Need Help - Knocking Noise - 65 Series 2a SWB Petrol

[grimmecm]

Hey everyone, need some expert help. My series 2a has started making a terrible knocking noise.

Here is a video (not mine) of the same noise and same conditions.
https://youtube.com/clip/Ugkx1a68wuDhhigGgjyk13myfPsy44IiPQOY?si=xES4_KfEwM VnQ0-8

He found the head gasket to be the issue but that doesn't appear to be my issue. So far I have replaced the head gasket, cleaned the cylinder head and piston faces, reset clearances on all tappets, new spark plugs and checked gaps.

The truck starts and idles fine/smoothly. Noise only happens when engine is under load. Noise is the same regardless of engine temp. Feels/sounds like it is in the back end of the engine.

Would appreciate any insight anyone has.

[charles1943]

Possible broken crankshaft or a bad connecting rod comes to mind. Possible dropped valve head??

[roverp480]

Sounds like something vibrating to me, transfer lever or a heat shield ?

[jimrr]

thrust washer someplace, or something in the bell housing. remove the drain plug on the bell and measure the end play on the flywheel or same on front of C shaft. if it's a real tinny issue probably something external but on the video the guy was talking all the time!

[biffidum]

It could be your wife trying to get into the garage... ;)

[biffidum]

In all sincerity, it could be pinging. Your timing may be too far advanced, or your advance mechanism is too aggressive (never seen this though - unless its the wrong distributor). Your valve lash may also need adjusting - which would also sound worse under too advanced timing as they bang shut. Or finally, you may have valve seat regression.

[jimrr]

what's the oil pressure like? mine does this and it needs new inserts so it waits for a rebuild. your sounds a bit tinny, not exactly a hard knock, at least on the audio.
if you have 50-60 psi oil your engine is prob ok, you could put some lucas oil treatment in it, that saved my dozer engine!!
other than that, biffidum could be tracking on this.

[biffidum]

Disconnect vacuum advance and drive. If noise is reduced under load - bingo. If not, check valves. Valve adjustment nuts should all show similar thread counts, if one has significantly more thread you have a worn valve seat.

[jimrr]

welll, ya, it does sound kinda like valves ...... but that doesn't happen overnight......... did you change gas type or torque the head or anything that'd affect valve train?