Originally Posted By: ZeeOSix
Originally Posted By: mechanicx
Still you are saying that the filter bypass is significanlty smaller and more restrictive than the filter oil feed hole. Whether the pressure is normal or high makes no difference. All that matter is whether the bypass is smaller and flows less volume than the feed or not. Making the bypass smaller and more restrictive than the feed is improper because the bypass would be restrictive at all pressures during bypass mode.
The pressure being high or low certainly does make a difference. You need to understand that if you double the pump's output pressure you roughly double the flow rate out of a positive displacement oil pump. The flow volume is what causes the delta P across the element, and if the filter's bypass valve is overcome by massive flow increase it's not going to handle all the flow. The filter designers don't specify a filter bypass valve to handle an oil pump pressure regulator failure.
Plus, you throw in cold thick oil with no pump pressure regulation and you've really got some insane delta P across the element, and no way a puny filter bypass valve is going to handle that flow.
Originally Posted By: mechanicx
Most oil filter bypasses appear quite large and at least as big as the filter feed.
From memory (and I will measure and compare next time I cut open a filter), the bypass valve area looks less than the sum of the base holes and main feed hole.
And when high pressure even excessive pressure opens the bypass the bypass also flows at a higher rate too. My argument is the only restiriction allowing up to 300 psi is the engine not the filter bypass.
I'm talking about the oil feed on the filter mounting pad on the engine usually being no larger than the bypass in the filter. The base hole size doesn't matter in this debate only the size of the oil feed on the engine vs. the bypass size.
Originally Posted By: mechanicx
Still you are saying that the filter bypass is significanlty smaller and more restrictive than the filter oil feed hole. Whether the pressure is normal or high makes no difference. All that matter is whether the bypass is smaller and flows less volume than the feed or not. Making the bypass smaller and more restrictive than the feed is improper because the bypass would be restrictive at all pressures during bypass mode.
The pressure being high or low certainly does make a difference. You need to understand that if you double the pump's output pressure you roughly double the flow rate out of a positive displacement oil pump. The flow volume is what causes the delta P across the element, and if the filter's bypass valve is overcome by massive flow increase it's not going to handle all the flow. The filter designers don't specify a filter bypass valve to handle an oil pump pressure regulator failure.
Plus, you throw in cold thick oil with no pump pressure regulation and you've really got some insane delta P across the element, and no way a puny filter bypass valve is going to handle that flow.
Originally Posted By: mechanicx
Most oil filter bypasses appear quite large and at least as big as the filter feed.
From memory (and I will measure and compare next time I cut open a filter), the bypass valve area looks less than the sum of the base holes and main feed hole.
And when high pressure even excessive pressure opens the bypass the bypass also flows at a higher rate too. My argument is the only restiriction allowing up to 300 psi is the engine not the filter bypass.
I'm talking about the oil feed on the filter mounting pad on the engine usually being no larger than the bypass in the filter. The base hole size doesn't matter in this debate only the size of the oil feed on the engine vs. the bypass size.
