LS cam change Changing a camshaft in the GM LS engine. The LS is a different animal as compared to the earlier small block Chevy By Mike Mavrigian
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ervicing a camshaft in any overheadvalve engine requires a degree of disassembly, but in the case of GM’s LS-series of engines, the task is a bit less tedious, since there is no need to remove the intake manifold, upper engine cover or lifters. Here we’ll explain the process. 1. Remove both valve covers. 2. Remove all rocker arms. 3. Remove the following components: • Water pump • Crankshaft pulley • Oil flter • Oil pan • Front engine cover (timing cover) • Oil pickup tube/screen assembly • Oil pump • Oil pump drive gear (slides off of the crank snout) 4. Rotate the crankshaft two full turns (360 degrees), and position the crank gear and cam sprocket dots (cam gear dot at 6-o’clock and crank gear dot at 12-o’clock). Once positioned, DO NOT rotate the crankshaft at any time during the process. (By rotating the crank two full turns, this causes the camshaft lobes to push the lifters up into the plastic lifter buckets. With no valve spring pressure, since the rockers have been removed, the lifters will “snug” into the lifter buckets, holding the lifters up and away from the camshaft, allowing a clear path for camshaft removal without the need to remove the lifters. Note that in order to remove the lifters, the cylinder heads must be removed. This feature (lifters secured in
When servicing the camshaft on an LS engine, there’s no need to remove the intake manifold or top engine cover, but you will need to disassemble the front of the engine and remove the oil pan.
As this example of a bare LS block shows, there’s no access to the lifters at the top valley. The lifters are located in the upper deck areas of the block and are held captive by the cylinder head. When removing or installing a cam, there’s no need to remove the heads either.
34 | July/August 2013
