3.6L Valve Choices
 

Hi All

I'm thinking of replacing the Porsche original valves (i.e. I assume they are Porsche valves because they have Porsche P/N's stamped on them) after having measured some of them and seeing around a 1/2 thou wear. Can I assume that the area under the keepers is the unworn size that the whole stem would have been when new? Any suggestions on what I should replace them with? Intervalves from our host are competively priced with others such as TRW, AE etc.. When the brand is indicated as OEM can I assume they are the same quality as what Porsche would sell at quite a higher price? My machinest has suggested ATE but I havn't been able to source them and I was wondering if their quality is the same as what one would get from a Porsche dealer?

TIA

valves
 

Intervalves are a quality part, in my opinion they have been better than the TRW, the price is very good as well.

Mike Bruns JBRacing.com

Totally agree. :)

Thanks Mike and Steve for your responses

After having measured all valves and seeing the typical wear patterns as expected (i.e. and mentioned above) I'm still confused as to the measurement I'm getting just below the keeper grooves which should be the valve stem size when new, as there is nothing which can cause wear in this area. The diameter measured ranges from 0.35230" to 0.35290" on different valves. I would have thought this measurement to be not only more consistent but also closer to the spec'd diameter of 0.35315". Is this a typical manufacturers tolerance and what I should expect when I receive my new valves? I'm also confused as to what Adrian Strether mentions in "Enthusiasts Companion" regarding the exhaust valve stem being "slightly conical" and ranging in size from 8.94 - 8.96mm or 0.35197 - 0.35276". Does this mean the stem is tapered and if so which end is smaller?

TIA
Bill

It's the exhaust valve stems that are tapered, or conical (dimensions b1 and b2)

The head end ("hot" end) is smaller than the keeper end ("cold" end)

http://forums.pelicanparts.com/uploa...1274134112.jpg
(C) Porsche AG 1995

Along these lines, what is the narrowest valve stem advisable in a 911 (NA and turbo) for proper heat transmission?

8mm.

Thankyou JCGE