I thought I would share one of the things I've been to in the last few months. I have a 2007 Avalanche that I purchased new. It now has 209,000 miles on it. I'm sure that some of you know that the Active Fuel Management can be a real problem on these engines. I'm a dedicated oil changer on my engines and I never had a problem until the truck reached 200,000 miles. Original everything in the drive train. So with my engine running great at that mileage one day and then...........BAM, a new noise. A knock that the dealer said was a rod bearing out. I did not believe that because the oil pressure never dropped and I had taken excellent care of the engine. I used a mechanics stethoscope and found the noise to be greatest when I placed the probe on the exhaust manifold at the head between cylinder #1 and #3. So I thought it was possibly a lifter, but the engine was still running smooth, just with a new knock.
Anyway, one of the bad things that happen to these engines is the induction of a lot of oil into the intake manifold via the crankcase ventilation from the drivers side valve cover. GM even brought out a redesigned cover which helped some. There's a lot more to it but too much to address here. There are two different types of lifters in these engines with four of the eight cylinders using a special lifter that are really a lifter in a lifter. When the computer calls for 4 of the cylinders to shut down the special lifters deactivate the valves for those cylinders. All done hydraulically via solenoid valves in the valley cover.
Some folks were using quarts of oil in under 1,000 miles. Mine was not using that much but was using more than it should. So the fix is to eliminate the Active Fuel Management by taking out the special lifters and replacing them with standard stock lifters. That also meant changing out the valley cover and turning off the AFM in the computer.
So with my new knock and the desire to eliminate the AFM I decided to remove the engine and rebuild it. This is not something I wanted to do as I'm 75 years old now and I really thought I was done doing these types of things, but I didn't want to spend 5 or 6 thousand dollars at a dealer and not know everything they had done incorrectly. This all cost me around $3,000 to do it myself, but it also costs me 3 weeks without my truck. One week removal, one week at the machine shop, and one week back together.
So here is what was causing the knock. #3 piston skirt broke. All of the pieces were in the bottom of the oil pan.
Here's a removal progress shot.
Heads off. Now I can get to those miserable bell housing bolts.
Engine coming out. That load leveler was a PITA and not worth the money. The reason is the engine sits back far enough under the cowl which makes it difficult to use it effectively because of lack of room over the engine.
Short block back from the machine shop. I had them assemble the short block for me. They bored the cylinders, replaced all bearings, new pistons, reground and polished the crank. I installed a new cam from Cam Motion. It's a little more cam than stock and the grind is meant for trucks. The new cam meant that I had to get my truck tuned in order to take advantage of the increase in power.
Assembly progress shot. The new timing gear and chain installed. See that orange engine stand in the background? That's one I made back in the 60's and of course it wouldn't work so I had to buy a new one from O'Reillys. Hopefully, I'll never need to use it again.
Progress shot. New oil pump installed.
Progress shot. Windage tray and pickup tube installed.
Progress shot. Front cover installed with new oi seal. I made an alignment tool on my lathe to make sure the seal was centered correctly on the crank nose.
Motor mounts and A/C compressor mount installed.
Reworked heads ready to be installed. I replaced the valve springs with some that were recommended for the cam change.
Engine back in the truck and the heads installed. Believe me, at this point, I had been under the truck and in the engine by A LOT of times! But I'm getting back in shape with all of the moving around.
Intake manifold installed. At last!
Here is a oil precharge tool that I made from PVC pipe. These engines are not like the older engines that you precharge using a drill and a shaft to drive the pan mounted oil pump. I tried my best to get the new pump to suck the oil up and charge the oil galleries but it just wouldn't do it. I filled this PVC tube with 5 quarts of oil and used about 20lbs air pressure to fill the galleries. It worked great.
This is a broken head bolt!!!! GM uses "Torque to Yield" bolts in a lot of places now and they SUCK! I chose to put the heads on after the short block was installed because it's a lot easier to get to those bell housing bolts as mentioned before. That meant that the cheap angle (degrees) meter that you can use to measure the amount of twist you put on the head bolts would be a bear to use when at the rear of the heads. I chose to purchase a new electronic torque/angle wrench to tighten the bolts. I thought that would be easy.................wrong! While tightening the bolts I could literally feel them stretching. Not a very comfortable feeling knowing from past experience that breakage is sure to come at some point. Well, I made it to the next to last head bolt and one broke. Luckily it was at the front of the passenger side head. Believe me there was a lot of interesting words being spoken and rather loudly too! I called the machine shop and asked the man about removing the bolt and he gave me an excellent tip. He told me to use a carbide burr with an oval tip so I could center the bit and create a crater in the end of the broken bolt which was down about 3/4" below the surface of the block. That made a place where the drill could center its self. I tried a left hand drill bit but it wouldn't grab and turn out the broken bolt because the bolt had loctite on the threads and it was pretty tight in the hole. I drilled far enough to be able to use an easy out type removal tool and I finally did get the bolt out. But I did decide to remove both heads and purchase a set of ARP head bolts that just torque in like any ordinary bolt. Much easier.
So it's all done now and running great. It did take three trips back to the tuner to get the PCM (power control module) tweaked to my liking.