HISPANO SUIZA V STUTZ OVERHEAD CAMSHAFT
In reply to your query on page 726, I enclose the appropriate pages of the Handbook for a 6-cylinder Stutz engine so that you may draw your own conclusions as to whether this valve mechanism represents an improvement on the original design of Marc Birkigt. It may prevent valve guide wear at the expense of being somewhat heavier. Certainly, engines in Australia have been known to cover in excess of 200,000 miles without the need for valve replacement.
However, the injudicious use of the "tommy bars" referred to in the manual can lead to tappet damage and having seen a car have one of these tappets break during adjustment for a hill climb competition I suspect that this was the reason for the valve failure and ultimate demise of the 8-cylinder Stutz in the Hispano Suiza match race of 1928.
As there were no twin-cam Stutz engines imported into Australia I cannot confirm that this system of valve actuation was used.
Melbourne KEN STUCHBERY
[The problem is one for qualified engineers; as a matter of interest we reproduce the drawing sent to us by Mr. Stuchbery of the Stutz tappet-adjustment, it, applies to the Blackhawk engine. — Ed.]