View Full Version : i have a serious question....
bowhay
03-10-2009, 08:06 PM
alright, my motor started knockin the other day, every thing is new though bearings rods pistons and all, so i pulled the motor and found that three of the oil punp bolts had vibated all the way out, meaning that thee was only one left holding it together, so i put some lock tight on them and put everything back together.
heres he question
can the oil pump cause the knocking i was hearing? :(
slickfuel
03-10-2009, 08:34 PM
QUESTION IS,..WHAT IS CAUSING THE VIBRATION ?????
was the rotating assembl balanced correctly, etc,....
or was it not assembled professionaly
is it a 454 bbc ???
cepx111
03-11-2009, 12:53 AM
Oh boy does this post bring back some bad memories, I had a similar experience except mine ended in a destroyed engine. They were probably just lose from the oil pump manufactor (melling of mexico).
Since then I always remove the oil pump cover bolts and generously use red loctite on them. NOTE: They're usually lose or close to it.
The knocking probably was due to the loss of oil pressure, motors tend to do that when they dont have any oil pressure.
I also reccomend a great big low oil pressure warning light positioned at EYE level, another thing I learned tearing that motor up, no oil pressure kills motors in a hurry.
Goodluck, Cp
curtisreed
03-11-2009, 05:07 AM
heres he question
can the oil pump cause the knocking i was hearing? :(
Yes, when it doesn't pump any oil and it knocks a bearing out of the bottom end. I would pull the main caps at least and have a look.
Curtis
bowhay
03-11-2009, 06:45 AM
yes the rotating assembly was balanced
and i checked the mains and few of the rod bearings and they all looked good
it almost sounded like the pump was rattleing around and hitting the oil pan
its a 350 sbc bored and stroked to a 385
curtisreed
03-11-2009, 06:59 AM
Bowhay,
I hope that didn't sound like a smart*** answer. How long did this motor run? Glad you could hear it over the exaust. If you don't mind who's pump was this? I have always taken apart new pumps and checked the gear clearance to cap dimension making sure it is .002-.003. I run a machine shop so I know how guys will let tolerances wander. :( I hope nothing was hurt in your motor.
Curtis
bowhay
03-11-2009, 07:09 AM
it was just a stock replacement gm high volume pump
was intstalled about a year ago, and i just put it back in
i didnt check the clearance but i didnt think it was necessary beacuase it had run for the entire time that i have had the truck
i really dont know
i just hope that when i get all the electrical hooked back up i can start the motor and it wont knock
desoto30
03-11-2009, 08:54 AM
Bowhay,
I hope that didn't sound like a smart*** answer. How long did this motor run? Glad you could hear it over the exaust. If you don't mind who's pump was this? I have always taken apart new pumps and checked the gear clearance to cap dimension making sure it is .002-.003. I run a machine shop so I know how guys will let tolerances wander. :( I hope nothing was hurt in your motor.
Curtis
X2 & yes on clearance.Generally,(& I have always found) the clearances are greater than the desired dimension,I might add that I always gently deburr the gears also.
curtisreed
03-11-2009, 06:56 PM
I just added the part about checking the clearance as a std. course of prep that I do on a new pump. This also makes sure the bolts are tight when I put it back together. Sounds like the bolts must have been a little loose and I have heard that high volume pumps will the possibility of chatter or vibration. Not sure how true that is just things that I have heard through the years. I never run a high volume pump myself in a SBC, have never found the need for it with the clearances we run. I hope it doesn't knock also. Good luck.
Curtis
dparker
03-11-2009, 07:06 PM
What I would like to ask is, was there any metal in the bottom of the oil pan or in the oil filter?
bowhay
03-11-2009, 07:17 PM
well its only a 4 day old motor
and there was a lil bit of fine metal dust but thats justfrom the bearings breakin in
bowhay
03-14-2009, 02:45 PM
got the motor back in today
and apparently it was the pump that was causin the knock
cus it sure aint doin it no more
thanks to everyone that gave input on what they thought it was
TheYellaBrick
03-14-2009, 05:48 PM
well its only a 4 day old motor
and there was a lil bit of fine metal dust but thats justfrom the bearings breakin in
uuuhhh...bearings don't 'break in' ,...they wear out....and start knockin'...
Any groovy grooves in the oil pump cap ? That might be the source of the metal 'dust'.
bowhay
03-14-2009, 08:04 PM
bearings wear in to each particular journal
which will leave very very fine metal particles
thats why if u dissasemble a motor u have to keep them matched if they arent being replaced
otherwise they will catch and spin
but the knocking stoped by fixing the pump so it doesnt matter anyway
Tod74
03-14-2009, 10:00 PM
well its only a 4 day old motor
and there was a lil bit of fine metal dust but thats justfrom the bearings breakin in
uuuhhh...bearings don't 'break in' ,...they wear out....and start knockin'...
Any groovy grooves in the oil pump cap ? That might be the source of the metal 'dust'.
I think he was refering to the silver look you always have in the oil of a new engine.