There are two common designs for diesel cylinder heads: large (huge) castings for 6 cylinder inline engines with 24 valves, and single-cylinder heads, each with 4 valves (such as found on the CAT 3500).
The single cylinder heads are the biggest challenge! Most seat and guide machines can only handle one single head at a time, requiring the operator to load, clamp, machine intake seats, change tooling, machine exhaust seats and then unload the completed head before loading the next head. A tremendous amount of time is wasted. Operator fatigue becomes a real concern as the operator has to spend so much time just loading and unloading and not getting the critical machine work done of cutting valve seats and honing valve guides. Rottler has developed fixtures that allow easy loading of four single heads and then, with one button operation, all heads are clamped at once. The fixture is designed to accommodate different height heads as often heads being remanufactured have been worked on before and are not equal thickness and also may not be parallel. After the heads are clamped, the SG100XY is able to machine all the intake seats unattended and after a quick tool change, the software automatically changes the program to cut all the exhaust seats unattended.
For the large 24 valve castings, Rottler has developed a servocontrolled 360-degree rollover fixture with power clamping. Easy and fast to set up, these huge castings can be rotated 360 degrees and leveled for many operations such as valve guide and spring seat repairs, injector tube repairs and even drilling out broken studs on the exhaust manifold surface on the side of the heads.