|
|
|
|
| Author |
|
|
Registered
Join Date: Nov 2004
Posts: 219
|
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 |
||
05-05-2010, 11:56 AM
|
|
|
Registered
Join Date: Oct 2003
Location: Central Fla
Posts: 1,864
|
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
__________________
The two most useless things to a driver are the braking distance behind you and nine-tenths of a second ago. |
||
|
05-05-2010, 05:45 PM
|
|
|
Registered
Join Date: Jul 2001
Location: Portland Oregon
Posts: 7,007
|
Quote:
__________________
Steve Weiner Rennsport Systems Portland Oregon (503) 244-0990 porsche@rennsportsystems.com www.rennsportsystems.com |
||
|
05-05-2010, 05:57 PM
|
|
|
Registered
Join Date: Nov 2004
Posts: 219
|
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 |
||
|
05-17-2010, 01:28 AM
|
|
|
Registered
Join Date: Sep 2007
Posts: 500
|
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)  (C) Porsche AG 1995 Last edited by jcge; 05-17-2010 at 02:11 PM.. Reason: (C) |
||
|
05-17-2010, 02:10 PM
|
|
|
3 restos WIP = psycho
Join Date: Feb 2005
Location: North of Exit 17
Posts: 7,665
|
Along these lines, what is the narrowest valve stem advisable in a 911 (NA and turbo) for proper heat transmission?
__________________
- 1965 911 - 1969 911S - 1980 911SC Targa - 1979 930 |
||
|
05-17-2010, 03:58 PM
|
|
|
|
Registered
Join Date: Jul 2001
Location: Portland Oregon
Posts: 7,007
|
8mm.
__________________
Steve Weiner Rennsport Systems Portland Oregon (503) 244-0990 porsche@rennsportsystems.com www.rennsportsystems.com |
||
|
05-17-2010, 05:10 PM
|
|
|
Registered
Join Date: Nov 2004
Posts: 219
|
Thankyou JCGE
|
||
|
05-19-2010, 01:48 AM
|
|
