2.2L Ecotec timing slack question

I just had the head rebuilt in my car due to a grenaded timing chain. I got a new kit that included all timing pieces as well as a new oiler. I installed everything using google as a guide.

There are 3 timing marks intake/exhaust cam and crank that need to line up with colored marks on the chain. I lined all these up and then released the tensioner to pick up all slack. I decided to turn the crank by hand a couple of times just to see if everything was in place and it seems to be working correctly except for something i'm not sure is an issue.

When i turn the crank to the point that slack is on the intake side of the engine I can push down on the chain and the intake cam moves back slightly creating a lot of slack in the chain even though there is no slack at all on the tensioner/ exhaust side of the engine. Is this normal? When i turn the crank a bit more, the slack goes away and i can get almost no play in the chain at all.

Since your question relates to a specific engine in this case, you might have better luck in the appropriate vehicle-specific forum. If you care to share which GM car this pertains to, one of the mods will move this to the correct forum.

-Rod

Oh, the great Ecotec timing chain question.....

We've had quite a few tensioner problems on these engines, and have replaced a few of these timing sets, let's see what I can tell you.

First......always turn the crankshaft clockwise. Anytime you work on a timing chain or belt, always turn the engine in it's normal direction of travel. Turning the engine clockwise tensions the leading portion of the chain, and leaves the slack at the rear, where the tensioner can compensate for it. Rotating the engine backwards will force the tensioner to retract and will leave tension on the leading portion of the chain.

Next......on the 2.2 ecotec motor, be sure the tensioner spring is released, and is applying tension to the chain. The tensioner plunger works much like a retractable pen. You push it all the way down once and it locks in, press it down again and it releases. The tensioner is oil-powered, the spring in the tensioner is just made to keep the plunger out when the engine is off and no oil pressure is available. We have seen some big issues with this system, because if you lose oil pressure or air is sucked into oil and gets into the tensioner. If the tensioner loses pressure just for a second, the plunger can be forced back far enough that it will "lock" itself back, and you lose all chain tension.

So......the complete process:

*Install timing chain, guides, and tensioner.
*Release tensioner and allow it to take up slack.
*Turn the crankshaft clockwise 2 full revolutions by hand, and recheck all timing marks to be sure they still line up.
*Make sure tensioner spring is still applying force to chain.
*Reinstall timing cover, drive belts, motor mount, etc....
*Make sure engine oil is clean and full (prime filter if it was replaced).
*Start engine and let it idle for 20-30 minutes to allow ALL air to escape tensioner. DO NOT REV ENGINE until engine has had a chance to purge all air from tensioner. The centrifugal force on the chain can actually push the tensioner back if there is air trapped, and cause the tensioner to lock back.

Shut the car off. Recheck all fluids and make sure everything is reinstalled and tight.
Start car, drive away. You're Done.

Rob Kuelbs

Richardson's Auto Care
11170 Ables Lane
Dallas, TX 75229 (http://www.richardsonautocare.com)

Auto Repair in Dallas, TX 75229 (http://www.richardsonautocare.com)