Oil pump catastrophic failure!!
Thread Starter
On The Tree
Joined: Jul 2012
Posts: 120
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From: Bowling Green, Missouri
Oil pump catastrophic failure!! I have recently got my swap project in running order and quickly had a catastrophic pump failure. I have a gen 3 5.3 and installed a used LS2 oil pump from a stock LS2 I purchased to rebuild in the future. The pump had about 100,000 miles on it but that is less than the stock 5.3 pump I had so I swapped it over. When installing there was no odd resistance and went on as normal. I didn't use a torque wrench on the bolts but used common sense when tightening so they were not excessively tight in my opinion.
I primed the system by cranking the engine without fuel and had pressure quickly. Started as normal and after some minor coolant/ignition bugs had the car purring like a kitten. Brought the engine up to temp and worked the air out of the coolant. All was right in the world. The car ran for over 15 minutes at idle and different rpm via throttle. Sounded good revving and had no odd noises. As I revved it again I heard a crunch in the front of the engine and immediately lost all oil pressure and very quickly started hearing a ticking (lifter sound IMO). I shut the car off asap and checked for anything obvious.
Knowing it was something internal I started the teardown thinking/hoping it was just a pickup tube bolt or something. As I got the timing cover off this is what I discovered:
Lots-a-carnage! Pump broke in half!
Any ideas as to what could have caused this? I understand debris is a likely culprit but I just can't see me having anything foreign in the engine being all new fluids, pan, pickup, heads, cam swap. What are your thoughts?
I primed the system by cranking the engine without fuel and had pressure quickly. Started as normal and after some minor coolant/ignition bugs had the car purring like a kitten. Brought the engine up to temp and worked the air out of the coolant. All was right in the world. The car ran for over 15 minutes at idle and different rpm via throttle. Sounded good revving and had no odd noises. As I revved it again I heard a crunch in the front of the engine and immediately lost all oil pressure and very quickly started hearing a ticking (lifter sound IMO). I shut the car off asap and checked for anything obvious.
Knowing it was something internal I started the teardown thinking/hoping it was just a pickup tube bolt or something. As I got the timing cover off this is what I discovered:
Lots-a-carnage! Pump broke in half!
Any ideas as to what could have caused this? I understand debris is a likely culprit but I just can't see me having anything foreign in the engine being all new fluids, pan, pickup, heads, cam swap. What are your thoughts?
I didn't use a torque wrench on the bolts but used common sense when tightening so they were not excessively tight in my opinion.
Even if there was a pre-existing hairline crack in the pump it would've only exploded at that exact spot. Looking at the pics it seems to have broken off right around several of the bolts, which leads me to believe the damage to the case came from the hardware installation. Whether that was pre-existing or not no one will know, but since you said it yourself that you just "eyeballed" the tightening down I would lean towards that as being the cause.
Didn't use a torque wrench on an aluminum component, and didn't center the pump during installation so the crank-mounted rotor was probably smacking the eccentric rotor into the pump housing. Expensive lesson for you.
I'd also put a dial indicator on the end of the crank & rotate it; just to be sure the crank end isn't bent & helping to cause the miss-alignment. That is some serious carnage. Yah, it leads to oil pump miss-alignment, but **** had to have been seriously over tightened &/or crooked to have cause that. +4 or 5 as to the shim alignment & then go easy on the tightening, but, don't under torque either.
You know what? I just re-looked @ the pics. It looks like there could have been a load from the pick up-tube that was tugging on the bottom of the oil pump. It could have been an equal culprit to having caused a miss-alignment great enough to break the housing. Make sure that you don't have to man handle the pick-up tube in order to align the tube to the oil pump. If you have to force the tube into position, it's gonna put a side load the pump. If the load is great enough, will cause miss-alignment.
You know what? I just re-looked @ the pics. It looks like there could have been a load from the pick up-tube that was tugging on the bottom of the oil pump. It could have been an equal culprit to having caused a miss-alignment great enough to break the housing. Make sure that you don't have to man handle the pick-up tube in order to align the tube to the oil pump. If you have to force the tube into position, it's gonna put a side load the pump. If the load is great enough, will cause miss-alignment.
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Thread Starter
On The Tree
Joined: Jul 2012
Posts: 120
Likes: 1
From: Bowling Green, Missouri
I'd also put a dial indicator on the end of the crank & rotate it; just to be sure the crank end isn't bent & helping to cause the miss-alignment. That is some serious carnage. Yah, it leads to oil pump miss-alignment, but **** had to have been seriously over tightened &/or crooked to have cause that. +4 or 5 as to the shim alignment & then go easy on the tightening, but, don't under torque either.
You know what? I just re-looked @ the pics. It looks like there could have been a load from the pick up-tube that was tugging on the bottom of the oil pump. It could have been an equal culprit to having caused a miss-alignment great enough to break the housing. Make sure that you don't have to man handle the pick-up tube in order to align the tube to the oil pump. If you have to force the tube into position, it's gonna put a side load the pump. If the load is great enough, will cause miss-alignment.
You know what? I just re-looked @ the pics. It looks like there could have been a load from the pick up-tube that was tugging on the bottom of the oil pump. It could have been an equal culprit to having caused a miss-alignment great enough to break the housing. Make sure that you don't have to man handle the pick-up tube in order to align the tube to the oil pump. If you have to force the tube into position, it's gonna put a side load the pump. If the load is great enough, will cause miss-alignment.
I guess I really should have used some shims. Lesson learned. The old pump combined with likely over-torquing surly had something to do with it. I'm not a newb by any means but I must have never thought to shim the pump. All these super budget build stories of junkyard success had my hopes up too high I guess.
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