Name the knock, my heep is giving me a fit.

[92DripCherokee]

http://www.youtube.com/watch?v=VEcXQ4jjxZI

Anyone up for a game of name the knock?:gee:
This is video of 2 cold starts, the wretched noise is clearly audible.
I'm hoping one of you guys have heard this one
It ain't loose torque converter bolts, I made sure of that.


knocks at start up and shutdown,
appears again when revving down
no start up knock when engine is fully warmed

does not change with RPM
has no repeating pattern

knock sound seems to come from center of camshaft galley.

flexplate is intact, bolts are threadlocked, no cracks on inspection

there is no vibration

oil pressure is constant 20 at idle 40 at cruise, 55 at cold start

motor mounts are all new, jacked engine up and started it, got the same knock

Trans bolts are all tight

Engine oil is full

there is no misfire, or loss of power

cat mount and catalytic converter are new. No noise from these components.Exhaust does not hit crossmember

Possible knocks:

cam walk (RIP)
crank walk (RIP)
cracked flexplate (would get better with warmup?)
dragging starter (would'nt knock at shutdown)

 

[smcdonaldaz]

not the mechanical fan or the fan clutch?

 

[StaleAle]

Sounds like the starter to me. If you listen it stops as soon as the starter stops cranking.

 

[hanaxj87]

It's sounds like torque convertor bolts loose. Did you check all of them??

It's something loose. The engine runs pretty smooth after start up.

I guess it could be a cracked flywheel.

I don't think it's anything in the engine. it just runs to smooth..

Good Luck

Nick

 

[92DripCherokee]

Arg, thanks all for listening.
The starter is still suspect, even though it doesnt seem to grind, scratch or squeel. The knock happens again at shutdown, and that's the tough one.


there was a short section of damaged teeth on the flexplate's ring gear. And a bunch of deep, fresh scratches in the torque converter's face that I can't explain. The rest of the flexplate teeth look perfect.

I had loose TC bolts 2 years ago, and it sounded like a bad piston pin, and vibrated nastily.

Got a new starter already, just in case.

 

[92DripCherokee]

bump!!!1

 

[92DripCherokee]

update- the new starter made no difference.