G161 Engine Knock Anomaly

[Anthiron]

I have a strange knock that I am hoping people smarter than me may be able to assist with.
It's in the G161 pushrod engine in my Luv Truck.

It has presented itself twice now. Once around a year ago and once today.
Sounds to me like a rod knock but I'm no expert. Pace matches engine revs. From inside the cab it at first sounded a bit like the crank fan contacting the radiator shroud (not it).
With the bonnet up its more pronounced and sounds deeper. Its there at idle, its there without load and its there under load.

What's odd though, is that both times it disappears.
The same sequence times.

knock starts, clutch in, pull over, shutdown engine.
Wait a bit, swear a few times. restart engine.
noise still there. shut down engine.
Swear some more.

Only a few km's from home and low traffic rural area. Decide to baby it home.
halfway home, noise stops and cannot be recreated.

Any ideas? Wrist pin?

Nick

[PR91]

Check the flywheel bolts.

[Farmer]

Yeah, a bit of trouble, but the flywheel would be my guess too, only because we once bought a P76 cheap with a knock like that. It was the torque converter drive plate with a crack in it. We had a similar knock in our 2002 Forester when it was only 50,000ks old. That was the dual mass flywheel that had failed. (The second one that failed was replaced with a solid flywheel, still working at 500,000 ks.)
Good luck.
Matt.