Oil accumulators

[cjshaker]

Can anyone tell us how long it takes their specific sized accumulator to blow-down on just a hot engine/hot oil with a non-running motor?............

BB, watch Marc's video that he posted. It shows the rate or "time length" of flow. It lasts about as long as Jay said, depending on the pre-charge and how much oil is in the accumulator. The line and oil ports themselves are the restricter. One thing you can bet on, if lots of racers use them, they're using them for a reason. Those guys don't waste money/space and weight for nothing.

[Qikbbstang]

I noticed the oil utilized in that Moroso Accumulator video was snake-oil. Obviously some people believe the video shows what really happens:

"BB, watch Marc's video that he posted. It shows the rate or "time length" of flow. It lasts about as long as Jay said, depending on the pre-charge and how much oil is in the accumulator. The line and oil ports themselves are the restricter. One thing you can bet on, if lots of racers use them, they're using them for a reason. Those guys don't waste money/space and weight for nothing."

What the video shows is pressurized reservoirs and un-pressured reservoirs hooked up and valve'd to an accumulator with what looks to be at least #8 lines.  The genuine "restriction" of oil flowing into an engines bearings, rocker assemblies etc is not even in the Moroso equation. I think Moroso really cheese'd on the video by synthesizing what happens and not actually using a real engine .  By their own demo the 3qt accumulator offers up only a 1-1/2qt of oil. The guy stating: "...a quart and a half and possibly another quart in the line" is absurd as if that's going to do something.
  I searched youtube and found an import where its accumulater is discharged into an off engine and maintains pressure for 15-20 seconds, again into an off engine as the guy on the video stated. I learned using the on/off ign switch to actuate the valve you are likely going to be idling with low pressure and not have that 4,000rpm 80psi stored for starting.

https://www.youtube.com/watch?v=uhRfUegqwxg
for purely shits and giggles:
https://www.youtube.com/watch?v=j0T8MWYuugU

[jayb]

BB, when I use the accumulator I rev up the engine to get the oil pressure up, then close the valve (I don't do this with the ignition switch, I do it separately), before shutting off the engine.  Then you get good oil pressure inside the accumulator for a long pulse available during cranking.

Again, mostly what you are worried about is shut down at the drag strip, or corners on a road course.  In all cases at the drag strip, and I imagine nearly all cases on a road course, you have the engine revved up pretty good (you are racing), so there is good oil pressure in the accumulator available in case of oil starvation at the pump pickup.

I know you are a skeptic ( ), but in this case I think your skepticism defies common sense.

[FordEver]

I have the 3 qt. with electric valve. Hot, I bring the rpm up get the max fill and PSI and shut off the valve, then the engine. Cold test, with the valve covers off, turn on the valve, within a few seconds oil at the rocker shafts. Normal cold startup switch on, PSI to 30-40, then when starts to fall off, then start engine and into staging lane.
Canton requires #10 line.
I have mine on the left apron, maybe gets some oil cooled outside the engine for a bit. I have it mainly for dry starts, any other pressure maintaining is a good thing.
An option for road race guys  a pressure valve  that opens at specified setting. to keep pressure up.
Many sanctioning bodys require a stock type wet pan, so this helps.
If you don,t like /believe in these, then don,t use/ buy them. Nice Mustang you have there.

[turbohunter]

Well, I think Moroso was just trying to illustrate visually what happens in the unit so all levels of intelligence could grab the idea.
And of course in illustrating visually, sometimes you have to physically cheat a bit to try to make it obvious/simple.
So "cheesing out"was probably a necessity. Hey, I work in Hollywood, I'm used to cheese.
But the more I studied the installation instructions of all the units, the more I like it.
My shade tree mechanic street smarts tells me it's a good thing.
Try this page on for size.
http://www.accusump.com/accusump_tech.html

[cammerfe]

You guys are doing a good job selling me on them, yet IF the FEs pumping capability is anything near the 24 gpm @ 4,000 rpm figure from FoMoCo a quart or two of pressure feed oil is gone through in a second or two at best right? ..............Jay you are far on the opposite side of the equation in your belief about "I'd guess that a 2 quart accumulator would keep the engine oiled for at least 15-20 seconds, which is all anybody should ever need."

Can anyone tell us how long it takes their specific sized accumulator to blow-down on just a hot engine/hot oil with a non-running motor?............

Yes, BB---

On my 390 in the truck, the pressure held for at least 15-20 seconds before the gauge began to drop and it didn't go to nothing for at least another 15-20 seconds. This in an engine with about 100K miles. I did do a bearing replacement before using it as a DD. Although the removed bearings looked OK, I figured the replacement was good insurance.

KS

[Autoholic]

I noticed it seems like BB is getting hung up on the flow rate of the oil pump, at least as part of his problem. The oil pump is not fed from the oil filter or oil accumulator, so its flow rate has little to do with this. It won't be consuming any oil from the oil accumulator, at least not directly. So the rate at which the accumulator oils the engine has no impact on the oil pump during loss of pressure, or how much oil the accumulator can provide for that matter. Remember, the oil pump pickup is in the oil pan, full of oil at start up. While running whenever it loses oil supply, the accumulator still has no impact on the oil pump. If you were to lose oil pressure for more than a minute, an oil accumulator wouldn't be able to help you out but a minute is a rather long amount of time when dealing with an engine, even during start up. Oil temperature is a different story and this is where the cold oil grade comes into play.

A quarter mile run is over inside 15 seconds, a hard corner on a track, with braking and accelerating, lasts less than 10. In 30 seconds at 6000 RPM, you're engine has turned over 3000 times. In 1 second, 100 times. At say 1000 rpm idle and start up, your engine turns over 17 times a second. The rate at which the oil moves from the accumulator to the engine will be determined by two things: The precharge pressure and the cold viscosity of your oil. I wouldn't rely on the hot viscosity because oil in the accumulator will not always be at operating temperature. 80-90% of the wear on your engine happens when the oil is not up to temp, which is mainly cold starts when the engine is dry. At idle, your engine only needs about 10 psi of oil pressure, per the 10 psi of pressure per 1000 rpm rule.

[Qikbbstang]

I think I finally got the math (if I did it correctly?...) where I can buy into what's going on. If the typical 3Qt accumulator holds and flows 1-1/2 Qts of oil in as mentioned 10-15seconds that's in the relm of 6-9 GPM flow through the motor. I can more then live with that 6-9GPM figure though it seems high. One time when I spoke with an engineer at one of the oil filter companies that told me a standard sized  FL1A filter could be counted on to keep up with a standard duty oil pump, but the filter would be into bypass often with a high volume pump.

I think of pumping 5GPM  through a typical spin on and cringe, that's as much as my 1/2HP well pump puts out and thinking about that much flow with the viscosity of even multi-weight oils flowing through a "nominally rated" oil filter is bound to build up delta-pressure. 
     More then ever the wacky 20GPM+ "spec" figures of Ford Hi-Perf FE oil pumps is tough to figure why build in so much excess capacity?   

 would be hard pressed keep up with the flow   

[Drew Pojedinec]

More then ever the wacky 20GPM+ "spec" figures of Ford Hi-Perf FE oil pumps is tough to figure why build in so much excess capacity?

BB,
You know a ton about filters, this is true, but it is apparent that you aren't all that savy on pumps.
The 20gpm figure you are getting is not at pressure through an engine, never was.  It's most certainly a free flow situation.  Add the bearing clearances into it and you've got a pressurized system that leaks excessively.
Due to varying conditions in an engine (bearing clearances due to temperature, rpm, et el) any pumps is going to be oversized on free flow in order to maintain pressure in a leaking system.  If a 20gpm pump inside an engine ever saw 20gpm it would mean you have zero oil pressure, which is obviously an undesirable situation in an engine.

This isn't that far removed from the 1/2hp well that claims to pump 20gpm at zero lift/zero head (the 5gpm you stated is really small).  It *can* produce that kind of flow with zero restriction, zero friction loss in the piping, etc.  In reality your 20gpm pump never pumps more than 8-10gpm.  If it was pumping 20gpm the piping (if pvc) would need to be 1.5inch just to keep flow speeds under 5ft per second.  More likely you have 1 inch piping which would be hitting that speed at 12gpm... in the case you have 3/4 inch piping you'd be hitting that speed at 8gpm.  In those systems it's important to stay under that flow speed because the frictional losses go up exponentially once you get near that flow rate.

thus.......
If you wanted 20gpm at 45psi from your well, you would ideally have a 3hp pump with a 1.5 or larger discharge piping and 2inch suction line.
Along the same lines, if you want ample flow and 60psi of oil pressure from an engine, you better be pumping ten times more oil into it than it can leak out.

[Drew Pojedinec]

On another note, as a filter man, you MUST realize that in an engine, an oil filter doesn't have to deal with pressure on one side only.....
If you think that, you should really get a gauge and put it on each side of a filter sometime.
With industrial engines I only ever really care what the pressure differential is.

[plovett]

I'm not necessarily agreeing with BB, but I've heard him say "Delta P" enough times to think that he knows the pressure differential is key.  Let's see what he says.

paulie

[Drew Pojedinec]

the viscosity of even multi-weight oils flowing through a "nominally rated" oil filter is bound to build up delta-pressure.

-BB

Yes, but him saying that, to me either means that 1. He doesn't actually understand the term, (unlikely considering his profession).  or 2. He has never checked on a running engine.

[cjshaker]

I think what Drew was pointing out was that filters have pressure on both sides, so it is not strictly a matter of full pressure on one side causing a filter to go into by-pass mode at all times. Unless a filter has lots of restriction, it can have 120 psi on one side as well as 120 psi on the secondary side (or very close to it), so no bypass will happen in that situation.

While the Fram filter I showed earlier had big consequences because of no by-pass, I like the Canton filter I use on my Mach 1 BECAUSE it has no bypass. I thoroughly DO NOT like the idea of unfiltered oil getting into the engine. I watch my gauge on every start-up, and it takes no longer to reach pressure than any ordinary filter I've ever used. And that's with 50w oil, although it never gets started in real cold weather and I let it thoroughly warm up before raising the rpms and driving it.

[Qikbbstang]

I have a pretty good grasp on pumps (I was a manufacturers Rep on the 10,000psi hydraulic stuff and that's how I got into filtration).  FE oil pumps are all gerotor pumps, by the book gerotor's are positive displacement. They are known as self priming as long as they are not bone dry.  Hate to argues but at a given rpm and the amount of fluid displaced per revolution of the gerotor there should be very minimal loss of fluid volume with pressure increases especially with a viscous fluids like oil. As far as leaks that's all downstream of the pump and filter (if you have oil leaks between the pump and filter you have a real mess)
As far as bearing clearances and leaks that is simply lubrication and heat removal in an engine.

The point I mentioned regarding delta-p is a typical spin-on oil filter flowing oil can not be expected to flow more then a few GPMs with delta-p increases/bypass.
 FoMoCo was the source of the 20+GPM @ 4,000. I think they are on a pipe dream with numbers that high unless the gerotor simply internally bypasses a significant amount of oil inside the pump and they certainly have the internal ports to bypass from pressure side of the gerotor to the suction side. 15-20GPM bypass

[Drew Pojedinec]

Good luck!