Thrust Pin

Ok I have been looking at this dang pin for the last 20 mins. WTF is it supposed to do? I checked the chilton and haynes and neither say. It just sits there on the end of the Cam bolt.

I don't have a manual at hand (away from home), but the basic idea of a thrust pin would be to prevent the camshaft from being pushed outward by the axial thrust of the bevel gears that drive the oil pump and distributor. Some cams have a special thrust bearing with a flange on it, but that doesn't work easily if your cam has to slide in from the end of the block.

Matthew Currie said:

I don't have a manual at hand (away from home), but the basic idea of a thrust pin would be to prevent the camshaft from being pushed outward by the axial thrust of the bevel gears that drive the oil pump and distributor.

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That's exactly the case on '87-'98 camshafts. Without the thrust pin, the cam can "walk" forwards and if it walks far enough, the lifters won't sit properly on the cam lobes and both will be trashed very quickly.
The cam bolt should have a recess in the middle where the spring and thrust pin sit. Both spring and pin are essential.

Earlier AMC 6 cyls suffered from "Cam Walk" (So did the V8s) so the cam button was added to keep it within spec. (there is a pad inside the timing cover it hits)