the cold air box in yet and all the engine heat is sucked into the interior by the ventalation system.
I've seen the front of the hood, by the power bulge opened up and will probably try this mod one day. This and the cold air box should help alot.
At Carlisle this year there was a company called Power Portal that had the vents for the hood. Similar to those on "Project Menace". Has anyone tried these?

 

Hey Richard, what is this product called and how is it applied? I have the lizard skin but have not applied it yet and am starting to think it will not be enough alone. While I have the body off I would like to nail down this heat problem. I was thinking put your product on then spray the lizard skin over it and it would not be so noticeable.

 

I did a search and found those Power Portal Wing Vents on the Eckler's website. They look very similar to what F22 is thinking. Good find!

John

 

I thought at first, Raymond was referring to the small 'ports' I saw on the original Project Menace drawing I hacked, but I checked them out and that is exactly what I'm talking about! Very cool!

They are universal and I'm wondering what width they are and how they mount? Is it.ppssible they mount from underneath and all you'd see is a trapezoidal hole with the mesh showing?

 

Yep, they fit! They look pretty good too, in the powdercoated black as well. If I didn't have my own design going, I'd buy them! The Engineer at work, as I mentioned, tweaked the design by first, rounding the outside corners and then (this is the cool part, he came up with in seconds, looking at the pic I created), he filled in all the 90 degree transitions between each set of rectangles, with flowing 'angled' transititions that 'waterfalled' inwards as each rectangle was reduced in size down to the next one. It immediately made it, much more 'unified' looking as a whole.

I want something that looks more like it was intended to be on a C3. Mesh is for race cars and I'd prefer a grill. Awesome catch, nonetheless and we're on the right track! I think it's going to be a combination of heat extraction and insulation that will help tame the heat in these cars.

Finally, I think it's possible to set up a short ram air system, running from the outer grills, flattening out underneath the headlights and then up and over the A arms, that would push cool air, up and into the engine comparment at speed.

 

Update: My Engineering bud, during lunch, came up with a CAD drawing of the hood grills that I'd like to see on my C3. First, I didn't want to go with anything that even smelled of the 80's or 90's and beyond. I didn't want something that clashed with the 'timeline' of the car, so I tried to envision what a typical GM designer would've came up with, during the early 70's or even late 60's.

I took hints from other GM hood grills of the 60's, which are typically 'square' and I did away with the idea of the flowing corners and loose curves, because, really, that came after the 70's.

I had two versions done, one with three sets of shorther vents, for each 'square' and another with just two sets of longer vents. Personally, I like the bottom grill, with two sets of longer vents. It's not as busy and it has a more 'unified' look.

They are going to be 36" long, broken up into 12" sections and the first one will be 6061, with a satin finish and all the inside edges, will all be powdercoated in black. There will be a set of two running down, each side of the hood. I will probably be making a set this week and have already talked to my sheet metal guy in my industrial center, who's a good bud too and he told me, no problem in pulling this off.

Let me know what you think.

 

Or you could put a set of these on your Corvette...

 

I wonder how it would look with each rectangular section actually separated from each other by an inch or so. When I visualize the hood with these vents I think the separation will actually look more integrated as a design. Just my 2 cents, I am no designer, just offering some thoughts.

I do like the other vents in black, but I wish they had airfoil shaped vanes rather than grills.

John

 

Instead of hood vents, would it be possible to force more heat out of the side vents? Ducting and/or fans possibly?

 

Regarding the separation, that's not a bad idea! Certainly food for thought. Let me chew on that and visualize it, because the only drawback, would be cutting six holes, versus two! But may well be worth the trouble and thanks for the feedback.

Food for thought....mmmmm?

 

Hi Adam and I was looking at that last night, with my shop partner. The right side vent with the AC box, hard lines and other assoc. paraphenalia, really is crowded in that whole lower area. There is maybe a mere inch or two, between some of that stuff and what I just described.

It may be possible, because the lower part, all the way where the bottom of the passenger door, meets the fender, has some space for sure, but it'd be a real exercise in creative duct work and then you'd have to fit a fan in there too.

I understand how tough it is, not to modify the appearance of these cars and there will be those, who for pure aesthetics, never want to do this and I'm ok with that. Ludemjo, has a great suggestion, for maybe breaking up the long design into three pieces and I'm considering that.

Though, last night, we figured out, that there is room for the ram air, without running under the headlights. There is space in the forward fender liner, right next to the radiator on each side and just slightly behind, to accomodate a 2" to 3" (or maybe even larger) round duct, but that size looks 'comfortable' so far. That will sure help and we're going to be looking at the design aspects of securely fitting something like that to the '74. The routing would be straight from the side grills and routing around the outside of the front part of the front fender, then curving up and into the fender liner, behind the radiator and it would be pointing straight up and out.

I haven't looked at the left side yet, but it isn't as crowded (I'm going from memory here!) as the right. We'd also have to look at how much air flow, you could get pulling the hot air down (opposite of which way it really wants to go) and how many CFM would it take to effectively accomplish that? Would there be fan noise coming out of the vents? All sorts of interesting things come up for sure, but wow, it's worth a look!

 

I think what is happening is that the air coming through the radiator ends up swirling in the top portion of the sealed engine compartment while some of the airflow does flow beneath the car and out the fender vents. This bubble of super heated air never has anywhere to go because the heat tends to rise and stay near the hood. The vents at the hood are an attempt to give that air an easy exit. I think you could do it through the side vents but you would need to pull a great deal of volume out these vents to try to get the hot air bubble to disperse. I think the proof is with the people who have driven without the hood and had no interior heat issues.

F22's experiment will prove this out I think.

John

 

Just got in the shop and discussing this with my Shop Partner and he likes the sectional idea as well. So he asked, why don't we make full size versions on the plotter of both designs, tape them to the hood. Take some pics and we'll compare them! Maybe a day or two to pull this off.

 

I think you've summarized it well and I agree, it would take a lot of air to pull it out the bottom. I'm not even sure the side vents are big enough! My brother designs high end HVAC systems and he works with calculations of duct sizing, air velocity and such and I'll run it by him tonight.

 

Have to agree - I also suspect that releasing heat from the top would be more effective than out the sides. Just tossing an idea out there.

I know I saw someone's project here on the forums and they had a fan pulling hot air out the side. It does seem like it was a pretty customized car and very possible that they had removed the AC and associated items on the passenger side firewall. That would explain how they had the room to do it.

 

I think I like the idea of adding louvers to the top of the hood, with the louvers pointing to the rear wouldn't it tend to pull the air out at speed with the air rushing past the louvers?