My buddy's 2010 Equinox (115,000 miles, just out of warranty) with the 2.4L Ecotec had a bit of grit in the balance shaft chain tensioner, and this caused the chain to slap/break, so he lost the water pump. The lack of cooling caused a blown head gasket, melted pistons, and some scoring in the cylinder walls. The block is already ripped out and disassembled, currently waiting at the machine shop for us to find out what size pistons we can get that are at around .030" over stock so he can bore the cylinders. That being the problem, we cannot find any pistons over stock (3.430" i believe). I am hoping that someone has bored their block and knows where to find new oversize pistons/rings for this aluminum money pit?

 

Welcome to the forum. The Ecotecs I know have cast aluminum blocks with pressed-in iron sleeves for the cylinder bore. What you're trying to do is not recommended. The repair of the cylinder wall consists of pulling the damaged sleeve, pressing in a replacement, and then trimming the top of the sleeve to deck zero. Special tools are required.

 

Well the dealership service department said they would take it to the machine shop and do exactly what I am doing, except there are no pistons so they would have them fabricated. GM powertrain and performance parts both say that the service info says the sleeves are replaceable, but the parts info says to replace the block. The performance parts rep found a reference to overboring the cylinder, but no pistons are available. See how clear this information is? This is why I love my Dakota with a Magnum 5.2 V8 that was used to to tow the equinox through 3 mountain ranges and over 800 miles. A cast iron block made in 1992 with 245,000 miles and no damage to pistons/block/cylinder walls/head with only basic service the whole way. Just trying to help a friend get his 2010 vic running again. There has got to be a piston that will match the rod/crank in this vic that is available in 88.25-89mm. . .

 

The inconsistencies are obviously due to this version of the 2.4L Ecotec being so new. The main catch I see, aside from weakening the bore on the SIDI 2.4L that has the compression ratio of 11.4:1, is how to modify the ECM to account for the significant engineering change. It sounds like they're willing to experiment, though, and you've made up your mind. Hope it turns out okay.

 

GM extended warranty to 10 years or 120,000 miles for 'chrome layer on balance chain pins may wear... chain to break, leading to engine damage...fuel pump plunger shaft seal may wear... fuel to leak into crankcase..."

Yeah, correctimongo, no real effort to alert most owners of this defective product...
... all their time arguing 'ignition switch' coverups???