Timing scale/distributor/camshaft alignment

[MunichTaxi]

When #1 piston is at TDC, the camshaft mark and the distributor line up also.
But the timing scale, behind the front pulley, is at 9 degrees ATDC.

My conclusion is that the rubber vibration dampner (betwwen the front pulley and the timing scale) has slipped, and thrown off the timing scale.

Anyone seen this happen before?

[300SDog]

And that's a brand new timing chain, eh? So there's no chance it shows 9 degrees of stretch.

Or if the timing chain jumped a few teeth on the camshaft sprocket, then could it have slipped on the chankshaft too? Or maybe the jump of the chain was directly transmitted past the distributor drive to the crankshaft too? Hell, it might have been like cracking a whip and sending a loop through the entire system.

Just thinking out loud here.

Never seen a TC tensioner go south. But can understand how sudden slacking that hops a few camshaft teeth might effect position of the crankshaft gear to the distributor drive sprocket too.

Wait a minute, what happens if you line up camshaft TDC with crankshaft TDC..... can rotating the distributor (as if setting ign.timing) make it agree with TDC everywhere else?

Dunno anything about vibration dampeners, never messed with them. But can see where the vibe dampener can be the simple culprit.

[250 Coupe]

There are two different designs for the pointers. Have the marks ever lined up or is this the first time you've tried it? You could have the pointer from one style and the scale from the other, at least I think that's possible.
Also, with the engine off and no oil pressure, you can turn the crankshaft quite a bit in the wrong direction before taking all of the slack out of the timing chain and moving the cam and distributor.


Michael

[MunichTaxi]

The new Timing chain is tight on the distributor side, and the distributor is lined up. So I have 3 things lined up: Camshaft mark, distributor mark and TDC on # 1 cylinder (triple checked that).

I am resigned to live with 9 degrees ATDC as my current TDC (because it is, isn't it?) and ignore the Timing scale behind the front pulley.

So anyhow, she fired right up today. However, there still is a loud noise from the water pump, that increases with RPM. I can shake the fan blades nearly 3/32" up and down, and side to side (Has been that way for a couple of months)

After the new water pump tomorrow, I'll keep my fingers crossed when I drive it.

BTW, the new tensioner never did "pump up" and release air when installed. I had to remove it, fill with oil on the bench, and re-install. After that, it was firm, with no idle stroke..

[cth350]

If you're replacing the water pump, that means you have the radiator out and the belts off. It's a great time to remove the pulley on the crank and look at that harmonic balancer.

You will need to remove the bolt at the crank center to remove the balancer.
If it has slipped, then you'll see that it's not on the woodruff key on the crank correctly (after removing the bolt and the washers.

You'll need an impact wrench or something to block the ring gear (after removing the starter). A nice hammer driven impact driver from sears won't set you back much. It's a stubby little handle that takes any 1/2" drive socket. Pick up a cheap rubber mallet to go with it.

If you do get this far, consider also replacing the front seal.

-CTH