In The Shop: Evo Cam Compartment

Let’s take a look at the cam compartment on a Harley Davidson Evolution engine.

The cam cover on an Evolution engine supports one end of the single camshaft.You need to “unload” the top end in order to disassemble the cam compartment on an Evolution engine. By “unload” we mean that the pushrods either have to be removed (solid pushrods) or need to be loosened (adjustable pushrods) The rocker box assemblies need to be removed in order to remove solid pushrods. Or, the solid pushrods can be cut out with bolt cutters if replacing with adjustable pushrods. If adjustable pushrods are already installed, they only need to be loosened; or completely “unadjusted ” and the rocker box assemblies can remain in place.

Watch the FMH Multi-Hour Evo Top End and Cam Project

*We should note: If only removing the cam cover for inspection, it is possible to do so without unloading the top end.

To do this; remove the spark plugs, lift the rear wheel, and shift the transmission into high (5th) gear. Then, slowly turn the motor over by hand (turn the rear wheel) until the notch at the end of the camshaft is at, approximately, 4 o’clock. In this position, there is the least amount of pressure pushing downward on the camshaft. The cam cover can be carefully removed by removing all retaining hardware and gently tapping with a non marring mallet. If disassembled this way, you will not be able to remove any other components. Everything is under pressure.

After the pushrods are removed, you will remove the lifter blocks and lifters. Try not to let the lifters drop down into the cam compartment when removing the lifter blocks. If re-using the same lifters, it is important that they are reinstalled in the same position and direction. If they drop into the cam compartment, you can lose this orientation. There is a specialty magnet/tool available or you can get creative with a couple of mechanics magnets.

With the lifter blocks and cam cover hardware removed, the cam cover can now be taken off. Be aware of the small spacer (looks like a thick washer) on the end of the breather gear. This spacer often falls off when removing the cam cover. Also, do not panic if the cam pulls out as you remove the cover. Lining up the timing marks is very easy on an Evo.

When the Cam cover is removed, you will see the cam/cam gear and the breather gear. You will also see the pinion shaft and gears. In the lower area of the case, you can see the oil pump’s pinion gear and part of the oil pump drive shaft.

More Evolution Videos here:

Watch our Twin Cam and M8 Cam Projects