Gearbox Tunnel

[Neil Clark]

Was the true purpose of the original tunnel insulation for noise or heat or both?  I don't mind the noise in the car, it's rather good, but it did seem warm in the cockpit recently.

[GFL]

I would imagine it was more for sound deadening that heat.

However, there is a lot of heat that comes off the Vitesse engine with it being a big lump of cast iron, apparently most is from hot air being pushed back from the radiator?

I suppose the exhaust and manifold don't help either.

I lined the lower/outside of my GRP Gearbox Cover with silver type stick on heat resisting type foil purchased from an Autojumble, I also used nuts and bolts at a few positions on the underside in case the glue failed due to the heat.

An additional layer of bitumen type sound deadening was added to the top of the cover, then a layer of underlay and the carpet helped keep a lot of the noise and heat out too.

Gary

[DanMi]

the biggest source of heat in the cabin is air leaking in from the engine compartment. The tunnel needs to be well sealed (generally they are not) and the rubber around the steering column, in good condition as well as any grommets etc. Making sure these are sealed will have far more effect than any insulation

[Neil Clark]

Thanks, very reassuring - I think I've done that fairly thoroughly with a new column rubber etc as well as around the tunnel.  There were a few unusual holes on the bulkhead as well so I simply plugged those with grommets or nuts and bolts.