Quote:
Originally Posted by BlueOval Ralph
Which means, if they are allowed, all seats will need to be replaced with a seat with a higher Copper contents.
This is not true I have been using ti valves since 1969 (they were released by Ford then for use in Tran's Am Boss 302 and 351 C), we used the first as Intakes as there was no Ti for Exhaust, it would not work according to TRW who was the first to supply. I have run the intakes till the margin was thin and started to chip (small V shapped cracks) we then took these valves and turned them down and made exhaust with a much thicker margin and lasted another couple years.
I WOULD NOT be in favor of the change!
Just trying to set the record straight.
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Ralph, then we will have to disagree.
For longevity, it is a known fact that you should change the seat material when using Ti valves.
Beryllium bronze seats, which is a Copper-based alloy is used for most applications because is softer and won't wear the Titanium as fast.
You may have got away with the standard seat because in the earlier heads due to the availability of Lead in gasoline. Therefore, OEM's got away with softer seats in cylinder heads.
According to an SAE paper that was written by Chevy engineers as realted to the developemnt of the 'Vette engine, they used a seat alloy called PMF-28.
Here is a great informative article as regards to the use of Ti valves:
http://www.enginebuildermag.com/Arti...lications.aspx