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| Illustration 1 | g00927077 |
(1) Left camshaft assembly (2) Bolts (3) Right camshaft assembly (4) Camshaft lobes (5) Joint for camshaft assembly | |
The 3512B diesel engine has two camshaft assemblies. The camshaft assemblies are located on each side of the engine. The camshaft assemblies are driven by the rear gear group. Each camshaft is a two-piece assembly that is bolted together. There is one camshaft assembly on each side. The camshaft is supported by seven bearings.
Each camshaft assembly incorporates three lobes for each cylinder. As the camshaft turns, each lobe moves a lifter assembly. Each outside lifter assembly moves a pushrod and two valves. The valves can be inlet valves or exhaust valves. The center lifter assembly moves a pushrod that operates the unit injector. The camshafts must be in time with the crankshaft. The relation of the camshaft lobes to the crankshaft position causes the valves and unit injectors in each cylinder to operate at the correct time. For further information on the camshaft for actuation of the valve assembly, refer to this System Operation, "Valve System Components".