When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I haven't been around much as I have a new hobby that keeps me quite busy but I was surprised this type of thread was still being discussed.
I have a stock small block and I know big blocks and any engine w/headers will cause a heat problem. I too had a heat problem when I first got my car. I took apart the HVAC system and made sure the "doors" associated with heat/air/defrost were operating properly and all door seals were replaced. Any grommets that needed replacement were and any holes/seals were patched/replaced. The 2 pictures are from the Chevrolet Chassis Service Manual. I would suggest a through reading of the service manual before attempting any fix.
I can now ride comfortably in my car during the spring/summer/fall regardless of the outside temp.
I haven't been around much as I have a new hobby that keeps me quite busy but I was surprised this type of thread was still being discussed.
I have a stock small block and I know big blocks and any engine w/headers will cause a heat problem. I too had a heat problem when I first got my car. I took apart the HVAC system and made sure the "doors" associated with heat/air/defrost were operating properly and all door seals were replaced. Any grommets that needed replacement were and any holes/seals were patched/replaced. The 2 pictures are from the Chevrolet Chassis Service Manual. I would suggest a through reading of the service manual before attempting any fix.
I can now ride comfortably in my car during the spring/summer/fall regardless of the outside temp.
I will be the first to agree that is perhaps most of the problem on my particular car. I have not done what you have done simply because the idea of tearing into the dash is very intimidating to me. It absolutely needs to be done for me to get full enjoyment out of the car, but I am terribly afraid of breaking something. I once attempted taking off the right side of the dash and chickened out after all the screws were out and it still wouldn't budge.
Someday it will have to get done though...one way or another...
I also need to add that there are plenty of cars out there that have a properly working HVAC system, that still seem to be brutal as far as interior heat goes. The thing we have found with this thread is that there is not just one answer for every car.
I regard to the heat coming into the cabin from the power steering columns, Most new cars and trucks that I have owned in the last 15 years have had dedicated fluid coolers for the power steering pump. The columns becoming hot must have been significant of an issue for the auto mfgs to have spent the money for the coolers.
skipmeister: I regard to the heat coming into the cabin from the power steering columns, Most new cars and trucks that I have owned in the last 15 years have had dedicated fluid coolers for the power steering pump. The columns becoming hot must have been significant of an issue for the auto mfgs to have spent the money for the coolers.
You may have a point.........Check the steering column temps belowof the non P/S project car/the steering shaft/column did have a big influence on the amount of heat transferred into the cabin/the 2nd set of mods reduced the steering column heat/ P/S cars may have higher temps.............
(NOTE: These test were done in the summer of 2014)
DISCLAIMER I WOULD HAVE NEVER DONE THIS TO AN ORIGINAL CAR!
1st SET OF TEMPERATURE MEASUREMENTS USING I.R.GUN ARE IN BLACK TYPE
2nd SET OF TEMPERATURE MEASUREMENTS USING I.R. GUN ARE IN RED TYPE
The hood was kept closed and was raised only to take temp readings......then closed until more readings were taken------It was H o t In that engine bay!!!!!!
89* F..........Ambient Air at front bumper.................94*F
Cold Air Intake Ducts (2) at front grills
1500 CFM pusher fan/2200 CFM puller fan
195* F ON /180*F OFF electric fan switch thru relay
50/50 Coolant/Water mixture
A/T shifter cable/ original 4-speed shifter opening is sealed and insulated to prevent exhaust-heated air from entering cabin area through the tunnel
Engine at operating temperature of 195* for 15 minutes before first testing was started..........2nd testing at 195*F
EXCEPTION: *****1st test....Radiator exhaust air deflector DIY modification diverts all hot air from radiator down under the car before it reaches the engine-----the engine receives NO airflow at this time as part of testing each modification as they are made to the engine bay....2nd test with mech. fan installed and blowing ambient air onto engine
This modification has caused the under-hood air temp. to be 130*F.....2nd test caused the underhood air temp. to be 105*F (which is lower than radiator exhaust air of 170* F that would normally blow directly onto the engine......TAKE THIS INTO CONSIDERATION DURING THE TESTING, AS IT SEEMS TO BE AN IMPROVEMENT******
Radiator 195* F............2nd test 195*F
Radiator diverter exhaust air below the car 170* F....2nd test 175*F
Radiator upper hose 195* F..........2nd test 195*F
Intake manifold at "stat" housing 195* F......2nd test 195*F
Air Cleaner Lid & housing 130* F.........2nd test 105*F
130 Amp Alternator 180* F..........2nd test 140*F
Valve covers 200* F..................2nd test 200*F
Oil sump/pan at lowest point 210* F...2nd test 210*F
Stock Exhaust manifolds above collectors 450* F.....2nd test 450*F
Steering Box by Exhaust manifold 160* F.....2nd test 130*F
Steering column at Firewall 100* F......2nd test 100*F (originally 130*)
Steering column inside car by gas pedal 100* F.....2nd test 100*F (originally 130*)
Steering column at dash mount 95* F......2nd test 95*F (originally 105*)
Steering column at steering wheel nut 90* F....2nd test 95*F
Exhaust pipes at firewall- footboard 300* F....2nd test 300*F
*Footboard inside the car 95* F (Entire interior of car is insulated/soundproofed with economy-grade Foil-backed heavy-duty bubble wrap)......2nd test 95*F
Exhaust Pipes under the floorboard 250* F.....2nd test 250*F
*Floorboard interior 95* F.......2nd test 95*F
Exhaust pipes at transmission crossmember 250* F....2nd test 250*F
*Floorboard "under seats" (seats are removed) 95* F....2nd test 95*F
*Cargo floor behind seats 90* F......2nd test 95*F
Exhaust temperature exiting mufflers 250* F......2nd test 250*F
*** Carb is taking in 90*F+ air rather than 170* F engine bay air from radiator......2nd test 94*F (Proven by G.M several decades ago)
***No radiator air exhaust is blowing on the engine at all....2nd test----mechanical fan is blowing 700 CFM ambient air on the engine at all times (this can be improved with a 1500 CFM electric fan)
***No air circulation around the engine or under the car for test purposes.....2nd test constant ambient air circulation
I WILL MAKE THESE CHANGES:
I will add additional Cold Air Ducts to a separate fan to force ambient air onto the engine bay and the firewall (rather than 170* F radiator exhaust air)---then I will re-test all the above readings....Mods were made and tested---see above
Then I will wrap all exhaust pipes from the exhaust manifolds to 12" past the transmission crossmember with a quality grade exhaust wrap (rather than old school "cloth wrap")---then I will re-test those readings.....I have not re-wrapped pipes yet.
(Members have said that it is better to allow air to circulate over and past the A/T--(which I doubted before this test-)--rather than installing insulation that could block/diminish air circulation around the A/T....after seeing the results so far---I must agree with them)
I realize that most members could not do the mods to their cars because of car originality.....This test was to see if 'temps' could be improved to help reduce the excessive heat under the hood and in the cabin. I was very surprised to see the large temperature drop in problem areas. I hope these results can make driving a Vette more enjoyable.[/QUOTE]
I have tried to address ALL the components in the engine bay that would produce a high amount of heat.....the readings in red type were the results from my second attempt of modifying the heat-producing components. As I move along with the project, I will post any under-hood mods that lower engine bay temps more than documented in test #2 (red type).
Last edited by doorgunner; Jan 6, 2015 at 10:48 AM.
wow...GREAT THREAD! lots of good info amongst those who are smarter than i!
pardon my ignorance...but what is the difference between Zero Clearance Heat Shield and DEI floor/tunnel heat shield?
(by product comparison...same)
would appreciate the thoughts of those who really know...
Thanks,
Ron
Sorry.....I have no idea.....but for twice the price....is the more expensive brand really worth it? I insulated/soundproofed the interior floor/firewall of my project for considerably less using HVAC aluminized wrap everywhere/Dynamat sparingly in high heat-spots and reduced floorboard heat from 130*F down to 90*F with ambient air temps. of 85*F.
Last edited by doorgunner; Jan 26, 2015 at 07:03 PM.
am leaning on going zero clearance on underbody, and
raammat on inside...
what did you do?
any thoughts on if this is over kill for 69 vert w sidepipes?
thanks,
R
I have no experience with ZeroClearance.....if it is quality stuff, you don't need anything more than the aluminized HVAC wrap for the interior/it also quietens the roadnoise....unless you REALLY need to spend some $$$$$ on the name-brand stuff....LOL!
Did you look at my build thread to see how I installed the HVAC wrap?
Ok, going to kickstart this thread again. Doorgunner talked about forcing air into the engine compartment and for those with steering column heat, I think that's what has to be done. I did over 150 miles in the '74 yesterday and the column stayed cool for about 50 to 60 miles, then started to slowly heat soak until it was blazing hot again.
Even after putting on Header Armor and insulating the steering box, the input steering shaft into the cockpit, measured 140 degrees and the brake booster was just as hot. On the inside, the steering column was about 120-125 degrees and the source of excess heat into the cockpit.
Even with my hood cutouts, I'm thinking the area in front of the firewall on the driver's side and behind the A-Arm is still a dead pool of super heated air, that does nothing. Doesn't move, doesn't circulate and it just gets hotter and hotter, till everything is saturated with heat. Boy, does that suck, because with the windows open, the air circulating around the cockpit, pulls the heat off the steering column and the support plate on the bottom and in turn, billows it around between your legs and up into your body.
So I'm going to install a big old scoop, ahead of the radiator in the open, clean air forward of the engine and then use ducting to clear the center frame and power steering and put air, right into that spot from below.
I found this on Ebay today. It is a vintage Datsun 240Z defroster system. It's all of $30, with free shipping. Note the big section (A), with the center part depressed and then back up. That's what I'm going to run under the center frame and back up into the rear part of the driver's side engine compartment.
I've got two scoops (B) and (C) that I can play with and plenty of extra ducting. I might even set up something with the side scoops using this 66-67 Mustang Defroster, as it looks really close to the shape of the side scoop on the C3. If it's close enough, I can just seal it and for $20, who gives a rats *** about the cost?
Of course it has to clear the Steering Ram and Exhaust. The grey square on the center frame is a plate that will support the hard plenum and then it will be attached to the side of the frame on the driver's side as well. On the front, the scoop will be attached to the two bars that hold the front nose on, and then the radiator support will be used to hold the front of the duct on.
I was wondering what would happen if you subtracted air instead of adding more? Use some of the ducting and an axial fan to pull air out of that area and perhaps out the side gills?
Does adding a cool air intake increase the underhood temp as the motor is not using the hot air?
I was thinking that if you cut out the back of the cowl hood in the scoop area (if that makes sense), then it would give the hot air somewhere to go, we all know hot air rises right? so instead of just letting it sit there under the hood it would have an exit and air flowing through the radiator would force it out... Just a thought
I was thinking that if you cut out the back of the cowl hood in the scoop area (if that makes sense), then it would give the hot air somewhere to go, we all know hot air rises right? so instead of just letting it sit there under the hood it would have an exit and air flowing through the radiator would force it out... Just a thought
The problem with that (and this is from what I understand), it's a low pressure area (it pulls air in, as into the cowl induction on the Chevelle's and other Chevy's (and on the '74 Corvette too).
Though, the thought temps me to do it and just cut the holes and see what happens!
The '74 is far from original and already has the hood cutouts. Maybe the holes in the upper part of the cowl area, might just help release all that nasty super hot air underneath there!
I was thinking that if you cut out the back of the cowl hood in the scoop area (if that makes sense), then it would give the hot air somewhere to go, we all know hot air rises right? so instead of just letting it sit there under the hood it would have an exit and air flowing through the radiator would force it out... Just a thought
If you have a say L88 hood- all that hot air end up in the kick panels- I have filled my holes so hot air won't get into the cabin.
I know I'm extremely late to this conversation. I stopped 90% of my heat problems coming into the cabin by installing a $10 shut off valve on heater hose that feeds the heater core.
I WOULD HAVE NEVER DONE THIS TO AN ORIGINAL CAR!
