Jump to content

Gearbox tunnels


dougbgt6
 Share

Recommended Posts

A lot of talk about plastic gearbox tunnels lately, I notice on another thread Richard,  rlubikey,  has put his sound/heat insulation on the OUTSIDE of his tunnel. Most of us seem to put it inside, Richard is obviously a lateral thinker. I'm wondering is it worthwhile having it inside AND outside the tunnel?

Doug

 

Link to comment
Share on other sites

Interesting point Doug.

Will placing on the outside deflect the heat, as the shield effect will be facing the incorrect way - i.e. shiny side out. ??

I think placing on the inside helps to protect the g/box tunnel, but that said the adhesive will probably last longer on the outside of the box.

I'm not sure if both sides is the way forward or beneficial - can you lift the tunnel with 2x sides stuck with Silent Coat :( ?? !!

Regards.

Richard.

Link to comment
Share on other sites

Vitesse Mk2

My plastic gearbox cover has had the Silent Coat treatment and this has significantly reduced both heat and noise . Hopefully by fully sealing the cover to the bulkhead will reduce the heat further, though it’s perfectly acceptable when compared with no Silent Coat treatment.

Recently found the old insulation which sat on the gearbox which needs to be tidied up so will fit that first . As Pete might say a case of “double bubble”

Paul 

Link to comment
Share on other sites

Hi Doug. Don't forget, I've got an all-metal g'box tunnel because of the engine-back config. Even so, each time you add a layer of insulation you improve (lower) the heat transfer. The aluminium facing not only reflects radiant heat, but it is a poor emitter of radiant energy too. What difference does this make when you have carpet over the top? I don't know the answer to that one!

One thing to consider with the increasing number of plastic (ABS? Does anyone know? In my business, it's really annoying when people just say "plastic") g'box tunnels, is that placing the insulation on the outside raises the temperature seen by the tunnel material which may soften and/or accelerate ageing. With the PI up front, it really can get very hot indeed down there. A few years ago I found out the hard way that someone had used domestic wiring cable for the OD wiring in the gear stick! Domestic cable insulation softens at 70'C.

Of course the thing that made the most difference was making sure the tunnel was totally sealed around the edges, along with all those little holes in the firewall. In this case, (forced) convection trumps conduction & radiation!

Cheers, Richard

Link to comment
Share on other sites

I’m just about to seal mine back up with an new plastic tunnel covered on the inside with silent coat but my overdrive wiring caused me to remove the old one in the first place. It’s free hanging and chafes on the overdrive housing which caused it to chafe and short out. I’ve replaced with all new wiring with the correct level of heat protection but should it be free hanging or is there somewhere to secure it?

Link to comment
Share on other sites

Hi Leon,

I've never found any purpose made securing points and have just routed the cables as best I can (sleeved in heat resistant tubing) Having got sick of the gear-lever part of the O/D loom on my GT6 Mk3 repeatedly shorting out over the years I've ditched it and gone for a column mount arrangement. That has removed the most vulnerable bit of the O/D loom from the gearbox area and will hopefully greatly reduce the number of times I have to take off the tunnel.

Wayne

Link to comment
Share on other sites

Leon.

These are how the wires are supported on my O/D gearbox, via P clips.

The biggest issue with wires fraying on the gear stick change is:

1- wires are not enclosed with a shrink wrap conduit

2- there is insufficient slack allowing the stick to moved around fully without straining the wires

3- the stick inlet hole where the button wires go through has not been checked & filed to ensure smooth edges.

All the above points play their part individually and collectively - in the seven years I have owned my Vitesse no issues with the wiring.

The wires by the bell housing have long been tidied up with a couple of cable ties which keeps them away from the transmission.

My next job is to glass fibre the particle board g/box tunnel which will make it very strong and resist wear and tear. The inside will have SC protection.

Regards.

Richard.

DSC00347 (2).JPG

DSC00348.JPG

Link to comment
Share on other sites

The sun is out! The sky is blue!

So the GT6 is on the drive. Got the old tunnel off, what a mess! The sound deadening bag's split and all over everything. :o Three corners broken off the tunnel, the whole of the top lip split AND only four screws & plates holding it in place. Who did this?!! :wub:  Basically it's a sieve covered in carpet. Do I really need the foot rest, just means more holes in the tunnel? Still loathed to cut a hole for the oil top up, but I suppose I will.

Doug

Link to comment
Share on other sites

That foot rest is a must! Mind you, it does sit pretty much where the gearbox oil filler flap would go. My tunnel's been repaired with fibreglass around the foot rest, which is why I've not cut a filler hole.

You can always procrastinate a bit more and do the steering wheel instead! ?

Gully

Link to comment
Share on other sites

On 3/31/2018 at 8:30 PM, dougbgt6 said:

A lot of talk about plastic gearbox tunnels lately, I notice on another thread Richard,  rlubikey,  has put his sound/heat insulation on the OUTSIDE of his tunnel. Most of us seem to put it inside, Richard is obviously a lateral thinker. I'm wondering is it worthwhile having it inside AND outside the tunnel?

Doug

 

First thing that comes to mind here with me personally is that the H-frame won't fit, nor will your carpet.

Anyone tried covering the gearbox and bellhousing in clingfilm, then spraying expanding foam into the tunnel cover? It's a lovely image...

Link to comment
Share on other sites

I cut the hole using a hacksaw blade and used the bit cut out as a cover with a piece of poly bag as a gasket. Out of sockets kit bits I made up a tool to undo/do-up the plug. Sold the GT6 in 2009. I have done the same on Vitesse, Herald and Spitfire.

I did an article on it back in July 2008.

Dave

11097.jpg

11150.jpg

Link to comment
Share on other sites

1 hour ago, dougbgt6 said:

Dave,

Excellent photo! Didn't realize the plug was so close to the side of the tunnel. 

I put recessed lighting in my bedroom and bought a special tool to drill large holes in the ceiling, I might use that on the tunnel.

Doug

Didn't realise the tunnel was so big that you'd need recessed lighting. I suppose it'll help you see the plug in the dark...

 

BTW I love expanding foam, I've a list of about six jobs that require it and when it reaches eight, I'll open another can of the stuff, so that when I start using it, I don't need to worry about it not stopping, I'll just run to the next job on the list. It's the Devil's Porridge.

Link to comment
Share on other sites

Colin,

I know what you mean; a half used tube of expanding foam is a used one, full of solid polyurethane.

But there is an alternative for small jobs, Gorilla Glue.    It comes in small, 60ml bottles, for about £4, works the same, you wet the workpiece before applying it, and it foams, but only slowly.     I've found it really useful for GRP repairs, and if you seal over the repair with tape before it foams and sets, you get a smooth surface, no need to rub down and use filler!       Stays slightly flexible, but grips like ... a gorilla!  The foaming can help reinforce a joint if allowed to expand inside the moulding.

The bottle does go solid if half used, but only slowly.

John

Link to comment
Share on other sites

This sculpture is entitled: "Aerosol man fights the foam monster"..... 

And John - you're right as I've used Gorilla Glue recently on wooden garden furniture and it foamed quite surprisingly, so much that it had to be trimmed back with a sharp knife..... never thought of using that! However, I know it uses moisture to start the curing process, hence works great on wood, and as I've recently cut through wooden beams for drain and sewer pipes I want to seal around the edges to prevent wildlife getting in under the floors so that may be an easier and less messy option... but does it work on metal?

(And before you ask, Doug, no I'm NOT going to glue my overriders on to the GT6 chassis, for all that I can't find a welder.) 

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

×
×
  • Create New...