Just got the exhaust valves in I ordered from aircooled.net, that are supposed to be for my year 914 1700. They have a dome in the face, which my stock ones do not. Just curious if anyone has experience using these on the T4? Anything I should be aware of, any change in performance or setup or tuning when rebuilding the engine/head with these?? Thanks,
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Full Version: Domed exhaust valve face, vs flat
OE Sodium filled
QUOTE(914werke @ Dec 4 2020, 07:51 PM) 
OE Sodium filled
Did all displacements use sodium filled exhaust valves, or just the 2L ?
Never re-use 50 yr old sodium filled valves !
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@dfelz
The disc will have a small affect on the chamber volume. Measure the volume of the disc with a medicine syringe and add thstvto the CR calculation.What did you compute as the compression ratio?
The disc will have a small affect on the chamber volume. Measure the volume of the disc with a medicine syringe and add thstvto the CR calculation.What did you compute as the compression ratio?
QUOTE(bdstone914 @ Dec 5 2020, 07:58 AM)
@dfelz
The disc will have a small affect on the chamber volume. Measure the volume of the disc with a medicine syringe and add thstvto the CR calculation.What did you compute as the compression ratio?
Thanks Bruce! I have not calculated CR yet, but will take the volume measurement of these valves before I install them. I’m still in the engine tear down and parts acquisition stage of the engine rebuild, and I don’t recall what we calculated the CR to be from the last rebuild (7 years ago now).
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