Franko6 said:
I've seen my share of these engines go through a dropped valve and not touch the cylinder walls. The fact the valve jammed into the seats is better than having it bouncing all over and creating more havoc. If the cylinder bores are ok, it's a cheaper fix by about $1500.
The head is likely trashed. The block may have escaped damage, but the piston will surely be trashed and the rod will be bent. If the cylinder is scored, I ditto what Jason says; be looking for a complete engine.
IF the cylinder escaped damage (not impossible), you can salvage the block with a rod/ piston. I recommend removing the next piston/ rod and make sure of rod weight and length.
Let me know what your cylinder looks like. I've got all the rebuild parts.
Btw: I've seen my share of this type of incident. I'm betting it was an exhaust valve that let go. What happens is the previous owner lost the timing belt, did a compression check and says, "It's ok." Replaces the TB and tensioner and calls it good. The Exhaust valve fractured from that strike and eventually broke off. If the valve didn't shake and bake too much, you'll see a 'clamshell' fracture going across the valve stem where it separated. That is the M.O. of a valve fracture.
Also, if you end up with a junk yard engine, get their return policy. No returns: no deal. Then take the head off. Inspect the cylinders and head. It's about $70 of parts but insurance you've got a decent engine.
__. Yeah, this points to the need for a "hands-on" diagnosis by somebody who really knows what he's doing.
__. Here's what we absolutely know -- There is catastrophic damage in this engine. What we don't know is how much damage is done to the cylinder walls or to the piston/rod(s).
__. If there's no damage to the cylinder walls (and that's *possible* -- although frank and I disagree on *probability*), then it's likely that rebuilding the engine will be cheaper than replacing with a used one.
But until the damage/amount is known, that's a decision that can't be made. Also, OP said that the head is "damaged but usable" -- I would want to see a second opinion by a specialist who really knows these heads;
my guess is that the head is trashed and unusable but the only way to know is to get a solid diagnosis.
__. Frank is also of the opinion that the piston is trashed and the rod bent. I'm going to guess that that's correct. It's not uncommon to see hidden damage on a piston -- sometimes, the crown of the piston is caved in (invisibly), sometimes there are cracks around the wrist pin which cannot be seen when the piston is in the bore, often a hit will "pinch" the edge of the piston down so that the piston ring is trapped. Any of these will mean that the piston must be replaced. Also, you should check "piston protrusion" -- the amount the piston sticks up above the head gasket surface should be in spec and the same across all four surfaces. But even if the piston protrusion appears correct (which will indicate that the rod is bent), then I would still pull the piston and rod on that cylinder to replace them.
Until the exact condition of the piston and rod are known, you won't know how much work needs to be done on the "bottom end of the engine".
__. Newzboys, you
*must* get absolutely a thorough, professional diagnosis of the items in red above. The info on this will make a difference in whether it's more cost-effective to rebuild the engine or get a used/replacement.
__. But, no matter how you go, you have BIG damage to this engine. If you can save any of the parts, you have to consider yourself lucky. But the only way to know is to have absolutely dependable diagnosis on the individual components. But until you have this info, it's all a WAIG. And, regarding the head, you definitely want to send this head to Frank for an inspection and diagnosis.