Valve stem sizes

Vielzidub 3 · Post by **Vielzidub 3** » Fri May 19, 2006 7:31 am

I really like the idea of using 7mm stemmed valves, but would need to fit new guides to my heads, but unfortunatly, I can't see them listed. Is this the case?!

http://www.aircooledtechnology.com/stor ... hp?cat=280

MASSIVE TYPE IV · Post by **MASSIVE TYPE IV** » Fri May 19, 2006 7:57 am

Yes, you will need a full 7mm set up from the guides to the valves and retainers.

7mm set ups are custom order and not shelved.

dstar5000 · Post by **dstar5000** » Fri May 19, 2006 8:36 am

Jake, going from a 9mm to a 7mm setup would add *about* how
much rpm potential with the *same* parts, i.e., the 9mm setup
would be good for 6500RPMs, where the 7mm setup would be
good for 7500 RPMS, resulting in a 1000 RPM increase in capability?

Not looking for total accuracy, just wanting to try to gauge the
$$ per RPM increase, when going to 7mm.

And yes, I understand that the reason to *go* to 7mm would
normally be because the combo dictates it, but some folks just
want to have all the bling, weither it is needed or not.......

Don

Vielzidub 3 · Post by **Vielzidub 3** » Fri May 19, 2006 4:43 pm

To shorthen the answer, whats the approximate (to the g) mass of say a 42mm x 7,8,9mm stem ?

Also how do the corresponding retainers vary in mass?
Collets I guess are ligher the samller you go (8mm weigh in at 2.5gramm a pair).