Quote:
Originally Posted by JN-Motorsports
Well, I hate to say this. but I beg to differ. H/V oil pumps have a larger (taller) gear set than a stock pump there for more contact surface which mean more drag requiring more effort to turn the gear. You can feel this if you have ever primed a engine by hand. Then place a 100lb spring on a H/V pump and hand prime an engine and you'll go holy cow!
If your in a habit of blueprinting an engine then your oil clearances will be fine for a stock pump with a higher pressure spring. I have had experiences at high rpm with a 25% increase volume H/P pump bending the spring pin on the distributor gear changing my timing by 15 degrees..
To each thier own.. I know what works for us and we run some 650hp 408 clevelands at 8500 rpm every pass.
Jeff
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A spring is a spring, and if you put a 100lb spring in any pump it will tear your arm off.
Years ago I did a lot of boat engines, I didnt want to keep guessing where my pump springs were so I made a jig for presetting them. The jig had a mount for the pump and a gauge. I would submerse the pickup into a bucket of oil, the discharge was restricted with a valve and returned the oil back to the bucket. Then I spun the pump with a 1/2 drill.
I had a customer that was determined to run a standard pump with loose bearing tolerence because he was also told that the extra drag from a HV pump would tear up his bronze gears.
To prove my point to this customer, I strapped a inch pound torque wrench to the drill and braced the handle against a post. I preset both a HV and a standard pump to 65lbs and spun each of them. They read exactly the same on the torque wrench. Needless to say, I installed a HV pump in that engine.
Rick
