Go figure?!? another oil question ?

[82Waggy]

<snip>

Pressure in a system with linear holes and moving parts cannot be the same in any one point in the system. It is my understanding of the engineering and physics behind this system. If in fact their were no moving part and only oil feed hole then the volume would be less at the far hole than the first. I agree that smaller hole cam bearings, smaller oil feed hole rockers would be great for a lower rpm motor.

Correct me if I am wrong

I think you are reffering to the valving action of the crank not necessarily feeding oil constantly through 360 degrees of rotation.

Think of a chamber pressurized to some psi. Attach a series of valves to it that are all timed to open and close sequentially. If there is pressure in the chamber while these valves are cycling it would be equal throughout.

Such a chamber is in effect what the lifter galleries are. The fact that oil is not being fed through each lifter or crank bearing all the time would make no difference as to the mean pressure being equal throughout the gallery.

Why would you feel the need to restrict oil flow through the valvetrain and cam bearings at low rpm?

[jeepsr4ever]

The short answer to your lasts question is that if the engine sat level and true and stayed at 3500rpm its whole life then their wouldnt be a need but most run low on oil from time to time and most wind it up even past their power range (depending on camshaft) some not all run up a grade sideways and hill climb so their are other variables we have considered.

Getting back to the valley line.

The example you posted about the valves is correct but I dont think it applies here (this is breaking it down further). Lifter movement and duration has alot ot do with oil pressure loss. Now the pressure bypass was engineered for the purpose of metering the volume/pressure to the block. The stock pump was designed to take up the loss in pressure using this bypass. Different things are at play here and one of them is the material the stock spring is made out of. Most high reving applications almost always mean more heat and this heat increases with extended RPM's. The stock pressure spring is made out of what the industry calls "music wire" and it is a general purpose spring wire. This material is known for its rapid fatigue rate above 210 degrees. When your extending your RPM and your engine is running hotter the pressure bypass valve opens at a aggressive rate if we could show a chart with engine temp vs. spring fatigue over time. When the spring fatigues and the rate drops the volume/pressure decreases and the pump starts to cavitate through the oil filter adaptor (if you can call this cavitation). The volume the pump puts out dramatically decreases when the spring fatigues and the heat from the engine is making the pump cavity expand. Now some use a high pressure oil pump spring for this purpose (but most do not understand the mechanics behind the spring). Using a higher rate spring will open the oil filter bypass more often and using a oil filter adaptor without a oil filter bypass can/will blow the filter off the adaptor. the oil filter bypass spring also fatigues and sends particulate from the top 1/3 of your oil filter into your oil journals. The advantage to the main oil line is that when this all happens the rear mains have a better chance of being fed. Many have spun rear mains from a lack of pressure either brought on by operating and higher temps or pushing most of the oil to the top of the engine with little flowback to the pan.

[LiquidSilver]

I have to say many many thanks for all the responses! I have read them all and almost all of the opinions make sense. I probably should have gave more info on how i was going to use this motor.

I do not see me taking this motor to 5500 rpm very often, mostly to get out on a highway from a on-ramp or the once in awhile off road adventure that might need a little oomfff to get me over something. I live where it gets really cold and i drive alot of miles up and down hills, not to much city driving. I plan on a mild cam and intake with throttle body injection.

This is for a daily driver CJ7 that i want to run without problems for 100K + miles. I have it set with the tire size and gears to be around 2,100 rpm at 60mph. I dont want to take any shortcuts on rebuild so i am gathering all the info that i can to make the best decision on what hard parts to buy.

Im still not sure what to take from all of the responses? Should i use the smaller cam bearings and pushrods? Or should i go with stock not mods?
I gather that the oil line is not going to hinder me if i do it in any config that i choose?

Once again thanks so much for all your responses, this is such a big help for me.

Mike

[jeepsr4ever]

Mike you can be alright if your not aggressive with the engine to run without any mods as many have. The things we offer cover most severe applications and in most cases are cheap insurance for a re-build. Each build is different and it is up to you want you want out of the motor present/future and what you need to spend to get it there and keep it there.

[82Waggy]

OK,

But I fal to see how the bypass line can remedy the problem of a fatiging presssure relief spring.

[jeepsr4ever]

OK,

But I fal to see how the bypass line can remedy the problem of a fatiging presssure relief spring.

When your pump is putting out less volume/pressure the sytem will eat up all available oil before the rear mains. You usually hear clacking before this happens....that is the sound of a motor near rebuild

[Mudrat]

This is for a daily driver CJ7 that i want to run without problems for 100K + miles.

Mike

Mike, THAT is the Holy Grail, and I don't think it's been found yet

[82Waggy]

OK,

But I fal to see how the bypass line can remedy the problem of a fatiging presssure relief spring.

when you pump is putting out less volume/pressure the sytem will eat up all available oil before the rear mains. You usually hear clacking before this happens....that is the sound of a motor near rebuild

But for all the reasons I previously stated, a bypass line cannot remedy a loss of pressure. The gallery is more than large enough to flow a sufficient quantity of oil to the system. Increasing the capacity of the gallery by adding a line will flow no additional oil if system pressure is lost. What you are describing is a failure of the flow source.

[jeepsr4ever]

Yes the source does fail and at times doesnt allow more than 10psi at 8000rpms at 230 degrees

[82Waggy]

Sounds like a problem that even a fire hose couldn't fix!