Valve sizes
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grasshopper
- Posts: 206
- Joined: Wed Aug 13, 2014 10:25 pm
- Your car is a: 1976 Fiat Spider
Valve sizes
Hi all. Where can I find specs on stock valve sizes for both inlet and exhaust for all sizes of twin cam engines ? Are they all the same ? I think 2ltr may be bigger ? Any info appreciated thanks.
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18Fiatsandcounting
- Posts: 3799
- Joined: Fri Mar 15, 2019 11:23 pm
- Your car is a: 1969 and 1971 124 spiders
- Location: San Francisco Bay Area
Re: Valve sizes
Grasshopper, the power is within you, but first you must seek to discover.
Since you're probably getting tired of that meme,
the stock valves are 42mm head diameter for the intakes and 36.5mm for the exhaust. It's the same across all the engine sizes although there are some minor differences between manufacturers.
You can buy performance valves of 43mm intake and 37.5mm exhaust, but you need to recut your valve seats. Even larger sizes are available, but it becomes complicated to keep pistons and valves from hitting each other and having enough valve seat width.
-Bryan
Since you're probably getting tired of that meme,
the stock valves are 42mm head diameter for the intakes and 36.5mm for the exhaust. It's the same across all the engine sizes although there are some minor differences between manufacturers.You can buy performance valves of 43mm intake and 37.5mm exhaust, but you need to recut your valve seats. Even larger sizes are available, but it becomes complicated to keep pistons and valves from hitting each other and having enough valve seat width.
-Bryan
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grasshopper
- Posts: 206
- Joined: Wed Aug 13, 2014 10:25 pm
- Your car is a: 1976 Fiat Spider
Re: Valve sizes
LOL. I never get tired of those replies ! Thanks for the info !