LS2 Filter Bypass Valve
Thread Starter
Safety Car
Joined: Jul 2001
Posts: 4,456
Likes: 6
From: Spicewood, Texas, USA TX-Texas
LS2 Filter Bypass Valve
Anyone with a 2005 service manual...can you help me out.
The LS2 has spring-loaded ball check valve in the block to bypass oil flow around the oil filter if the filter is stopped up. Does anyone know the differential pressure specification across the filter for the bypass valve to open? Based on my "other life" experience, I would think it would be about 20-25 psi...anyone know specifically?
Another related question: I presume the oil pressure reading shown on the dash gauge is downstream from the filter, i.e. measured at the galleries feeding the main bearings...Can anyone confirm?
The LS2 has spring-loaded ball check valve in the block to bypass oil flow around the oil filter if the filter is stopped up. Does anyone know the differential pressure specification across the filter for the bypass valve to open? Based on my "other life" experience, I would think it would be about 20-25 psi...anyone know specifically?
Another related question: I presume the oil pressure reading shown on the dash gauge is downstream from the filter, i.e. measured at the galleries feeding the main bearings...Can anyone confirm?
Team Owner
Joined: Oct 2004
Posts: 27,420
Likes: 64
From: San Clemente CA
Originally Posted by JmpnJckFlsh
Anyone with a 2005 service manual...can you help me out.
The LS2 has spring-loaded ball check valve in the block to bypass oil flow around the oil filter if the filter is stopped up. Does anyone know the differential pressure specification across the filter for the bypass valve to open? Based on my "other life" experience, I would think it would be about 20-25 psi...anyone know specifically?
Another related question: I presume the oil pressure reading shown on the dash gauge is downstream from the filter, i.e. measured at the galleries feeding the main bearings...Can anyone confirm?
The LS2 has spring-loaded ball check valve in the block to bypass oil flow around the oil filter if the filter is stopped up. Does anyone know the differential pressure specification across the filter for the bypass valve to open? Based on my "other life" experience, I would think it would be about 20-25 psi...anyone know specifically?
Another related question: I presume the oil pressure reading shown on the dash gauge is downstream from the filter, i.e. measured at the galleries feeding the main bearings...Can anyone confirm?
I think the bypass valve you are talking about is in the filter. There is a pressure relief valve bolted to the filter housing. It maintains the proper pressure in the block. If it also is a bypass valve the manual does not tell the pressure. ( This is on page 6-290) Hope this helps.
Racer
Joined: Oct 2005
Posts: 324
Likes: 0
From: Holly Michigan
19 psi is when the valve begins to open (bypass).
The sensor is after the filter, the filter dampens the pressure signal so the sensor doesn't experience significant spikes, causing sensor failure.
And to clear up any previous misquote, there are no bearing that are lubricated with unfiltered oil unless the filter is in bypass mode.
Also, the filter bypass does protect against a pluged filter although that is not the actual purpose for the valve, but rather to protect against an over pressurized filter due to cold start up. Very cold weather.Pressures over 150 psi can cause the filter seal to blow out and can cause the filter can to leak at the seam holding the can to the base plate.
The sensor is after the filter, the filter dampens the pressure signal so the sensor doesn't experience significant spikes, causing sensor failure.
And to clear up any previous misquote, there are no bearing that are lubricated with unfiltered oil unless the filter is in bypass mode.
Also, the filter bypass does protect against a pluged filter although that is not the actual purpose for the valve, but rather to protect against an over pressurized filter due to cold start up. Very cold weather.Pressures over 150 psi can cause the filter seal to blow out and can cause the filter can to leak at the seam holding the can to the base plate.
Thread Starter
Safety Car
Joined: Jul 2001
Posts: 4,456
Likes: 6
From: Spicewood, Texas, USA TX-Texas
Originally Posted by AFTERBURN
19 psi is when the valve begins to open (bypass).
The sensor is after the filter, the filter dampens the pressure signal so the sensor doesn't experience significant spikes, causing sensor failure.
And to clear up any previous misquote, there are no bearing that are lubricated with unfiltered oil unless the filter is in bypass mode.
Also, the filter bypass does protect against a pluged filter although that is not the actual purpose for the valve, but rather to protect against an over pressurized filter due to cold start up. Very cold weather.Pressures over 150 psi can cause the filter seal to blow out and can cause the filter can to leak at the seam holding the can to the base plate.
The sensor is after the filter, the filter dampens the pressure signal so the sensor doesn't experience significant spikes, causing sensor failure.
And to clear up any previous misquote, there are no bearing that are lubricated with unfiltered oil unless the filter is in bypass mode.
Also, the filter bypass does protect against a pluged filter although that is not the actual purpose for the valve, but rather to protect against an over pressurized filter due to cold start up. Very cold weather.Pressures over 150 psi can cause the filter seal to blow out and can cause the filter can to leak at the seam holding the can to the base plate.
To clarify for some that could misread it, the 19 psi is the DIFFERENCE in oil pressure between the upstream side and the downstream side of the oil filter...NOT the absolute value of the oil pressure. This means, if your oil pressure gauge is reading 70 psi when cold, considering the maximum pressure drop across the filter (assumes bypass opened; depends on the oil temperature), the oil pump could be generating up to 90 psi or more.
It would be interesting to know at what differential pressure the filter media begins to collapse (if the bypass didn't exist or open), but I presume that leaks and other more obvious bad things happen before that.
People never know about all the stuff engineers do that keeps them out of trouble.
Last edited by JmpnJckFlsh; Feb 19, 2006 at 02:19 PM.
