Cam shaft snapped in half

I have a 2005 Sunfire with a 2.2L Ecotech. On the freeway my cruise control shut off and the car started making a tick or knock. I parked it and left it until I could look at it. Turns out the cam shaft had snapped in half. The part of the camshaft by the #4 cylinder was really dry and what seems to have happened was that some sort of oil clog occurred, part of the camshaft dried up, seized and snapped. The engine didn’t appear to be maintained very well by the previous owner. A friend and I checked the compression on #3 and #4 and they both were ~120 pounds. So now I am left with the decision to get a new engine or a new cylinder head. The new cylinder head is obviously cheaper (about $500 to $600 cheaper) but I’m worried it will not solve the problem that caused it in the first place, meaning the cam shaft not being properly lubricated. But since compression seems good and oil is now squirting every which way, should that not be a problem anymore? I am less of a mechanic than my friend so I don’t know what to do. I welcome any advice.

When the camshaft snapped, did it do any damage? I’d expect that portion of the valvetrain to stop working, but unless something awful happened I wouldn;t expect it to damage the head.

So, that leaves you with the possibility of cleaning up the head and just replacing the camshaft and its split bearings.

If there was lubrication failure, then the “dry” cam journal would have galled the machined surface in the head that the cam rides on…It would have made an obvious mess of the aluminum head and itself…if you have removed the damaged cam, the damage to the head should be obvious…It sounds like oil flow was somehow lost to just one cam journal…It’s oil passage became plugged up somehow…Obtain a lubrication diagram for this engine and trace the oil passages to find where the problem is…Find out how each cam journal is fed with oil…

120 pounds seems really low. It should probably be closer to 180. You’re probably better off replacing this engine with a different one since you said it’s evident this one was not well maintained, has suffered an apparent lubrication failure, and is not giving very promising compression numbers.

What is the price for a new engine? What is the price for a new head? But if the car is in good condition otherwise and has over 100,000 miles a good used engine is usually a good option.

I would just fix what is broken…

You should run compression tests on cylinders not affected by the broken camshaft. A 120 PSI sucks and it sounds like the problem was caused by a clogged oil galley.

I can’t help but wonder if the previous owner who you say did not maintain the engine properly, used synthetic oil and changed it on time. Synthetic oil per GM 6094M is specified for my 09 Chevrolet, also with a 2.2 Ecotech engine; possibly yours too. It’s easy to believe that someone would ignore that.

to clear up a few points, the one journal by the dry spot was galled just a bit. and im pretty sure compression was 120 unless i remembered wrong but we did test compression on the cylinder that was affected and on another one that was unaffected and they were the same. i can get a replacement head for $150 or a new engine for $750. im just trying to gauge the cost vs risk ratio. im leaning towards fixing it and keeping an eye on the glog situation to see if if manifests itself again. i do have a question though. when we tested compression on the “dry” cylinder and saw oil flow, does that suggest that the supposed glog is gone? i may even just wind up fixing it with a new head and selling it. my wife and i bought it in an emergency situation and have since then gotten an additional vehicle.

There is no way on Earth I would put a reman cylinder head on this engine based simply on the compression figures and eliminating any ol galley clog from the equation. The 120 PSI sucks, pure and simple. Odds are if a wet compression test was performed you would see those numbers rise and that means a piston ring problem. A wet test should have been performed at the same time as the dry test.

I also don’t see a reman head followed by trying to sell the car as being cost effective; and that’s assuming this lack of oil problem doesn’t rear its ugly head a few minutes after the engine is started and take out what has just been done. Just my opinion and good luck in your decision.

Chances are the cylinder head is designed in a way that the oil is supplied to the cylinder head close to the camshaft gears, and lubrication to the camshaft journals to the opposite end of the cylinder head is provided through the hollow camshafts themselves.

Chances are one of the camshafts had an internal clog due to poor maintenance, which then prevented the camshaft journals past the clog point to receive any oil lubrication under pressure. Any splash lubrication provided by the other camshaft lobes is not going to get between the journals and the journal caps, hence why it seized.

I would need to see the cylinder head to make a determination if the shrapnel from the cam damage might have gotten down into the oil pan, and possibly into the oil pump. A good cleaning of the oil pan and the oil pump screen, plus a new oil filter is a must if only the cylinder head is going to be replaced.

I would highly recommend an early oil filter and oil replacement within the first 250 miles after cylinder head replacement at the very least if you decide to replace just the head and camshafts.

Its not the best choice of repairs, but you’ve been running on low compression before the damage, and didn’t have any complaints. If economics mean that the lower cost option is the better one for you, you are better off doing so. Just make sure you do an oil and filter change at the 250 mile mark to get any small shrapnel out of the engine after the work is performed.