2012 Equinox 2.4L engine rebuild, looking for insight from experienced engine builders

[jfbrubaker1969]

I have a 2012 Equinox with 170,000 miles on an oil burning 2.4L Ecotec engine. My daughter was not good about checking the oil and the timing chain skipped enough teeth that I have 13 broken rocker arms and 13 corresponding bent valves.

My plan right now is to do a significant overhaul on the engine, keeping the block in the vehicle. Rebuild the head with new valves, new rockers and hydraulic lifters. Replace the pistons and rings (and maybe connecting rod bearings) to hopefully resolve the oil burning problem. I'm considering doing the EGR oil separator mod as well. New timing chain set, new phasors and VVT solenoids, new oil pump. Water pump was replaced about 2-1/2 years ago.

I pulled the head today and removed the cam shafts. Most of the camshaft bearings look fine, but two of the bearings did have a single scratch that I can just barely catch with a fingernail. I did a quick inspection of the cylinders and did not see any sign of damage or scarring, but after 170,000 miles, there's no trace of cross hatching on the cylinder walls.

So my questions for the experienced builders are: How much wear is acceptable for things like the camshaft bearings, connecting rod bearings and cylinder walls? What other things do I need to pay attention to that could cause issues (especially with keeping the block in the vehicle)?

My plan is to post a bunch of pictures showing the current wear of the items I am concerned about.

Thanks for taking the time to read my post and for any helpful pointers.

 

[jfbrubaker1969]

Now for the picture dump. I'm going to break the images up in separate posts to keep them organized by component. This first group is the cam shaft bearings.

Exhaust bearings



Intake bearings

 

[jfbrubaker1969]

Here are shots of each combustion chamber. You can see how bad the carbon build up is, it's also very apparent how badly the valves got bent.

Cylinder 1


Cylinder 2


Cylinder 3


Cylinder 4

 

[jfbrubaker1969]

Here's the exhaust cam. I took pictures of each group of lobes/journal and then rotated the cam 180 degrees and took another set of pictures.

Cylinder 4 lobes/journal


Cylinder 4 lobes/journal - rotated


Cylinder 3 lobes/journal


Cylinder 3 lobes/journal - rotated


Cylinder 2 lobes/journal


Cylinder 2 lobes/journal - rotated


Cylinder 1 lobes/journal


Cylinder 1 lobes/journal - rotated

 

[jfbrubaker1969]

Here's the intake cam. I took pictures of each group of lobes/journal and then rotated the cam 180 degrees and took another set of pictures.

High pressure fuel pump lobes and journal


Cylinder 4 lobes/journal


Cylinder 4 lobes/journal - rotated


Cylinder 3 lobes/journal


Cylinder 3 lobes/journal - rotated


Cylinder 2 lobes/journal


Cylinder 2 lobes/journal - rotated


Cylinder 1 lobes/journal


Cylinder 1 lobes/journal - rotated


VVT journal

 

[jfbrubaker1969]

Here's the cylinder head intake cam journals.

 

[jfbrubaker1969]

And the cylinder head exhaust cam journals.

 

[jfbrubaker1969]

Three valves are straight, can you guess which ones?

 

[mikem691]

This is awesome that you are documenting this here. I will be following. One question. In the opening post you have the milage at 270,000 and 170,000, which is correct?

 

[jfbrubaker1969]

This is awesome that you are documenting this here. I will be following. One question. In the opening post you have the milage at 270,000 and 170,000, which is correct?

170,000 is correct, I fixed the typo in the first post.

 

[jfbrubaker1969]

After I stripped everything out of the cylinder head, I mixed up Simple Green HD Pro cleaner (which is safe for metals) and hot water in about a 1:5 ratio. With the container I have, it could only cover about 2/3 of the cylinder head, so I soaked the bottom side for about 6 hours and then flipped it over and let the top side soak overnight. I am super impressed with this cleaner and will be using it exclusively to clean engine parts from now on! I pulled the cylinder head out of it's bath and put the cam shafts in for a soak.

I spent about 3 hours with various brass bristle brushes and my pressure washer on some of the spots that required additional cleaning. For those that don't know, brass is softer than aluminum, so it won't scratch the aluminum, this is very important on mating surfaces!!!

I was very surprised at the amount of carbon build up in the intake ports, it was so thick in some spots I had to use a screwdriver to scrape it off! Since the 2.4 is a direct injection engine, I was expecting this, but after researching it online, it appears to be a common issue with the 2.4 Ecotec.

After I finished, I used my air compressor to blow off as much water as possible and let it sit in the sun for a few hours. I made a careful inspection of the valve seats and they all look to be in great shape. With the cylinder head done, I pulled the camshafts out from their bath and cleaned them up with the brass brushes as well. While the cylinder head and cam shafts don't look brand new, they do look pretty damn good!

Before and after:




Here's a shot of the valve seats. My eyes aren't as good as they used to be, so it's helpful to have a high res pic to zoom in for a close inspection.


And finally the camshaft. There are two oil seals on the front of the camshafts that are important for the VVT (Variable Valve Timing). While the seals that are currently on the camshafts look to be in good shape, I figure it would be stupid not to replace them at this point.


I have the valve springs soaking in the cleaner and I'll be soaking the camshaft bearings overnight as soon as I go to the store and pick up some plastic cups so that I can soak them individually to keep them from getting mixed up.

 

[pipwax]

Very interesting work!

 

[jfbrubaker1969]

So over the weekend I finished cleaning the head, concentrating on removing the remaining built up carbon in the intake ports. I lapped all of the valves and got them installed, installed the new hydraulic lifters, rocker arms, cams and the VVT cam sprockets. So at this point the head is ready to reinstall.

Today I dropped the oil pan and removed the pistons. I gave the cylinders a wipe down and with my flashlight at the right angle, I was able to see there is still some cross hatching on the cylinder walls. I'm still going to measure the bore, but I'm feeling pretty good that I won't have to pull the block and get the cylinders bored oversize. I also inspected the connecting rod bearings and journals and didn't see any sign of scoring, that's a big win in my book!

I'll see if I can get some pics posted later tonight.

 

[jfbrubaker1969]

Here are the latest pics.

Cam bearings all cleaned up



A close-up pic of the valve seats I took after lapping to make sure they looked good. All the valve seats looked perfect (zero pitting) and good contact area between the seats and the valves.


Valves stem seals, valves, valve springs, keepers and hydraulic lifters installed.


Rocker arms, cams and VVT sprockets installed and torqued to spec.


I soaked the ends of the spark plugs in some cleaner and lightly scrubbed them with a brass bristle brush, they cleaned up really well. I was hoping they would since they are less than 3 years old.

 

[cavell]

So, you paid “retail” for equinox. And don’t want to buy a new $4000 motor to fix it? I found a 2015 w/98k miles for $1k. Seems to me it’s almost not worth putting in a new motor?