Plenum

[Andy_J_G]

I have been offered an exchange plenum, which has been highly polished, for my 4.0 Griffith. The new one is off a 3.9 rover unit, did TVR modify the plenums at all or would it be a direct replacement, does anyone know?
Cheers

[Mark Adams]

It's just the same, unless anyone bored out the throttle body.

Do make sure the throttle butterfly initial position is set correctly, as on another post in this section. Also make sure there is no polishing compound anywhere inside the plenum or airways.

You don't need the heater pad under the throttle housing either, but bolt holes must be blanked if it is removed. The easiest way to do this is to shorten the pad bolts and stick them back in the holes.

Bolt on and enjoy!

[spend]

Mark Adams said:

.. The easiest way to do this is to shorten the pad bolts and stick them back in the holes.

I thought some had a shank on which interferes with this, IIRC they are 1/4" UNF thread I just replaced them with some short capheads.

[Barkychoc]

spend said:

Mark Adams said:

.. The easiest way to do this is to shorten the pad bolts and stick them back in the holes.

I thought some had a shank on which interferes with this, IIRC they are 1/4" UNF thread I just replaced them with some short capheads.

There are 3 shorter setscrews that need cutting down and refitting in the plenum.
The longer bolt (with the shank) doesn't need to be replaced as that one is a blind hole.