4.6l 'Locked Engine' any experience?

[Number4]

I'm looking at a 2003 Explorer Limited that has the 4.6l with 146,000 miles. Owner says it's got a locked engine. Not sure what he's calling locked up.

I may be picking it up for $1,000 depending on its overall condition. I've yet to see it.

Anyone here deal with a 4.6 that is locked up? Or know of one.
I'm hoping he's mistaken as I want to salvage and sell the engine to recoup most of the $1k.

I know the timing can go, if the timing did fail catastrophically, how rebuildable is the engine?

 

[Duranged84]

When you get it, try to turn the crankshaft by hand, if it doesnt budge, try to turn it backwards (can free it up sometimes if a rod has broke or bent and locked it in the position it normally rotates while running. If it wont turn either direction, its probably better off as a parts engine, pretty much intake, accessories, bolt on stuff. If it only turns backwards it may still be just a parts engine. Will need a tear down to find out.

 

[boominXplorer]

I just had a customer with a locked up 02 4.6 and I brought it back to life. It had been ran row on oil and locked up the passenger camshaft. It then broke the key on the timing sprocket and went about 120 degrees out of time. Doing so it bent 3 valves and broke one completely and wedged it into the top of #4 piston.

When I got it the crank would move about 10 degrees if that. Once I pulled the head off it would the rotate all the way around. I replaced the #4 rod/piston, right cylinder head, timing chains and all connecting rod bearings (just because). I was able to repair the engine inside the truck. The truck now has about 1500mi on it and still runs great, nice and quiet.

The reason I went that route is because explorer 4.6s are EXPENSIVE. They have a desired aluminum block that is year 02-05 explorer only. I could not find a good used engine under $1500 and ended up charging $1700 out the door for all the work I did. The02+ iron block 4.6 and aluminum block 4.6 share the same heads and internals.

 

[Number4]

Thanks for the info guys, I was supposed to meet up with the seller but he's stopped responding. We'll see what happens.

If I get it, I'll be removing the engine anyway, so some basic inspections should let me know the damage it looks like. Parts engine if anything.

 

[Duranged84]

BoominXplorer, Good info, I'll have to keep that in mind. Think a person could get that lucky with a DOHC 4.6? Have my eye on one myself thats also locked up, If I could save the motor it would make the deal even better. Ready to build an Aviator...

 

[Number4]

Saw the explore yesterday, it's at a repair shop. Overall the vehicle itself is in pretty decent shape it's been sitting since before the pollen came from the pines, maybe longer.

The shop guy tells me it's got a bad transmission along with the engine. I'm not quite sure how the shop guy knows that it's got a bad transmission if the engines already bad.

Almost seems like the shop is scamming or something.

 

[boominXplorer]

BoominXplorer, Good info, I'll have to keep that in mind. Think a person could get that lucky with a DOHC 4.6? Have my eye on one myself thats also locked up, If I could save the motor it would make the deal even better. Ready to build an Aviator...

The DOHC engine is a beast all of its own. It is much more expensive to work on. It is found in only 02-05 aviator, mach 1 and marauder. It has a very similar issue with the drivers side head. I bought one once that barely ran and come to find out the drivers head had locked up and it was running off the passenger bank only! Just a good 03+ drivers side head with newer part number used goes for $400. If you search you can find my old for sale thread on here with pics where I was trying to sell the aviator as-is.

 

[Duranged84]

I like a good challenge lol, $400 for a head sounds better than $2500+ for a used motor. I can't ever seem to find a deal on an aviator when I have the money. Lost one a couple weeks ago that just had a top end knock. 140k miles, white with grey interior, sunroof, everything but rear entertainment. Exactly what I wanted. $1500 but had just paid bills and couldn't swing it. It went quick.