Oldblue

With whose parts? AC Delco ?

terryk

Yep. I use GM parts unless there is some compelling reason to do otherwise.

firemangeorge

And. A lot of those "GM" parts are made by outside vendors such as Cloyes and many other companies.

donbrew

Pretty sure Cloyes is the OEM.

Oldblue

I believe you’re correct, but I like the kits Cloyes provide , less expensive than GM individual parts.

terryk

I got the valve cover off today. Other than the oil return line from the turbo to the valve cover refusing to come off (I finally removed the line from the turbo in the end) it was pretty quick and straight forward.

On first inspection, there was no slop at all on the chain between the cam gears or on either side down to the crank. I looked around with the borescope and didn't see anything but it's pretty hard to see much anyway. With the spark plugs out, I took two 24mm open end and trying turn the cams. It rotated easily (I wasn't sure how much pressure I could put on the cams themselves) but the chain went slack . Maybe a 1/4" of play bewtween the gears. I wouldn't expect there to be any. I took the top guide off and the slop is even more obvious.

So next week, the cover comes off and onward I go.

Questions (minor):

1. Two valve cover bolts didn't have the plastic sleeve. One goes in the front corner with the metal sleeve but I don't know where the other one goes or if it was just missing the sleeve.
2. Does the turbo return line at the valve cover require a fuel line tool or other special tool? I pried on it a bit and it would back up but but didn't cover off. I didn't want to wreck the line. As I said, I finally took the line off at the turbo.

Thanks again for all of the input!

Terry

RJ_RS_SS_350

The valve cover bolts, the sleeves may have stayed in the valve cover.

That line is part of the PVC system. While boosting, crankcase vapors are drawn to the mouth of the turbo through that line. It doesn't usually come off without destroying it. I have replaced it with a section of 11/32" PCV hose and some clamps. Actually, I have a catch can plumbed into that line as well.

Oldblue

That slack is enough to warrant changing the timing and balance shaft chains , tensioners and guides

terryk

Thanks for the confirmation Oldblue. Based on what you've said and other threads, that's the plan. I did order the guide and sprocket bolts too. I'll be curious what I find once the cover is off. Looking down in there I didn't see any broken guides but you can't see much of anything beyond the top stuff. I do want to do the water pump while I am there. Hopefully the turbo doesn't make it a pain in the butt. I have a feeling it will be a repeat of the wastegate solenoid ... all by feel. :)

But the water pump can't be any worse that removing a Duramax turbo!

Oldblue

Get a fresh crank shaft bolt while you’re ordering parts .