Insane Heat

[FF33rod]

Okay, after putting the first 100 miles on the hot rod I have concluded that if I'm ever going to drive this more than a half hour at a time, I need to fix the insane amount of heat in the cockpit.

I'm looking for input from the experienced community on what you tried, what helped and what didn't. Having used Lizard Skin products along with the FFR sound & insulation package and double wrapped the mufflers with DEI product, I've done pretty much all I can in those areas. There aren't any openings through the firewall or floor to frame, those have all been sealed. I've pretty much concluded that the issue is heat coming from underneath, going around the chassis/frame and into the cockpit. What have you done to stop this?

I'll openly admit to the first thing I need to do is put a boot around and otherwise seal up the eBrake going through the floor. Next?

Thanks
Steve

[JimLev]

Have you wrapped the exhaust pipes?
If you have AC have you turned it on?

[FF33rod]

Have AC but haven't charged the system yet. Obviously that will help but I'm interested in getting as much heat out first.
As for the exhaust pipe wrap, I personally believe that it will help in a very localized spot but if you do the whole system it does very little and pretty much the same amount of heat is trapped under the car. I can feel hot air moving around in the cabin so I know it's coming from somewhere - for example, up through the chassis where the striker mounts are in front of the doors. Hoping to hear from guys that have have searched that type of thing out.

Steve

[Brave Salmon]

The only suggestion is to look at it one part at a time. You say the striker mounts are a heat source. Look for a way to plug the area around the striker panel with insulation. You can use some old fashioned fiberglass insulation from the pink panther to narrow it all down. If that helps there, go onto the next area that leaks heat and follow the airflow to its source. I've used another driver to keep the car moving while I poked around inside from the passenger seat to find the leaks. Don't be discouraged, just keep after it and you'll get it. Once you positively know where the hot air is from, you can find a creative way to use more heat mat, foam, or a solution that best fells the void, so to speak.

[33fromSD]

I can sympathize, I'm dealing with vapor lock in my 302 carbonated engine due to the massive heat in the engine bay which I am working on curing.

I'm lucky in the sense of the cockpit.....I went the rag top route (basically used for winter storage only) and I only run this thing with the top off so I get great airflow in the cockpit but I can definitely feel the heat on the carpet on the floor, I can't imaging how hot it would be in the cockpit running with the hard top.

I don't have AC (again since I'm running topless) but honestly as warn as these cockpits get, I'm not even sure how much the AC will keep up with heat radiating up.

I also went with seat risers so my seats are not directly on the carper so that helps a bunch too with heat radiating up through the seats.

Having mine on the lift last night to put some heat wrap around my gas line, I was looking around and there is really only a couple spots where heat (besides radiating up) can get in and those are the emergency brake opening and the seams where the floor meets the firewall or the frame. I'm going to take some high temp sealer and close those holes.

I may look into to seeing if there is an aesthetic external thermal sheeting I can possibly put un the floor boards especially above the exhaust.

May be a losing battle meaning there are steps that can be taken to "reduce" the heat but with the aluminum flooring and the exhaust about 1/2" from the floor, there will always be a lot of heat. just my opinion. Another area for excessive heat is the aluminum firewall, that thing gets really hot...... I was measuring 138F the other night right by the exhaust with an infrared thermometer. I may have to put aside aesthetics on the firewall for some type coating to help reduce the heat.

Jim

[wallace18]

If you are running the sides of the engine area and do not have any openings to let the engine heat out you will get lots of heat in the cockpit. In FL with A/C I have found the sides need to be open. The first 2 33's I built had no heat issues. The newest one I did for my wife does. See the differances.

E1754744-617A-48AB-94A6-E50A5D63459B_1_105_c.jpeg2E9B2C60-9026-4123-828B-BA65E3727201_1_105_c.jpeg49542071-6367-411B-B557-9CB02263DC10.jpeg

[J R Jones]

Steve, I have done aerodynamic development in wind tunnels but when time and budget were not available I found alternatives.
I did air box ram air development on a private aircraft runway and confirmed the results on the chassis dyno with a leaf blower to simulate air speed.
You could look for air leaks with an assistant and a leaf blower.

I use only aluminum or silver paint on engine compartment panels to minimize heat adsorption.
My 1929 Mercedes resto-mod has an aluminum hood with louvers top and sides, and the escaping heat finds it's way into the open cockpit.
I am considering one or two exhaust fans to pull air out of the engine compartment and under the car.
jim

[NAZ]

I can sympathize, I'm dealing with vapor lock in my 302 carbonated engine due to the massive heat in the engine bay which I am working on curing.

I'm lucky in the sense of the cockpit.....I went the rag top route (basically used for winter storage only) and I only run this thing with the top off so I get great airflow in the cockpit but I can definitely feel the heat on the carpet on the floor, I can't imaging how hot it would be in the cockpit running with the hard top.

I don't have AC (again since I'm running topless) but honestly as warn as these cockpits get, I'm not even sure how much the AC will keep up with heat radiating up.

I also went with seat risers so my seats are not directly on the carper so that helps a bunch too with heat radiating up through the seats.

Having mine on the lift last night to put some heat wrap around my gas line, I was looking around and there is really only a couple spots where heat (besides radiating up) can get in and those are the emergency brake opening and the seams where the floor meets the firewall or the frame. I'm going to take some high temp sealer and close those holes.

I may look into to seeing if there is an aesthetic external thermal sheeting I can possibly put un the floor boards especially above the exhaust.

May be a losing battle meaning there are steps that can be taken to "reduce" the heat but with the aluminum flooring and the exhaust about 1/2" from the floor, there will always be a lot of heat. just my opinion. Another area for excessive heat is the aluminum firewall, that thing gets really hot...... I was measuring 138F the other night right by the exhaust with an infrared thermometer. I may have to put aside aesthetics on the firewall for some type coating to help reduce the heat.

Jim

If you're using the OEM style mechanical fuel pump -- stop that! That's what leads to vapor lock. The fuel vaporizes easier when pressure is lower and the engine mounted pump has a long suction line of reduced pressure exposed to the heat.

[NAZ]

Steve, lot's of good advice here. I especially like Jim's leaf blower trick.

From my experience, exhaust wrap is only marginally effective and given room, heat shielding works better. The farther away you can locate your heat sources the lower the temp will be as the inverse square law applies. Unfortunately, the Hot Rod doesn't have much room for anything and not even enough to run a proper size exhaust system on a high performance engine. So after all the air leaks and other low hanging fruit is taken care of, your best bet is to insulate the chassis / body areas adjacent to the heat sources. But I wouldn't expect too much from wrapping the exhaust or even the ceramic coatings lot's of people like to use. And use heat shielding wherever you have the space.

Whatever heat you're experiencing I bet mine is worse. I have so many openings I can see the road between the body and chassis when I drive. And my windows don't roll down. That's why it's called a HOT rod.

[FF33rod]

Thanks guys, some good advice there. I'm going to reach out to Jamie and Bill as well since they use their cars a ton

I like the leaf blower trick! that will be easy to do.

Tom, interest comment about the engine side covers. Cover vs no cover is obvious but it's interesting how your wife's car still has a fair bit of opening along the side but with quite a different result. I put the Buick Ventiports in mostly for show but thought surely they would help with heat, maybe not!

Putting the hot in hot rod, LOL, love it

Steve

[33fromSD]

If you're using the OEM style mechanical fuel pump -- stop that! That's what leads to vapor lock. The fuel vaporizes easier when pressure is lower and the engine mounted pump has a long suction line of reduced pressure exposed to the heat.

No mechanical pump...

[NAZ]

No mechanical pump...

Great! Gasoline vapor pressure at 160F is ~5 PSI so whatever you can do to keep the lines from heating and keep the fuel pressure higher as near to the carb as practical will help prevent the issue.

Beside routing the lines away from heat sources and insulating the lines, here's some other ideas. If using an external pump, it's best to keep the fuel pump suction line as short as practical so a pump mounted as close to the tank and below the bottom of the tank is better than above the tank or any distance from the tank. A fuel filter on the suction side should be mounted vertical to prevent air entrapment (I like to mount mine in the tank at the end of the pick up if it can be made easy to service). A larger line will help reduce pressure drop on long runs. And mounting the fuel regulator close to the carb with a higher pressure supply will add a margin to prevent vapor.

[33fromSD]

Great! Gasoline vapor pressure at 160F is ~5 PSI so whatever you can do to keep the lines from heating and keep the fuel pressure higher as near to the carb as practical will help prevent the issue.

Beside routing the lines away from heat sources and insulating the lines, here's some other ideas. If using an external pump, it's best to keep the fuel pump suction line as short as practical so a pump mounted as close to the tank and below the bottom of the tank is better than above the tank or any distance from the tank. A fuel filter on the suction side should be mounted vertical to prevent air entrapment (I like to mount mine in the tank at the end of the pick up if it can be made easy to service). A larger line will help reduce pressure drop on long runs. And mounting the fuel regulator close to the carb with a higher pressure supply will add a margin to prevent vapor.

I actually need to move my fuel pump. I thought I'd be clever for easy servicing and put it on the lower frame in the engine bay (forgetting electric pumps work better pushing vs. pulling fuel) so my guess is as the heat builds in the engine bay as well as the line under the car the pressure drops thus making the pump becomes ineffective in keeping up and what little fuel is in the line it is vaporizing due to the heat by the time it gets to the carb.

I'll move it to the back by the tank, insulate the whole fuel line, add the fiber spacer I bought for between the carb & intake (to insulate the carb from the direct heat from the intake) and I think my vapor lock situation will be solved.

Jim

[peterh226]

Sorry to hear about the heat issues. I hope the Gen2 is better, but that does not help you much. Have you tried removing the hood side panels to see if that helps? I think the ports look cool, but don’t really flow much air. Maybe you can feel how much air comes out of them with the leaf blower process.

[33fromSD]

Sorry to hear about the heat issues. I hope the Gen2 is better, but that does not help you much. Have you tried removing the hood side panels to see if that helps? I think the ports look cool, but don’t really flow much air. Maybe you can feel how much air comes out of them with the leaf blower process.

Peter, mine is a Gen2, I have no way to compare temp between Gen1 & Gen2 in the cockpit but I can confirm that there is still a lot of heat in the cockpit with Gen2.

I'm running the insulation between the aluminum floor panels, FFR's sound deadener (both the mat & foam sheets) too. Mine isn't a huge issue though since I'm not running with a hard top, so I get a lot of air flow, but if I had a hard top I'm guessing it would be very toasty in the cockpit. I can confirm that even with the insulation & sound deadener under the carpet, the carpet itself is fairly warm to the touch.

The only time I really notice the heat driving around is when I'm stopped at a longer stop light, then you can feel the heat rising up.

Jim

[Gbeck]

I'm fighting the same issues on my Gen 2 Type 65 Coupe.

In spite of applying Lizard Skin to the under side of the chassis, it's not long before the heat soaks into the sheet metal and the frame. I'll be applying DEI Floor/Tunnel Heat Shield to try to reflect heat away from the chassis where possible. I'm also using DynaDeck on the floor and tunnel to block some of the heat and noise coming inside.

Fitting a boot around the eBrake helped a lot as did blocking other places where air was finding it's way into the cockpit.

[stacked33]

I added a cowl vent as I was not going with AC. It is a life saver. I also insulated the cockpit well too.IMG_20140524_082225_172.jpgIMG_20140524_082239_522.jpgIMG_20140524_082307_227.jpg

[N2mini1]

Get a cheap digital infrared thermometer like everyone has been using to check your temp during Covid. Bout every store has one for sell. Harbor Freight etc.. Then you can actually check temps in different places to know where to work on. Passenger could even do it while your driving down the road to see where hot air in coming in from..

[mburger]

My suggestion would be to get a thermal imaging camera so that you could visually and easily find your heat sources. Combine this, with the leaf blower test and at stand still. You could even have a passenger use it while on the road. Lots of different styles available from standalone handheld to imaging devices that plug into your smart phone. While this won’t keep the heat away, I think you first need to find the biggest source of heat and attack that.
I have no experience with this and it is for an iPhone. This is only an example to give you ideas.
https://www.amazon.com/FLIR-One-Ther...a-359611389735

[Brastic]

I was about to state that I do not have this issue. I got my car running in March and my first long (200+ mile) drives were in the cold(40-55F). Then I had the hot rod on jack stands for two months as I was adding stuff. This month I drove in the heat (80-90F) and wow are you right about the hot air blowing in. Even with the sound proofing and carpet, hot air just makes it into the cabin. I was happy to test the AC. Funny that I did not notice this on the Cobra....Oh yeh, no roof.