CB PERFORMANCE DRY SUMP PUMP.

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Re: CB PERFORMANCE DRY SUMP PUMP.

Post by Marc » Tue Jun 14, 2016 10:34 pm

Passatman wrote:...Marc how was the fit of the pump in the case, did you have to o ring it and which case are you using?
I've never used a dry-sump setup on the street, only on racecars where hot-idle oil pressure is never really an issue, with stock AE/AH/AK/etc. Type I cases...but on those occasions where idling was necessary (say, on a red-flag) the pressure was not impressive. I can imagine needing to hold the idle speed up a bit to keep the light out in traffic on a hot day. For street use it'd probably be smart to O-ring the pump - that's never a bad idea, wet- or dry-sump. The cast-iron housing pumps (i.e. Melling) are by far the worst offenders since steel/iron only expands about ⅓ as much as light-alloy and big leaks develop on both the inlet & outlet ports when things get hot. Probably the WORST there is for good hot-idle pressure if not O-ringed. With an aluminum pump it's not so risky to run non-O-ringed, but it'd be a minor expense when considered in light of your whole build cost.

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Re: CB PERFORMANCE DRY SUMP PUMP.

Post by RHough » Sat Jul 16, 2016 6:48 pm

I'm planning my dry sump installation for the Karmann Ghia.

I have some questions for everyone. (Nothing new) :mrgreen:

I want to have a 100% reliable oil system so overkill is fine.

The CB pump 21mm pressure side looks like it oils through a convoluted passage to get to the case. Since the case passage is already blocked with a plug, How big a deal would it be to full flow the pressure pump outlet? That would get me to a somewhat thicker version of what I have now. Including the 90° fitting that the return oil has to flow through.
Oil Pump.JPG
I'm adding a 2qt Accusump too. It's huge!
Accusump1.JPG
It will fit in the left rear fender behind the trim and the hose can exit below the bumper bracket.
Accusump2.JPG
AccusumpOutlet.JPG
Dry Sump Tanks are a hot topic. I know this one works for road racing ...
Oil Tank.JPG
Oil TankBack.JPG
It was designed by Honda for the CB 750
cb750tnk.jpg
Now I come to the options and questions ...

Option 1 is to put the filter and Accusump on the pressure side as it is now:
Option1.jpg
Option 2 is to use the scavenge side, don't full flow the pressure pump and use the oil full flow inlet for the Accusump.
Option2.jpg
So far the stock doghouse cooler and pressure relief systems are working just fine. Oil pressure is good and temperature at the oil pressure sw port is 180 after about 20 minutes. I've never seen much over 200. I don't know that I'll need an external cooler/oil t-stat in the future but that adds the plumbers nightmares and restricts flow on one side or the other.

Oh ... and a windage tray?
windage tray.jpg
Questions.
Since the CB pump will need a small pulley for clearance why not use a full flow fitting back into the engine instead of the 90° elbow that is used to clear the tin and full size pulley?

Is there any gospel about the filter on the scavenge side vs the pressure side? Seems to me that the pressure side is the better choice since we don't want to restrict the output of the scavenge side? We are already asking a pump designed for a gravity prime to suck a mixt of oil and air ... on the other hand would the filter and option external cooler help deaerate the oil going back to the tank?

What should I do about cooling fan speed with the CB dry sump sized pulley? The flow for heat is almost a requirement in Canada as well as for the oil cooler. What works for you?

Windage tray? Yes or No?

Is the system overkill for Autocross and Track Days?

Last; pros and cons of keeping the deep sump. Better to keep any oil in the engine higher to prime the scavenge pump or keep the extra capacity for drain back events?

Notes on the tank selection:
The tank in a dry sump system does not have to be huge, only big enough to keep the pressure pump primed with air free oil. The Honda CB750 system holds about 4.5 litres including a filter change. The Accusump will store about 2 more. Total oil capacity 6.5 litres +/-.

With 2 litres in the Accusump a total tank drain back to the engine would be about 3-3.5 litres at the most. so I don't need to worry about that. IMO it is more about shape than size when it comes to dry sump tanks. After changing from a low mounted and larger oil tank in the sidecar, the little stock tank mounted with the same head as the stock bike cured the chronic bearing failures we were having. I have faith in the design.

I'll monitor the oil pressure and wire in an alarm any time the Accusump is working (Oil Pressure below 20-25 psi). I might even rig a test feed hose with a clear section to get a visual on how much air (if any) is in the return oil.
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Re: CB PERFORMANCE DRY SUMP PUMP.

Post by Piledriver » Sat Jul 16, 2016 10:29 pm

On a T1 the windage tray and pushrod tubes are a win, or at least doesn't hurt.
On a T4 (or WBX), there's a wide, 5 quart sump down there, so the factory windage tray is worse than useless, esp with DS.

A steel/iron "full flow" cover works, as would a thin iron cover for a Melling pump...
It may allow a full sized pulley combined with the right button head bolts.(may not matter)
You can use a full sized pulley on a T4.
Some of the T1 pulley setups have a steel "hub" those could be spaced out a tiny bit to excellent effect.

You can put a pressure fitting in the outlet side of the pump easily, doesn't have to be huge.
You want the largest bore fitting you can get on the inlet side of the pressure stage (gravity fed)

You can get better 90 degree fittings with a radiused bend, or feed from the bottom if you use an external relief valve.

If you still need a DS sized crank pulley, you combine that with a 356 generator pulley and you are magically back at the ~original pulley ratio.

I would stretch that tank to ~8 quarts and run 6.
Mount it under the deck with only the filler showing.
Its low enough then.

Lose the deep sump, its only a low hanging potentially engine destroying target for rocks and stuff with DS.
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Re: CB PERFORMANCE DRY SUMP PUMP.

Post by Marc » Sun Jul 17, 2016 12:19 am

RHough wrote:I'm planning my dry sump installation for the Karmann Ghia...The CB pump 21mm pressure side looks like it oils through a convoluted passage to get to the case. Since the case passage is already blocked with a plug, How big a deal would it be to full flow the pressure pump outlet? That would get me to a somewhat thicker version of what I have now. Including the 90° fitting that the return oil has to flow through....
Your proposed diagram is of a strange hybrid of wet-sump & dry-sump plumbing. Is it your intention to plug the pressure-side passage in the case and use a "wet-sump" external-outlet cover on the CB dry-sump pump? Might be a slight gain to that setup from eliminating the tortuous return path native to the pump...but you'd still run the filter on the scavenge side, on the way to the tank.

The CB dry-sump pump uses the stock path for the oil going from pressure-side of pump to the bearings (the case is NOT plugged for this pump, nor is there any external outlet from the pressure side as is provided by an external-outlet cover in a wet sump full-flow filter installation). The filter would go in the loop going to the external tank; IF you also wanted to run an AccuSump, it would need its own independent connection to the oil galleys - the restriction of a standard 90° ell fitting would not be an issue if all it serves is the AccuSump.

A "standard" size (6") power pulley won't reduce your fan's speed as much as the tiny 5¼" one that the dry-sump pump needed before they came up with the thinned sand-seal pulley available now, but even with a thin/flat Melling-style cover both the top edge of the cover and the back side of a non-sand-seal power pulley need to be clearanced some. To replace the belt you need to loosen the pulley bolt and pull it partway off. If you don't have any qualms about running a "slip-in" sand seal and spacers to move the crank & alternator pulleys out, CB's #1953 will clear their pump.
No stock-size pulley has any chance of fitting above the pump. If you were to use instead a "proper" 2-stage pump (i.e. Bugpack or Autocraft) you'd already have a non-restrictive pressure-pump outlet fitting, but the increased length of the pump would make the 5¼" crank pulley the only option (and may also require modifications to the exhaust system).

The aftermarket return fittings for a wet-sump full-flow setup avoid the need for drilling/tapping the case for a proper return fitting, but they use a highly-restrictive banjo fitting and require the removal of the control plunger & spring so are best used with a cooler that's in series with the filter, equipped with a thermostatic bypass valve. So, while one would be fine for connecting the AccuSump it would disable the normal functionality of the stock cooler system, delaying engine warmup even more than it already will be due to the increased oil capacity....plus, they often leak.

Windage tray works well enough on a wet-sump setup in normal to reasonably-spirited driving, but if you get really rowdy (e-brake J-turns, for example) the oil will get atop it much faster than it can dribble back down - pump will starve for about 5 seconds, long enough to damage rod bearings. Also interferes with the cam lobes on any serious-lift cam unless it's ground on a reduced base circle.
I ran them once upon a time but never will again. "Windage tubes" offer much of the benefit with no liabilities.

For dry-sump the deep sump, the tray and the extended tubes are completely pointless IMO, don't bother.
A "sump-bump" lowered pickup might be justifiable, but I've never found one necessary. I also fail to see what possible need there should be for an AccuSump on a dry-sump system beyond offering the ability to pre-oil the engine before startup (provided you remembered to isolate it before shutting off the last time).

Image

Suction-side filters are a bad idea; Citroen uses them on the 2CV engine and gets away with it, but they're not for me. Epoxy a strong magnet to the outside of the sump plate (a "cow magnet" or one of the round ones that're ubiquitous in Detroit auto transmission pans) if you choose not to run a pickup screen. I've always run the screen and never had any problem. If a big enough chunk of steel gets into the pump it'll lock the gears (the drive gear is just a press-fit to the shaft on most; even if it's attached with a key that'll shear when faced with an indigestible bit).
RHough wrote:...I'll monitor the oil pressure and wire in an alarm any time the Accusump is working (Oil Pressure below 20-25 psi). I might even rig a test feed hose with a clear section to get a visual on how much air (if any) is in the return oil.
Expect to be seeing that alarm a lot when you aren't above ~2000 RPM or so with hot oil...the CB dry-sump pump has a hard time just keeping the stock pressure warning light out at hot-idle.

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Re: CB PERFORMANCE DRY SUMP PUMP.

Post by RHough » Sun Jul 17, 2016 10:15 am

Thanks for the replies!

I can mount the tank through the apron so the oil lines and drain are under the car and the filler and vent are in the engine compartment. There may a limit due to the CSP Python muffler and tailpipe. I might consider adding capacity to the tank only if it does not provide air free oil to the pump. Oil capacity beyond the amount required to de-aerate the oil only adds to warm-up time and oil change expense.

Looking at the CB pump it appears the oil inlet from the tank is on the right side of the car and the scavenge oil comes out the left side? That makes it easy to plumb the scavenge side to the existing filter location then over to the tank with fairly straight hose runs.

The main oil galley in the case is plugged as part of the existing flow flow system. So a full flow cover on the CB pump and a nice low restriction elbow makes for short lines to plumb the Accusump.

The main reason for the Accusump is to keep the engine alive in case I'm wrong about the oil tank size and the pressure pump gets a milkshake from the tank. Once the dry sump system is sorted the Accusump is just pre-oil and backup.

I was planning to o-ring the CB pump as part of the install to minimize any losses and to keep hot idle OP as high as possible. The Accusump system light would be wired in parallel and could include an idle cut switch if the light on at idle bothers me.

I'm running windage PR tubes now and the windage tray is sort of a paranoid belt and suspenders idea. I don't know that oil starvation was a factor in the engine failure but since the engine is out for rebuild anyway I might as well go full monte while it is easy.

I'm also starting the conversion from Webers to EFI. The crank pulley will need a crank angle wheel as well as clear the pump / tin. I hope CB can supply a pulley with a trigger wheel so I don't have to send the new pulley to Mario for machine work. Maybe get the CB#1953 with trigger from Mario?

Hose sizes? The Accusump uses -10 hose ... Any gain in making the pressure side all -10 or stay with the -8 with the -10 just from the tee to the Accusump? On the Scavenge side -8 to the filter and tank return? Then -10 for the tank pump feed line? The tank is steel and I'd like to have AN fittings welded on rather than used the spigot/o-ring that Honda used. Good source for the AN stuff?

Thanks!
Last edited by RHough on Sun Jul 17, 2016 12:02 pm, edited 1 time in total.

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Re: CB PERFORMANCE DRY SUMP PUMP.

Post by RHough » Sun Jul 17, 2016 12:00 pm

Revised system schematic:
Revised1.jpg

Oil Tank height and siphon?

One of the things that concerns people is placing the dry sump tank low enough to limit the drain back to the sump with the engine stopped. This was never a problem with the Honda system I'm familiar with. The tank was mounted well above the pump so I looked to see how they prevented the tank draining back into the engine.

They used a pressure pressure controlled check valve that closed the pump pressure outlet at zero pressure. It was a simple plunger/spring valve between the pump and the oil gallery that opened at very low pressure as soon as the engine turned over and there was oil pressure.

In the Type 1 the cooler relief valve is in the right place to do the same thing. It closes the output from the pump when the engine is stopped. It opens to bypass the cooler when the oil is cool then opens to allow flow through the cooler when the oil is warm and the viscosity drops. I think that means any oil draining back from the tank would have to pass through the cooler in the doghouse? Any air in the engine side as the oil drains past the bearings and lifters would end up in the top of the cooler? As long as the oil level in the tank is below the top of the doghouse cooler the cooler and relief valve should act like a siphon break? Does that make sense to anyone?
drainback.jpg
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Re: CB PERFORMANCE DRY SUMP PUMP.

Post by FJCamper » Sun Jul 17, 2016 1:53 pm

Hi Randy,

In my opinion,I applaud your ingenuity in planning your dry sump system, but I believe you're over complicating it.

My model for dry sump systems is the 911 RSR's, 934's and 935's we raced at Brumos. This was my first hands-on experience with dry sumps. When I needed to rig my own oiling system and dry sump for VW racing, I copied what I had seen on the Porsches, and what the 550A manuals and photos showed me.

The CB dry sump pump is by no means the best pump available, but it will do the job. Our friends who race the really quick red Bugs in South Africa redrilled and ported their CB pump to increase flow, and like Marc, noted that the pump's internal flow design is a bit convoluted.

We race three of these Chumpcar/LeMons endurance races a year, a minimum of 7 hours for one day and a maximum of 14, and the CB pump has come through with flying colors. It will even produce just enough idle pressure to keep the oil warning light off if your cooling system is up to it. We have a big, multiplate cooler in the Blitzwagen.

I think Accusumps are great, but never ran one on my own cars. For VW's I am a big proponent of the cheaper, wide but narrow deep sump for low cost racing oiling. And in my life, we've knocked at least two of the deeper sump designs off engines, both in street use. I know the hazards.

Always run your filter on the OIL OUT side of your dry sump pump. The oil is at its hottest, and the pressure is at its greatest as it enters the filter. The oil then goes from the filter to the cooler, then the oil tank, defoams, and is picked by the suction side intake for return to the engine.

Do not put anything in the return line with the possible exception of a low-restriction, in-line AN-fitting filter.

We recently had the still-unsolved incident of a blob of fine Brillo pad-like material that made it from the oil tank, through the oil pump, to the oil pickup. We use the "oil suction" kit screened pickup.

Actually, your motorcycle oil tank might just make a great tank. The Porsche 550A with the 4-cam engine used a 6-qt tank. We use 3-gallon tanks in our Bug and Ghia simply because that's what's available.

I advocate using a windage tray and windage push rod tubes because they do help to keep oil out of the 3-4 side cylinder head. You can have up to a quart of oil suspended in the heads at high RPM. We know this because we made a valve cover with a Lexan window in it and watched it run on the engine stand with windage and non-windage tray engines, and G-forces were not part of the equation!

At 3000 RPM, no tray, the 3-4 side was half full of oil. At 5000, almost full.


FJC
Last edited by FJCamper on Sun Jul 17, 2016 5:36 pm, edited 1 time in total.

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Re: CB PERFORMANCE DRY SUMP PUMP.

Post by RHough » Sun Jul 17, 2016 3:09 pm

Thanks Frank,
I'm the president of my local Overthinkers Anonymous group.

I'm doing the calculations now for hose and fitting sizes. Goals are to have a feed tube from the tank to the pump large and short enough to get laminar flow and close to zero loss between the tank and pump at 4 gal/min since 4.2 gal/min is the flow rate for a stock 26mm pump. The 21 mm pressure side should deliver about 3.5 if the output is a linear function of size. The scavenge side from the pump to the filter and tank can stand a bit of restriction for pure oil since the emulsion of air and oil should have lower specific gravity and viscosity than oil alone. The full flow hose from the pump to the engine includes the tee for the Accusump valve and a 90 degree elbow so I may have to accept a small pressure loss and transitional flow in that line. It will be no worse than a standard flow flow system in any case. It's looking like -10 for the scavenge circuit to the filter and tank, -12 for the tank to pump feed, and -6 or -8 for the pressure loop to the engine with a -10 off the tee to the Accusump.

My experience with oil lines and g loads makes me pretty anal about a gravity feed to the pump at all times. The easy way to insure that is to check the angle of the oil level to the pump inlet. One g loads require the oil level to be above a 45 degree line from the pump inlet. If the lowest point in the tank is above 45 degrees it is even better. I've seen oil starve in relatively short horizontal lines feeding the pressure pump. Less than one g lateral was enough to kill an engine. If I was thinking about a remote tank in the nose of the car I'd run a high volume, low pressure feed pump from the tank to the engine pump that was 100% gravity fed from the tank.

Topic branch- You mentioned you use an electric scavenge pump for the 3-4 valve cover. I don't remember seeing that documented on the forum. Got a link to a thread or to the supplier of the pump?

Back to over thinking. :-)

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Re: CB PERFORMANCE DRY SUMP PUMP.

Post by Piledriver » Sun Jul 17, 2016 3:32 pm

The electric scavenge pump has been discussed in the past, and has been used for awkward turbo installations...but simply not venting the 3/4 valve cover, (ex valve guide bleed by provides postitive pressure) or feeding it purge air with a check valve and pulling some case vacuum keeps the 3/4 rocker box clear of oil.

You can buy excellent quality low popoff pressure check valves from Swagelok or Parker in naval brass or SS down to 1/3 PSI, with viton seals.

However...I suspect the slow to-sump leakage path to be through the pump itself, the shaft bore between stages is not sealed, just a relatively tight tolerance hole><shaft clearance.
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Re: CB PERFORMANCE DRY SUMP PUMP.

Post by RHough » Sun Jul 17, 2016 4:14 pm

Piledriver wrote:The electric scavenge pump has been discussed in the past, and has been used for awkward turbo installations...but simply not venting the 3/4 valve cover, (ex valve guide bleed by provides postitive pressure) or feeding it purge air with a check valve and pulling some case vacuum keeps the 3/4 rocker box clear of oil.
Exhaust valve guide leaks past the valve stem into the valve cover? I assumed there were seals on the guides. Bob Hoover wrote about proper valve guide seals in his blog back in 2003. OTOH there are many VW engine builders that don't use them. In a contest between exhaust bleed by and manifold vacuum bleed on the intake I would think it more likely to have low pressure from intake vacuum bleed than high pressure from exhaust pressure bleed?

A one way valve that prevents vacuum in the valve cover seems a logical way to make any positive pressure force oil back down the pushrod tubes. That would preclude using passive crank vents in the covers to generate vacuum in the case though.

Very interesting.

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Re: CB PERFORMANCE DRY SUMP PUMP.

Post by Piledriver » Sun Jul 17, 2016 4:20 pm

There are some excellent threads dedicated to PVC system setup started by FJCamper and Ray Greenwood, worth a read, may be in the stickies of the type4um or drag racing forums as they may predate this forum.

I use restricted manifold vacuum and have a check valve and a low pressure adjustable vacuum break feeding the 3/4 rocker box vent from the air cleaner plumbing (pulled from the idle air circuit)
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Re: CB PERFORMANCE DRY SUMP PUMP.

Post by Marc » Sun Jul 17, 2016 4:24 pm

The Bentley oiling diagram, while schematically correct, is somewhat distorted with regard to the length/location of the galleys...it's more like this:
Image

Image

Note that the passage to the cooler is always open; when the oil is cold and pressure high the control valve opens up the bypass to go straight to the bearings, and the majority of the flow goes that way because it offers less restriction than the cooler. I fail to see what "anti-drainback" function is offered by the flywheel-end relief valve, its purpose is to protect the cooler from overpressure (~65 psi) but the size of the dump-to-sump hole is too small to achieve that at high RPM when cold.

We always used AN10 hoses/fittings to & from the tank, and I know others who used 8AN and reported no problems - AN12 would be overkill IMO. If you'll be using a spin-on filter, avoid the ubiquitous type with 90° bends in the casting - the few extra inches of hose needed to plumb an adapter with straight-in passages offers little restriction compared to those 90s. It's not likely to be an issue, but Diesel Rabbit filters can handle at least as much pressure as Fram HP-1s and are better filters.

I experimented briefly with Teflon valve stem seals but found that the (limited) benefit was outweighed by the need to shorten the guide considerably to make room for them with standard-length springs and valves, and wasn't enough to justify the complications of going to longer valves/springs.

If you're determined to use an external-outlet cover on the CB dry-sump pump, be sure to check how well the outlet port matches up with the internal chambering of the pump.

A large ball valve placed in the line from the tank to the pressure pump is convenient for reducing the mess when removing/installing the engine, and for isolating the tank when the car's going to be idle for more than a few days - it takes that long for a significant amount to ooze into the crankcase around the pump's drive shaft. If you're concerned about forgetting to open it before firing, you could rig a microswitch to a warning light that comes on with the ignition until the valve is opened.

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Re: CB PERFORMANCE DRY SUMP PUMP.

Post by FJCamper » Sun Jul 17, 2016 6:09 pm

Hi Randy,

Yes, we used a 12v (heavy item, too, all brass innards) scavenge pump on the Blitzwagen for a while. The pump was mounted to the vehicle floor just aft of the rectangular dry sump oil tank. I didn't like the weight and plumbing complications, but the pump worked.

A am very anal about weight on my race cars.

Once we had the dry sump system sorted out, I decided to disconnect the valve cover scavenge to see if the CB pump was actually scavenging the case pressure as they imply. What we found was unexpected but welcome. We had no immediate way to measure case scavenging, but we saw that while running, the oil on the dipstick was just visible on the tip end of the dipstick! Wow, talk about a dry sump.

RPM windage isn't much of a problem when the sump oil depth is half an inch? Turns out that's almost exactly the distance from the oil pickup opening to the engine case floor.

While I, being old school, like front mounted oil coolers, the hard truth is the shorter the distance from the engine to the cooler, the better. And for racing, better protected.

Here's all the info I have on the 12v pump. No brand name! Ebay special.

12v Oil Scavenge Pump
Reliable, Easy to Install, Easy to Use Pump!

Features:
Self Priming
Corrosion resistance
Soft Noise Absorbing Mounts
Pump body: Brass
Gears: Bronze
Shaft: Stainless Steel
Seal: Fluoroelastomer lip seal
Motor: DC 12v

Specs:
Flow Rate: 2.5 GPM
(150 Gallons Per Hour)
Ports: 3/8” Female JIC
1/2” Barbed Fittings Included
Amps: 5A@12v
Self priming: 5 feet
Lift: 15 feet
Color: May vary (White or Black)

Turbocharger oil scavenging has always been an issue. You might have 50 psi feeding the turbo but the slightest restriction in the "drain" will immediately send oil past the exhaust seals, burning up oil and ruining your turbo. In the case of remote mounted turbo systems, rear mounted systems, or in systems mounted below the engine oil level, some form of positive scavenging has to be engineered. That is where this pump comes into play.

This pump is a gear pump, the best kind of pump for oil scavenging. Bronze gears.
Brass pump body. No diaphragms to fail like our competitors pumps. Gear design for maximum scavenge.

12vdc with splash resistant wiring. 3/8" female entry and exit with 1/2" barbed fitting included.

The same oil that it scavenges also lubes up its gears.

This is a racing part, please do not expect the product to be quiet.

These pumps are suitable for remote turbo systems as oil scavenge pumps. In this case the engine supplies the oil pressure and the pump simply returns the turbo oil to a point above the sump level.

Can also be used for various other applications. (Oil transfer, water pump, etc)

Dimensions:
Length: 6.25"
Motor Diameter: 3"
Base: 3" x 4"

FJC

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Re: CB PERFORMANCE DRY SUMP PUMP.

Post by RHough » Sun Jul 17, 2016 6:42 pm

Marc wrote:The Bentley oiling diagram, while schematically correct, is somewhat distorted with regard to the length/location of the galleys...it's more like this:
Image

Image

Note that the passage to the cooler is always open; when the oil is cold and pressure high the control valve opens up the bypass to go straight to the bearings, and the majority of the flow goes that way because it offers less restriction than the cooler. I fail to see what "anti-drainback" function is offered by the flywheel-end relief valve, its purpose is to protect the cooler from overpressure (~65 psi) but the size of the dump-to-sump hole is too small to achieve that at high RPM when cold.

We always used AN10 hoses/fittings to & from the tank, and I know others who used 8AN and reported no problems - AN12 would be overkill IMO. If you'll be using a spin-on filter, avoid the ubiquitous type with 90° bends in the casting - the few extra inches of hose needed to plumb an adapter with straight-in passages offers little restriction compared to those 90s. It's not likely to be an issue, but Diesel Rabbit filters can handle at least as much pressure as Fram HP-1s and are better filters.

I experimented briefly with Teflon valve stem seals but found that the (limited) benefit was outweighed by the need to shorten the guide considerably to make room for them with standard-length springs and valves, and wasn't enough to justify the complications of going to longer valves/springs.

If you're determined to use an external-outlet cover on the CB dry-sump pump, be sure to check how well the outlet port matches up with the internal chambering of the pump.

A large ball valve placed in the line from the tank to the pressure pump is convenient for reducing the mess when removing/installing the engine, and for isolating the tank when the car's going to be idle for more than a few days - it takes that long for a significant amount to ooze into the crankcase around the pump's drive shaft. If you're concerned about forgetting to open it before firing, you could rig a microswitch to a warning light that comes on with the ignition until the valve is opened.
All good points.

As far as the drain back issue goes. The oil cooler drains over time. One side drains through the #2 main web passage in the centre of the engine and the other side drains back to the sump through the pump. The relief valve that by-passes the cooler when the oil is cold is closed when the engine is stopped. This closes the direct gravity feed from the pressure pump to the lower oil gallery and as soon as the #2 main side of the cooler drains to below the level in the tank the only path the oil has to drain is through the pump itself (as Piledriver suggests). Since the pressure pump is not open to the sump as it is on a wet sump system the drain back path should be limited to the clearance between the pressure pump shaft and the scavenge side of the pump. I assume this is fairly tight to prevent the scavenge side from pulling oil from the pressure side. I don't know any of this to be a fact, just overthinking out loud. :-)

The hose size deal is pretty important. When you look at HP loss and fluid speed in the hose a small change in diameter and added fittings have a big effect. Fluid speed is what determines turbulent or laminar flow. Laminar flow inside the hose is free HP. Turbulent flow reduces the effective diameter of the hose. I agree on the -10 for the scavenge plumbing and I found this nice filter mount that is tapped for 1/2" NPT that is perfect for -10

https://www.cip1.ca/ProductDetails.asp? ... 12-3015-11
filtermount.jpg
The tank outlet is 16mm so -12 from the tank to the pump is a natural choice. Even though the pump inlet is 3/8 or 1/2 NPT no reason not to use a bigger feed hose unless the NPT to -12 fitting won't fit.

If your experience is the CB pump flows well enough using the internal passage I'll stop worrying about that now that I'm going to put the filter on the scavenge side. That leaves a short -10 hose for the Accusump to the old full flow inlet. Cool!
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Marc
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Re: CB PERFORMANCE DRY SUMP PUMP.

Post by Marc » Sun Jul 17, 2016 6:50 pm

The overpressure valve at the flywheel end is only open when pressure is >65psi, so there's no direct drainback to the sump with the engine off but the cooler is never isolated, nothing shuts off the "hot" passage from oil pump to cooler or the "cold" passage from cooler to main galleries, ever. You'd be surprised how long oil can stay in the cooler, too, with no "vacuum break" to admit air in...it will drain eventually, but that small amount of oil isn't going to be enough to cause hydraulic-locking of the bottom end. I wouldn't lose any sleep over that. It's that full dry-sump tank that could potentially drain through the pump and/or siphon through the cooler which makes an isolation valve wise. I once saw a team use a truck to attempt to push-start a car that had so much oil in the sump that the starter couldn't rotate the crank...the result was grenaded pistons and bent connecting rods, all because they couldn't be bothered to take a few minutes to drain the crankcase down by a couple of quarts.

I doubt that the flow rate to or from the AccuSump warrants 10AN plumbing, 8AN should be more than adequate - but if you've got the room for it, the larger hose/fittings can't hurt....except that generally, a larger-diameter line is going to be more prone to kinking than a smaller one at the same radius, so if space is tight and the hose needs to have some tight bends in it that's a liability of using bigger hose than needed.

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