Considering Different Valves ?

[haasad]

Hi all,

I'am considering the potential to get mass out of the valve assemblies on my own car. I know and will apply the usual trick of titanium caps but have been wondering about sourcing and trying valves with smaller stems . Has anyone tried using say 7mm stem diameters ( obviously with smaller guides and seals ) . Any obvious pitfalls I am failing to see ?

[304065]

Page Title

[Eagledriver]

The most obvious pitfalls to me are cost and durablility. I assume your car is air cooled. Smaller valve stems will not conduct heat as well as the larger ones. Much more likely to have a valve overheat and fail. A bit more information as to the engine type and purpose would help.

-Andy

[haasad]

Sorry yes that would be helpful, 2.8 twin plug, headers "s" cams . only need 2k per year, good quality fuel with lots of lead (I use avgas). Not a racer just for my own pleasure ?

Great work by extreme ther,e I'm not in that league

andy

[Henry Schmidt]

You could try some of these. Del West Titanium with Casidiam coated stems. Note the 9mm stems with 3 groove Porsche retainers (old school)

Weight comparison:
Intake 105 vs 68 grams
Exhaust 85 vs 58 grams

The last engine we built with these ran 200 hrs before a freshen up and the valves and seats were perfect. Even the bearings in the GT3 Titanium rods were perfect.

[Spenny_b]

Originally Posted by haasad

Hi all,

I'am considering the potential to get mass out of the valve assemblies on my own car. I know and will apply the usual trick of titanium caps but have been wondering about sourcing and trying valves with smaller stems . Has anyone tried using say 7mm stem diameters ( obviously with smaller guides and seals ) . Any obvious pitfalls I am failing to see ?

Hi, I'm getting my heads ported and rebuilt using Schrick hardware, Ti retainers, larger valves & associated springs. This is for a 964 Turbo (930 engine, more-or-less)

Being done by Richard Chamberlain @ CTR Developments up nr. Huntingdon. Would recommend giving Richard or his son Matthew a call and buying through them. This is the stuff he's been using in his own (935) and customer race engines for years and years, so very well proven.

[PFM]

Haasad,

You might want to talk with Ferrea, they do some nice hollow stem valves.