reducing interior heat

[wa5ngp]

I'm happy to say that my '73 has become more of a daily driver. Lately with temps in the 100+ I'm thinking of doing things to reduce interior heat. I'd appreciate any comments from others with similar efforts.

I thought I'd start with some sound deadning stuff with insulation on top for the floor boards and stuffing insulation between those plastic body side panels and the body exterior.

I notice that the gear shift lever gets really hot. Is that just conductive from the tranny and engine or is it from the exhaust pipe and hot air coming up the boot? I thought about wrapping the exhaust pipe and header but that invites rust. On newer cars I see nice heat shields between body and exhaust pipes. Maybe a trip to a junkyard would yield some ideas and parts that could be adapted for the 240.

I have an ac that works marginally, needs a new expansion valve and could also benefit from a honda blower.

its more fun driving it everyday now.

don

[Ttiger]

General insulation would help, but there is a lot of glass area so the sun just bakes the inside.

I put a rear window louver on mine and it made a huge difference. There are several kinds, one that you drill holes and a few that you don't.

Make sure your rubber shift boots (under the console - on the floor) are not torn. You'll get tons of hot air through the shift lever area if they are.

You can get the A/C to blow cold with a little work. The L-6 engine can handle the load no problem. Just make sure your radiator is clean.

Edited July 19, 2009 by Ttiger

[Zs-ondabrain]

I use a 15% window tint, it reduces heat and Ultra-violet rays as well. I know it sounds weird putting a dark material on a car to cool it down, but it's what the tint does that's important.

A/C will help when working properly and fully charged. A good blower like the Honda Conversion is never a Bad idea.

If you don't mind tearing things apart, DynoMat and a few other companies make excellent Anit-Heat, Anti-Noise materials, that can be added to the firewall, floor, doors and anywhere else you feel the need to reduce heat.

[five&dime]

15%!!! That is super dark. Is that legal in WA?

[Z Tyler Z]

15%!!! That is super dark. Is that legal in WA?

Sadly here in Wa, 35% is as dark as we can go as we can go legally, but I've yet to meet someone in my area that has been pulled over for having darker tint. It's not really enforced were I live in WA.

[Jeff G 78]

15%!!! That is super dark. Is that legal in WA?

I bought a BMW 320is years ago from Atlanta while I was living in Ohio. It had 5% on all the windows! I drove it home from Georgia to Ohio and I didn't even make it to my house before I was stopped by an Ohio state trooper. I was just a bit over the 50% limit

As far as your '73Z goes, I know they are old school, but if you can't do dark tint, rear window louvers do a great job. What I found is that the car heats up from the sun load and then the floor heat gets to you. If you cut down on the solar heat, the underbody heat will not be an issue. I used the over-the-trim style on a few previous Z cars and liked them a lot.

[Zs-ondabrain]

15% is farely dark but Like Tyler said, It's not that much of an issue around here and I'm just ten minutes from Everett. I think 35 or 30% is the legal limit but as long as you roll down your windows when a Cop is near, they usually leave you alone.

I've actually had conversations with the local PD, from inside the car, and they never even mention the tint. I guess the rest of the car is too much of a nice distraction. Maybe?

[ConchZ]

I have a 73, and live in Florida, so I know about heat. Here's what's worked for me.

1) Getting your AC working right can be interesting. Two years ago, my PO installed the Honda fan, and put a new compressor in where the air pump used to be. He used a Sanden 709 (model 7409) compressor, which he told me is mounted in the exact mounts that used to hold the air pump. He charged up the system himself with R134a. He never got the AC to cool very well, though. When I got it, the air flow was intermittent, despite the fan running at a constant speed. It was also only mildly cool. I took out the HVAC control panel in the middle of the dash so that I could see inside the ducts. Search this site for how to do that. There was a 3x5 inch x 1/4" thick piece of foam floating around in there. This explained the intermittent air flow. Shortly after this, the compressor started rattling, and the air got less and less cool, while the rattle got louder and louder. I ordered a new Sanden 709 for $200 and had a mechanic put it in right. He says from what's coming out of the lines, it appears that the PO didn't properly flush them of the old R12. Mixing the old R12 with new R134a is not good, as it leads to corrosion and clogging of the system. While my system is currently cold, it may not stay that way if it develops leaks. Also, don't forget a new receiver/dryer if you change your coolant. Finally, you might want to clean your evaporator coil with some coil cleaning spray. After 36 years, its probably pretty clogged.

2) The hot shifter can be helped by replacing your rubber inner shifter boots. There's two of them. It won't completely solve the hot shifter, but it helped me a lot. While you are at it, you can replace your shifter bushings, which will improve the smoothness of your shifts, and only cost about $5. While you are at it, buy a motorcycle cable lubing tool and a can of cable lube at a motorcycle shop. Use this to lube your choke cables. If you've taken out your AC controls, you can also lube up those cables. It'll make you happy, prevent future problems, and it'll only cost about $15.

3) The hot floor can be helped by pulling up the vinyl and insulation on the hump and putting down Raamatt or Dynamat on it, as well as under and behind the seats. I don't recommend putting it over the entire floor, as you might want to inspect the metal for rust once in a while. I used 3 layers of Raamatt, followed by 2 layers of Ensolite. My hump's factory insulation did not survive removal, so I put the vinyl back in without it. The heat under the drivers seat was solved, but the tunnel was still hot, so I wrapped the exhaust under the floor with this exhaust wrap. I'm not too worried about it rusting out my exhaust, as it doesn't seem to hold water, and the exhaust heat will surely dry out whatever moisture does get into it. This wrap solved my heat issue. If my exhaust does rust out, then I get to upgrade my stock sized pipe to a bigger one, and I'll use stainless. I wish I hadn't glued in the hump vinyl without any more insulation, though. I may pull it up and put in some more this winter when its not so hot outside.

4) I have a rear window louver from the PO. It does help, but I think the car looks better without it, so I may switch to a tint someday. These louvers do rattle a little, too. The thing I do like about them is it keeps people from easily seeing what's in your hatch area.

5) Take off your interior panels. The doors and the plastic panels on the inside of the hatch. Search this site for info on how to remove them without destroying them. Take this opportunity to clean them up, patch any cracks, and if they are faded, you can repaint them with SEM paint. It's also a good time to replace your antenna if necessary. Before putting them back on, put that Raamat on the inside of your outer door skins and on the inside of the outer skin around the hatch area as best you can. Every little bit will help with heat and sound. (inspect those doors for rust before installing Raamat, and treat any you find with POR15.) Next, glue 2 layers of Ensolite on the outside of your restored plastic hatch panels. This really helped me with the heat. Without this insulation, you are basically sitting in a solar oven, as that out skin gets very hot in the sun, and radiates it right at you inside the car.

6) When parking in the sun, use a sunshade on your front window. Obvious, I know, but thought I'd throw it in with the rest of it...

Hope this helps. Enjoy your newly quiet and cool car....

Matt

[Walter Moore]

I bought a BMW 320is years ago from Atlanta while I was living in Ohio. It had 5% on all the windows! I drove it home from Georgia to Ohio and I didn't even make it to my house before I was stopped by an Ohio state trooper...

That sounds like Ohio. (No offense to those who live there...) I worked for a company based in Akron for 5 years. I think a line from that really old movie "Gumball Rally" sums it up best:

"We have good news and bad news. The good news is from what we can tell no state has enacted the death penalty for speeding. The bad news is we haven't heard back from Ohio."ROFL

[Jeff G 78]

...I worked for a company based in Akron for 5 years. ...

What company? I am from Akron.

[wa5ngp]

Thanks for all the ideas.

Fortunately, for me I have covered parking where I work. Otherwise I doubt I could drive the car daily in 105 deg heat. Like you all say, sitting outside in the sun creates a horrible heat soak of the interior that's almost impossible to overcome.

I've had louvers since 1976. To me my car looks naked without them. Darker windows, I dunno, I don't want to look like I'm a member of the Sopranos or something like that. :pirate: and I like to see out at night too.

I'll start with replacing the floor insulation with new sound and thermal insulation and get some up on that firewall as much as I can. Newer cars have heat shields inside the engine bay that shields the firewall. That would take more effort with all the openings for cables etc.

I was thinking a heat shield on the exhaust would not help as I'd think that flowing air as I drive along might manage that. That air must not be enough, otherwise the shifter would not get so hot. The rubber boot has been replaced. So I'll try to figure out something there with exhaust pipe tape being another option.

I had already fashioned some heat shields for under the carbs and that made a nice difference in reducing vapor locking. So that would say shielding exhaust underneath should be a useful thing. Despite the record heat this year vapor locking seems to be less a problem even after a very long hot soak. I wonder if the gasoline formulation has changed a bit so its less volatile?

I have an aftermarket ac setup with a sanden compressor. I had the old 1 lung York for a long time. The Sanden is a lot smoother and takes less hp. However, I think the original 36 year old expansion valve does not work as the low side pressure is very low no matter how much freon I put in there. I'm going to wait to replace that expansion valve as I'm afraid its going to be quite a chore to break loose those fittings that have been intact for 36 years. That will be a job for winter when I don't need the ac since it will probably take a few weekends of effort.

regards

don

[Inf]

There is still a fair amount of heat coming off the transmission tunnel due to the exhaust. Most of the heat that makes it's way into the cabin that way is from all the infrared the exhaust pipes are radiating. I would think that a shield would be a benefit, similar to how a shield helps keep the carbs from getting too hot from radiation from the exhaust manifold/headers. There is a fair amount of air blowing around in the engine bay, after all, so I think in both cases convection is a little bit less of an issue to begin with.

I'm finally moving into a new place with a real garage (hooray!) so I'm considering taking the carpets and vinyl out and installing some insulation. The transmission tunnel gets exceptionally warm after a long drive.

I also have a Sanden compressor, from the current MSA A/C kit... Not trying to get too far off topic, but I need to investigate this weird vibration that I can feel through the pedals and body panels whenever the compressor kicks in. Everything seems to be bolted down tight... ?