Timing Chain Replacement - 2006 LY7 V-6 3.6L

[ktrsb]

Now remove the ECM bracket (actually, I may have done this before the alternator, but shouldn't be a biggie). To assure the intergrity of the ECM connectors, and the ECM's ground to the bracket, we are removing the bracket and displacing it. Do not remove the ECM connectors or the ECM from the bracket. The rearmost bolt, on the side, has a clip in front of it that also has a 10mm head bolt. Don't confuse the two, but it might make it easier to remove the clip bolt first.









Clip bolt:

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Now the cam covers and coils. Disconnect the coils and carefully pry back the harness retainer:

Coil connector locked:


Coil connector unlocked:





Don't forget the rear bolt:



You can remove the cover with the coils just loosened, or take the coils out entirely. I suggest numbering them with a silver sharpie first.


The right side harness protector has these clips that slide off:

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Now the spark plugs.

Go to 'Vatozone and get a deep spark plug wrench like this one:






Plugs have 161K on them, probably running too rich and varnished engine. New one for comparison:

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Now time to remove the front cover.

First, the harmonic balancer has to come off. My impact was powerful enough to take the bolt off. There is a flywheel lock that requires removal of the starter, but I didn't need it. The harmonic balancer puller is just your standard 'Zone issue free rental. Use a 1/2" drive socket as a spacer:



To get the cam covers off, you should have pulled the connectors for the cam position sensors and phaser solenoids, but do it now if you haven't:



You can pull the front cover with the phasers attached, as I did, but you probably ought to mark them and pull them anyway. Here is what the cover looks like:



There are 22 bolts that have to come out, and I was too lazy to look at each one and try to remember where it went. So I printed out the tightening diagram from the manual on two pages and taped them to a box:



Then, removing them in order, I punched them into the box as they came out (a knife helps punch the hole):



Be careful - the bolts have rubber insulators on them:



Once you get them all out, there is a jacking hole and pry points. Be patient when prying. And you will get more coolant out of the back of the water pump, where the cover mates to the block. You do not need to remove the water pump.













Here is what the cover looks like off (not mine, but you get the picture):

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OK, here's the fun part - you need to turn the crank so that the cam timing marks are somewhere near the 12:00 position. That's right - no need to line up all the marks, they are only for installation. (And there's no way you could anyway, since they go out of position the minute you start the engine).

Here are the marks you are looking for - the EX for exhaust cam, IN for intake, with a triangle for the right side, a circle for the left:







The crank gear will have the dot around 9:00 pm and the slot for the pin / keyway at around 3:00 pm:



Secure the cams with the special retaining tools (which are crazy pricey unless you find them on eBay), or have a buddy with two 20mm wrenches (yeah, right, you know you are going to hand him a couple of Crescents) hold the cams on the flats provided just forward of the forward cam lobes:



This prevents the cams from popping from spring pressure when you remove the chains.

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Remove the tensioner bolts and tensioners, the tensioner shoe bolts and shoes, the guides, the chains, and the gears. The factory manual says the primary guide on the oil pump is not replaceable, but I got one from a dealer for around 10 bucks.

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I had never heard a noise like mine was making, and not being familiar with the engine otherwise, I suspected but was not certain that the noise was from the chain, especially before the cold start rattle started. Other candidates were bearing noise from the water pump, tensioners or the fan bracket assembly. As I disassembled the engine, I checked all of these, and they were smooth and quiet. So what about the chain components?

Well, there's your problem:













And the timing chain was "stretched" and worn on the outside (new chain on left for comparison):

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Now time to clean up this mess:

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Finished product: