Changing GM 2.9L Timing Chain and Guides

Before reassembly, you must clean all parts to be reused thoroughly. All gasket areas need to be properly cleaned. Do not use a die grinder and a abrasive disc. We call them cookies. Instead, use plastic scrappers and utility knife blades. The gasket surfaces on the block are easily cleaned with the blade. Remember to clean underneath where the oil pan mounts to.

The front cover and oil pan is not so easily cleaned. These should really be put into a parts washing system after gasket material is removed. To remove gasket material, start with the razer blade working your way around. There is a little channel, or groove, that gets filled in with gasket maker that needs to be cleaned out. Take the plastic scrapper and remove all residue.

Retiming the engine is rather easy. The chain is marked with multiple black links. Start your reassembly by putting reassembly lube on the camshaft bearing surfaces and roller rockers. Set your chain onto the removed cam, lining up a black link with the timing mark. Allow the chain slack to flow down toward the crankshaft as you align the camshaft back into it's place. Be sure the chain is wrapped around the cam gear – as once the cam is in place, the chain doesn't have enough room to be put on the gear. Find manufacture specs and sequence and tighten the camshaft caps. Rotate the camshaft so that the timing mark is again in the 11 o'clock positon.

Install the driver's side timing guide. Tighten both bolts at this time. It's imperative that this guide be put in first since it curves over the water pump housing.

Lay the new camshaft sprocket for the intake camshaft into place, while working the chain around it. Keep the chain tight in it's span between camshaft gears, then set the black link aligned on the timing mark located on the sprocket. Hand tighten the camshaft bolt at this time.

Pull the chain tight against the drivers side timing guide. Orientate the crankshaft sprocket to align with the keyway. Keeping the drivers side of the chain pulled tight, align the mark on the crankshaft sprocket with the black link closest to the mark and slide it into place. It should be right on - leaving little to no slack between the drivers side guide and the crankshaft sprocket.

While holding the chain from moving, install the tensioner side timing guide and insert the top bolt to hold it into place, tighten at this time. Install the tensioner. A new tensioner is collapsed shut and held that way. It should install easily without much of a fight. Once the tensioner is in place, there should be NO slack between the cam gears, both cam marks should still be at 11 o'clock and 1 o'clock, and there should be LITTLE TO NO slack between the crankshaft sprocket and the drivers side timing guide. All marks should be aligned with a black link. If everything is as that, you are good to pull the grenade pin (timing lock) on the tensioner by going below and using a pair of pliers to remove the plastic wedge. Finally, tighten the intake camshaft sprocket to manufacture specs.

You can now turn the engine over by hand. Do at least 360 degrees. Notice the timing marks no longer line up, should be one tooth off. This is normal.

After all parts are cleaned like mentioned above, lay yourself a good bead of quality RTV gasket maker around the front cover gasket. The bead doesn't need to be too thick – usually a 1/4 to 3/8 bead is plenty. To much RTV will get smooshed inwards into the engine and will eventually break away and get into the oil system, usually causing engine failure.

You should be following the groove with the RTV. Be sure to do around the water pump housing as well. Remember to replace the oil pump pressure outlet O-ring seal. The bead of RTV goes on the inside edge of any bolt holes. It would be wise to also do a small amount around the holes in the center of the cover to prevent oil bleed out of those bolt holes. Alternatively, you can place a small amount of RTV on those bolt threads near the head of the bolt while installing those.

Once the front cover is installed and tightened down, you can now install your pickup tube and gasket. Lay a similar bead of RTV as noted above for the oil pan, and then install the oil pan into place. Tighten everything down.

The rest of the install process is reverse of removal. Pay attention to the order in which these steps are performed – it is essential they are performed in the same order as was originally described for ease of access. A few extra steps must be performed... remember to add new engine oil, change the oil filter, and fill the cooling system with a vacuum filing device