I know another knock story-but but ive got a '70 455 and I just picked it up its still in the lesabre -Its got a knock but its real weird-the knock changes when i move the distibuter-when i advance it ,it knocks hard when i retard it the knock basically disapears-????????????thought it was a flywheel noise but know idont know-somethings it knocks and creeks at the same time(like a flywheel) Anyone have anything to add?? thanks Brian :TU:
Normally, pinging like that is purely attributable to too much timing (i.e. too far advanced). So what you say seems to make perfect sense. Is there a reason you don't think this is the case? -Bob Cunningham
Is it a deep rhythmic knock, similar to a bad main bearing? If the timing is advanced enough to ping at idle, then it would probably be very hard to start and idle roughly and stall frequently. Now the only way I can think that the timing would have an effect on the bearing would by how much force it exerts on it, everyone knows more timing makes more power which may exacerbate a worn bearing problem. Thats just my guess though.
Brian, I'm not clear on whether this is bearing knock or is it pinging when you drive it? Is the sound at idle, as you advance and retard the timing? I've never heard a motor ping at idle, unless it was straining against a load, like up on the converter. Could it be timing chain slop or a problem with the fuel pump arm? Kinda hard to diagnose without actually hearing it. Put a timing light on it, and find out where the timing is, and whether it is steady or not. Another thing to try is to isolate the cylinder you think it is coming from. Then pull the ignition wire off that plug. Could be a rod bearing or wrist pin.
thanks for the awnsers guys It definetly knocks,it does start alittle hard and runs abit ruff-sounds like a slapping knock ?? That just it i cant tell if its a bearing knock or not?this is all at idle-the trans slips bad so i havent driven it.this is with no load on it-cold-Seems high in the motor .I know it could echo and come up.had the valve covers off and they look ok.Sometimes when i start it(always when i start it it turns over slow like timeing is off but i dont think enough for this knock)the motor makes a weird squicking noise.So i wasnt sure it was the bearing and when i retard it the knock gos away .and rev it to keep running . Ill probably just pull the motor-and go from there. I duno
Brian, Is it rythmical, or does it come or go? Before you pull the motor, take the inspection cover off, and take a good look at the flexplate. Check for loose flexplate to torque converter bolts, and for cracks in the flexplate itself. It can sound like a bearing knock that comes and goes, and will get worse as the engine runs rougher.
I had the same thing you are describing and it turned out to be a rod bearing. If you are pulling the motor anyhow I would not start it again no reason to damage the crank. Hope thats it is not , good luck.
Yah im thinking its a rod-a little silver came out today of the oil pan. Crap thanks for the respondes guy-thnx alot Brian
