An oil pressure concern

[mhub91]

i know they all physically bolt in i just didnt know if the flow and or pressure was different from d21 / s13 / L24/6/8 pumps

[datzenmike]

The KA24E has 13% longer internal rotors than the regular L and Z series pumps. I haven't messed with an L28ET pump but it's different part number. Likely this is just a different pressure relief valve spring. All pumps seem to put out 50-60 PSI so I don't think it matters much. If racing the rule of thumb is 10 PSI for every thousand RPM expected to run. You can stack washers under the relief spring to raise the pressure. No amount of stacking can raise the idle pressure. This is a function of how much oil the pump puts out at idle vs. the amount of oil that bleeds past all the bearings. Generally the oil bleeding past the bearings is about the same at any RPM and as you rev up, the pressure rises quickly.

 

My old L20B had a hot idle oil pressure of 17PSI. With no other change that an S13 oil pump the hot idle pressure rose to 29 PSI from the increased volume available. I have KA oil pumps on all my Datsuns.

[mhub91]

The KA24E has 13% longer internal rotors than the regular L and Z series pumps. I haven't messed with an L28ET pump but it's different part number. Likely this is just a different pressure relief valve spring. All pumps seem to put out 50-60 PSI so I don't think it matters much. If racing the rule of thumb is 10 PSI for every thousand RPM expected to run. You can stack washers under the relief spring to raise the pressure. No amount of stacking can raise the idle pressure. This is a function of how much oil the pump puts out at idle vs. the amount of oil that bleeds past all the bearings. Generally the oil bleeding past the bearings is about the same at any RPM and as you rev up, the pressure rises quickly.

 

My old L20B had a hot idle oil pressure of 17PSI. With no other change that an S13 oil pump the hot idle pressure rose to 29 PSI from the increased volume available. I have KA oil pumps on all my Datsuns.

 

 

Thanks for the info. Slightly confusing, however I'm interpreting this as "KA oil pumps only help oil pressure at idle".

 

Didn't know the shim trick to raise pressure. Neat. Thank you. 

[datzenmike]

Any oil pump can put out 50-60 PSI. The high volume pumps have more reserve volume so they will have higher pressure at lower speeds... subject to the 50-60 PSI setting of the relief valve. This is ideal for cars with a spray bar for the cam or an extra draw on the system such as an oil feed pipe for a turbo.