Quick question guys - regarding the camshaft key, which is also the key for the injector pump drive gear. I installed the cam key and noticed that the portion of the key that drives the injector pump gear only seems to have a few hundreths of an inch of the key protruding from the camshaft where it engages the pump drive gear. This doesn't look right to me, is that the way it was designed? Here is a picture of what I mean. The only portion of the key that engages the injector gear is that front portion that is barely protruding from the shaft.

I suggest that you go buy a new key. That one looks a bit buggered up. That key should protrude evenly the whole length of the key slot in the cam. That jagged edge should be a straight line.
Ted

Thanks, yeah that key is messed up, and I do plan on trying to find a new one this morning, that's the one from my old shaft I just threw in there so I could post this picture. My question though, is that the way the key is designed, with such a small area protruding from the camshaft in the front of the key for driving the pump gear?

That's the design. My thinking on it is; the pump gear is bolted pretty tightly against the timing chain sprocket. There seems to be quite a bit of surface contact on the gears in that area holding them in alignment. That probably holds them in place pretty good unless the IP locks up. I have never heard of that happening though. I think most key failures are probably old age issues. I would probably replace all the keys with some age on them if I had mine tore down as far as you do. Just less to worry about, and keys are pretty cheeeep.. ;-)
Ted

Real lame design by GM. You really need to loctite the pump drive gear and key on. There is not enough key exposed to pump drive gear and they have been known to come loose. I have mentioned this several times and it seems you are the first to actually take notice. Congradulations!

We talking "Green Loctite" here? That's what I used. Smeared some where the gears contact too.
Ted

I sheared my key due to my own error. But when I took it apart I was unable to see what it looked like before hand. So....I didn't know that it was notched from the factory. Hmmmm...I put replaced it with an unnotched one. I hope it doesn't matter. Must have been done so it shears easier to protect something else, I guess.

Thanks, all. Good tip about the loctite. I agree, lame GM design.

Went to the dealer for a replacement key. The replacement part is a regular key without that notch in the front. Makes way more sense to me.

The notch is where it has broke off. The tip of the key just barely engages the pump drive gear which is only held on with one bolt. The key engages the cam gear just fine. Now tip of the week: Did you know you can change the crank gear location to advance the timing with an offset key? The computer won't even know it.
Thought to ponder. If you advance the crank gear and you want to keep the cam in stock position. Do you also need a cam gear offset key? Can it be done? Hmmmmm?
Read my sig. Have fun.

Yeah, in closely examining it, I can see that the old one was sheared off in the front where the pump gear mounted. It was sheared so cleanly that it looked like it was made that way plus there was just enough protruding that it would engage the gear. I knew that didn't make any sense. Got a couple new keys, problem solved.