Timing Chain Oops!

[craigster]

I replaced the head gasket on my e21 and followed the manual when reassembling it. I was careful not to let the timing chain slip off the lower sprocket. However when I followed the manual I thought I had let it slip and changed it by one tooth according to all the instructions, TDC, mark on crank pulley and distributor all aligned. I shoulda left it alone. Now I think it's "running" one tooth off.

My question is this: How do I get it back to the right timing?

Do I have to pull the head or should I pull the lower timing cover? How will I know when I have it right?

[autox320]

Just undo the front top timing cover. Roll over and see if lines up. If not can just undo the tensioner to get slack. Then undo and move the cam gear again. Put the tensioner back in and roll over 2 times see if lines up straight. Gear should be inline with the oil bar. Crank pulley line with pointer.

[Dave1965]

One tooth off and you probably lucked out like me without having valves hitting pistons.

Did the same thing and when I restarted had the SMOOTHEST IDLE...at like 250rpms.

LOVE THIS CAR!!!

[epmedia]

Always Triple verify the cam/crank timing marks by turning the engine BY HAND in normal rotation direction (CW from front). The ignition distributor orientation is set last.
* Stop turning if there's any binding! (ie: pistons hitting valves)

Your '79 probably has two marks on the cam sprocket, use the mark with the #2 stamped next to it.

click to enlarge
tdc1-m10-bk.jpg

TDC Compression! stroke #1 cyl. After verifying cam/crank timing marks, set the ign distributor to this orientation:

click to enlarge
dist.gif

I confess I once had mine a tooth off as well, it idled like crap! I was like: how did I manage to do that ???

[craigster]

Thanks Guys,
I had it apart and the chain was tight even with the tensioner spring removed completely. I'm afraid I won't be able to get the sprocket off the cam shaft. Have any of you experienced that?

[epmedia]

Thanks Guys,
I had it apart and the chain was tight even with the tensioner spring removed completely. I'm afraid I won't be able to get the sprocket off the cam shaft. Have any of you experienced that?

With the tensioner removed, the chain may be tight on one side and loose on the other side. Is this the case? - if so, you probably just gotta turn the crankshaft a teeny-tiny bit to release tension on the tight side of the chain.

*set the crank/cam timing marks TDC compression stroke #1 before removing the cam sprocket (or close as you can get it).

[tlapham]

The cam springs will keep it tight at various positions, except #1 TDC. much easier to remove/adjust at that orientation.