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Discussion Starter · #1 ·
Hx: 2011 Honda Pilot EX-L with 175K miles.
4k miles ago I finished a rebuild of the majority of the engine from head gaskets up (only cleaned up cylinders and oil pan, and associated elements. reseated valves, replaced both camshafts, gaskets, pumps, plugs, etc...
  • drove well for 4 months until a rattling heard in the engine.
  • knowingly a bad decision, I decided to try to get it home... and then the engine stalled and I needed to be towed home.

Opened the engine up and found a loose and crushed tappet nut from the rocker arm valve adjuster nut on the 6th cylinder intake valve. Thought I got lucky and replaced it and put the engine back together.... of course, nothing is that easy.

Fast forward ....took the engine apart down to cylinders in front of the engine. Removed both belts, etc.. Front cylinders 4,5,6 look as they did before, valves and rockers seem fine, rear camshaft turns and feels as it should but I can't get the crankshaft to turn to move the pistons and appears stuck/locked.

Which brings me to my question(s): Is it possible that the episode caused the cylinder head to be pushed down too far and now is locked up? If so, can I fix this without removing the oil pan, exhaust, etc....

If this isn't the case, any ideas?

Thanks for your help!
 

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Hx: 2011 Honda Pilot EX-L with 175K miles.
4k miles ago I finished a rebuild of the majority of the engine from head gaskets up (only cleaned up cylinders and oil pan, and associated elements. reseated valves, replaced both camshafts, gaskets, pumps, plugs, etc...
  • drove well for 4 months until a rattling heard in the engine.
  • knowingly a bad decision, I decided to try to get it home... and then the engine stalled and I needed to be towed home.
Opened the engine up and found a loose and crushed tappet nut from the rocker arm valve adjuster nut on the 6th cylinder intake valve. Thought I got lucky and replaced it and put the engine back together.... of course, nothing is that easy.

Fast forward ....took the engine apart down to cylinders in front of the engine. Removed both belts, etc.. Front cylinders 4,5,6 look as they did before, valves and rockers seem fine, rear camshaft turns and feels as it should but I can't get the crankshaft to turn to move the pistons and appears stuck/locked.

Which brings me to my question(s): Is it possible that the episode caused the cylinder head to be pushed down too far and now is locked up? If so, can I fix this without removing the oil pan, exhaust, etc....

If this isn't the case, any ideas?

Thanks for your help!
Did you get the valve timing off by turning the cam by itself? Perhaps your rear bank pistons are jammed against the valves? You probably should remove the rear head as well as the front, and inspect everything.
 

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Discussion Starter · #3 ·
Did you get the valve timing off by turning the cam by itself? Perhaps your rear bank pistons are jammed against the valves? You probably should remove the rear head as well as the front, and inspect everything.
Thanks for responding. I happen to go ahead and pull the rear head off yesterday and was able to push down 2nd piston with my hand, there was no resistance. Still not able to turn the crankshaft, wondering if one of the piston arms is messed up??
 

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I hate to think of this, but this sounds like you may need to either drop the engine or if you can, drop just the bottom in place and see what the crankshaft, piston rods and connectors all look like. Neither an easy or desirable job to do, but it may give you the answers you seek. I would only do this as the last resort if nothing else works.
 

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Thanks for responding. I happen to go ahead and pull the rear head off yesterday and was able to push down 2nd piston with my hand, there was no resistance. Still not able to turn the crankshaft, wondering if one of the piston arms is messed up??
If the crank won't move, but the pistons do move, that's a bad sign. Your no. 2 piston is no longer connected to the crankshaft. Sounds like major engine damage.
 

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If the crank won't move, but the pistons do move, that's a bad sign. Your no. 2 piston is no longer connected to the crankshaft. Sounds like major engine damage.
I was just going to say.
 

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Discussion Starter · #7 ·
I hate to think of this, but this sounds like you may need to either drop the engine or if you can, drop just the bottom in place and see what the crankshaft, piston rods and connectors all look like. Neither an easy or desirable job to do, but it may give you the answers you seek. I would only do this as the last resort if nothing else works.
Thanks for responding. Yes that does not sound fun:(. I am presently trying to get a look by removing the exhaust and oil pan, which is a super pain as the bolts on the exhaust are quite rusted. Do you think it is worth a peek in through the oil plug hole to use a camera scope? I have a cheap one, that some times is helpful.
 

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Thanks for responding. Yes that does not sound fun:(. I am presently trying to get a look by removing the exhaust and oil pan, which is a super pain as the bolts on the exhaust are quite rusted. Do you think it is worth a peek in through the oil plug hole to use a camera scope? I have a cheap one, that some times is helpful.
If you were able to push cylinder 5 piston down but you can not rotate the crankshaft, that is an indication of a broken pistion rod. This kind of thing happens when water/coolant gets into the engine and eventually it seizes up. Does you motor oil look normal?
 

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Discussion Starter · #9 ·
Nail grease, thanks for your comments. To answer your question: Cylinder 5 was already down when I pulled the front head. Cylinder 2 was able to be pushed down when I pulled the back. Cylinders 3 & 6 are down and 1 and 4 are up. crankshaft won't turn.
You are right I have noticed some indications of oil and coolant mixing, and I did most of the engine work in dead of MN winter so maybe some things were off?? How do you suggest I proceed? I really need to save this beast as I promised my wife I could. I ordered replacement head bolts and a gasket set thus far. thanks for your help.
 

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Nail grease, thanks for your comments. To answer your question: Cylinder 5 was already down when I pulled the front head. Cylinder 2 was able to be pushed down when I pulled the back. Cylinders 3 & 6 are down and 1 and 4 are up. crankshaft won't turn.
You are right I have noticed some indications of oil and coolant mixing, and I did most of the engine work in dead of MN winter so maybe some things were off?? How do you suggest I proceed? I really need to save this beast as I promised my wife I could. I ordered replacement head bolts and a gasket set thus far. thanks for your help.
My opinion would be to get a used engine. Preferably one I could check out first. You are definitely at a crossroad. Is the vehicles condition worth buying an engine for? Especially if your having it done at a repair shop.
 
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Thanks for responding. Yes that does not sound fun:(. I am presently trying to get a look by removing the exhaust and oil pan, which is a super pain as the bolts on the exhaust are quite rusted. Do you think it is worth a peek in through the oil plug hole to use a camera scope? I have a cheap one, that some times is helpful.
I'm not sure what you will or will not be able to see. Never dropped the bottom of a Honda motor, nor do I ever intend to, God willing and creek don't rise. Theoretically you should be able to get a good look. Nail Grease may well have and could possibly give you an idea. I'm old school, ie; engine out, on motor stand. Which I no longer own, nor does the current garage have an I beam running across it with a beam trolly and hand chain hoist.

You can try the scope I suppose, but be very careful. A piece of camera left in the block is not going to the situation. The horoscopes I have seen that mechanics use have a narrow well covered and attached camera end. Not sure how sturdy the scope you are talking about might be.
 
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