HELP, loud knocking noise in my engine.

[aectk]

hi, does anyone know what is wrong with my engine,
i have a supercharged vt. a week ago i replaced the gearbox, pretty sure its not the problem but thought id mention it just incase, car went fine for a few days then one morning i went to take off and a light knocking noise was coming from the engine, by the time i got to the end of the road i had to turn back, it got louder, now its quiet loud, it happens when i start the car, it will sound fine for a few seconds then when it starts knocking, i disconnected gearbox and ruled that out, its coming from the engine, took off rocker covers and its not that, checked oil and it was only replaced a few days ago and now it has very fine metal shavings in it, powder fine shavings. there is nothing in the sump that i could see or feel. i have no idea what it is, another bloke said it happened to his but he just got a new engine, ive priced the engines and im not keen on that idea. the car still runs fine, all the power is still there, along with a loud knocking noise.

[coasty]

big end bearing for sure.

[HamaTime™]

+1 to Big end bearing. probably shards of metal in your sump as well...

[db_notso]

do an oil change with a strainer under oil and check for debri
with out hearing sound.... could be a harmonic balancer let go
or loose flexplate bolts or clutch for that matter (man or auto?)

what do you mean you disconnected the box? removed it from engine? or just shaft etc.

[accentstencil]

I'm also thinking harmonic balancer perhaps.

[db_notso]

if its the balancer the noise will be louder at the front of the engine than at the back OR underneath at the back
if balancer noise will knock louder when engine decelerating NOT when accelerating
(in this case i mean revving motor faster=accel and slower =decel)

[aectk]

i was told today it may be timing chain, the guides wear out i think he said, so thats what im checking next, how would i check if its my harmonic balancer?
thanks for all the replies, big end bearing would make a grinding noise i thought? this is a knocking maybe a knock per second, 2 at the most per second.

[aectk]

also, i drained oil, as i changed it a few days ago it should have been clean, no chunks just fine metal shavings. powered metal would be the best way to describe it, all through the oil

[db_notso]

then it is probably big end bearings if oil is contaminated or chain has worn through guide into metal backing or oil pump is worn out and has interference in it
any of these the motor will have to be pulled down and checked sorry buddy

metal in the oil especially as fine as powdered or grainy is deffinatley major and most likely to be crank related ase your noise you describe at idle matches crank speed

[aectk]

damn, has anyone put supercharged heads and charger on a stock motor? does it work well or have a short life? not sure if the bottom end of the motor was the same as stock or if the L67 had something different, i know the cooling is different, the thermostat is at the back like the series one vn's.

[db_notso]

i "think" the coolant and oil galleries are different size/position but to be honest never had two stripped down at the same time to check if parts like head are interchangable