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I’m at 308,000 miles. Original engine.

I did have to do the headgaskets at about 250k, so I had the heads done professionally and did the timing and oil pump myself.

These engines aren’t nearly as fragile as people claim. Literally any aluminum head can drop a steel seat. The 5.7’s can do it, Chevy LS engines can do it. ANY engine can do it.
 

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Wow a whole 100k!
Quite the low mileage find.

I’m at 308,000 miles. Original engine.

I did have to do the headgaskets at about 250k, so I had the heads done professionally and did the timing and oil pump myself.

These engines aren’t nearly as fragile as people claim. Literally any aluminum head can drop a steel seat. The 5.7’s can do it, Chevy LS engines can do it. ANY engine can do it.
My machinist said there's nothing wrong with the engine to half a million miles if you can swap out the intake seats for ones with proper (ever so slightly tighter) tolerances and don't overheat it.

Did your head gaskets melt from the inside out like mine did? Nobody ever changed the coolant and it gets acidic over time. Used to see it on GM intake manifolds a lot in the late 00s.

Mine had the OEM 23 year old water pump when I pulled it apart (and a brand new radiator, and the wrong coolant).

What happens is people don't do it, and then ***** about the engine being made of glass because they broke in some horrifical way at 160Kish.

If you are mindful and do all the PM's they potentially go a lot longer. But, it's a big job and unless you were around a lot of Mercs it seems insane to take an engine apart like that for maintenance. It's not but it seem like it is.
 

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the 287 is a push rod iron amc though? and the 4.7 is Over head cam. dont see any real way to compare. From that we go to dual over head cam. More complexity with more issues. single cam v8s were very simple. Iron heads that did not drop a seat after a hot lap..... but over heat most anything is asking for trouble.

I read somewhere that the 3.6 was another Merc design too. That they dropped and Fiat brought in back 2011ish. That is a issue as well with rollers wearing out taking out a dual head is expensive. I believe much of the issues in that is the the way those heads have NO exhaust manifold but a single port. inside the casting manifold that traps heat inside the head more then say 1 port for cylinder head as has been like forever. or an oil issue or just bad parts..pick one.. maybe all the above..
 

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the 287 is a push rod iron amc though?
True, but only of the AMC 287 that was in production. The 287 that we know as the 4.7 PowerTech was never produced when AMC was still alive. It was still just on paper when Chrysler bought them....
 
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