Timing Chain Replacement Help

[burbistheword]

Hey guys, I'm a newbie to engine maintenance so this might be a simple answer but I'm currently replacing my timing chain because the cover was leaking. My question is about the crankshaft sprocket. I removed the camshaft sprocket and chain but as I was removing the crank sprocket with a two jaw puller it rotated clockwise a bit and I stopped in my tracks. How do I go about getting it back in line without possibly messing up the timing? Thanks in advance!

 

[GoToGuy]

What caused you to replace timing chain and gears? A three arm puller for an even pull. And hold the puller to counteract the turning force for puller. It would only turn on crank if clear of woodruff key.
If your a noob , you should absolutely be using the Factory service manual. It's a process and learning guide especially in your case. Do right the first time.
There is a sticky above to the free PDF downloads of your year truck.
Next time start with , Year, Make, model, Eng etc. They all look the same until you open the doors and hood.

 

[L31MaxExpress]

All you have to do is line the timing chain sprockets back up dot to dot prior to re-installing the chain. Don't overthink it. A socket large enough to slide over the crank and catch the keyway or a crescent wrench wide enough to do the same will easily turn the crank without damaging anything.

 

[movietvet]

You can slide the keyed old sprocket back on and turn the crank back. As long as you end up with dot to dot, you should be ok.

In the future, you should supply vehicle/engine info with your posts. You can put the info in your signature, so it is always viewable.

 

[PlayingWithTBI]

Just to clarify what everyone else is saying, there's a Woodruff Key on the crank which keeps the sprocket from going on/off any other way but the right way. It doesn't matter if the crank rotates a little. Then when installing the new sprockets put them on and align dot to dot, crank to cam gears.

 

[burbistheword]

Thanks for all of the insight! Sorry for not clarifying it's a 1999 Gmc Suburban k1500 with the l31 vortec. Just so i understand correctly, I could turn the crank without the camshaft sprocket and chain on, back to the point where they were dot to dot and it wouldn't harm the motor? I would have to rotate it clockwise twice for it to truly be back in the same position and match up with the cam sprocket, correct?

 

[PlayingWithTBI]

I would have to rotate it clockwise twice for it to truly be back in the same position and match up with the cam sprocket, correct?

Nope, just once. The crank turns 2 times for every one revolution of the cam so, with the dot on the cam gear at 6 O'clock turn the crank in any direction until its dot is at 12 O'clock, then throw on the chain.

 

[burbistheword]

What caused you to replace timing chain and gears? A three arm puller for an even pull. And hold the puller to counteract the turning force for puller. It would only turn on crank if clear of woodruff key.
If your a noob , you should absolutely be using the Factory service manual. It's a process and learning guide especially in your case. Do right the first time.
There is a sticky above to the free PDF downloads of your year truck.
Next time start with , Year, Make, model, Eng etc. They all look the same until you open the doors and hood.

I believe the old chain and gears are still in good condition but I figured while I was already replacing the cover might as well replace the chain and gears with the truck at 170,000 miles. I've been following the Haynes manual and a few videos on youtube but I'll definitely have to check out and download those PDFs. Thanks!

 

[burbistheword]

Nope, just once. The crank turns 2 times for every one revolution of the cam so, with the dot on the cam gear at 6 O'clock turn the crank in any direction until its dot is at 12 O'clock, then throw on the chain.

Okay awesome thank you!

 

[Schurkey]

I would not turn the crank FORWARD to return to "dot-to-dot".

I would turn the crank in the opposite direction to whichever way you moved it accidentally. HOW FAR did you turn the crank when you were trying to remove the crank gear?

Unless you've removed or loosened the rocker arms, some of the valves are going to be open, and you don't want to smack them with a piston as the crank turns. Hopefully, you haven't already done that.

Remember that "dot-to-dot" with the crank dot at 12:00 and the cam dot at 6:00, is firing #6, NOT #1. When BOTH dots are at 12:00, the distributor should be firing #1.





Haynes, Chilton, Clymers manuals make great emergency toilet paper.