Viteese Mk1 2lt Gearbox cover

[Colin Lindsay]

The Herald chassis is awaiting spraying in one corner, four recently blasted Herald wheels are being repainted in the middle of the floor, I'm welding and grinding out wear marks in Herald backplates in another corner, the GT6 is stripped out yet again waiting for an overdrive solenoid which is not going to be delivered in time for the next run and the Herald estate tub is being treated for tub sag in the final remaining corner.

...and you guys want me to start something new?Might as well...

 

[Colin Lindsay]

On 12/08/2020 at 20:51, classiclife said:

It's straight forward Colin and you will have the knack within minutes.

So it is! I bought the slightly larger kit from eBay, arrived yesterday and I started on one of the old cardboard Herald tunnels that had lost all of the insulation and was cracked and flopping about. I don't think I put enough activator in the resin - the instructions were to use half of the bottle with half of the tube, but I was only practising, so used about a tenth of each, and it took hours to set. I put two long strips on the cabin side of the top edge where it becomes vertical and seals against the bulkhead, where it was very warped and cracked, and on checking this morning it's perfectly straight and solid. I'm actually very surprised at how rigid it has become with just the two thin strips. I've trimmed it back this morning and later on will start on the inner faces where again it's badly cracked and needs attention. I'm very pleased with the results so far, once I insulate it with Deadmat it'll be better than new. 

I've to call in with the mate who repaired my Herald hardtop and who does all of my fibreglass repairs later today, but he's an absolute expert who knows all of the tips and tricks so I'll say nothing about doing it myself in case he gets offended... 

[Guest]

That sounds very positive, Colin - you will be looking at buying a Lotus Elan restoration next, now you are mastering fibreglass !!

Once I had rubbed down my g/box tunnel prior to remedial work, I gave it an initial coat of resin using a paintbrush - this provided a very hard base coat shell once it had dried overnight. From there I did the patching onwards and proved to work out nicely, I am glad I did not believe it was beyond salvage. 

I think it is too easy, in many cases, to dismiss the original fibreboard tunnel; it can certainly be reclaimed by going down the fibreglass matting route IMHO. 

Good luck.

Richard.

[Colin Lindsay]

1 hour ago, classiclife said:

Once I had rubbed down my g/box tunnel prior to remedial work, I gave it an initial coat of resin using a paintbrush - this provided a very hard base coat shell once it had dried overnight.

That's actually something I have already thought about... just brushing the entire thing in resin alone as a sealer / strengthener. The top will be repainted, but hidden under the carpet, and the underside will be invisible to all but me and the MOT Inspector so anything that makes it more durable will be very interesting.

Incidentally - here's a question for the physicists / technicians amongst us. I want to both soundproof and heatproof it (as far as can actually be done) and also the ABS GT6 version that's arriving today from the Club shop.

The original had foam stuck to the cardboard, and with a foil liner; foil closest to the gearbox. Does it make any difference at all if the silver heatproof material is stuck to the inside of the tunnel and THEN the soundproofing is put in place, or if the soundproofing is attached to the outer tunnel then the foil is placed over that so that the first layer is the foil? I'm just curious!

 

[Guest]

6 minutes ago, Colin Lindsay said:

ncidentally - here's a question for the physicists / technicians amongst us. I want to both soundproof and heatproof it (as far as can actually be done) and also the ABS GT6 version that's arriving today from the Club shop.

The original had foam stuck to the cardboard, and with a foil liner; foil closest to the gearbox. Does it make any difference at all if the silver heatproof material is stuck to the inside of the tunnel and THEN the soundproofing is put in place, or if the soundproofing is attached to the outer tunnel then the foil is placed over that so that the first layer is the foil? I'm just curious!

Like many others, Colin, I have used Silent Coat (SC) and also Dodo mat which is 0.2mm thinner but seems to do an equally good job:

https://www.deadening.co.uk/products/dodo-dead-mat-hex-30-sheets

This item in the main is for soundproofing but does have heat resistant qualities. TBH, I would just use this matting or the slightly thicker SC on the inside of the tunnel; the make-up is such that the foil is on the open side and that has to deflect some heat to be distributed elsewhere or evacuated by vehicle movement. This is not from a scientific angle just a humble Vitesse owner who is happy with the outcome of the product and application.

It has been is situ for nearly five years and is still as good as the day it was fitted.

Hope that may assist ??

Regards.

Richard. 

 

 

 

[NonMember]

3 hours ago, Colin Lindsay said:

Incidentally - here's a question for the physicists / technicians amongst us. ... Does it make any difference at all if the silver heatproof material is stuck to the inside of the tunnel and THEN the soundproofing is put in place, or if the soundproofing is attached to the outer tunnel then the foil is placed over that so that the first layer is the foil?

In terms of the effectiveness of heat resistant and sound dampening materials, the order doesn't really matter. However... that's not what we're dealing with.

The silentcoat stuff is, as Richard says, primarily intended for sound reduction. But it's not a sound insulator in the way a block of foam would be. It's designed to reduce drumming of sheet metal panels, and does so mainly by adding enough mass that the resonant frequency is inaudible. It's also a bit flexible, which helps reduce the overall "Q-factor" of the assembly so that it just doesn't resonate very well. A fibreboard gearbox cover isn't particularly resonant anyway, so it actually acts as a sound dampener itself.

Sound waves travel through air by compression pulses but can't travel through an impermeable material like that. Instead, the pulses hitting the barrier transfer the energy to movement of the barrier, and this movement causes compression pulses in the air on the other side of the barrier. If the barrier can be made unwilling to vibrate, such as by adding sponginess and mass with silentcoat, then this transmission of sound doesn't work.

So what's the point of that discussion? Well, the method by which Silentcoat works as a sound deadener relies on it being stuck directly to the resonant panel it's deadening. Sitcking it to a foamy mass won't do anything. Ah, but, you say... it's the thermal insulation, isn't it? Well, no. That's the aluminium foil on the surface, which doesn't do anything for convected or transmitted heat (well, except spread it around a bit) but does help with radiated heat. Of which there isn't very much because nothing's that hot. Mostly the foil serves to keep the gooey bits from sticking to all the muck that's flying around. Having a complete, intact cover without any holes in it is, as JohnD pointed out a while back, the most effective means of heat control.

[Colin Lindsay]

1 hour ago, NonMember said:

Having a complete, intact cover without any holes in it is, as JohnD pointed out a while back, the most effective means of heat control.

Thanks Rob - I'm fitting a brand new cover which has just been treated to the Dodomat finish, but I'm aware that it's mostly sound-deadening / anti-resonance for metal panels; these new ABS covers are quite thin, rigid enough to do the job but not thick enough to deaden engine, exhaust or road noise. Assuming that it's properly sealed and fixed in place then it will keep warm air out - on the run last weekend the gearlever was hot to touch and the CD player kept cutting out as it got too warm, so while some of that must be addressed now by the new tunnel and seals, plus the insulation I've just added, I just want to achieve the optimum against both heat and noise before I tighten down all the screws and leave it for the next few years. That's why I was considering some form of soundproofing mat / material over the top of the Dodomat, and why the curiosity arose of what goes first.

[johny]

yes wasnt the heated gear stick the reason why the last Spitfires had an insulating piece midway?

[Colin Lindsay]

New tunnel fitted to the GT6 today, completely insulated with Dodomat and new seals in place - first impressions are that it's a huge amount quieter than the original cardboard tunnel, and secondly the carpet was not hot to touch. Long run of a couple of hundred miles tomorrow so I'll see how it performs then but looking good so far.

The other tunnel for the Herald has been fibreglassed, cleaned up and painted with a clear primer prior to a good matt black topcoat. I'm very pleased with the way it turned out; it was too solid to dump but too cracked to use, so it's been saved for a few more years. It too will get the Dodomat on the underside.

 

[Guest]

Well done Colin - a top result. Good luck on the drive tomorrow.

East Sussex TSSC fish & chip run tomorrow evening, but only 25x miles !!

Regards.

Richard.