Over the years we have used titanium valves in both large and small engines.
We prefer Del West 3 groove valve for both intake and exhaust.
We had some issues with 3 groove retainers but by fitting each retainer by hand (lapping to tighten the fit) we cured all issues.
We easily see 200 hours without issue.
We run the valve against custom made seats using Amco 45 nickel-aluminum bronze.
These Valves are 39mm ex and 45 mm in for 69 S and 906
