Gearbox tunnel sound deadening - fitting

[johnnyj]

Hi folks. I have the original gearbox tunnel sound deadening pad/panel which I would like to fit back onto my resto. It is the thing which goes under the car and is made of a kind of fibre board coated in rubber/bitumen.

I am having a hell of a job working out how to re-fix it, as the original fixings (rivets? some kind of pin & clip?) aren't obvious - just some tiny pins on the inside of the tunnel which look like broken off rivets. I could simply drill through it and screw it to the gearbox tunnel, but that would leave screws protruding into the cabin, under the carpets somewhere and I wouldn't know where they would come out (or what I would be drilling through on the way).

Glue I think would be too iffy, effected by heat etc. Maybe I bin it and use dynomat or similar, but I'd still have the adhesion problem given that it is under the car.

Just wondering if anyone has any thoughts or previous experience of re-fitting an original one?

Should have said, the engine and gearbox is currently out of the car.

Thanks

John

[busheytrader]

Hi John,

The fixing you describe sounds similar to those on my DHC. A metal pin fused to the bulkhead, pokes through the rubber sound deadening pad, and a flat washer gripping it in to place in the foot wells.

Maybe there's something suitable these guys can offer. I've used them a few times for non standard items. https://www.carbuilder.com/uk/nuts-bolt ... orderBy=15

I'm not a fan of stuff that can trap moisture against metal on a car. I'm fighting the results on a classic Mini. Might be worth using a spray or brush on sound absorbing alternative to refitting the board?

Adam

[saabfast]

I can't even recall seeing it on mine but it is sometime since I had the gearbox out.
You could cut off the existing pin remains and use insulation stick pins in the same position to hold it in. These are a little long but the pin is trimmed off after fixing.
https://www.ebay.co.uk/itm/62mm-stick-p ... Sw-Rle6f4T
An alternative is to drill through next to the existing pins and use small nuts, bolts and washers from the top to fix it so only the head is inside the car.

[johnnyj]

Thanks Bushy and Saab, some great suggestions there. Looking at the options, I reckon the stick pins will work if they are inserted from the inside of the car, so the square bit remains inside (under the carpet) with the pin going through a hole and protruding into the gearbox tunnel. That should work! The only problem is finding someone who will sell me half a dozen rather than a bag of 50!

Cheers

John

[busheytrader]

I must confess I don't remember a noise insulation pad on the underside of my DHC. I've replaced the propshaft with a modified SD1 item and I had lots of scraped knuckles replacing the remote gearstick housing bushes a few years ago. How far back does this insulation reach?

[johnnyj]

Hi Bushey, it extends from the engine bay end to the gear lever. In the photo below it is XKC2931, although interestingly it is only listed for the DHC on the Rimmers site. Weird, as mine certainly came off my FHC and is factory original.

Cheers, John

[Beans]

XKC2931 is the sound deadening material sitting on top of the transmission tunnel.
I have seen the (what I think is a) heat shield on a few cars, but never on the later Canley or Solihull.
Weirdly enough it is not listed in any of my parts catalogues spanning the range from 1975-78 and 1979 onwards.
Could it be a TR8 specific piece?

[Chubster]

This shows the part in question I believe, it was originally fitted on my car which is a 1977 Speke however it was soaked in oil so I did not use it although would like to find another good original one.

[johnnyj]

@Beans, thanks for the info. I think you are right, the part I quoted is for the interior sound deadening (although the Rimmer picture looks just like the external item). I couldn't find the exterior heat shield listed for a DHC, and what you have said about the TR8 is interesting. It is a mystery, as I can't imagine mine having been retro-fitted from a TR8 as my gearbox is original and I don't think it has been removed previously.
@Chubster, thanks so much for the link and info. You are spot-on with the picture and part. Mine is also a 1977 FHC. The part was also covered in oil and some bits broken, so I had to repair it with fibreboard, rivets and bitumen!

Now, back to the job of somehow getting it attached....

Cheers, John

[Rich K]

Hi Saabfest, looks like those fixings would also work for the insulation on the bulkhead/firewall behind the dashboard.

[saabfast]

The longer ones are pretty standard fixings for insulation on HVAC ductwork. They just bend the pins over rather than cut off as it is then clad.

[johnnyj]

Just realised that this isn't exactly like mine, but pretty close. Mine extends further forward, right to the seam where the tunnel meets the engine bay. One thing I don't recognise is the thing hanging down from one of the holes - now I'm thinking "yikes, what have I forgotten?". I'll have to crawl under the car tomorrow to make sure....

Highlighted in yellow.

John

[darrellw]

I believe that is the A/C (AirCon) drain tube

[Chubster]

The picture link is from the Facebook page of the Triumph wedge owners association and the original post is from the US, I posted it as a link so its strange that it only shows the picture(??) There is a drain hole here on my non air con UK Car it may just be the chap has added an additional pipe so it does not drip onto the gearbox. I have copied the link below so lets hope it shows the full thread.
https://www.facebook.com/photo.php?fbid ... ater&ifg=1

[busheytrader]

Are you going for maximum originality / building a concours car John?