crate LS7 low oil pressure
11-16-2008, 01:28 PM
#1
Staging Lane
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crate LS7 low oil pressure Guys,
I've got a new LS7 crate engine installed in a project car that isn't making oil pressure on cranking. Here's the set up-
- The installation required that the intake manifold be turned 180 degrees, so the stock oil pressure sensor had to go - the fitting was removed, and the valley cover was drilled/tapped for a plug which was installed with sealer/threadlock.
- the oil pressure sensor is a SPA design, which is installed in a Lingenfelter adaptor block bolted to the side of the engine just above the oil filter. All that seems to be sealed up properly.
So the engine has been cranked for extended periods to try to get oil pressure before starting. The spark plugs were even removed to get the engine to turn over more quickly. So far the gauge is only reading 1 PSI.
The level of the oil tank has dropped, and the oil filter is full of oil, so I'm pretty sure the oil tank lines are installed correctly (feed line to the front boss on the oil pan) and the oil is getting to the engine.
The engine is a dead stock LS7, only modification is the intake manifold reversal.
What am I missing here? Is it possible the pressure sensor is in a bad location?
Sorry for the long post, and thanks in advance for the advice.
Tom
I've got a new LS7 crate engine installed in a project car that isn't making oil pressure on cranking. Here's the set up-
- The installation required that the intake manifold be turned 180 degrees, so the stock oil pressure sensor had to go - the fitting was removed, and the valley cover was drilled/tapped for a plug which was installed with sealer/threadlock.
- the oil pressure sensor is a SPA design, which is installed in a Lingenfelter adaptor block bolted to the side of the engine just above the oil filter. All that seems to be sealed up properly.
So the engine has been cranked for extended periods to try to get oil pressure before starting. The spark plugs were even removed to get the engine to turn over more quickly. So far the gauge is only reading 1 PSI.
The level of the oil tank has dropped, and the oil filter is full of oil, so I'm pretty sure the oil tank lines are installed correctly (feed line to the front boss on the oil pan) and the oil is getting to the engine.
The engine is a dead stock LS7, only modification is the intake manifold reversal.
What am I missing here? Is it possible the pressure sensor is in a bad location?
Sorry for the long post, and thanks in advance for the advice.
Tom
11-16-2008, 03:13 PM
#3
my stroker motor was the same way. i tried and tried and tried with no results. i was told i might have to fire it up to create pressure and sure as $hit it made pressure very quickly after firing
11-16-2008, 03:52 PM
#4
It won't show pressure when cranking, you have to move the key to the run position for any pressure to show. I just went through this last week on my build. Turn the key all gauges are at zero, release the key and I got 20 psi on the oil pressure gauge.
11-16-2008, 06:11 PM
#5
Staging Lane
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Vettenuts -
my car does not have a GM harness in it. In order for the engine to crank, the whole harness has to be energized, and the gauge does show 1 psi. Maybe I need to fire it up for 5 seconds to get oil pressure.
Maybe it has something to do with the oil pump design? It only builds pressure once it gets to a certain RPM?
Tom
my car does not have a GM harness in it. In order for the engine to crank, the whole harness has to be energized, and the gauge does show 1 psi. Maybe I need to fire it up for 5 seconds to get oil pressure.
Maybe it has something to do with the oil pump design? It only builds pressure once it gets to a certain RPM?
Tom
11-17-2008, 10:53 AM
#6
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Why don't you hook up a mechanical gauge. You could get an adaptor for the sender fitting hole, or tap in somewhere else. On non dry sump systems there is a cover above oil filter that can be drilled and tapped. Not sure if this used on dry sump system.
11-17-2008, 07:04 PM
#7
you need to slightly pressurize the external oil tank while you crack. I wouldn't suggest firing the engine without having all the oil lines primed up. Disconnect the return oil line and rig something up with an air compressor. All you need is a couple psi. Have a friend help you.
