Is this normal cam wear for a flat tappet cam on the rear of the block






And a couple pics of the front cam bearing. I don't know how long this cam has been in this block.






ANd the lobes. I believe this looks like normal wear

 

It all looks pretty normal to me.

Looks like they put that rear cam tunnel plug in a little too deep.

 

Is that what sets the depth? looks like a freeze plug from the outside?
The cam sticks out the front a ways. I can measure it.

 

^^ What Sofa said... or a core plug with a little too much dome height.

That one last little "whap" with the mallet was one too many. That said, the scuffing/polishing was so light that I doubt it was causing any problems and it would have run a long time that way. There is no apparent galling, so little or no metal was being shed into the oil from that end.

 

Yes it is pretty much the same thing as a freeze plug. It's supposed to be installed so that its edge is just under flush to the surface of the block. Just enough to be able to hold a slight ring of sealer which will help retain it and keep it from leaking.

The depth that the cam sits in the block, is determined by the cam timing chain sprocket. It rubs against the front of the block.

The cam is pulled HARD to the rear, by the load imposed on it by the oil pump via the dist gear; and by the lobes, which are taller toward the rear than the front, mating against the base of the lifter which is slightly convex. The whole lobe/lifter interface forces the cam rearward and also forces the lifters to rotate on the lobes.

The rearward force on the cam is PLENTY to dislodge the plug and push it out of the way enough to cure any problem it might have caused.

When you build a motor, you can put the cam in without the sprocket, and make sure it can go in just a bit farther than where the sprocket will hold it.

 

Good info. Thanks guys!