Valve Timing Alignment On GM 3.7L Vortec 5 Cylinder - GMC Canyon, Chevy Colorado, Hummer - 2004-2012

[@exQuisite_Cellar]

Apprectiate your great explanation on timing alignment on GM 3.7/3.5L...

[@motorcarnut]

Thank you!

[@AllysonClarke-t2t]

I made a mistake on my timing chain job. I didn’t mark the sprocket when I changed it out for a new one as we installed a new timing chain. Around the two minute mark on the video, you mentioned locking down the flats with the special tool and realign the sprocket to the cam shaft. I have the special tool to hold the cams flat. How do I adjust the sprocket to to be aligned correctly? Is it simply loosen the bolt and adjust or is it more?

[@motorcarnut]

If the sprocket is new it’s already in locked position and ready to be aligned

[@lilrblnluv8986]

I have the 07 Colorado 3.7L 4wd 260,xxx miles and the timing jumped causing lack of power while acceleration, engine stall and no crank questions is do u think its worth fixing or do u think i farther damaged the engine like valve etc?

[@motorcarnut]

You may of damaged some valves. But if it’s worth fixing depends on your own situation. It will cost a significant amount and with those miles probably more than the truck is worth.

[@lackyluciano5004]

Greeting I need to change the gasket on the engine head how. If I remove the chain and take out the cylinder head, should the timing be adjusted afterwards or should it remain as it is?

[@motorcarnut]

If it moves, you’ll have to do it the correct way.

[@DavidTheMechanic]

Mark everything

[@AllThingsRusty]

So before you released the tensioner was there slack in the chain between the cam sprockets?

[@motorcarnut]

Yes, that’s normal.

[@Mike-qo4kp]

How do you advance the cam phaser?

[@motorcarnut]

If it's a new gear they come packaged in the advanced position. But, to ensure, you just want to hold the cam in place and turn the gear clockwise till it stops.

[@Mike-qo4kp]

@Motorcarnut I actually figured this out, the advanced position just means locked. The reason they say to be sure is if reusing the old phaser you need to blow the oil out of it so the lock pin will engage. That's it. I wish the service Manual explained better. The default position for the phaser is fully advanced because all it does is retard the exhaust timing at idle or low speed. I also learned the hard way not to use aftermarket timing parts. I reuse the oem intake and crank sprockets I found ac Delco now makes the old Delphi phaser for the 3.7s. I tried aftermarket phasers and chains and sprockets and they are terrible. The phaser isn't even machined properly the oil passages are wrong there is play in the lock pin and the body is wrong for for cps to be able to read it's position. I got a oem phaser from rock auto for $160 I think, the dealerships don't make them anymore. And if you have say an 07 canyon or colorado you have to search under 08 to find correct oem parts. I also picked up a chain made in Thaiwan that is provably a little better than oem, I think INI makes it. The tensioner I went with cloyes top notch. Aftermarket timing parts should not be used. The ac Delco phaser has ZERO play in The locked position. I do believe over time it's the tensioner and phaser that wear out creating slack In the chain which when torqued by the starter makes the chain stretch and cause a wide variety of engine problems

[@motorcarnut]

@Mike-qo4kp Great write up and accurate

[@AllysonClarke-t2t]

I made a mistake on my timing chain job. I didn’t mark the sprocket when I changed it out for a new one as we installed a new timing chain. Around the two minute mark on the video, it was mentioned locking down the flats with the special tool and realign the sprocket to the cam shaft. I have the special tool to hold the cams flat. How do I adjust the sprocket to to be aligned correctly? Is it simply loosen the bolt and adjust or is it more?

[@ЛюсикСтерлягова]

👍🏾

[@motorcarnut]

Thank you for the comment!