Thank you sir for the info...my plans are to convert a small diesel to an alternating valve engine. I have invented and patented this design. It uses a cam which turns one revolution for each 4 crankshaft revolutions, using one intake valve and one exhaust valve each 4 cycles while the other two valves are at rest. The next four cycles, those that were at rest, are used while the first two are at rest. By doing so, the alternating valve train runs at half speed and does not move so fast that stiff valve springs are needed. I have expermented and have valves working just fine with a 15 pound spring where as 150 to 180 pound spring was previously used. Early study indicates near 15 to 18 foot pounds of torque are saved. I will send anyone who asks a detailed write up as to how it works but may have to snail mail it as I'm old and not good with computers..do not know how to post the entire write up with drawings....thanks again for the info regarding the 4 valve diesel....jim whitmer
j.whitmer@cox.net