ENCHANTMENT

Having had a few days off, I had a momment to ponder various thoughts. Of particular interest to me is the topic of the elimination of heat build up in my 80. Living in NM, we are not required it have a front license plate. Has anyone open the area behind where the plate would go? It seemed logical that this would allow more cool air to reach the radiator and there fore the engine compartment. If I did cut an opening I thought that a dark perforated metal plate would easily cover the opening and not make a noticable void. Another tract my brain went was to wrap the headers with tape (Similar to the thermo-tec product). Several years ago the thought was that when wrapped, headers would suffer a very short life because of high heat and water getting behind the wrap and rusting them. Since we don't get much rain and less snow and I usually don't take the beast out in inclement weather, I'm not too worried about the moisture. Any one with experience with wrapped headers? Any other thoughts about getting heat out of the engine compartment? I know that there were several articles in The Shark Quarterly about some of the earlier racing C-3'swhich might have some information concerning cooling, which I will research.

My last thought was concerning insulation under the carpeting in the cockpit. I have found a number of different insulation products all with different thicknesses. The one I am tentatively ordering is called Heat Shield and it has a 3/8" insulating pad with a reflective mylar surface. Will the extra 3/8"+ interfer with refitting all the interior pieces? In particular I am concerned about the console.

Thanks in advance and have a exciting New Year!

mrvette

I have heard that ceramic coating is the way to go on headers....I have never bothered with anything on my car, as the cast iron is so much more heat retentative than steel tubes, I thought the improvement was worth it right there, now having said that......I would take that outside air door on the pass side, pull it out of there, disconnect the dash pot, wire it shut and seal it off with silicone sealant, and just remove the inside kick panel flapper door, so the car is on inside recirc air all the time....keeps that hot air out of the system....second, consider a metal shielding plate between your exhaust pipes and the floorboards....under the car....
next, for your interior insulation, go to Home Depot, plumbing section, and buy a ten buck roll of foil back 1/2 thick hot water heater wrapping, and replace all that dried out falling out jute on the firewall and floorboards...
then buy some 1/4 thick foam with foil on either side,.....cheap again...
then lay it under the carpeting and consold tunnel....
make damn sure ALL firewall holes are sealed TITE!!!!, same for consold tunnel/tranny shifter areas also....
make sure there are NO leaves/trash in the blower system, in front of the a.c coils, for sure.....with the mod on the flapper doors, that will be about zero of a problem in the future....

might want to check all the interior flapper door operation make sure it's all 100%, anything less, like heater door, and it's a dead loss.....
make sure your heater core has two vacuum controll valves in it, one in each line, that way the core stays cold, unless told otherwise....

GENE

BLT-71

ENCHANTMENT: As for the opening of the grill, I have seen a duct system made for C-4 to do just what you thought of and think it or the idea of it can be utilized on the later C-3s.
As for the thermal tape it does work but is a pain to wrap properly and does not last forever. The ceramic coating does cost more but is more recommended and has a warranty.
Lastly, the underlayment thermal barrier material works very well and will reduce heat and sound. Many companies make similar products.

mrvette

OH, on that license plate thing, YES openig up that area will add about 30% more cooling air flow....and YES it did break the back of that overheating problem on the highway when I first moved down thee, that ONE simple thing stopped about 70% of the overheating....the last thing was the o'drive 700r4 tranny.....

GENE

ENCHANTMENT

Gene,

I agree, the biggest positive change was gained when I went to the 700R4. The 420 SBC still is a bear when it comes to producing heat. Even with ceramic headers I feel that wrapping them is needed. All the suggestions about blocking air leaks in the firewall and surrounding areas will be tackled in shortly.

Many thanks!

phoenix

Welcome to the forum :D:D

I can answer the interior insulation question for you. I completely insulated the interior of my 76 (before it was totalled) with ceramic 3/8" fabric insulation. I used it everywhere, under the entire carpet, behind the tach/speedo console, dashpad, center console etc...

Everything fit fine except... the parking brake cover, the center console (shifter) and the pedals. I had to actually remove the extra insulation around the gas pedal because my foot kept binding. Also, the insulation around the parking brake cover and shifter cover had to be thinned. It splayed out the plastic too much and wouldn't sit right.

Other than that everything else fit. The gas pedal was the real issue.

Good luck :)


BTW for what it's worth. I bought all of the insulation from mcmaster.com (industrial supply company) They sell the same insulation in rolls for MUCH less than the auto suppliers. :cheers:

MoMo

I live in Colorado. And while we don't get up to quite the temperatures you do, we do get warm in the summer, and often get a lot of the southwestern weather patterns throughout the year. So I have been tackling the heat problem in my 68's engine bay. By the way, you didn't say what year you have.

There are some things you can do. The license plate area was originally intended for cooling air for the radiator and engine compartment. I would remove it if I were you. I doubt if it would look bad without a plate there, try it and see. If you want to put something there to prevent road debris from having an unobstructed path to your radiator, which is a good idea, you can get some kind of wire mesh screen and spray paint it black and put in there so that it's not visible.

Another trick is one that Zora Duntov did in 1967 for the press release of the new 1968 shark Corvette. That had a 427 big block and he only had 3 weeks to prep it for the press after he got out of the hospital. He put a chin spoiler under the nose and cut two wide slots in the metal just above the chin spoiler. This worked and provided enough cooling air to allow the 427 to be thrashed by the press.
Looking under the nose of my 68, there is a mount for a chin spoiler, so I put one on. However, there are no slots cut into the metal just ahead of the spoiler. I think it may be that I have a very early 68, so that modification may not have made it to the production line in time. Mine was actually built in the fall of 1967.
I've been thinking about opening that space up the way Duntov did. It's hard to convince myself to, because that's one of the unique features of my Corvette, so I'll only do it if my custom radiator won't be able to sufficiently cool my new 427.

Another neat idea I had was to build a couple of sheetmetal scoops just in front of the front crossmember and route the cooling air up into the engine compartment using dryer duct. You could have the duct blow cool air directly on the front of the carburetor and intake manifold. Sitting idle at a light, this wouldn't help, but out on the highway, it should help a lot.

One thing I did when I was stuck in traffic was to pop open the hood. As long as you're put-putting around in city traffic, it won't hurt anything for the hood to sit in the popped position. But push it back down if you get on the highway. Heat rises, and that gives the heat a good way to escape.

This summer I am customizing a new hood for my big block. It's a small block hood that'll have a stinger scoop grafted on it. The carb will be raised up high enough with a phenolic spacer to push as much of the K&N air cleaner outside of the hood top as possible. The stinger scoop will be divided. The carb will get the cold cowl induction air for the engine to ingest, and the ram air in the front will pour onto the front of the carb and intake via a slot in the hood, inside the front of the Stinger scoop.

I didn't want to cut up my original hood, so I picked up one at a Dead-Corvette junk yard for $100. And I'll glass that. The scoop was $45 to order and is fiberglass.

I also use that same heat insulation, and while it helps, it isn't enough. I got a woven fiberglass mat with aluminization on one side and glued it to the bottom of the firewall using weatherstrip adhesive. That helped a lot, but is STILL not enough.

I think the fix might be like what I have between my turbocharger and the firewall on my Shelby Charger, and that works great. A sheet of sheetmetal spaced away from the firewall about half an inch. I thought about that on the Corvette's firewall, but have not explored that option yet.

Just keep on insulating. You might want to employ a cut-off valve for your heater core, but have a bypass so that the hot coolant can route back to the radiator. Most of the year, you can have your heater core bypassed. You can just "short circuit" the heater hose back to the radiator as a temporary fix. Not having hot air circulate full time through your heater core will help a lot.

Anyway, that's my 2 cents. Any of these ideas you like?

DEVOUR

The area behind the front license on my 82 has a steel plate about 8" square supported by 4 steel tubes. It serves as a great battering ram when dumbbuttes in pickup trucks try crossing three lanes of a boulevard at 45mph so they can turn left...at the last second of course. I hit his class C trailer hitch on this spot and it tore the nose piece, but saved the entire front end. You will have to do some mods to collect air around this piece or cut a hole so the air can pass through.

As far as cooling the engine compartment, has anyone experimented with allowing air to pass through the fiberglass piece below the window where the wiper motor goes through? Sealing the radiator area makes sense because you force air through the radiator, but opening the area below the window would allow the hot air to escape easier than going beneath the car or out the side vents.

One possible problem with this is if you get the same effect as cowl induction and the air tries to go into the compatrment rather than out.

Lt1er

The radiator is the limitation. With a good radiator and existing front vents your car should not run much hotter than the thermostat.

Header rap is a no no. It can hold so much heat in that the metal will begin to glow and it causes the pipes to flake apart. I would only use it on good stainless steel headers that can take the heat.

You can buy vented hoods that help flow hot air out.