1906 Vanderbilt Thomas engine

[StanleyRegister]

This 817 ci 4-cylinder was in the Thomas race car that ran the 1906 Vanderbilt Cup race.  It was described as "inlet over exhaust," but the rocker arm angles make it look like the intake valves were closer to the piston than the exhausts.  What you can see of the exhaust pushrod guides seem to be in line with the intakes, so it looks like a single camshaft.  I don't think any production Thomas engine before or after looked anything like this.  Does it resemble any other engine of the time?

[1912Staver]

It looks like a single cam to me as well. I think the exhaust valves would be in the same position as on a T head with the intakes more over the pistons. So sort of 1/2 T head , 1/2 overhead valve. Interesting design.

[wayne sheldon]

"F" head?

[arcticbuicks]

yes likely like some british cars.....and early jeeps ?

[wayne sheldon]

Reo used an "F" head design for quite a number of years. Four cylinder cars during some of the 1910s, with open upper valve trains.  And then for a number of years on six cylinder engines with covers over the valve mechanisms. Trucks and taxis (a couple of friends had one years ago) also used the open valve train four cylinder engines well into the 1920s. The Reo four cylinder, although much smaller than the Thomas engine, looks similar. I don't know if it is a single or dual camshaft, however I expect it would be a single camshaft given the cost advantages.

[arcticbuicks]

kaiser car