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PhilipB

Installing a rear firewall

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I’m looking to fit a rear firewall to OGB (a TR2) as recommended by many.

 

I know this topic has been dealt with or referred to a number of times and there are lots of encouraging comments and some photos of the how the bottom of the firewall is riveted to the floor but I can’t find any photos of how to fix the top.

 

I’m OK with the general principle, aluminium angle to the floor and inside faces of the wheel arches to which the firewall is then riveted but I’m struggling with the detail of how to attach the top of it to the front of the rear deck and seal it.

 

The rear cockpit liner (tank board) is fitted by pushing the top edge into bent strips under the rear deck. This locates the top edge of the liner under the front edge of the rear deck and then a couple of screws into the floor hold it in place. It would be really easy to just pop rivet the firewall to the front edge of the rear deck but it looks as if it gets tricky where the rear deck curves forward at the sides but also the nicely trimmed cockpit liner would have to be mucked about with and it would need self tappers on the top to hold it in place

 

The photo below shows the space to be filled showing the tabs under the rear deck that the cockpit liner locates in (acknowledgements to Revington TR for the photo and who also describe fixing the top edge as being “the tricky bit”!)

 

On the basis of a picture is worth a thousand words, does anyone have any photos of a firewall fixed and sealed to the rear deck and which also allows the cockpit liner to be fitted? Also any recommendations for sealant.

 

Thanks

 

Phil

post-12767-0-37015300-1457430048_thumb.jpg

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I can't suggest any TR2/3 specific ideas but has "intumescent foam" been mentioned to you?

It seals gaps and swells if heated by a fire so maintaining the seal.

John

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Thanks John

 

At one level, any sealant does a job, but upside down, trying to get, or be got, out (heaven forbid) I think a fuel resistant seal is the order of the day.

 

One would hope that there wasn't any fire present, in which case we are, potentially, in the deep, deep poo!

 

Phil

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one further query if i may

 

i am told the fuel tank on an early 3a comes out (as it will be on friday) via the passenger compartment rather than boot

 

if a firewall is fitted by rivetting, is the tank then effectively a workshop job to get out

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Firstly well done for recognising the importance of a fuel tank bulkhead seal between yourselves and the fuel.

 

Never fitted a sidescreen car with a firewall only TR4 but looking at your photo could it be possible that the top edge could be bent underneath the rear fibreboard clips and then bent up and secured (pop riveted) to the bottom of the channel which goes around the cockpit ? Any firewall fitment is sealed either with a non tumescent sealer which as explained under fire conditions swells and helps prevent leaks, or as I've always done using a windscreen sealer which is non setting underneath the firewall.

 

The bottom line is it's obviously possible because of the number of sidescreen cars competing in motorsport (banned if no firescreen in place) and somebody with one completed will no doubt advise shortly. However sometimes priorities demand compromises and if securing the firewall means a front edge of cockpit fitment with an small unobtrusive alloy seal over the edge of the rear fibre board screwed to the cockpit front edge then my choice would be for this, (is that area viewable under the hood sticks and hood ? The over the wheel arch area is the most difficult part on any of the TRs and requires a little fiddling and sealing but it can be done, the equivalent of fitting the gearbox back onto the engine with it in the engine bay.

 

I don't know if a cockpit removal is the ONLY way for the fuel tank to come out on an early 3a, from my days of owning one (30+ years ago) I can't remember, butin my view if it won't come out through the boot then removal of the firewall for fuel tank removal and the added safety the firewall gives again is a worthwhile compromise.

 

Mick Richards

Edited by Motorsport Mickey

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John,

 

Thanks for correcting me, yes intumescent, my other spelling means something else entirely ! Never a barny with you John, as if !

 

Mick Richards

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Do I have to rivet (to me this seems to be just more rust opportunity!) Can I not just seal in place with something like CT1 ?

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Up to you as long as it seals and stays in place.

 

Mick Richards

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