Low oil pressure on rebuild
10-06-2019, 09:03 PM
#1
Rennlist Member
Thread Starter
Low oil pressure on rebuild
I have a 2000 996 with 107K miles. Full rebuild with oversized LNE cylinders and pistons, F6I pinned IMS and IMS Solution, rebuilt heads, new main bearings, coated rod bearings, etc. done by local experienced Indy. Running BR30 oil.
The problem: Oil pressure is 5 bar at 3-4K rpm and 3-4 bar at idle when cold. I picked up car with the fresh engine on a hot day—94-degrees outside— water temp around 200F, oil pressure at 3-4K rpm is 4 bar but it dropped to less than 1 bar at idle and engine died. Several times. Would not stay lit unless maintained above idle. Engine builder said it showed no fault codes. Two days later, 75F day, idle o.p. with hot engine was about 0.8 bar and idle is smooth. So, engine builder says it’s normal function, let the ECU relearn, etc. Is the issue running a 30 weight oil or is it more likely due to improper build such as main bearing clearances.
The problem: Oil pressure is 5 bar at 3-4K rpm and 3-4 bar at idle when cold. I picked up car with the fresh engine on a hot day—94-degrees outside— water temp around 200F, oil pressure at 3-4K rpm is 4 bar but it dropped to less than 1 bar at idle and engine died. Several times. Would not stay lit unless maintained above idle. Engine builder said it showed no fault codes. Two days later, 75F day, idle o.p. with hot engine was about 0.8 bar and idle is smooth. So, engine builder says it’s normal function, let the ECU relearn, etc. Is the issue running a 30 weight oil or is it more likely due to improper build such as main bearing clearances.
10-06-2019, 09:38 PM
#2
Rennlist Member
30wt oil...
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Mike Murphy (10-18-2019)
10-06-2019, 09:42 PM
#3
Isn't BR30 a 5w-30 break in oil?
Copied from Driven website:
How many miles has it been driven with this oil?
Copied from Driven website:
Good for full power pulls on the dyno, one night of racing or up to 400 miles on the street.
10-07-2019, 04:01 PM
#5
Rennlist Member
Thread Starter
Still need help!
Flat Six or LNE recommend 30 wt oil for break in, so low op is normal function. Engine builder indicates could be too-low idle, not a low pressure issue, that causes stall. This is e-throttle, so would need new throttle body or ? Comments?
10-17-2019, 12:32 PM
#7
Rennlist Member
We recommend BR40 for break-in. Many years ago, there was no 40 wt available, so we had to use a 30 wt, but that hasn't been the case for a very long time.
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10-17-2019, 12:34 PM
#8
Rennlist Member
I have a 2000 996 with 107K miles. Full rebuild with oversized LNE cylinders and pistons, F6I pinned IMS and IMS Solution, rebuilt heads, new main bearings, coated rod bearings, etc. done by local experienced Indy. Running BR30 oil.
The problem: Oil pressure is 5 bar at 3-4K rpm and 3-4 bar at idle when cold. I picked up car with the fresh engine on a hot day—94-degrees outside— water temp around 200F, oil pressure at 3-4K rpm is 4 bar but it dropped to less than 1 bar at idle and engine died. Several times. Would not stay lit unless maintained above idle. Engine builder said it showed no fault codes. Two days later, 75F day, idle o.p. with hot engine was about 0.8 bar and idle is smooth. So, engine builder says it’s normal function, let the ECU relearn, etc. Is the issue running a 30 weight oil or is it more likely due to improper build such as main bearing clearances.
The problem: Oil pressure is 5 bar at 3-4K rpm and 3-4 bar at idle when cold. I picked up car with the fresh engine on a hot day—94-degrees outside— water temp around 200F, oil pressure at 3-4K rpm is 4 bar but it dropped to less than 1 bar at idle and engine died. Several times. Would not stay lit unless maintained above idle. Engine builder said it showed no fault codes. Two days later, 75F day, idle o.p. with hot engine was about 0.8 bar and idle is smooth. So, engine builder says it’s normal function, let the ECU relearn, etc. Is the issue running a 30 weight oil or is it more likely due to improper build such as main bearing clearances.
The throttle re-learn as instructed by another poster is a good idea.
10-18-2019, 01:10 PM
#9
My 2cents
My experiences were similar to those of the initial posting...96K miles, #6 cylinder "holed", fully rebuilt engine installed...checking account emptied.
With the "new" engine, oil pressure is steady 2-3 bars once fully warmed and cruising at 50-60 mph....and absolutely no oil leaks (really) !!
Anything less than 2-3 bars on a recently rebuilt and fully warmed engine would be deeply suspect to me.
relinuca
With the "new" engine, oil pressure is steady 2-3 bars once fully warmed and cruising at 50-60 mph....and absolutely no oil leaks (really) !!
Anything less than 2-3 bars on a recently rebuilt and fully warmed engine would be deeply suspect to me.
relinuca
10-18-2019, 01:16 PM
#10
Rennlist Member
996 oil pressure sending units are not very reliable in my experience, if you don't like what you see try buying a new one.
10-18-2019, 01:19 PM
#11
Rennlist Member
My experiences were similar to those of the initial posting...96K miles, #6 cylinder "holed", fully rebuilt engine installed...checking account emptied.
With the "new" engine, oil pressure is steady 2-3 bars once fully warmed and cruising at 50-60 mph....and absolutely no oil leaks (really) !!
Anything less than 2-3 bars on a recently rebuilt and fully warmed engine would be deeply suspect to me.
relinuca
With the "new" engine, oil pressure is steady 2-3 bars once fully warmed and cruising at 50-60 mph....and absolutely no oil leaks (really) !!
Anything less than 2-3 bars on a recently rebuilt and fully warmed engine would be deeply suspect to me.
relinuca
10-18-2019, 06:04 PM
#12
Rennlist Member
My engine idles at 675, but bumps to 800 or 850 with the AC button depressed. And if the engine builder wants 30-weight, you might have to listen. But then switch to 40 when you can.
Its possible the rebuilt engine just has slightly larger tolerances, resulting is a bit less pressure.
Its possible the rebuilt engine just has slightly larger tolerances, resulting is a bit less pressure.
Last edited by Mike Murphy; 10-18-2019 at 06:43 PM.
10-19-2019, 03:14 AM
#13
Three Wheelin'
10-19-2019, 05:14 AM
#14
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Porschetech3 (10-19-2019)
