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The 3 Holes Confuse Me...

> Rob, there is one more thing you can try,
> you have to be careful doing it, but it may
> work. Put your motor at top dead center then
> remove cam shaft bolt.INSTALL WEDGE and
> remove sprocket.Get a pair of vise grips and
> clamp them on the camshaft dont clamp on a
> journal.Note starting point of cam by making
> mark with paint or wite out and then twist
> cam clockwise and counterclockwise.You
> should get valve to piston contact within
> about 20 degree turn of cam in either
> direction.Try to find halfway point and stop
> turning cam.Then without turning cam or
> crank try to fit cam sproket gear back on by
> skipping a chainlink back or forwards and
> trying 1, 2 or the 3rd dowel mark.You can
> move the cam a little to get sprocket on
> just try not to move it much oneway or
> other.this may get you close enough to pass
> emissions My best guess is that you retarded
> the cam since it runs so poorly.This is
> assuming you still cant get timing cover
> off.It might work or it might not but I cant
> think of any other suggestions at this
> point! Later ,norm

Thanks for the advice, Norm. I still can't get the cover off, so I'll try turning the cam like you've suggested.

What my brain just can't figure out is how to properly use the 3 different holes on the cam sprocket. I know one's for a new chain, the others are for varying degrees of stretch or wear. But it just doesn't make any sense to me on how putting the pprocket on using the different holes will change my cam-to-crank timing.

Here's what I mean. As an analogy, I picture taking off one of the front wheels. There are 4 lug holes, and I mark one of them and its corresponding lug. Then I remove the wheel, and rotate it one lug hole one way or the other, and then put it back on.

What have I changed? Nothing, as far as I can tell. I took a wheel and rotated it one hole, but that didn't change its spin at all. Kind of like taking a glass of water sitting on a table and rotating it a quarter turn: I didn't change a thing....

The only thing that makes any sense to me that way is that if I set the crank to TDC, then removed the cam and set it to EXACTLY TDC (which is the hard part, since moving it just a tiny bit off TDC will cause a 1-link difference when I put the chain on). Then I could put the cam sprocket back on at the TDC mark, and THEN re-rotate the camshaft to make its pin fit into one of the 3 holes.

That's the only way I can think that the 3 different holes have a purpose: it seems to be that they allow compensation for the differing spin rates of two sprockets spun together by a chain that changes its own length (with wear/stretch). I'll have to set the cam to TDC first, set the cam sprocket at the TDC mark, and then hold the sprocket in place at the (now imaginary) TDC mark and rotate the cam to fit into a non-center hole.

Do I have the logic right?

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