valve stem diameters
Turbo Mini Forums

I know the turbo exhaust is 5/16"

What about the inlet ? Is it simply 1/4" ?

What about readily available valve guides ? Are they usually for 1/4" valves ?

Has anyone dropped to circa 6mm stems ? If so, are guides available ?

Just curious before I price up some Inconel exhaust valves, as obviously it will be easier to do a swap with easy to obtain guides.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

The standard valve size is 9/32". about 7.1mm.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

6mm are used already in highly modified heads , but when i flow tested one it appeared to only offer a gain at high valve lifts.

WWW.FORCE-RACING.CO.UK PLEASE CLICK HERE

Just thinking to get the valves made, to suit easily available valve guides.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

6mm are available from specialised valeces, {paul ivey] for the A series.

WWW.FORCE-RACING.CO.UK PLEASE CLICK HERE

The main reason (apparently) for 6mm stems is to reduce the valve train weight. This is important to Miglias as the STR930 cam produces nasty harmonics which plays havoc with valves and springs.
Paul

I seriously doubt it!