pinging/valve rattle on new engine

[Purdue72]

Well, I guess I jumped the gun and said it was fixed. With 40 miles on a remanufactured engine I'm getting the same thing we all experience with 60k+. Some call it pinging, I call it Valve train rattle. Any rate it sounds like a handful of bb's in the valve cover(s). I can only assume I'm running lean because of the KKM. It took about 35 miles to trip a CEL, I'll have to check codes when I get home.

Any suggestions out there? Ithink I exhausted SteveVB and Billy77 already.

 

[MrShorty]

Pinging aka spark knock aka predetonation has a different source than valve train rattle, and both noises are fairly common to the 4.0 OHV. First thing to do is determine which noise it is.

 

[Purdue72]

Yes, but is is common on a remanufactured longblock with less than 50 miles?
How would you determine which one it is? and I'm not being a smart-ass.

On my first real drive today coming to work, I was on I-75. Traveling at 70mph holding @2000 rpms, I then attempted to reach say 75mph to pass a semi so the guy behind me could pass me and I thought it was going to blow-up. Like I said, it sounded as if a handfull of bb's were just dumped into my valve cover(s) and they were bouncing all over the place.

I doubt my intakes are leaking, I torqued them to spec.
I shouldn't have any crud on my valves.
I cleaned my IAC already
I did the "reset" procedure when I installed my KKM

I can only assume that either the MAF needs to be cleaned (will do anyways)
or That the KKM is causing it for some reason.

I'm at a loss.........

 

[MrShorty]

Under those conditions, I'd bet it's spark knock.
Dirty MAF is certainly a common culprit in causing Spark knock.
You've tightened the lower intake manifold, and they should have used a new gasket when assembling the new motor, so that should be good.
That few of miles, it shouldn't be carbon buildup in the cylinders.
Definitely clean the MAF, and be sure to carefully check everything for any vacuum leaks or any leaks downstream of the MAF.
If that doesn't do it, then consider these uncommon causes of pinging in this engine that I've heard of: Bad ECT sensor (leans mixture out if it indicates a false high temperature), dirty/bad fuel injectors (fuel doesn't get into cylinder causing it to run lean). An O2 sensor that gives a false "rich" signal and causes the engine to run too lean. A leaky AT vacuum modulator has also contributed to ping.

 

[Purdue72]

Thanks MrShorty,
I'll give it all a shot.
What puzzles me is that all I did was a longblock swap and this spark knock/ ping / whatever wasn't even half this bad with the old motor.

 

[Purdue72]

Update, for the interested.

Took the Explorer to Ford today. They did a diagnostic/test drive for me for $70 and I found out "the #1 cylinder is dropping on power balance" For another $70 they're doing a "leak down test" and compression check for all 6.
However, since it's a remanufactured engine from "someone else", they won't touch it and I'll have to get the X to Rock Hill, SC for warranty work. My biggest fear is that something did inadvertently (sp?) get in there and punch a hole in the #1 piston, thus voiding the warranty. Hindsight, I should of just got a crate motor! Except for about 100-150 miles since the swap, I haven't driven my Explorer since the middle of last November!

 

[Purdue72]

bump

 

[Purdue72]

The leak test proved a 100% leak down on #1 cylinder today. They didn't remove the head(s) but they're positive I have a hole in the piston. Insert explicative here:___________! What are the chances that there wasn't anything accidently "ingested" and that this will be covered under my warranty? I have to tow it 250 miles to find out and I'm a bit worried.