Also, side note: DAMN those valve springs. I bought 4 different kind of spring compressors, and unfortunately the old "screw down" variety is the only kind that works. Removing the springs -- whether the heads are on or off the engine -- is just a beast of a job.

 

Curious how a valve stem ends up in the intake with no damage to the cylinder. This engine must have been abused to hell and back. There is a vid on YT where a farmer ran one 50K miles with no oil changes. A local Ford dealer told me you wouldn't believe the abuse some of the 6.2L get. Some survive to very high mileage. He said in his opinion no other motor would last that long with that abuse. He told me one was run 24/7 for years, used offroad. Not much of an oil change history.
There is a reason they are still selling it as a base engine on 2023's. Some fleets demand it, or will go elsewhere.

Probably a good idea to seafom every so often.

Also, removing cats on a modern engine is not a good idea. To get their mileage, power, and emission targets out of such a huge engine, they are using everything they could.
They provide backpressure and everything is designed to work as a system. The rear o2 sensors also may factor into a strategy to control the engine ( to a small degree), beyond just a check for cats. Without them there could be guesstimation and weird issues. Who really knows.
Weak fuel pump could have been a factor too, but by the time that would happen someone would have to have driven the truck many miles with almost no power. There is lots of compensation built in.

 

 

Awesome thread!

 

thanks. Truck has been a major PITA but I’m willing to suspend judgment on the 6.2 and just believe I got sold a heavily abused lemon. Hopefully when I put it all back together it’ll run strong for at least another 100k miles. Otherwise I’ma drive it off a cliff!

 

Side note (lost my post text) -- according to the machine shop I had five separate bent valves. Bent as in, the valve cutter couldn't even turn them properly. Weird because on visual inspection they looked fine, but according to the machinist, even a small deflection can cause serious performance issues at speed (which is, of course, exactly what was happening). Those valves are replaced, the heads are like new (again: cannot recommend JB's Aussie Machine in Burien, WA highly enough! Great work, fair prices), the block deck and front cover mating surfaces are prepped, and I hope to get started on the reassembly this weekend.

 

I wonder if the long springs are the achilles heel on this motor. I know one rebuilder uses shorter springs with a hat. That motor was likely abused. Ford told me for some reason those 6.2L are pushed to the absolute limit. They said they know of one that ran 24/7, was also used as a generator offroad, aside from pulling way over its paygrade all day.

 

Well I got the heads back in. Need to reset the timing and put everything back together!

 

Well I got all the timing gear in. Now… front cover, intake manifold, accessories, flush and fill coolant, refill oil… hehe… long way to go!

Got rags in the intake ports. Rainy PNW isn’t always friendly to open engine cavities…

 

Looking forward to more updates, I have same codes and issues but mine issue only occurs when engine gets hot and pulling trailer under load on incline… makes no sense.. issue started after wiring issue from a a/c repair that shop said was a PCM failure was actually a ground issue to pcm.

 

Well I think my truck was a bit of an exception. By far the biggest non-trivial cause of multiple misfires on the 6.2’s is the valve springs, which are definitely the Achilles heel of the 6.2 modular. I’d start there (after ruling out, you know, plugs and coils and wires…)

 

Complete tuneup was performed with intake cleaning, made a huge difference in fuel mileage but odd thing is I have same year same mileage.. just coincidental…

 

Mostly just need to put in the intake manifold, crank pulley, and accessory drive stuff.


Still got the intake ports blocked until manifold is in.

 

How did your engine reassembly go for you? Very good thread!

 

Sorry for not following up. Truck purrs now. For a beat-to-hell service truck with >175k miles on it, it runs like new. Still looks like crap, though -- lol.

There IS a coolant leak from somewhere I need to track down, it's a slow leak. But the truck isn't overheating, and there's no problems with performance or oil/coolant mix, so I'm 100% confident it's not something serious like a block issue or a leaky head gasket.

My current struggle is a lot simpler (although in summer heat, not fun either): replacing the missing tailgate. I have an aftermarket replacement that bolted in, but getting the hinges aligned has caused me to shed blood, sweat, tears, and spilt beer...