SLP HD oil pump / bearing failure???
10-14-2008, 08:47 AM
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SLP HD oil pump / bearing failure??? I have a heavy duty SLP oil pump that will install this week.
For relief valve spring instructions:
"The oil pump is supplied with a relief spring that is equivalent to the original GM design. If higher pressure is desired, remove the blue spring and replace it with the enclosed red spring. By using the red spring, the pump bypass pressure increases by 5psi. Note. Changing the relief spring will not change the low idle pressure."
Ok, here are my questions and or doubts:
Basics:
If what we are dealing here is a relief valve, then I suppose that the pump will push pressure up to the relief valve pressure and spill over by relief when the pressure exceeds the spring assigned pressure. That makes me assume that if a higher relief pressure is used then the pump will allow higher pressure oil push throught the engine before reaching the relief pressure, higher than GM stock.
I assume that is good for hydraulic lubrication. By that I mean maintaining metal surfaces apart by keeping oil (fluid) pressure like between a bearing and crank. Lifters would be nicely fed. That said I thought I should swap the spring in my new pump till read about bearing failures due to using the high pressure spring on heavy duty oil pumps.
Doubts:
Some people have posted here and there that their engines have failed under racing conditions because they had installed the high pressure spring. They report that under high rpm conditions the oil reserves were depleted by oil being pumped in excess to the engine upper valley thus causing crank bearing failure.
May sound logical at first glance but then it just does not make sense to me. It does not because, if the oil has a higher pressure, it sould drop down to the oil pan as fast as it is pumped up, UNLESS unknown to me there is the possibility that it can accumulate somewhere in the upper valleys faster than it will drain down. Some people knowledgeable in the subject have told me there should be no engine failure related to the higher pressure spring, not be unless the reported failed engine was running low in oil.
Since, I am new to all of this I want to double check with you guys before I commit myself one way or the other with my engine. If I should not worry about any failures by using the higher pressure spring, then I should not worry about any lower pressures to the lifters if I do the small pin hole mod to the cam retaining plate, which is a subject on another thread.
Those who know about this subject, please comment.
For relief valve spring instructions:
"The oil pump is supplied with a relief spring that is equivalent to the original GM design. If higher pressure is desired, remove the blue spring and replace it with the enclosed red spring. By using the red spring, the pump bypass pressure increases by 5psi. Note. Changing the relief spring will not change the low idle pressure."
Ok, here are my questions and or doubts:
Basics:
If what we are dealing here is a relief valve, then I suppose that the pump will push pressure up to the relief valve pressure and spill over by relief when the pressure exceeds the spring assigned pressure. That makes me assume that if a higher relief pressure is used then the pump will allow higher pressure oil push throught the engine before reaching the relief pressure, higher than GM stock.
I assume that is good for hydraulic lubrication. By that I mean maintaining metal surfaces apart by keeping oil (fluid) pressure like between a bearing and crank. Lifters would be nicely fed. That said I thought I should swap the spring in my new pump till read about bearing failures due to using the high pressure spring on heavy duty oil pumps.
Doubts:
Some people have posted here and there that their engines have failed under racing conditions because they had installed the high pressure spring. They report that under high rpm conditions the oil reserves were depleted by oil being pumped in excess to the engine upper valley thus causing crank bearing failure.
May sound logical at first glance but then it just does not make sense to me. It does not because, if the oil has a higher pressure, it sould drop down to the oil pan as fast as it is pumped up, UNLESS unknown to me there is the possibility that it can accumulate somewhere in the upper valleys faster than it will drain down. Some people knowledgeable in the subject have told me there should be no engine failure related to the higher pressure spring, not be unless the reported failed engine was running low in oil.
Since, I am new to all of this I want to double check with you guys before I commit myself one way or the other with my engine. If I should not worry about any failures by using the higher pressure spring, then I should not worry about any lower pressures to the lifters if I do the small pin hole mod to the cam retaining plate, which is a subject on another thread.
Those who know about this subject, please comment.
10-14-2008, 09:36 AM
#2
TECH Senior Member
Yes it can happen especialy under high lateral loads involving Gs and in drag due to the forward to back Loads.
Oil returns under gravity and when the forces inside the motor are above that of natural gravity, you better have plenty oil. Therefore the usage of dry sumps in racing, or high volume oil pans.
For most of us a 50>60 PSI at WOT is safe
Also pressure is not all that matters, what you are trying to achieve is lubrication. That requires the right viscosity under conditions and VOLUME. High pressure pump doesn't necessarily mean right volume on the parts at the right time. Reason why GM restructured their LS blocks from 97/98 and later ones.
Oil returns under gravity and when the forces inside the motor are above that of natural gravity, you better have plenty oil. Therefore the usage of dry sumps in racing, or high volume oil pans.
For most of us a 50>60 PSI at WOT is safe
Also pressure is not all that matters, what you are trying to achieve is lubrication. That requires the right viscosity under conditions and VOLUME. High pressure pump doesn't necessarily mean right volume on the parts at the right time. Reason why GM restructured their LS blocks from 97/98 and later ones.
10-15-2008, 08:57 PM
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You only need higher pressure if your motor was "looser" on bearing clearances. Running a high pres. pump on a stock lower end is a waste IMO. The bearing clearances and the weight of the oil determine the oil pressure.
