I think this is tech, anyway, I thought I'd share this with the group.

During my recent engine rebuild I decided to install both a transmission tunnel heat shield and the transmission collar in an attempt to reduce the awful heat my 69 produced. I've been driving around for several weeks now and I am thrilled to say that the heat is dramatically reduced!!!! Anyone considering doing this cheap project (well, not too expensive) while the engine/transmission are out should do it!!!

Frankly, I was not impressed when I saw the parts in the box. The tunnel heat shield looks like a flimsy piece of molded padding covered with a sheet of furnace tape. My original clips were still mounted in the tunnel and installation of the heat shield was quick and easy. I suppose that one could do this installation with the tranny / shifter still in place by cutting a slice in the shield at the shifter hole and sliding the heat shield around the tranny. Not sure I'd want to do this laying on my back though.

As for the collar, it is just a thick piece of foam. I think any heat resistant foam padding would work. I slipped the foam in after the engine / tranny went back into the car. I pushed it as far down the firewall as I could reach and added some weather stripping adhesive to keep it in place. So far, it hasn't moved.

 

Mark,
This info is excellent!
My convert's cabin temp is absolutely unbearable here in the desert. I'm installing a new interior in about a week so I'm going to do something underneath the carpet.

I wasn't real clear on your procedure...
Did you install this stuff under the carpet or under the floor? Where did you buy? What brand/supplier? And what did it cost?
Best,
Greg

 

Mark..My 69 has tunnel insulation and....plastic splash shields at footwells with temp insulation underneath....I'm going to add these splash shields/insulation to my 78...last weekend my 78 footwells got to 132 F in 29 Palms,Ca (Raytek readings)...the 69 is much cooler under similar conditions..



Rich

 

Pull the shields and take a good look at the insulation. I roasted my feet for years thinking the insulation was good. Only to find what looked like good insulation around the edges was a shell of what should have been there. New insulation made a big difference.

 

I'm changing out the 69 shield insulation when I do the install on the 78...the 69 stuff is foil backed on one side...foil towards engine...
Rich

 

Greg,

The tunnel insulation actually mounts from beneath the car. There are a set of sharp metal clips rivited up inside the tunnel. You align the heat shield with the shifter and boot, then push the heat shield into the sharp clips. Once the clip pokes through the heat shield you bend it over and that's it.

Think of it this way, you are under the car looking up at the tranny and drive shaft. The shield is mounted above / behind them both.


Here is a link on Corvette Central's web site for both the collar and the tunnel heat shield. I suspect all the usual suppliers have them in stock.

http://www.parts123.com/parts123/yb.dll?parta~partsort

Since my heat shield was long gone, I assumed that the clips and rivets were missing as well. I ordered new ones, then found that the originals were still there during the install. Someone would almost have to pull the clips out on purpose for them to be missing.

 

Just go to Corvette Central and type in Transmission tunnel heat shield. Their link has a diagram.

 

Rich,

My car still has the plastic splash shields but no insulation. I was planning to insulate there as well, but am concerned that water might get trapped in the insulation (assuming I might eventually be caught out in the rain). Has water been an issue with yours?

 

Not at all...but have not driven it in heavy rain..think the shield minimizes rain getting in there.......this time I'm using some alumninum duct tape at exposed edges of insulation..



Rich

 

I covered my transmission tunnel area with aluminum foil tape to help ward off some of the radiant heat. I have no before and after temperature data to share but I believe the improvement made it worth the effort.
If you were to apply all of the heat insulating ideas that have been discussed on the CorvetteForum onto one Vette, I'm pretty sure it could survive re-entry into the Earth's atmosphere. :LOL:

 

On my 1970 Big ol' block with headers...i used to have it REALLY bad ; it was like being in a slow cooker especially at stop lights. A few years back, i underwent a major insulation job in attacking the problem. Heres a brief synopsis :

TOPSIDE :

1. I took up all of the carpetting, front and back, and added two layers of 3/8" thick insulation roll which has an aluminum foil on one side. Got this at www.jcwhitney.com . They offer a 24 foot x 4 foot roll for $79.

2. I took off the center console and added the same on the topside of the tunnel and on both sides down to the floor. This bulged the sides out a bit but not too excessively.

BOTTOMSIDE:

1. I measured and cut to size one long length of the insulation roll and wrapped it around the underside of the tunnel to within 3" of the Headers pipes. I used their high temp. spray adhesive which really bonds well.

2. I wadded insulation behind each metal heat shield next to where you place your feet.

3. I found some AeroSpace foil material which drastically radiates heat off of it. I think the name brand was called 'Eagle Shield' and it was used extensively in home attics especially in the South to greatly reduce heat gain into 2nd story ceilings. I think the manufacturer is now out of business but it may be possible to obtain some via a google. So, i applied this to the outside of the metal heat shields in a double layer.

The results were astonishing to say the least. The only time i feel the heat now is from the Headers coming in thru the windows if i have them rolled down while at a stoplight for more than 1 minute. I might add that it greatly cut down on road noise too.

 

I believe the most effective way to attack cabin heat is from both engine side and inside cabin...just inside does not work out here in the desert or where I live in El Cajon,Ca...

Miker..that foil tape you did really looks good...it must be effective against radiant heat...if you can get some "after" readings in 90-100 F weather,that would be helpful...good discussion/ideas guys..
Rich

 

Here is a link to 'Eagle Shield' heat barrier film : Radiant Barrier Insulation Certified by the Space Foundation
Address:http://www.eagleshieldinsulation.com...nsulation.html

I was given a demonstration with this stuff about 15 years ago ; the guy had a wooden box with a high intensity heat lamp inside. The box was divided into two sealed off sections. The Eagle Shield was only in one section and directly in front of the HEat Lamp. A thermometer was in each side. After he turned the Heat Lamp on , within 5 minutes it was over 130 f. in the side without the Eagle Shield ; in the side with Eagle Shield i honestly cant remember the final temp...but it wasnt much above room temp.

Anyways...just thought id throw this info out there. The product may be useful to you in others ways perhaps.

(Disclaimer : Im not a distributor of this product nor am i affiliated with the Company in anyway ; further, i am not involved in an extra-marital affair with the wife of any of its Officers).

 

Another good product is Thermo-tec...Summit has it for many different applications..

http://speedzone24-7.com/aluminized.htm

 

Is the insulation between the floorpan and the heat shield any special type of insulation?

I'd like to add these to my '76 and I see several vendors selling the shield and mounting bracket but no mention of the insulation. Is is just plain old fiberglass insulation sandwiched in there?

- Alan

 

Before you go too much further take a look at this fix. I've recommended it to many people who have had a lot of success with it.

https://www.corvetteforum.com/techti...=241&TopicID=3

 

zero clearance with the stock trans tunnel and aluminum duct tape over seems

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I crammed fiberglass insulation behind the metal heat shields and the floor boards. Doesnt smolder.