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-   -   Valve spec questions for 2.4L (http://forums.pelicanparts.com/porsche-911-technical-forum/234198-valve-spec-questions-2-4l.html)

Mukilteo911 08-02-2005 07:39 PM

Valve spec questions for 2.4L
 
Valve spec questions for 2.4L

Rebuilding my heads and pulled the valves and speced them out.
Need opinion on if they are within acceptable tolerance for a street car.

I measured the stems right below where the keepers are, where they don't get wear and down the stem to see if they have worn. All measurements up and down the stems were consistant to .01

The worst figures are:

Intake stem dia: 8.93
Intake head dia: 45.92

Exahaust stem dia: 8.91
Exahaust head dia: 40.06

Valve guide internal dia:
Intake: 9.05
Exhaust: 9.08

These heads have been rebuilt for sure, the guides are not stock. Should I replace the valves and guides, or are they good enough?

I find it strange that all the valves were so consistant up and down the stem even in the non wear area, any ideas?

jluetjen 08-03-2005 02:43 AM

The factory spec for valve stem diameter is 8.97-0.012 for the intakes and 8.95-0.012 for the exhaust. The valve head diameter is 46+/-.1 for the intake and 40+/-.1 for the exhaust.

The specs for the valve guide bore diameter is 9.000-9.015 for both the intake and exhaust.

Mukilteo911 08-03-2005 05:20 AM

I have seen the specs in the book. Although I have heard rebuilders quipp at sticking to such close specs and wonder how true to the spec you have to be on the valves. Sometimes in the real world application you can fudge some, is this one of those areas?


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