Firewall/tunnel/underfloor insulation on a 69
Last week I received my package from Corvette Central which included the under floor insulation pieces. These are kind of 'L' shaped pieces that are sandwiched between the metal plate and the floor, between the toe-board and the splash pan and into the front of the transmission tunnel over the bell housing. When I installed them, the problem area is where the firewall and tunnel meet. It's kind of like wrapping the end of a Christmas present, only this stuff is a lot stiffer and results in a fold or bunched up piece at the top of the insulation. It's kind of hard to explain, but if you have done this you know what I'm talking about. Seems like there should be a slit or something to allow for the overlap. How did the factory do this? Do original cars have wadded up insulation up near the top of the tunnel at the firewall? Just doesn't look like I think it should. Ken
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Re: Firewall/tunnel/underfloor insulation on a 69
I don't have a copy of that. So, did the dealers drop the transmission to do this? I find it hard to believe they could have done it without doing so. By auxiliary, what do you mean? Was it a dealer installed option? I have the tank sticker, and it is not listed on it. KenComment
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Re: Firewall/tunnel/underfloor insulation on a 69
Ken-------
I can tell you that my original owner 1969 built in mid-September, 1969 never had most of this insulation installed from the factory. The only piece it had was the foam rubber "collar" above the bellhousing. The plastic lower firewall stone shields and the under-floor metal shields were present but not the insulation. I've got to believe that mine was not the only car built this way.In Appreciation of John HinckleyComment
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Re: Firewall/tunnel/underfloor insulation on a 69
Ken
When was your car built? Early 1969 model year cars came with the L piece but later ones did not.
I can post a picture for you later today of what it should look like when I get home.
JohnComment
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Re: Firewall/tunnel/underfloor insulation on a 69
Unless you intend to flip your 1969, and maybe even if you do, you should get a copy of the 1968-69 TIM&JG and the 1969 Assembly Instruction Manual (AIM) from the membership office in Cincinnati.
The standard factory installed underbody heat insulation consisted of a fiber shield above the transmission, a foam collar over the bell housing, and the metal toe shields. ALL 1969 Corvettes received these.
The Auxiliary heat shielding consisted of aluminum foil covered fiber pads installed between the toe shields and added metal shields between the toe shields and the frame cross member that supports the undercar exhaust and rear transmission mount. It is this auxiliary shielding that is covered in the TSB. Best of my memory that TSB has a start serial number for the factory install. It gives part numbers (not that the numbers will do you any good now 45 years later) and most importantly illustrations of how all these parts were to be installed for those customers who complained of excess heat in the cockpit. These were intended as instructions to dealership personell as to how to install these items.
The standard heat shielding I referred to is very difficult to install with the transmission in the car, and at the factory was attached to the body before it met the chassis. The auxilary heat shielding can be easily installed with the car fully assembled.
Many will debate the effectiveness of all of this shielding, but if you find evidence of the auxiliary shielding on your car you should replace it if you are doing a proper restoration. As Joe points out, at some point this auxiliary shielding install was discontinued by the factory and it appears they only installed the pieces they had on hand until that supply was exhausted.TerryComment
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Re: Firewall/tunnel/underfloor insulation on a 69
My Oct '68 '69 had all of the insulation. The retrofit in the service bulletin applied to '68 cars whose owners complained of excess heat. I just replaced all of this when the engine and trans was out. I can't see any way to replace the tunnel insulation with the trans in place. And I did have to do some cutting on the footwell insulation to get it to wrap the corners. I marked the bend and removed the insulation to that point leaving the foil there. I wrapped the foil around the bend and fastened to adjoining insulation with contact cement. Worked very well and is not very noticeable unless you get underneath and really look. Here are 4 pictures of the installation prior to the engine install. I know is hard to see some detail but I hope this helps.
JeffComment
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Re: Firewall/tunnel/underfloor insulation on a 69
Jeffrey, thanks for the photos. Yours came out better than mine. I ended up folding part of the insulation and used JB Weld (because that's what I had on hand) to hold it all together. This is probably one of those projects that you need experience at to make it turn out looking good. My car was built Dec. 19, 1968, per the NCRS Data Report, and it originally had all the insulation when I bought it in '73. I've got the engine & transmission out now, so decided to get rid of the pieces that remained and put in new. KenComment
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Re: Firewall/tunnel/underfloor insulation on a 69
Ken,
I'm pretty happy the way mine turned out. It is not an easy install at all. I purchased mine from Paragon and laid what was left of the original over the new and it was right on except for the clips that hold the wires which I had to cut through the insulation. Also had to open up the transmission tunnel opening for the shifter cable. Other than that it went well. Before I removed the tunnel insulation, I used blue tape to mark the ends so the new piece went in the same way. I found that using contact cement enabled me to just press the folds together and not have to tape or clamp anything together. Of the subject a bit but is you car an A/C car?
JeffComment
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Re: Firewall/tunnel/underfloor insulation on a 69
No, it's a cheapo! Coupe, 300hp, 4 spd, posi, AM-FM stereo. Head rests were standard. Fathom green, black vinyl interior. I have added ps. KenComment
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Re: Firewall/tunnel/underfloor insulation on a 69
Terry
While I'm a big fan of everyone having a copy of the 1968-69 TIM&JG and the 1969 Assembly Instruction Manual (AIM) and using them. This not a good case of where to use them. The current 1968-69 TIM&JG does a poor job of describing the changes the underbody insulation and corresponding shields went through.
Both model years appear to have used several different configurations. None of which are clearly called out in the TIM&JG. I have posted about the 1968 model year changes several times in the past:
https://www.forums.ncrs.org/showthre...692#post473692
The TSB in the TIM&JG on this subject must also be read carefully. It describes to dealers how to make the early cars match the final configuration used on the assembly line. It does not describe all the intermediate configurations used in actual production.
I'm not as sure on the 1969 changes that occurred to these item late in the model year as I simply haven't looked at enough cars. One thing seems clear is that not all 1969 cars received the large L-shaped insulation. Joe Lucia reports this configuration in this very thread. From the little I've observed this is what I believe happened in 1969:
-The first 1969 configuration was the same as the last 1968 configuration.
-Sometime in the model year the L-shaped insulation was dropped. Even after the insulation was dropped they continued to use the large rectangular shields for a while.
-Finally the large rectangular shields were removed. Their purpose to protect the insulation from road debris damage was no longer needed.
The TIM&JG and AIM are great guides. I use them all the time, but they don't cover everything. There are always going to be questions to answer on this forum.
JohnComment
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Re: Firewall/tunnel/underfloor insulation on a 69
I agree with you John. What is more neither the TIM&JG nor the AIM will ever answer ALL the questions. Both of us, and many others here, even the younguns, will go to our/their graves with questions unanswered. The many changes made during production simply defy answers.
Your observations about the general sequence of the under body heat shielding corresponds with my general observations, but I am not convinced that engine choice did not have some influence on the factory installation as well.
My suggestion regarding the AIM and TIM&JG was initially to clarify terminology so that we all could be sure which shielding Ken, and subsequently the rest of us, were talking about. Because some shielding was installed on all cars, and because of his question about transmission removal, I was not sure on first reading if he referred to the 'standard' - for want of a better word -- or the 'auxiliary' shielding. And to be honest I am still not sure but I have kept my responses to cover both and that seems to be the trend for others as well. I believe Ken would have and may still benefit from the illustrations in the AIM & TSB that is included in the TIM&JG. The knowledge in the TIM&JG is not exclusively in the judging text.
Further, if one is this far into work on their Corvette both of those references are essential for other items they will cover. And the Chassis Service Manual and perhaps the Overhaul Manual will also be assets. I am continually amazed at the individuals (not in this case) who from the questions they ask clearly do not possess or know that there is on-line access to some of these basic library references and yet they have the body off the frame or the engine out of the car or are about to do either or both.TerryComment
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Re: Firewall/tunnel/underfloor insulation on a 69
As has been said many times on this board, the AIM is a snapshot in time. The page that details the tunnel insulation and the shields etc. (UPC 1, page B6 in my AIM) shows that the revision was made 10-4-68 and has no mentions of the footwell insulation. It indicates that the shields were added, the brackets changed and the screws, nuts and rivets were added. It does not show the retainers for the footwell insulation. My Oct 25 build date car had all of the above and the insulation. Below is a photo of what was left of that insulation before it was removed and replaced. The best one could do to try and determine what was originally on their car is to see if there are the retainers (same as tunnel insul retainers) or any remnants of the insulation itself. It is possible, of course, that the retainers were installed but the insulation was not. If the retainers are there, look closely to see if there is any remnant of insulation under the folds.
JeffComment
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Re: Firewall/tunnel/underfloor insulation on a 69
Terry, I guess I was referring to what you are calling the 'auxiliary' insulation, not the formed piece that goes over the transmission. To me, it's all 'transmission tunnel'. Tuesday is our chapter meeting and I will be able to see a new copy of the TIM&JG then, but I still don't see how the dealer could put this in without removing the transmission and maybe even the bell housing. My car has a strange history, which I won't go into now, but the engine was replaced under factory warranty some time after it was 6 months old. If my build date 12/19/68 doesn't fit, then maybe they put the insulation in when they replaced the engine. KenComment
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Re: Firewall/tunnel/underfloor insulation on a 69
Ken
I have a 69 that was built just one week before your car on Dec 11. You should have the large L-shaped piece of insulation. My car is currently getting the caliper re-sleeved so I don't have it available to take any pictures of it for you. It should look like the attached pictures. The car in the picture is actually a very late production 68 but the early 69 insulation/shield configuration for the transmission tunnel/floor plan area was the same.
JohnComment
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