custom dry sump oil pump do-able!!

[acannell]

Quote:

Originally Posted by Dr. Johny Dodge looks like you could use the power steering bracket to mount the pump somehow under it I'd think you could make the pump fixed in position and still use the same tensioning method already used by just tightening the belt by the ps pump position say , push the new pump up under the lower section of the belt so the belt has to go over the hump of the pulley - might need a slightly longer belt though

i grabbed an extra AC idler pulley i had laying around and stuck it under the steering belt right where you are talking about..looks like that gives me 1.75" behind the pulley! and there is space on every side to get hoses/fittings out.....hmmmmmm

[Dr. Johny Dodge]

one thing I'm wondering now as I've just thought of it
all the race motors I've seen have the pump mounted down low beside the oil pan rail or lower
I'm wondering if the pump needs to be mounted low to prevent it from looseing it's prime

[acannell]

Quote:

Originally Posted by Dr. Johny Dodge one thing I'm wondering now as I've just thought of it all the race motors I've seen have the pump mounted down low beside the oil pan rail or lower I'm wondering if the pump needs to be mounted low to prevent it from looseing it's prime

from what I've read, gerotors are self priming (fingers crossed)...

[acannell]

wait a sec..

it might not be a good idea to push up on the belt from underneath because that reduces that wrap around the steering pulley...but maybe it would end up being so minor its not a big deal..this gerotor pump shouldnt require much to drive it i dont think..

and pushing from above on a vbelt may also be somewhat unrecommended...apparently thats not always a great thing on v-belts..

none of this will stop me of course...

[acannell]

okay some more thoughts on this..if anyone knows about this kind of design please add your thoughts! i am by no means a mechanical engineer..

-im not sure how the shaft should be sealed, maybe an axle type seal where it enters the pump housing? how much pressure can that type of seal hold?

-and what about the bearing? space is tight, so maybe a sealed ball bearing is appropriate because i assume it can handle more load than a bushing of the same thickness...although i could totally be wrong about that. maybe it can even provide the seal so that a seperate seal isnt needed?

[anarchyjet]

If you are to the point of running a dry sump, then you should have already ditched the PS pump. Mount the DS pump in place of the PS pump, line up the pulleys and use a dedicated belt. I would also make it a dual stage vacuum pump and suck from 2 points on the pan.

[acannell]

it looks like there are lots of steel gerotor rotors available off-the-shelf for oem stuff...a harley davidson pair shows up on ebay alot and retails for $30..im not sure what its dimensions are exactly though.

on the other hand, since there is only about 1.75" of space, i think the entry and exit ports may need to be in the radial direction, i.e. the sides of the pump, which means ports will need to be made in the outer rotor, and thats probably not going to be an off the shelf item.

id like to have a little bit more of a plan before i take a stab at it, the moroso pump uses a lip seal (like an axle seal), and a seperate bearing/bushing...the picture makes it look like it has two of them..i wonder if its just two bushings, or two bearings or what. whatever i use will need to be pretty thin.

im thinking the rotor should use radial space to stay thin, so maybe a 3/8" rotor thats 3" diameter, and bearings that are 1/4 diameter, with a 1/4" lip seal....add the front and back plates and i think it might fit

mcmaster has keyed shafts for cheap..normally a slot in a pulley is "broached" which isnt something i can do, so i can mill the slot and file it square i think..

[IROCNOROLL]

Cool Ideas, but you maybe want to look at a wee little bit more homework here.

If you look at pro dry sump applications, the first thing you will see is a toothed belt drive, not a v-drive belt. There is no room for belt slip when you are looking at the health of an engine. Granted there is at least one pressure pump in the pro stack, but either way it must be a 100% positive drive system.

Maybe look at using the chain drive system for the balance shafts and keep the scavange system inside the motor. Positive drive, stealthy installation, and easy to plumb out the rear of the block to a tank.

A scavange system is just that. Pull as much oil/air out of the engine as fast as possible. you are not after a big pressure outlet, but definitely big flow volumes. The other purpose of a dry sump scavange system is to pull the crankcase to a low pressure (vacuum) situation to help with ring sealing amongst other goals.

Mounting the pump as low as possible relative to the bottom of the pan has several benefits. Priming as noted here earlier is one. Efficiency of the pump is another as it is easier and more efficient to push the oil out of the pump with pressure than it is to draw the oil up a foot or so above the pan to a pump. It is always also best to keep all the weight as low as possible in a chassis.

Realize the the material you use for the pump rotors must be tough. A scavange pump is not always pulling a steady supply of oil. There will be a lot of air in there as well. This can lead to chatter in the gears when you are pumping aerated foam. Also soft materials like aluminum are more prone to imbeddability of any foreign material that may find its way into an engine. Oil can foil seals are a good example. Pull that thru your pump with aluminum gears and it will at least in part be embedded into one or both gears for ever.

FWIW.

[acannell]

I think I did plenty of homework, lets not lose sight of the forest from the trees here. The stock pump will provide pressure so the reliability of the oil system will not be affected in that regard. If the scavenge pump fails for any reason, the oil pan will fill up and the external reservoir will drain, and this can be detected before the stock oil pump is starved of oil. It may even be possible to allow the system to operate as a wet sump if the scavenge pump fails.

This is not a complex system, no matter how exotic sounding it may be. All it is a simple gerotor pump that sucks oil from the oil pan. This scavenge pump will draw very little power and torque, so belt slippage is not an issue. You could probably run the scavenge pump on a spring loaded roller off the back of the belt on the camshaft sprocket, the torque is that low.

Driving it using the balance shaft chain system is a neat idea, but not something I want to tackle. That could actually be really cool.

I'm making it out of aluminum because thats all I can machine on my tiny mill. It would probably be easier, even for a prototype, to buy a pair of inexpensive steel rotors and just machine the housing for them, but I'd like some experience making a gerotor from scratch, so I'm doing it this way. That said, there are aluminum lobe type dry sump pumps. I dont really see why particles being embedded in the rotors would matter. But the rotor design I'm thinking of has 5 thou of clearance axially and radially so I dont see that happening anyway.

My PCV system wont be changing. A breather system may be required on the external reservoir, however.

Talk is cheap, and if we want anything _new_ or _different_ we have to stop worrying about how things are currently done, which gets us nowhere. We have to turn off auto-pilot and start designing things based on the fundamental ideas at hand and within the limits of what we can do and still make an inexpensive system.

If you want a race system, go buy a multistage pump and pulley and mount it low and voila, there is your $600 (minimum) dry sump pump.

The goal here is to make a cheap as possible dry sump system that bolts on as easily as possible.

Quote:

Originally Posted by IROCNOROLL Cool Ideas, but you maybe want to look at a wee little bit more homework here. If you look at pro dry sump applications, the first thing you will see is a toothed belt drive, not a v-drive belt. There is no room for belt slip when you are looking at the health of an engine. Granted there is at least one pressure pump in the pro stack, but either way it must be a 100% positive drive system. Maybe look at using the chain drive system for the balance shafts and keep the scavange system inside the motor. Positive drive, stealthy installation, and easy to plumb out the rear of the block to a tank. A scavange system is just that. Pull as much oil/air out of the engine as fast as possible. you are not after a big pressure outlet, but definitely big flow volumes. The other purpose of a dry sump scavange system is to pull the crankcase to a low pressure (vacuum) situation to help with ring sealing amongst other goals. Mounting the pump as low as possible relative to the bottom of the pan has several benefits. Priming as noted here earlier is one. Efficiency of the pump is another as it is easier and more efficient to push the oil out of the pump with pressure than it is to draw the oil up a foot or so above the pan to a pump. It is always also best to keep all the weight as low as possible in a chassis. Realize the the material you use for the pump rotors must be tough. A scavange pump is not always pulling a steady supply of oil. There will be a lot of air in there as well. This can lead to chatter in the gears when you are pumping aerated foam. Also soft materials like aluminum are more prone to imbeddability of any foreign material that may find its way into an engine. Oil can foil seals are a good example. Pull that thru your pump with aluminum gears and it will at least in part be embedded into one or both gears for ever. FWIW.

[acannell]

well, this isnt the exciting update i had hoped to have, but:

the good news is: i was able to machine custom rotors for the dry sump scavenge pump on the big full size cnc mill I have access to. what a joy that machine is! i should have got it a valentines gift...sigh

all that i had laying around was 304 stainless, and it was 1/4" thick, so i set up the design software to come up with rotor geometry for 10 liters per minute per 1k rpm, with 1/4" thick rotors.. i arbitrarily chose 6 lobes for the inner rotor. i actually think 1/4" thick is right on target, so that this pump will fit in the shallow space available in between the psteer pump bracket and belt.

the bad news is, the rotors jam and dont rotate. i would have been pretty lucky to just dump the output of the design software into the mill and get something that rotated nicely.

the reason they jam could be a bunch of things. this is my first time going from the gerotor design software all the way to a machined rotor, and there are alot of links in that chain. just like machining anything really. the clearances are not outrageous here, in fact they are defined as 0.005" in the software, which the big mill can easily handle. i think the problem is in the way i converted the profiles into geometry was messy. sort of like converting a bitmap into vector, not ideal. much better to just draw the vector from scratch using the actual math that the rotor is based on. thats what ill do next time around.

BUT! its really not that far off, I took a dremel with sandpaper (not the grinding wheel) to the rotors and was able to get them to almost start turning. i can probably salvage them and use them in the initial prototype if need be.

on the other hand, my teeny sherline could make copies of these in aluminum without too much trouble, or maybe i can make another pair on the big mill.

i could really use some help on some of this, please chip in with your knowledge:

now to come up with a housing design of some kind. can someone help with this part? what do you all think should be the bearing system for this?

remember its low torque, because this is not a pressure pump, just a bucket brigade from the sump to the reservoir.

im thinking a pressed in shaft, with graphite impregnated bushings on both sides and a lip seal on the pulley side?

or would ball bearings make more sense?

all this stuff is available from mcmaster, shafts, bearings, bushings, lip seals..everything, so really once a good idea for the housing is figured out, its plug and play and i could have the parts in a day or two.

[GLHNSLHT2]

A Fadal can't even mill a round hole

[GLHNSLHT2]

Quote:

Originally Posted by anarchyjet If you are to the point of running a dry sump, then you should have already ditched the PS pump. Mount the DS pump in place of the PS pump, line up the pulleys and use a dedicated belt. I would also make it a dual stage vacuum pump and suck from 2 points on the pan.

Have to disagree, I'm to the point or running a dry sump but will never ditch the powersteering. Not sure where you came up with that but numerous forms of racing have dry sumps and powersteering. Even the pinnacle F1 has powersteering.

Quote:

Originally Posted by IROCNOROLL Cool Ideas, but you maybe want to look at a wee little bit more homework here. If you look at pro dry sump applications, the first thing you will see is a toothed belt drive, not a v-drive belt. There is no room for belt slip when you are looking at the health of an engine. Granted there is at least one pressure pump in the pro stack, but either way it must be a 100% positive drive system. Maybe look at using the chain drive system for the balance shafts and keep the scavange system inside the motor. Positive drive, stealthy installation, and easy to plumb out the rear of the block to a tank. A scavange system is just that. Pull as much oil/air out of the engine as fast as possible. you are not after a big pressure outlet, but definitely big flow volumes. The other purpose of a dry sump scavange system is to pull the crankcase to a low pressure (vacuum) situation to help with ring sealing amongst other goals. Mounting the pump as low as possible relative to the bottom of the pan has several benefits. Priming as noted here earlier is one. Efficiency of the pump is another as it is easier and more efficient to push the oil out of the pump with pressure than it is to draw the oil up a foot or so above the pan to a pump. It is always also best to keep all the weight as low as possible in a chassis. Realize the the material you use for the pump rotors must be tough. A scavange pump is not always pulling a steady supply of oil. There will be a lot of air in there as well. This can lead to chatter in the gears when you are pumping aerated foam. Also soft materials like aluminum are more prone to imbeddability of any foreign material that may find its way into an engine. Oil can foil seals are a good example. Pull that thru your pump with aluminum gears and it will at least in part be embedded into one or both gears for ever. FWIW.

+1 to all of this. Do it the correct way once instead of wasting your time trying to re-invent the wheel.

With access to a mostly real CNC mill you could be making brackets to mount a real pump where the water pump is, and making adapters to turn our motors into reverse cooling setups with electric water pumps and then be able to make some REAL power without detonation.

[acannell]

Quote:

Originally Posted by GLHNSLHT2 Have to disagree, I'm to the point or running a dry sump but will never ditch the powersteering. Not sure where you came up with that but numerous forms of racing have dry sumps and powersteering. Even the pinnacle F1 has powersteering. +1 to all of this. Do it the correct way once instead of wasting your time trying to re-invent the wheel. With access to a mostly real CNC mill you could be making brackets to mount a real pump where the water pump is, and making adapters to turn our motors into reverse cooling setups with electric water pumps and then be able to make some REAL power without detonation.

there isnt anything incorrect about what Im doing. i want a custom pump the way I want it, and making it myself is how I'm getting there.

let me guess how you know a fadal cant mill a round hole, someone else told you, right?

talk sure is cheap, isnt it.

[GLHNSLHT2]

Look at the pics you posted. Does it say Fadal anywhere that's clearly obvious? Maybe just based on that and me knowing what kind of machine it is would lead you to believe I just might have a little experience on Fadals??? You'd sh1t yourself if you got to play on the machine I get to play on each day.

I'd also make a ton more stuff if I had access to cad/cam software. But I don't so if I can't draw it on paper out of my head with any more effort that I want to put into it I don't make it.

Sorry, maybe incorrect isn't the correct term. But you're not really gaining anything doing it your way and are possibly just causing more reliability issues IMHO. But go for it. I just think time and energy could be better spent elsewhere on the whole thing with bigger gains for your buck.

[acannell]

Quote:

Originally Posted by GLHNSLHT2 Look at the pics you posted. Does it say Fadal anywhere that's clearly obvious? Maybe just based on that and me knowing what kind of machine it is would lead you to believe I just might have a little experience on Fadals??? You'd sh1t yourself if you got to play on the machine I get to play on each day. I'd also make a ton more stuff if I had access to cad/cam software. But I don't so if I can't draw it on paper out of my head with any more effort that I want to put into it I don't make it. Sorry, maybe incorrect isn't the correct term. But you're not really gaining anything doing it your way and are possibly just causing more reliability issues IMHO. But go for it. I just think time and energy could be better spent elsewhere on the whole thing with bigger gains for your buck.

im not gaining anything by learning to design and machine an oil pump from scratch? seriously?

i use solidworks 2001 which im sure you can get for next to nothing these days, and cambam, which has a long free trial and is then $200 or something like that.

what was the actual problem you were having with the fadal? im pretty sure i can make a 3" circle on my sherline within .001" in aluminum, so i cant imagine the fadal would have any issue with it. they've been around for decades, are made in usa, and definitely major players in the commercial/industrial machining industry, its hard to imagine they cant mill a circle. you dont think it was probably the toolpath or something more machining process related and not the actual mill itself?

hopefully these machining threads give other people an insight into what its like to make parts for our cars for a beginner. so far the only part i've made for the daytona is the coolant mod adapter.

one of the main ideas behind this dry sump pump is that its a quantum leap in my skill level from making a static part like a bracket or coolant adapter, to an actual working, fairly close tolerance assembly that actually does something. i wont get any better at making things if all i ever do is make brackets and flanges.

maybe someone else will decide to buy a sherline or use their mill at work, or something like that, and make some parts for us. or maybe they will buy a $50k haas for me in trade for coolant mod adapters. still waiting on that...any day now im sure..make sure its single phase plzz