Does chain tensioner change cam timing?
 

Folks, before I took the engine apart, balancer was at 3 BTDC when the cam dots lined up. R&R cyl head, got the cams back to dot-to-dot, but now when i roll the motor over, the dots line up at near 10 BTDC.

Please tell me the chain tensioner has to be pumped up to take the slack out of the chain, and it retreats a few degrees.

Otherwise I'm stumped. 5 degrees inst jumping a tooth. ( it couldnt have jumped, I had the chain lashed to the gear all along. )

Get the chain too show 3 degrees again by bunching it up and moving it on the cam sprocket. Remove the tensioner too do this.(zero if you replaced the chain). I would pull the IP and make sure the "marks" are lined up then re time it.

Sorry, I re read your post and see we are not talking 617/6, may be the same procedure but, I dont know.

Aint touching the IP man! Yeah, I can fiddle with it. An offset bushing would be good!

You've only been turning the engine clockwise... right? If so, I don't think the tensioner will make a difference.

I know some folks around could pull the head without loosing IP timing but, admittedly, not me. The chain jumps due to compression but also when turning the vacuum pump. I suspect thats what caused me to lose timing when fussing around getting the chain back on the sprocket. At any rate this is when I leaned about IP timing;)

On yours I think the "tool" too lock the IP can be used, making timing pretty easy.

You didn't jump a camshaft sprocket tooth. But I suspect you may have jumped a crankshaft sprocket tooth.

The crank turns twice while the cam turns once. If one camshaft sprocket tooth is 18 degrees, a crankshaft sprocket tooth is 9 degrees. That's pretty close to the 7 degree change you are seeing.

If this happened, it may be due to compression kicking the crank ahead. The better strategy is to remove all glow plugs and turn slowly so compression is not an issue while turning over the engine.

Also, when I change my next 617 timing chain, I'm going to install a 240D tensioner to hold the chain tighter. The 240D tensioner does not have a ratchet and only uses a spring when there's no oil pressure.

So, consider my theory that you have skipped a crank tooth.

Were you turning the car engine over from the crankshaft bolt or the camshaft bolt?

Ken300D

>>If one camshaft sprocket tooth is 18 degrees, a crankshaft sprocket tooth is 9 degrees.

Numerically, the ratio is right, but, if on camshaft tooth makes 18 degrees of difference in cam timing, one crankshaft tooth makes 36 degrees of difference!

Uh, nevermind. Once I got the engine spun over a few times via the starter, its at 3 BTDC. You must have to turn it over a few times.

Now the missing fan belt sans diagram.