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[email protected]
Samba Member
Joined: June 24, 2015
Posts: 719
Location: Rialto. CA
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 Posted: Wed Jun 12, 2019 12:08 pm Post subject: 5.5 or 7mm valve stems |
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| I've notice a lot of guys go to the 8mm valve stems on there 356 engines now days ..what are your thoughts about 5.5 or 7mm valve stems I know the denzel used 7mm valve stems and seemed to benefit from them why not the 356 ???? |
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Starbucket
Samba Member
Joined: April 30, 2007
Posts: 4026
Location: WA
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| Posted: Thu Jun 13, 2019 1:30 pm Post subject: Re: 5.5 or 7mm valve stems |
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| They go to larger valve stems because the guides are worn so it's cheaper and better for the head to ream original guide to 8 and buy new valves. |
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Bulli Klinik
Samba Member
Joined: January 16, 2005
Posts: 2079
Location: Bulli Klinik, Colorado Springs
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| Posted: Fri Jun 14, 2019 8:49 am Post subject: Re: 5.5 or 7mm valve stems |
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| Starbucket wrote: |
| They go to larger valve stems because the guides are worn so it's cheaper and better for the head to ream original guide to 8 and buy new valves. |
Porsche 356 valve stems are 10mm. the reason some choose to go to a smaller valve stem is to reduce weight in the valve train. Guides get replaced when you do a thorough valve job and reamed for the appropriate valve stem size.
You could certainly go to a smaller stem size, lighter lifters, pushrods, etc... Though unless you're racing, there will be very little gain in relation to what is lost. If that's you're plan, I would consider consulting someone who builds race engines and ask their opinion.
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Mike K
Bulli Klinik
Colorado Springs |
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