knocking sound.......scary
Thread Starter
Burning Brakes
Joined: Feb 2006
Posts: 841
Likes: 0
From: High Desert California
knocking sound.......scary
I just brought the car back from the muffler shop and when we started it, there was this loud knocking sound that goes with the revolution of the motor. What could it be??? We just pu this motor together and has beeen running it for 3 consecutive days with no problem other than the loud open headers. Any possibilities where the sound is coming from?? Before we take the motor out AGAIN.................
I was told to take the oil pan down and check the connecting rods.
I was told to take the oil pan down and check the connecting rods.
Melting Slicks
Joined: Nov 2001
Posts: 2,668
Likes: 43
From: Eastern US XX
Originally Posted by 81cali
I just brought the car back from the muffler shop and when we started it, there was this loud knocking sound that goes with the revolution of the motor. What could it be??? We just pu this motor together and has beeen running it for 3 consecutive days with no problem other than the loud open headers. Any possibilities where the sound is coming from?? Before we take the motor out AGAIN................. I was told to take the oil pan down and check the connecting rods.
I was told to take the oil pan down and check the connecting rods.
Thread Starter
Burning Brakes
Joined: Feb 2006
Posts: 841
Likes: 0
From: High Desert California
350 vortec motor. when we were setting the timing, it was tough but could be turned. Now, we tried it with a breaker bar and the motor won't turn. instead, the bolt was starting to tighten more. I also tried to crank it and the starter can't turn it.
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Race Director
Joined: Feb 2005
Posts: 16,100
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Only engine I screwed up that I built was a VW engine I pumped up..I set the thrust bearing to tight on the crank...I started it,drove only two blocks and the sucker seized....spec was .005" and I had ziltch..
Hope yours is something simpler....
Rich
Hope yours is something simpler....
Rich
Thread Starter
Burning Brakes
Joined: Feb 2006
Posts: 841
Likes: 0
From: High Desert California
Hey Rich,
we took the pan down and there was a lot of fuel mixed in with the oil. Yesterday, i was having problems with the regulator and so what i did was connected the pump straight to the carb, bypassing the regulator while i figure oput how to adjust the pressure. what happened is that the pump was pumping too much gas for it to burn.... . what do i do now, change all the bearings again. is there an easier fix to this?
we took the pan down and there was a lot of fuel mixed in with the oil. Yesterday, i was having problems with the regulator and so what i did was connected the pump straight to the carb, bypassing the regulator while i figure oput how to adjust the pressure. what happened is that the pump was pumping too much gas for it to burn....
. what do i do now, change all the bearings again. is there an easier fix to this?
Racer
Joined: Apr 2005
Posts: 402
Likes: 4
From: Nassau
Hopefully the reason it wont turn over is that the cylinders are full of fuel. take out the spark plugs and try turn the motor over by hand. im betting fuel will spray out everywhere. Hopefully you didnt damage the main bearings with the lack of lubrication the gas in the oil would provide. I doubt you would have bent the connecting rods just trying to turn over by hand but you might want to check that too. If there was a banging sound I think it might be your main bearings. I hope Im wrong, Good luck man
Race Director
Joined: Feb 2005
Posts: 16,100
Likes: 17
Originally Posted by 81cali
Hey Rich,
we took the pan down and there was a lot of fuel mixed in with the oil. Yesterday, i was having problems with the regulator and so what i did was connected the pump straight to the carb, bypassing the regulator while i figure oput how to adjust the pressure. what happened is that the pump was pumping too much gas for it to burn.... . what do i do now, change all the bearings again. is there an easier fix to this?
we took the pan down and there was a lot of fuel mixed in with the oil. Yesterday, i was having problems with the regulator and so what i did was connected the pump straight to the carb, bypassing the regulator while i figure oput how to adjust the pressure. what happened is that the pump was pumping too much gas for it to burn....
. what do i do now, change all the bearings again. is there an easier fix to this?1.It is possible you seized a piston...it is also possible the thrust bearing is gone..I would pull tranny first on the outside chance a flywheel bolt broke or something...that could hang the engine up..
Have you removed a valve cover ?? You may want to pull a head..You could check to see if a piston has hit a valve..???
I'm just grabbing at straws..when I seized mine,I just pulled the engine and went from there..but that was easy on a VW...
Edit..just seen the spark plug removal suggestion...do that first..good idea..
Rich
Last edited by rihwoods; Aug 8, 2006 at 04:09 PM.
Pro
Joined: Oct 2002
Posts: 708
Likes: 0
From: somewhere south of normal
Originally Posted by 81cali
#7 connecting rod in 3 pieces........... NOW, what do I do????
NOW, what do I do????OUCH......
If it were mine I would go through the entire motor, not just try and replace the broken rod and piston. It takes a lot of force to break a rod into three pieces, and you still don't know what caused the failure. Crank should be checked, all bearings, and the cylinder as well. Loud headers can hide problems that you could normally discover right away.
Time for a rebuild.
Drifting
Joined: Apr 2002
Posts: 1,716
Likes: 4
From: New Baden Illinois
Originally Posted by 81cali
#7 connecting rod in 3 pieces........... NOW, what do I do???? I'm thinking of pulling one head out and pull the piston from the top.
NOW, what do I do???? I'm thinking of pulling one head out and pull the piston from the top.
If the connecting rod broke, there is a chance that you dinged up the block near that cylinder. Make you check that area. Also, if you broke that rod because fuel was not allowing the piston to go to the top, there is also a chance that some of the other rods may be bent. You will need to check all of them to be safe.
I feel your pain.
Race Director
Joined: Feb 2005
Posts: 16,100
Likes: 17
Originally Posted by 81cali
#7 connecting rod in 3 pieces........... NOW, what do I do???? I'm thinking of pulling one head out and pull the piston from the top.
NOW, what do I do???? I'm thinking of pulling one head out and pull the piston from the top.Rich