Once I remove the head I will see the top of the piston, but how will I be able to see damage to the piston rod at that point? Don't I need to remove that from the bottom side to see if it is damaged?

 

Remove the head and see what the top of the piston looks like. The piston more the likely will be smashed. See if there is damage to the cly walls, your best bet is to remove the engine. It's not bad to do, if you don't have a hoist it will come out the top. You already have the timing cover off so it clear, I did check on the front pipe and will need to be replaced if you go with the 4.6. The wreckers should give you a deal on everything. I am going with the 5.4 getting through ASR rebuilders. They are based in the States so you should get a better deal then me. I was quoted 4,000.00 Canadian. Rock auto is cheaper but don't know who is the rebuilder. I think it was around 2,700.00 complete with phasers and chains. If you need any more help just let me know.

 

Having a heck of a time getting the exhaust manifold off. I see from others this is a common problem. Even the bolts clamping the pipe end are too tight. Already rounded the first of two nuts.

My questions is, if I can get the pipe off, will the exhaust manifold come off with the head? Is that the easier way to remove them both? Otherwise I've got to get the 8 manifold nuts off the studs.

 

The manifold will come out with the head. It's tight and will be heavy but it will come out.

 

Great. Now to get the pipe off. One nut is rounded but I think I can cut that one. The harder to reach side is being very difficult.

 

Try heating the nut with a torch most of the time that will help break them loose, just don't burn anything.

 

Ha, right. I will jack it up some to get more room then try with my oxy/acet. Hopefully this is a quick heat and more focused than the mapp gas. And will have a chance of reaching up there.

 

Finally got the head off. Took it out with the exhaust manifold attached. Here are pics of the undrside and the piston. Piston is at tdc so I have not yet looked at the cylinder wall. I need to sort out the timing chain before I rotate it. I want to avoid timing this thing if possible since I disassembled it in a random position. The valve pieces are jammed into the valve openings. What do you think?

 

Looks like the head is done! That engine has been running real rich, even looks like it's been burning oil. Are you going for rebuild or used? Just watch your core charge they may charge back because of head damage!

 

I have not been burning any significant amount of oil. The engine was actually running almost perfectly up until this happened. I'm going to investigate if this head can be machined and repaired. If the cylinder looks good I think I should repair it. Looking for opinions here.

 

Here is what I would do: Go ahead and take the other chain off and pull out the cam to make sure all of the valves are closed. Just loosen all of the cam cap bolts a few turns at a time until you can remove the caps. Do not mix up or rotate the caps, they are machined to the head and cannot be mixed. Now you can rotate the crank without worrying about the other valves hitting. Get a feeler gauge and a straight edge and measure from the top of the damaged piston to the deck surface. Then rotate the engine until the next piston is at TDC and do the same. If the measurements are the same then the rod is not bent. Pull the oil pan and the damaged piston to inspect the cylinder for any scoring. I think the cylinder will be ok because all of the damage to the piston is in the middle of it. Replace the piston and the head and you should be good to go. Also I would replace the phasers, tensioners, and guides while its apart. The wrist pin is full floating so you don't need to have the rod pressed off the piston. While the other cam is out remove each roller rocker and check the bearing for the roller. Any slop in the bearing gets a new rocker. Maybe a good machine shop can repair your head but I think it's done.

 

70f, thank you for the advice. I have one question... Why do I need to worry about the valves on the other side hitting anything? If I am turning the engine with the timing chain in place, aren't they still in time? The driver side is so far unaffected, right?

Another question I have is what may have caused the failure. Are both these cam lobes getting oil from the same source? I realize the second one may have been caused by mechanical interference from the loose pieces from the first failure, but maybe not? I was wondering if they are both getting oiled from the same source and it was somehow blocked then that may have caused them to fail?

 

I just suggested that so you won't accidentally get one cam 180 degrees out from the other and so you can check the other side's roller rockers. You will prob find a few rockers with loose bearings. The cam lobes fail because the rollers lock up and drag on them. They get oil from the hole in the tip of the lash adjuster and matching hole in the rocker. If the chain tensioner seal is leaking then that reduces the amount of oil that flows through the lash adjusters.

 

I will have the head looked at for repair tomorrow. Now about that piston, I was thinking I was good to go as is. But I see the wisdom in replacing it. I don't know how the roller rockers come apart. I guess it will be clear when I remove the bad cam.

Thanks guys, keep,,it coming. I'm in way over my head.

 

I would not run that piston. It could have small cracks in it or be distorted a little. The bearing for the roller fails then the roller seizes and drags on the cam lobe. It's just a small needle bearing carrying the load of the valvespring for thousands of miles. The roller for a 3v is prob 1/2 to 2/3 the size of a 2v engine. The smaller roller means it has to spin faster for the same RPM vs a 2v engine.