Re: Snapey's 1935 Racing Biposto

Posted by Matt snape On 2011/6/22 2:34:53

Hi 55 - glad you have enjoyed the ride so far.

Hmmm - a cross flow side valve... it's good to see someone else with a perverted sense of the practical like myself LOL. The conversion would be neigh on impossible using any existing block that I know of, as you would require the block surface to seat the valves in and an additional cam to operate them. Although it may well have been played with 'in the day' I think that the natural restrictions that exist to air flow in the side valve design when you are trying to keep compression ratios relatively high would have stopped development. Although now I think about it I am pretty sure that Packard did build a number of V12 aircraft engines that used a central cam shaft to operate valves on both sides of the cylinder???? I would have to go back to my 'Master Engine Builders' book to be sure.

My father is currently developing a supercharged, methanol burning race engine for use in one of his period based specials, which uses an in line 4 cylinder 'F-head' Willys engine. The inlet valve is overhead and the exhaust is side-valve and this provided approx 25% more power than the same engine capacity in standard side-valve format in its day. The inlet valve is HUGE and he hopes to get well above 200hp from this 2.25 litre engine.

As for the 'Commer Knocker', Commer was the brand name of these trucks built by the Rootes Group and the 'Knocker' was the nick name given to the truck because of the distinctive noise it made. It was an unusual engine with 3 pairs of pistons which worked opposeded to each other in 3 cylinders and then drove to a single crank shaft using a connecting rod and rocker assembly. The supercharger acted to 'scavange' the cylinder meaning the engine ran as a 2 stroke with piston exposed ports. Indeed it think it very English in that it is so different but also in the fact that it worked rather well - the only weak link being the shaft that drove the blower. Check outhttp://en.wikipedia.org/wiki/Commer_TS3 for more information.