Offshoreonly.com - Oil pump selection. HV/HP or HV/ normal P

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Quote:

Originally Posted by stevesxm (Post 3635420)

thats the SECOND basic rule of engineering...

never fix anything that isn't broken.

Hmmm....i was always told (Back when i was in school)it was

1. Make sure its safe
2. Keep it simple
3. Explain it clearly

:D ;)

WOW !!!!!!!!!!!
I shouldn't have too, but I think I need to defend my level of expertise.
As a matter of fact, I agree with stevesxm, bearing clearance is one of the many important parameters in any engine, and yes, I do know exactly what each bearing clearance is, but decided to skip that level of detail, but rather give a general description.
I do appreciate the input from all who have gone before me, expert or novice, which most of us are and want to learn from other's mistakes and experiences. As for rules and re-inventing best practice, I am old enough to remember when roller cams were exotic and front engine dragsters were state of the art until someone tried something different. If it wasn't for creative "average Joe's" there would have never been a chopped, fender-less Model A Ford with a decked flat head engine in any other color than black.
Point is, I will end up making the final choice on oil pump pressure. I find this forum a very good place to get information and hear about other people's experiences, Pro's and shade tree guys alike. The more you know, the better. Thanks guys.

i've always been told that the chevy pump is plenty good for stock and most builds...but hey,what do i know....im a harley mechanic

Quote:

Originally Posted by stevesxm (Post 3635297)

there is so much wrong with this reasoning in this thread , its hard to know where to start...

" clearences around .003 " you don't know ? simply the single most important number on your whole assembly and its a guess ?

and the "more is better" is just nonsense. if you over volume or over pressure the sytem you simply drive the bypasses open non stop, pump heat into the oil for no gain, and wear out the cam gear with the additional drag.

it is a common novice mistake that is supported by folklore and continually handed down by theads like this.

the simple hardcore unassailable fact of the matter is that unless you have increased the mechanical loads in some material fashion such as supercharging or increased revs extremely high static compression ratios, or you were really stupid and put big crank clearences in it then the all thats required is the oil pump and spring that it came with that gave you 50 psi hot at off idle revs. everything after that is wrong to some degree.

i simply do not understand why every conventional big block bottom end that gets built on here has to be reinvented as if the formula for the clearences and pressures hasn't been a matter of absolute fact for 50 freaking years... what exactly is it that has suddenly changed from what has worked forever ?

fyi,the pump in question can produce app 250 lbs pressure,on all oil pumps,the releif valve opens and control,s the pressure,in my opinion,any marine engine will benefit from the addaquit pressure from useing the higher pressure spring.a marine engine gets run at higher rpm range for long periods of time compared to a car engine,it is not uncommon to run a marine engine at 4000 rpm for extended period of time,unlike a car that runs at app 2000 rpm at 70 mph.maybe the engineer who decided to include 2 springs has no idea about what he is doing!