Tunnel covers plastic or fibreglass

[Michael Watts]

Hi spitfire1500 rebuild, original tunnel cover beyond use. Which is the better option? the plastic replacement or fibreglass replacement? Also dou d deadening that is waterproof any thoughts on best solution.thanks Mike W

[johny]

Dont know on the Spitfire but for other models plastic has a better reputation for fit than fibreglass. However I seem to recall problems with the lip of the plastic cover being difficult to seal so people have cut it off😲

[Paul H]

If my Vitesse is anything to go by fibreglass should be avoided . It didnt fit and needed major surgery to get seal of the engine heat . I used Silent Coat sound deadening . Also added a gearbox oil filler access door . To secure i used  Milk bottle screwcaps as oversized washers to cover the holes 

 

 

Paul

IMG_3340.HEIC

Edited October 4, 2023 by Paul H

[dougbgt6]

I got the plastic one and as Johnny says there is a protruding lip around the bottom which isn't on the original. I presume this is for rigidity and attempting to cut it back might not be a good ides., It raises the cover slightly and I needed a double layer of draft excluder tape to seal. DON'T buy the fitting kit, a waste of money, draught excluder works fine and you've all ready got those strange washers, if you want to use them, I used self tappers. Good idea to cut an access hole for gearbox topping up.

I used SalientCoat sound/heat deadening on the inside of the tunnel. 

Doug

 

 

[Unkel Kunkel]

Approaching the problem  of a damaged tunnel can begin by  simply repairing the original   card/ fibre type tunnel with fibreglass  resin.If the tunnel isn’t saturated with gear oil the resin soaks in quite well and can produce a very strong repair.

Moving on to  replacement tunnels, the consensus does seem to favour the ‘plastic’ rather than   fibreglass.It seems they seem to fit better  and are a bit more ‘bendy’ to take up gaps when fitting.

Fitting it in place - don’t waste money on the ‘self- adhesive sealing kit ‘ which seems be very disappointing and rather expensive.

Instead , use a thicker gasket material,- a single B&Q rubber,  garage closed cell type foam floor tile sold in packs of  of six will produce as much gasket for this job as you could ever want and   is oil resistant and very compressible.

There are lots of ways of securing the tunnel to the floor and bulkhead from large self tappers, roofing bolts and washers etc.

I opted for using ‘ floating anchor/ nut  plates’, like the sort  as used in aviation industry, and  bolts.

 

 

 

Edited October 5, 2023 by Unkel Kunkel