(video Included) Timing Chain Tensioner, Is This Normal Or No?

Anthonyryan86

New Member
Jul 4, 2016
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Setting the timing on an 04 gt, before taking off the chains I set to tdc and marked chain at cam mark and the 6:00 mark on the crank. My chains had no visible links to differentiate but after the chains came off the 2 marks lined up at opposite ends so I felt confident in that.

I also marked the position of the camshafts with the cam cluster caps for extra security. After resetting the timing, the camshaft to cluster marks lined up and also the crank and cam/chain marks lined up.

After double and triple checking the marks I spun it by hand about 10 rotations to check for binding and everything went smooth however the passenger side tensioner seems to jump at a certain point giving the chain some slack and then tightening back up as it continues.

Is this normal for only one tensioner or is there and underlying issue with either that or the timing? I included a video to explain better

 
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Gearbanger 101

Straight Outta Locash
15 Year Member
Aug 10, 2002
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Nothing to worry about. You have oil actuated timing chain tensioner on either side of the block. They're only functional when the engine is running and pressurized with oil. If you'll notice each time you detect the chain getting slack, the piston of the acuator on that side collapses. This is because the oil pump isn't spinning, keeping them pressurized with oil.

They tend to bleed down overnight and often more drastically as the miles pile on. This is why you may probably here a "Brrrrrrapppp" from you timing cover during cold start.

Unless you've got a lot of miles on the engine, I wouldn't worry about them. If the miles are high and the chains rattle after each start up (even warm) it couldn't hurt to replace them.
 

wmburns

SN Certified Technician
Aug 14, 2009
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+1 on above.

Consider that the tension on the chain is not constant. It rises and fall with the cams. Applying more tension as the cam rises and then once the cam is past highest lift, the valve spring will then want to rotate the forward after crossing over.

Repeat your experiment and note when the chain goes slack. I suspect there will be one cam past the point of highest lift.

As mentioned above, things are much different in a running motor. Things are happening faster AND the timing chain tensioners will be under oil pressure.
 

Anthonyryan86

New Member
Jul 4, 2016
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Thanks for the quick responses guys! I did look at the cams when the chain loosened and it was at a pretty high point. I'm glad it's fine too because getting those tensioners on when they don't have a locking mechanism is a PITA. Hopefully I'll have it running by next weekend its been almost 2 months now -.-. Thanks again!