® Avoiding bent valves

The official Honda service manual warns against bending the valves while installing the rockerbox or cam cover. It can happen pretty easily. But it is even easier to avoid it, once you are aware of the danger.

Because the engine's valves are at an angle, and the rockerbox installs straight down--not at an angle--it is possible for one or more rocker arms to catch a valve stem on its side instead of straight onto its tip. Tightening down the rockerbox then bends those valves.

The manual has you avoid this mainly by watching where the rocker arms are as you install the rockerbox. Pro Honda mechanics went a step further. We loosened the rocker adjusting screws until they were flush with the rockers. This makes doubly sure the valves won't be caught on their sides as the rockerbox proceeds downward. It also makes installing the rockerbox generally easier as there is less valve spring force to deal with.

As any career Honda mechanic will tell you, the o-ring on the rockerbox should be supplemented with Hondabond 4 sealer. This is an unusual case, as rubber and sealers are not usually combined.

Another thing to be aware of is the tach drive gear machined into the camshaft. The right side of the rockerbox will tend to hang up on this gear, making it look like it won't install. Turning the crankshaft back and forth is all that is needed to mesh the gear and allow the rockerbox to settle down. Due to the cam lobes however the rockerbox will still sit unevenly at first placement, but the right and left sides will be much closer to level than when the cam gear is out of mesh.

Tighten the screws and bolts slowly and evenly, constantly on the lookout for the rocker arm and valve interference mentioned above, and any hangups in general. Slow is the way. You should use the factory fasteners here, not Allen (socket head) screws. The aluminum threads in the head are not very deep and will not stand misuse. Once the rockerbox is fully seated, I use a cordless impact on the Phillips screws and a torque wrench on the hex bolts.


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