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Just putting a thought out to the more experienced Vette owners. Would it be beneficial to put fans in the fender area vents to help extract some of the heat?
Has anyone came up with a way to move more air through the compartment or to cut down on the heat.
When I had my car painted, the original hood was cracked beyond reapir. I bought a hood from a 76 and cut three oval ports in the cowl to open up airflow. Works like a champ. At idle and low speed it acts as a vent. At WOT it creates the cowl induction effect. I can pull my air cleaner bare handed with the motor at temp. I don't have any pics at the moment but if I can get out to the garage today I'll snap a couple.
I would bet that if you have the original 73 hood, removing the flapper mechanism and opening the cowl might provide the same effect.
hot air rises, so fab some vents, scoops etc to rid the heat? Old hot rods used louvers so when stationary it had somewhere to go
When moving the compartment can build pressure, give the air somewhere to go even if it just means spacing the rear of the hood up
Seal the air cleaner to a source of cool air youll notice a difference
Been wanting to get a flat glass hood for my A body and create something that looks pleasing yet does both.
Noticed in our 00 and 01 E series there is a second firewall that envelops the engine isolating heat from the firewall...isolates electronics, brake stuff etc also.
As air runs across the hood it could create a low pressure area so if there was a cutout of some type it would literally pull heat out. Look at the ZR/ZL1 camaros and vette hoods, food for thought.
Except that the area at the rear of the hood and base of the windshield has a HIGH pressure condition that would not allow exit air (but could provide inlet air!).
Last edited by 7T1vette; Sep 12, 2019 at 01:42 PM.
Except that the area at the rear of the hood and base of the windshield has a HIGH pressure condition that would not allow exit air (but could provide inlet air!).
This is true. When I had a C3 which was my DD in the hot and humid Maryland summers I used to drive with the hood popped open and the headlight buckets open to create better air flow. When at speed the open hood does draw in outside air (notice I didn't say cool because Maryland summers don't have cool air) which helped cool the engine compartment. When you were stopped at a red light the open hood would let the engine compartmewnt air escaspe. The open headlight buckets allowed better flow when driving too. My engine never really ran "hot" but providing the better air flow to get rid of the underhood temps helped the air conditioner provide semi-cool air rather that warm air. Those early C3s had crappy A/C to say the least. Good luck with your car.
Last edited by Jims66; Sep 12, 2019 at 02:33 PM.
Reason: spelling....
Here is a pic of the three vent holes I cut in the 76 hood I added to my 73. As said in my previous post it stays way cool and provides open cowl induction at speed and WOT. I also have all factory cooling parts in place, ie; front spoiler, fan clutch, radiator shroud. Good Luck!
Replace the foam seal between engine compartment and transmission hump and put in an aluminum radiator. The a\c in my 77 put out 50 degree air wit the roof open.
I sure wouldn't want something that keeps the heat in. Some people refer to that as a insulating blanket for the hood. Its really a sound deadener. When the C3s first came out, some (test drive) customers complained of too much engine noise. A sports car with too much engine noise? Go figure.
The use of header wrap will void any warranty claim on your headers. If they are old and narly then do as you wish. Myself, I think the wrap looks awful. Its like you are trying hide blemished / rusted headers.
As far as the C3 heat in the engine bay, just block off the heater core hose and live with it.
Actually it is a fire blanket meant to smother an engine fire as well as insulate sound.. The plastic discs that hold it inplace are meant to melt and drop the blanket to smother the fire. Doesn't seem to be something that would do anyhing for an engine fire.
180*F....normal operating temperature for a Chevy V8 engine....is only 30*F short of boiling. You can't even touch something that is 160*F without getting flesh burn. But that is all to be expected inside a C3's engine compartment. If the actual coolant temp is 180F or less, your engine does not have a "heating" problem. If too much of that heat leaks into the passenger compartment, you have a heat leakage problem.
Actually it is a fire blanket meant to smother an engine fire as well as insulate sound.. The plastic discs that hold it inplace are meant to melt and drop the blanket to smother the fire. Doesn't seem to be something that would do anyhing for an engine fire.
That's an old wives tale because it might have happened once. The intentional design of the pins / disks is to hold the blanket to the hood during assembly lines.
It was not intended to smother a fire.
Some Google C3 fire pictures show just how well that sound deadener blanket burns. And that's all it is. No fire retardant involved.
In fact it burns better than the fiberglass hood. Scary stuff.
But that was 40+ yrs ago. Todays hood blankets should be better.
Last edited by HeadsU.P.; Aug 5, 2021 at 04:33 PM.
Bypass heater core
Install foam block on bell housing
Don't wrap your headers, have them ceramic coated preferably inside and out.
Install heat barrier under the carpet
Those things practically eliminated the heat in my car.
If you have headers uncoated then that is the primary source of your heat. it's something like 800* uncoated vs 300* coated in temperatures generated from the headers.
Although wrap is not favored as a few have expressed here, I would consider it if you're wanting to knock that heat down. Yes it may end up rusting out the headers, but then you could buy coated ones when the time comes to fix the problem.
Imagine all the components under the hood that are getting cooked every time you drive. Eventually they will have to be replaced due to the excessive heat. Lot's of rubber under there.
Bypass heater core
Install foam block on bell housing
Don't wrap your headers, have them ceramic coated preferably inside and out.
Install heat barrier under the carpet
Those things practically eliminated the heat in my car.
but with after market AC that has a water valve so no hot water goes through the heater core when not calling for it...
Good point regarding the hoods cover blanket..
I was told when I 1st bought my 78 that the blanket would keep the hood from becoming distorted from the hot suns heat lets say at cruise ins and car shows etc and not necessarily from just doing short local runs..
Kinda would like to know if it is safe to remove the blanket and just take my chances..
And OMG how hot the engine bay is and yes I have all of the heater hoses closed off!!!
How about some serious input C3 Gurus!!
Check your timing. Follow Lars' instructions, not the GM spec.
I run both cars with no blankets. Underhood temps are about 180 degrees.
I have the underhood blanket and the tunnel blocked and my a/c modernized, R-34 and VIR replaced, heater core turned off with a manual valve. Engine runs at maybe 180. A/c works very well with tops on and keeps it tollerable with tops off. I also have a three row aluminum radiator and have insulated the floor, firewall and rear compartment. The biggest change came when I blocked the air flow thru the tunnel. No change in engine temp, huge change in cabin temp..
Last edited by jimbo8125; Aug 6, 2021 at 11:49 AM.
Reason: spelling
That's an old wives tale because it might have happened once. The intentional design of the pins / disks is to hold the blanket to the hood during assembly lines.
It was not intended to smother a fire.
Some Google C3 fire pictures show just how well that sound deadener blanket burns. And that's all it is. No fire retardant involved.
In fact it burns better than the fiberglass hood. Scary stuff.
But that was 40+ yrs ago. Todays hood blankets should be better.
this is straigh from the ecklers catalog.
Ecklers Corvette understands your hood insulation serves a very critical safety purpose. It’s not there to merely offer sound suppression from your engine or to protect your paint from heat. Your hood insulation is there to offer you some protection in case of an engine fire. During heavy heat, the plastic clips that hold the insulation in melt dropping the insulation on top of the engine to smother and reduce the spread of flames. Because of this, some hood insulations are made to only cover the engine and not fully cover the inside of your hood. Running a car without hood insulation can be a critical safety error that no one should make. Our affordable hood insulations are carefully sourced from quality manufacturers and made from modern asbestos free materials. Enjoy your classic safely with quality replacement hood insulations from Ecklers Corvette.1976-79 (C3) Hood Insulation
