I repair/replace allot of driven equipment that uses keys; motors, gearboxes, pump impellers, shafts and so on. Most folks wouldn't see as much in a lifetime what I work on in one week and I'm the guy who only gets involved when the shiite has hit the fan. I was speaking of "best practice" in my field. We get one chance at it while it's stripped down, we replace everything we can before it's buttoned back up because the one thing you didn't replace will almost always invariably fail and you'll be visiting the same thing over and sooner than later. It's like having one headlight bulb burn out, do you replace just one or do you replace both? Get the logic? I hate do-overs and I've done my share. I'm not saying these keys fail, not at all, I'm just sending a little hard earned experience your way. Don't worry about it so much, it's two gears and a chain. What could go wrong?

 

Says it all.

You don't want the one in 50k key failure to happen to you.
......

 

I agree. I also abhor doing things twice. If I replace a power steering pump I replace all the hoses, the pulley, etc. I do a whole system. Usually more costly but it’s piece of mind.

 

I just did this on my 97 and to be honest all I did was slip the old gears off then line up the new gears on the new chain so that the casting in the cam and the key in the crank lined up when they slipped on. I torqued the cam bolt and I was done. I don't see why you would need to rotate anything once you have the old sprockets and chain off unless you are deep into it for another reason. I've been driving it for 1.5 months now.