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Topic Review (Newest First)
03-24-2012 07:36 PM
327NUT Schurkey, this thread is 3.5 yrs old.
03-24-2012 06:13 PM
Schurkey
Quote:
Originally Posted by curtis73
No, but since the drag on the pump is exponential, (a function of the square of the speed and the pressure based on viscosity) and the pump spins the same speed as the engine (double the cam speed), try spinning that pump to 6000 with some cold 10w40 in the case. Now you've quadrupled the pressure, which (other factors excluded) has multiplied the drag on the pump by at least a factor of 16 - and that is simply from the oil pressure. That doesn't take into consideration the exponential increases in friction on the driveshaft, the drive gear on the cam, and the gerotor friction inside the pump.
What gear mechanism causes the oil pump to spin at crankshaft speed?

Oil pump runs at DISTRIBUTOR speed, which is same as camshaft speed, because the cam/distributor gear ratio is 1:1, which is 1/2 the crankshaft speed due to timing gear ratio.

SBC and BBC do not use a gerotor design except perhaps as specialized aftermarket equipment, but you're correct that higher RPM would cause additional friction even with spur gears.

Quote:
Originally Posted by Guy Hiltz
as to DoubleVision's statement that a high volume oil pump takes 12 or mor hp to drive,I would have to see a back to back dyno test beforeI would believe it.
Guy
First Guess: The cam/distributor gear cannot transmit 12 horsepower.

Second Guess: Cam/distributor gear would have problems transmitting 2 horsepower with any reasonable life-span.

Quote:
Originally Posted by machine shop tom
IIRC, the stock-volume BBC pump actually pumps less volume than a stock-volume SBC pump because the additonal teeth on the gears in the BBC pump teeth occupy more volume..........
Taller gears. Larger diameter, too, I think.
09-14-2008 02:42 PM
CNC BLOCKS NE We have seen engines come in the shop with BBC pumps and have seen the rear main cracked from I would say the extra weight of the BBC pump and being a 400 cap is weaker then a 350 cap because of the housing bore size it may not be a good idea to run that pump.

We have seen that the Milidon pick up fit to tight it the pump cover causing distortion in so beware.
09-14-2008 10:25 AM
machine shop tom
Quote:
Originally Posted by barnym17
The simple fix for the stock small block oiling system is DON'T FIX IT ,IT AIN"T BROKE!
Bingo.

tom
09-14-2008 07:33 AM
SSedan64 Here's a few good pump Mods>
http://www.chevytech.com/2c63.html

By David Vizard
http://www.gofastnews.com/board/tech...ower-mods.html
09-14-2008 06:30 AM
barnym17 The simple fix for the stock small block oiling system is DON'T FIX IT ,IT AIN"T BROKE!
09-13-2008 04:53 PM
machine shop tom IIRC, the stock-volume BBC pump actually pumps less volume than a stock-volume SBC pump because the additonal teeth on the gears in the BBC pump teeth occupy more volume..........


tom
09-13-2008 03:44 PM
curtis73
Quote:
Originally Posted by ScoTFrenzel
4000 to 6000 rpm will NOT quadruple the pressure, nor the volume.
Oil pressure is controlled by a spring loaded pop off valve, which controls not only the pressure maximum but the overall volume pumped into the galleries.
Bypassing only reroutes the output to the input side of most of the pumps.
Actually it does on any of my builds. 20 psi at idle up to an 80 psi pop off... that's quadruple. Not quadruple the absolute pressure, but quadruple the pressure relative to atmospheric.

Quote:
IMO most shafts fatigue and twist off do to harmonic pulsations, not "oil pressure" that somehow? spikes to a million pounds and twists it off.
You're right, harmonics play a very small role in pump fatigue, but I was intending to demonstrate how 15 hp drag is plausible at peak pressures. Racers don't upgrade to 7/16" drives because they're afraid of vibrations, they just have twisted small ones off too many times to risk it.

Quote:
Dyno tests show that 60 amps draw on an alternator pulls 1 1/2 hp beyond the mechaincal load, which, I do not know how much power it takes to turn an alternator at 5000, do you?
No, but again, my point was to demonstrate that you can't judge something by its performance outside of the real operational parameters. Comparing an oil pump's drag by spinning it with a drill to being anything like operating parameters at redline and 60-70 psi is pretty pointless. Sure it only takes 1/8 hp to produce idle-like pressure in an otherwise empty block, but it takes a heck of a lot to produce 60 psi while spinning 6000 RPM.
09-13-2008 02:07 PM
ScoTFrenzel I swear======
I put 3 quarts in a Toyota 4 cyl PU years ago just to make it hit the end of the stick....

and he put another 100,000 on the engine after that, and sold the truck still running.
09-13-2008 01:59 PM
oldbogie
Quote:
Originally Posted by Stroke
Oil Pressure?

I thought you could just dump 3 1/2 qts oil in and then add two bottles of stp, YIKES!

Heard the best one ever the other day. Checked the oil level on a 4.6 Lincoln, what oil? I added 2 1/2 qts and made sure I told the owner they had such little oil. Response was that for this car, you couldn't add oil until the light came on and then only 1/2 qt. Some men, you just can't reach. Jus blabbin...
Old Amos and Andy line when the station attendant (1950s) showed them the oil level on the dipstick; " Now Amos, who ever done heard of puttin' oil in a new Cadillac".

Bogie
09-13-2008 01:54 PM
Stroke
Oil Pressure?

Oil Pressure?

I thought you could just dump 3 1/2 qts oil in and then add two bottles of stp, YIKES!

Heard the best one ever the other day. Checked the oil level on a 4.6 Lincoln, what oil? I added 2 1/2 qts and made sure I told the owner they had such little oil. Response was that for this car, you couldn't add oil until the light came on and then only 1/2 qt. Some men, you just can't reach. Jus blabbin...
09-13-2008 01:47 PM
ScoTFrenzel
Quote:
Originally Posted by curtis73
No, but since the drag on the pump is exponential, (a function of the square of the speed and the pressure based on viscosity) and the pump spins the same speed as the engine (double the cam speed), try spinning that pump to 6000 with some cold 10w40 in the case. Now you've quadrupled the pressure, which (other factors excluded) has multiplied the drag on the pump by at least a factor of 16 - and that is simply from the oil pressure. That doesn't take into consideration the exponential increases in friction on the driveshaft, the drive gear on the cam, and the gerotor friction inside the pump.

People say the same thing about alternators because they spin so freely. Put a load on them and spin them to 5000 rpms and then see how freely they spin.

Oil pumps take considerable HP to run. Otherwise, why would manufacturers use a heat-treated chrome-moly 3/8" shaft to drive it?
Just a side note.
As for people spinning 6000 rpm on cold oil..... yes I have seen a few retards in action. LOL

4000 to 6000 rpm will NOT quadruple the pressure, nor the volume.
Oil pressure is controlled by a spring loaded pop off valve, which controls not only the pressure maximum but the overall volume pumped into the galleries.
Bypassing only reroutes the output to the input side of most of the pumps.

I know that SBC are notorious for poor oil pressure, hoping for at least 10 psi per thousand rpm, but most pumps have pressure springs set around 55 psi. maximum, which "should" be reached well before 5500 rpm. I have seen many that hit 55 psi at 3000 rpm with hot oil.
(Thos of you who have a Ford, yours probably idles with 55 psi hot )

IMO most shafts fatigue and twist off do to harmonic pulsations, not "oil pressure" that somehow? spikes to a million pounds and twists it off.

Dyno tests show that 60 amps draw on an alternator pulls 1 1/2 hp beyond the mechaincal load, which, I do not know how much power it takes to turn an alternator at 5000, do you?

JMO Thanks for the reply.
09-13-2008 01:46 PM
oldbogie
Quote:
Originally Posted by dallam11
I'm freshening up my 400SB Chevy with new rings and installing a set of used Vortec heads. Just for insurance, I am going to discard the old oil pump and install a new one. Here's my question...can I install a BB oil pump? If so, do I need a different length intermediate shaft? I like the idea of the big block pump having more gear teeth and producing slightly more oil volume without being much harder to turn than the small block pump....Do you gents agree?
Yeah, I'm a big fan of using the big block pump. It bumps the hot idle and lower RPM oil pressure up which these engines need if they're used hard at low and moderate RPMs or certainly if they are raced where frequent gear changes and high loadings are experienced which is the case on road track and short ovals.

The down side is the big block pump delivers a lot of oil you don't need in the RPM ranges from 3 to 6 thousand so the relief is dumping a lot of unused oil your spending a few horsepower to heat up and dump back in the pan. But I've found this a cost of providing better bearing protection in the lower revs.

Yes you need the shorter intermediate shaft and use a steel rather than plastic coupling.

With the Vortec, GM has had a lot of bottom end warranty issues related to insufficient oiling on hard working engines. I consider the BBC pump and using a 15W40 or 20W-40 oil to be significant insurance against these issues. Especially if you work the engine hard and live in a hot climate.

Bogie
09-13-2008 01:42 PM
dallam11 Here ye, here ye gents..there is certainly a lot of differences of opinion about running the big block pump in a small block. Reading all of the posts I have decided the go ahead a run the STOCK BB pump! I made the decision after one of the gents above stated there is a Moroso part number for a pump shaft that is offered just for this conversion...if Moroso sells parts for this BB pump adaption, then it is OK to do it in my book! Also, my 400 motor will be no lazy day loofer. The cam is out of a ZZ4 and I am going to mildly port the Vortec heads. The thing will have to be putting out over 400 horse power and then some. I really think I need a little more than what a stock oil pump can furnish here and in my opinion and the same for some of your opinions, the stock BB pump is just the ticket without being pricey and going overboard in consuming horsepower. Thanks!
09-13-2008 01:24 PM
Stroke There are other alternatives for pumps, the BB pump is just one of them. If you want a really good pump buy a Titan. The idea of more gears in the BB pump was one plus of running it in the SB, thinking like this anyway - more gears equals more pulses per revolution... helping to eliminate, or distribute those pulses more evenly, diminishing the larger pulses from the SBC pump that might wreak havoc on the distributor and spark timing. I like to run them just because.
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