Oil Pressure drops to Zero at WOT
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Oil Pressure drops to Zero at WOT I have a new LS2 ported oil pump with new o-ring on a H/C built 347 motor. Oil pressure was steady at 40 cold and 35 hot.
After few days, oil pressure started to go down to 30 hot then fluctuated to 28 and jumped to 15 then 20 at hot idle.
At WOT it drops to zero and motor slows done and stalls. I start it and oil goes to 15 and fluctuates again. Same thing happened again at WOT.
Removed the oil pressure sender next to oil filter and started the motor and it splashed oil which means pump is working. put back the sender and tried WOT and the same thing happened again.
Motor runs normal except for the fluctuating oil pressure and zero pressure at WOT then stalling.
Any idea what to do?
Edit: It's LS2 ported oil pump not Melling.
After few days, oil pressure started to go down to 30 hot then fluctuated to 28 and jumped to 15 then 20 at hot idle.
At WOT it drops to zero and motor slows done and stalls. I start it and oil goes to 15 and fluctuates again. Same thing happened again at WOT.
Removed the oil pressure sender next to oil filter and started the motor and it splashed oil which means pump is working. put back the sender and tried WOT and the same thing happened again.
Motor runs normal except for the fluctuating oil pressure and zero pressure at WOT then stalling.
Any idea what to do?
Edit: It's LS2 ported oil pump not Melling.
Last edited by bluecamaroz28; Feb 23, 2008 at 01:11 PM.
Drain your oil, cut open the filter, and look for shavings/bearing material. If by some miracle there are none drop the oil pan, make sure nothing is obstructing the p/u tube and verify it is bolted to the main stud like it should be. If all that checks okay then replace the pump. What kind of oil/additives are you running?
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I am using Nordskog Digital Gauges with electric sending unit.
Weber Racing built me the short block. First oil pump was my used SLP from my old working short block. Pump took a dump and didn't lift oil. Put a new LS2 ported oil pump and it worked. After couple of days, I had this problem.
I don't think oil type has to do with this. It's either the pump or cam/crank bearings.
Going to remove the engine and check things.
Weber Racing built me the short block. First oil pump was my used SLP from my old working short block. Pump took a dump and didn't lift oil. Put a new LS2 ported oil pump and it worked. After couple of days, I had this problem.
I don't think oil type has to do with this. It's either the pump or cam/crank bearings.
Going to remove the engine and check things.
Last edited by bluecamaroz28; Feb 23, 2008 at 01:09 PM.
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Bad news. main/rod bearings damage with two rods needing replacement and crank grinding to 0.020 to clean.
Any idea what could have caused this with new LS2 ported oil pump. I should have mentioned that with 1st oil change, before oil pressure fluctuation starts, I noticed metal shaving in the oil.
Is it the rebuild, Weber Racing, or my oil pump to blame??
Any idea what could have caused this with new LS2 ported oil pump. I should have mentioned that with 1st oil change, before oil pressure fluctuation starts, I noticed metal shaving in the oil.
Is it the rebuild, Weber Racing, or my oil pump to blame??
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No. I didn't run it With SLP not priming or lifting oil. After I installed the 2nd oil pump and made sure it has oil pressure, I ran it .
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[QUOTE=bluecamaroz28;8774176]I am using Nordskog Digital Gauges with electric sending unit.
Weber Racing built me the short block. First oil pump was my used SLP from my old working short block. Pump took a dump and didn't lift oil. Put a new LS2 ported oil pump and it worked. After couple of days, I had this problem.
You mentioned that pump didn't lift oil. Can you please describe how you determined that and how did you prime the oil system prior to start-up?
Weber Racing built me the short block. First oil pump was my used SLP from my old working short block. Pump took a dump and didn't lift oil. Put a new LS2 ported oil pump and it worked. After couple of days, I had this problem.
You mentioned that pump didn't lift oil. Can you please describe how you determined that and how did you prime the oil system prior to start-up?
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Basically the pressure gauge was reading zero and immediately the engine was switched off.
Oil was filled through the back of the engine, sensor hole behind the intake. We did try to start it couple of time. Each attempt was for few seconds to check the oil pressure gauge.
Not trying to blame WRE here rather than trying to find the real cause of problem.
Oil was filled through the back of the engine, sensor hole behind the intake. We did try to start it couple of time. Each attempt was for few seconds to check the oil pressure gauge.
Not trying to blame WRE here rather than trying to find the real cause of problem.
Last edited by bluecamaroz28; Feb 26, 2008 at 11:41 AM.
A friend of mine just had the same problem here, no oil pressure. 2 main bearings were spun and there was some bearing material inside the Pick Up tube, our guess was bearings were too tight and didn't have enough clearance to get the crank spinning well. BTW check your other bearings, my friend's cam bearings were also hurt due to the oil low pressure. Whats the clearance (rods/crank) you used on this engine WBE?
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A friend of mine just had the same problem here, no oil pressure. 2 main bearings were spun and there was some bearing material inside the Pick Up tube, our guess was bearings were too tight and didn't have enough clearance to get the crank spinning well. BTW check your other bearings, my friend's cam bearings were also hurt due to the oil low pressure. Whats the clearance (rods/crank) you used on this engine WBE?
How can you tell if bearings were too tight? I guess oil starvation damage will happen no matter what clearance you put to the bearings.
I am not sure how much is the clearance but I am sure Weber Racing can answer that for you.
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The problem was that the engine ran with no oil pressure even for a brief period of time. It is so critical to have proper lubrication especially at inititial startup. This is why it is so important to prime the engine prior to starting. All it takes is for the oil film to be absent for a fraction of a second in which time the bearing surface contacts the crank surface and will scuff or transfer bearing material to the crank almost like solder. Once this occurs the engine will continue to eat itself with increasing severity.
This is why it is a good idea when running a brand new engine, with all other indicators good, that the oil dipstick to be pulled out and wiped off on a clean white towel or cloth and observed for contaminants or debris every few minutes. If this is done the problem can be caught early enough to discontinue running the engine to minimize damage.
This is part of what can be very painfull about engines. You have to do hundreds of things right and if even the slightest detail is missed the whole project can go bad.
This is why it is a good idea when running a brand new engine, with all other indicators good, that the oil dipstick to be pulled out and wiped off on a clean white towel or cloth and observed for contaminants or debris every few minutes. If this is done the problem can be caught early enough to discontinue running the engine to minimize damage.
This is part of what can be very painfull about engines. You have to do hundreds of things right and if even the slightest detail is missed the whole project can go bad.
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The problem was that the engine ran with no oil pressure even for a brief period of time. It is so critical to have proper lubrication especially at inititial startup. This is why it is so important to prime the engine prior to starting. All it takes is for the oil film to be absent for a fraction of a second in which time the bearing surface contacts the crank surface and will scuff or transfer bearing material to the crank almost like solder. Once this occurs the engine will continue to eat itself with increasing severity.
This is why it is a good idea when running a brand new engine, with all other indicators good, that the oil dipstick to be pulled out and wiped off on a clean white towel or cloth and observed for contaminants or debris every few minutes. If this is done the problem can be caught early enough to discontinue running the engine to minimize damage.
This is part of what can be very painfull about engines. You have to do hundreds of things right and if even the slightest detail is missed the whole project can go bad.
This is why it is a good idea when running a brand new engine, with all other indicators good, that the oil dipstick to be pulled out and wiped off on a clean white towel or cloth and observed for contaminants or debris every few minutes. If this is done the problem can be caught early enough to discontinue running the engine to minimize damage.
This is part of what can be very painfull about engines. You have to do hundreds of things right and if even the slightest detail is missed the whole project can go bad.
In fact, the guy at the dyno said that I should check the engine when he felt it's not running right and saw the metal debris on the dip stick. I was thinking a faulty gauge but as you said, the damage may already have happend before it gets to the dyno.
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you pumped all the oil to the valves and more than not the oil was restricted due to two things one the flow back to the pump in the heads the oil drains need polished as well second oil was not warmed up to flow or even a shitty oil filter sorry seen it many of times you spun no 1and no 2 rods and your cam bearings are scrached time to tear her down the more additives you add the thicker the oil when you crack the throttle and let it come back and crack it agin you got a dry sump that is why if you got room run a ph373 long filter on it its a true 1qt filter and if the room is there a 6or 7qt pan 
Unplug your coilpacks and injectors. the put power to the started and turn the car over and over again for maybe 5-10 sec. That will bring the oil up and it should be plenty enough to start the motor and it should only have 0 oil pressure for the most of 2 sec. I dont think this guy did that.
did your oil pressure swing up when you gave the car some throttle when you first started the motor? did you install the oil pump? did you shim it properly? if you had the engine built by someone they should have given you a build sheet, I would verify clearences on the journals that are not damaged. did you see any cap shift? also is it a stock crank? was it checked for strightness? im not trying to say it was your engine builder for sure but theres always the possibility of that
