Thought about asking this in the 5.4 section but there seems to be a lot more traffic in here. I've had a 99 f250 5.4, 2v, for a little over a year, motor would tick/rattle over 3000 rpm and use a fair bit of oil. Had a leaky passenger head gasket. Well i let her go too long between checking the oil and it reminded me by starting to tick at all rpms, and louder than previously (tick speeds up with rpms). No change after topping it back up. A couple days later the constant tick went away, followed a few hours later by a very loud symphony of banging metal. Truck lost power and stalled out, I restarted and managed to get of the highway before it stalled out again, and towed home. same noise in neutral, in gear, clutch in/out.
I assumed i'd jumped time/broken a timing chain/bent or broken a valve... something that should be immediately obvious upon opening it up, but after opening it up, pulling the heads i've seen nothing that indicates a problem, other than evidence of a weak chain tensioner. seems that one timing chain has been happily grinding a 1/8th groove into the oil pump. I would guess that was the rattle i'd been hearing. All the pistons move, up and down, valves open and close and show no sign of hitting the pistons, spark plugs were tight. It'll be a while before i can pull the engine to get the oil pan off, but there were no pieces of anything in the oil when i drained it. Does this sound like rod bearing failure? if not, anyone have an idea of what im missing?

 

I've heard/read of the timing chain tensioners failing and causing ticking and noises. Before I went to far, I would do a leak down test on each cylinder. You may just need a new head gasket for the oil burn and a new timing chain set with tensioners.

There is a great article about mustang mod motors and how to rebuild them with new cams and the differences in the winsor vs romeo heads. It's worth the 10 minutes to read and might give you some insight on your problem.

 

Thanks for the reply ReAX, i'll try to find that article. Have you heard of weak tensioners letting the chain slack off enough to stall it out? I know these are interference motors, but if it happened to jump one cog would that be enough to cause running issues, and noise, yet not cause physical damage to the valves and or pistons?

 

I'd suspect slack from the tensioners failing could cause speed issues with CPS. That's my only real guess as to why yours could run rough with a timing issue and not suffer any damage. I only know what I read on these so far though.