Installed motor, on startup, horrible rod knock type noise, lifters possibly??
12-23-2003, 03:39 PM
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Installed motor, on startup, horrible rod knock type noise, lifters possibly?? A friend of mine just finished installing a used forged 346 ls1 shortblock in his car. The shortblock came out of another running car (i witnessed) that was perfect running, no noises, came out of the car for a stroker, had about 2-3k miles on it.
While putting it together the motor has been upsidedown on the engine stand for a couple weeks sitting there waiting on parts...the stock lifters are completely drained no oil in them etc.
Normally i put all the lifters emersed in oil for a while and it bleeds all the air out and are full of oil when i install them...this wasnt done on this motor because he didnt know to do that.
when he started the car, it instantly went to 60 psi oil pressure and instantly horribly loud knocking that is fairly rythmic with the engine. Under the hood its horribly loud and typically i would instantly assume rod knock/spun bearings. But it also sounds to me like its coming from fairly high in the motor and i really suspect maybe all the lifters arent pumped at all are just making a TON of noise because the valve train isnt nearly working right...
The car runs smooth and nice, any ideas?
Also I unplugged the drivers side coil pack and the noise didnt change, plugged back in then unplugged other side, and the noise didnt change.
While putting it together the motor has been upsidedown on the engine stand for a couple weeks sitting there waiting on parts...the stock lifters are completely drained no oil in them etc.
Normally i put all the lifters emersed in oil for a while and it bleeds all the air out and are full of oil when i install them...this wasnt done on this motor because he didnt know to do that.
when he started the car, it instantly went to 60 psi oil pressure and instantly horribly loud knocking that is fairly rythmic with the engine. Under the hood its horribly loud and typically i would instantly assume rod knock/spun bearings. But it also sounds to me like its coming from fairly high in the motor and i really suspect maybe all the lifters arent pumped at all are just making a TON of noise because the valve train isnt nearly working right...
The car runs smooth and nice, any ideas?
Also I unplugged the drivers side coil pack and the noise didnt change, plugged back in then unplugged other side, and the noise didnt change.
12-23-2003, 03:50 PM
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If the lifters didn't have any oil in them, it will be extremely loud on startup. It will take a good 4-5 minutes for everything to completely quiet down. If the motor has good oil pressure, I wouldn't be too worried about the knock, especially if you know the motor was in good shape when it came out.
Jason
Jason
12-23-2003, 03:56 PM
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if absolutely NOTHING else was changed, it's probably the lifters. be sure that it's not p/v clearance. that will destroy a motor in a hurry.
my iron motor made a similar noise on startup but only took about 20 seconds to go away.
my iron motor made a similar noise on startup but only took about 20 seconds to go away.
12-23-2003, 09:03 PM
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i just hope when i start mine up it doesnt do that! i submurged the lifters for about a day and a half then put them in... but its gonna be another week maybe before i start it up??? !!!!!!
