On 19 Nov 2003 at 10:30, John Mitchell wrote:
> While replacing my interior, Ive decided to switch to the
> plastic transmission cover and was wondering if added sound deadening
> material was needed. It just looks so much thinner than the
> fiberboard original.
I put one of TRF's plastic tranny covers on my Spitfire a few years
ago. It does allow a bit more noise through, but the extra noise is
not bothersome. However there is another consideration. The
original cardboard cover had fiberglass insulation stapled to the
inside. Some of the fiberglass had been pulled off over the years
and most of it had become oil-soaked because it was in direct contact
with the gearbox. (We all know how porous to oil British metal can
be, an intergral feature of the external lubrication system.) The
absense of fiberglass against the gearbox means that there is much
more airflow around it!
I haven't measured anything to back up my observations but I assert
that the greabox and car's interior both run cooler now. Perhaps the
original insulation once kept the car cooler at the expense of higher
gearbox temps, but after it became oil-soaked it certainly shouldn't
have worked as intended.
Just my $.007.
--
Jim Muller
jimmuller@pop.rcn.com
'80 Spitfire, '70 GT6+
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