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Old 04-23-2008, 12:27 AM   #41
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THis is something i explored alot in college. Finding a reliable way to do a dry sump, and for the miata it just came down with all the adjustments and additional parts the places of failure increased more than i felt comfortable. Pricing wise i would be surprised if we find something cheaper and more reliable then billet gears.

Although, someone do it, and then do a group buy on parts.
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Old 04-23-2008, 12:30 AM   #42
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Chevy oil pumps are designed to be submerged in oil. It's gonna leak like a sieve if you try to mount it externally. Also I don't think it has the proper tolerances to be able to prime itself if mounted high, and I wouldn't want to rely on a check valve to keep it primed. You're better off saving up for a well proven dry sump setup, belt drive like the water pump.
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Old 04-23-2008, 12:37 AM   #43
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Quote:
Originally Posted by bryanlow View Post
Chevy oil pumps are designed to be submerged in oil. It's gonna leak like a sieve if you try to mount it externally. Also I don't think it has the proper tolerances to be able to prime itself if mounted high, and I wouldn't want to rely on a check valve to keep it primed. You're better off saving up for a well proven dry sump setup, belt drive like the water pump.
Well, that's not what I wanted to hear. Hmm. That could be a problem. I guess it would leak where the driveshaft goes into the pump? Guess I need to get one and disassemble it and see how it's made. Doesn't the oil pump's bypass valve dump out too?

Perhaps a power steering fluid pump could be adapted to work.
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Old 04-23-2008, 12:58 AM   #44
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Pat i vote for an electric but i want the capability of 70 psi minimum at 7K rpm i dont feel safe turning 7K and only having 40 psi OP, so if the system kept presure around 40-80 psi while running that would be ideal for me. Also to win out it needs to be able to mount low, and simple to install.
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Old 04-23-2008, 01:17 AM   #45
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Just a couple of uneducated thoughts...

What will the HP requirement be at zero degrees ambient? Granted, 5w30 or 0w30 shouldn't prove to be too much trouble.

I think that the pressure won't be much of an issue. As said, it should bypass and be done with it. Just have enough at high RPM and you will be covered at the low end.

http://www.surpluscenter.com/sort.as...c&keyword=MADL Finally, these guys are local to me. This is just one page of the 12v motors that they have. They are divided by CW, CCW and mounting style. If they have something that will work, it will be very inexpensive. I didn't go through it, just got the link.
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Old 04-23-2008, 02:54 AM   #46
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An interesting option, 12 volt "hydraulic power units" for industrial / farm / snowplow equipment: http://www.piercewrecker.com/12_volt...CTION%20MODELS
http://www.williamsmachineandtool.co...nt_piston.html

Also, check marine salvage / surplus places. Electric hydraulic pumps are found on some watercraft to operate the autopilot, trim controls, outboard tilt, and such.


edit: One last thought. A power steering pump is a good hydraulic pump, and an alternator is a good electric motor. Both are available cheaply, and both are proven to operate reliably in harsh environments.
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Old 04-23-2008, 03:35 AM   #47
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I wouldn't trust my engine to an electric oil pump.

Either use hardened steel machined gears or drysump. This extra over elaborate engineering is just going to cause failure. Remember, overcomplex design is a sign of a bad engineer.

Chevrolet has been using the same type of oil pump mounted onto the front of a crankshaft in their Gen III SBC's, and I've yet to see a failure proven because of the oil pump.
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Old 04-23-2008, 01:50 PM   #48
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Yeah, I'm torn on this.

On the one hand, I like having the option to pre-oil the engine at startup, and to put the oil pump itself on a timer to post-oil the turbo after I shut off the engine. That would eliminate the need for a cool-down period.

On the other hand, elesjuan is absolutely 100% correct. Crank-driven oil pumps are dead-simple, and they have a 100+ year track record of proven reliability. The one issue which our pump seems occasionally to exhibit on highly modified engines seems to have been adequately addressed by the production of a stronger aftermarket gear. I do tend to suspect that the operational failure rate (defined as a loss of oil pressure while operating) will be higher for an electric pump. The question would be whether the catastrophic failure rate would be higher for the crank-driven oil pump (destruction of the pump) vs the electric system (failure of electric pump accompanied by failure of the engine to immediately shut down).

Let's say for instance that you put an ignition kill on the engine to shut it off if the electric pump stops making pressure. What happens if the electric pump craps out while you're in gear doing 80MPH. You'll have to be sure to immediately de-clutch and get into neutral, or the engine will keep right on spinning sans oil pressure.
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Old 04-23-2008, 02:10 PM   #49
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Well, what about both? Leave the stock oil pump in place to do the job, but add an electric oil pump so the engine now has two pumps. Buy an oil filter relocation kit so we can tap into the oil feed after the crank driven oil pump. Install a 1 way valve in that line so oil can only come out of the pump. Then, install a one way valve on the electric pump and tie both pump outlets together. Now, if the electric pump was switched on with the mechanical pump not spinning, it will supply the engine with oil. The 1 way valve in the mechanical pump will shut so that oil does not simply bypass through the pump (which it would only do if the gears were broken). Now, we have the reliability of the stock oil pump with the advantages of the electric one. We can now turn on oil pressure before and after starting, as well as build a safety device that cuts on oil pressure if the mechanical pump were to ever fail as well as a warning light or something.

In this case, a simple electric diaphragm oil pump would suffice, since it's not continuous duty and not overly critical anymore.
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Old 04-23-2008, 03:19 PM   #50
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Quote:
Originally Posted by patsmx5 View Post
Well, what about both? Leave the stock oil pump in place to do the job, but add an electric oil pump so the engine now has two pumps.
Because the stock oil pump would still explode... defeating the whole purpose of this thread's discussion.

Honestly guys, you are making this way more difficult than it needs to be. A simple aluminum block off plate with a seal journal for the crank and a place for the pickup tube to mount with an AN inlet/outlet mounted in place of the stock pump would realistically cost ~$175 in machining. So market price for re-sale would be $300 minimum. Then you have the cost of a proven reliable electric oil pump designed by someone who knows what they are doing as apposed to slapping a SBC unit onto a mcmaster motor. These run around $300-450. So... If you have the hook up for parts you are looking at about $500 total. Might as well just get the billet gears at that point unless the ability to run oil through with the engine off is really meaningful to you, or you just really want a shinny piece of aluminum on the front of your block with more stainless braided lines.
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Old 04-23-2008, 06:58 PM   #51
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Are the belt-driven pumps commonly sold for dry-sump use adequate to generate primary pressure, or are they only good for scavenging? Because right there is a pump already designed for external mounting, able to deal with high temp, high-viscosity oil, and with a provision for coupling it to an external drive.
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Old 04-23-2008, 08:06 PM   #52
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Joe, most that I've seen the pump that bolts to the motor for a dry sump is really two pumps. One is a scavenging pump that pulls oil from several spots and pushes it into the tank. Then the other pump takes oil from the tank and pumps it into the engine.

Arkmage- Yea, My original idea was mechanically driven SBC oil pump. I was thinking it *may* be a cheaper alternative and perhaps prove better. First sentence was I was thinking out loud. I'm spiting out what I think and taking comments and suggestions. If there was a simple easy way to spin the SBC oil pump close to the oil pan at 1/2 engine speed, it would be a lot more feasible. Still, as mentioned the pump is not a sealed unit. Obviously it would need to be or else be enclosed in something that could return oil to the motor and keep oil from spraying everywhere. I know, that's just more and more stuff.


The idea of adding the second electric diaphragm pump would not be in the context of my thread title. However it would be satisfactory in some regards.

It would be cheap and easy though. The entire electric pump would be about 100 bucks. I would need a couple 1 way valves from a hydraulic store. (family runs a hydraulic business, how convenient ) Would also require a coil filter relocation kit as the pump will need to pump cooled oil anyway, and the kit comes with the sand which bracket we'll need to redo the oil lines.

This would do a couple of things. It wouldn't stop the oil pump from breaking, but in the even that it did, the electric pump could instantly power on delivering oil to the engine to save it's life. THAT would be good enough for me. As Paul mentioned he thinks he shattered his gears in his 99', but he didn't notice he lacked oil pressure for about 30 seconds. That's certainly not ideal. Had this system been in place, it would have kicked on to keep the engine lubed and thrown a light on that says the pumps running. Granted he could have just added a light or loud buzzer or something to tell him if he lost oil pressure, but then it's still up to the driver to quickly disengage the clutch if the car is moving when the gears break.

Of course the added benefits of the electric oil pump are being able to start the engine under full oil pressure, even if you just changed your oil, as well as being able to cool the engine and the turbo after shutdown.

Overall, the SBC oil pump mechanically driven or electrically driven is not looking good. Perhaps I could make the pump a sealed unit, or deal with that but mounting it up high is not good, and driving it with an electric motor for hours on it while I'm driving down the highway isn't comforting either.
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Old 04-23-2008, 08:25 PM   #53
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A site I ran across a while back while researching motorcycle turbo systems: http://www.rbracing-rsr.com/oilsystems.htm

Dedicated electric pre / post-lubers: http://www.pre-luber.com/

A similar discussion: http://www.ten-tenths.com/forum/showthread.php?t=87112

A patent on the subject: http://www.patentstorm.us/patents/58...scription.html
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Old 04-23-2008, 10:37 PM   #54
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By leaving the stock pump in place you really haven't solved the problem. You've still got the weak link and may still end up with a ruined motor. If the thing fails, a second pump may be able to supply enough pressure for you to limp home, but what about all the little bits and pieces left in the oil passages? The little pieces end up tearing up your crank and camshaft journals. If you're really looking for a fix, I say take the ring out of the stock pump then get one of these and enjoy peace of mind.
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Old 04-24-2008, 05:50 AM   #55
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Quote:
Originally Posted by patsmx5 View Post
My point was that crank flex is going to happen, no matter what. You can try to suppress it with the main bearing support girdle (How much is that?) or billet caps. Of course, 4 bolt caps would be a better solution but that would be really expensive if it's even possible.
If the MBSP from a Protege BP fits the cost will be whatever your local pull-a-apart charges.
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Old 04-24-2008, 09:02 AM   #56
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Quote:
Originally Posted by silentbob343 View Post
If the MBSP from a Protege BP fits the cost will be whatever your local pull-a-apart charges.
the MSBP might fit but you are still going to need the oil pan and pick up from a 01+ Miata Engine.

So you might as well get all of that from an 01+ Miata Engine
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Old 04-24-2008, 02:14 PM   #57
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Quote:
Originally Posted by MX5-4me View Post
the MSBP might fit but you are still going to need the oil pan and pick up from a 01+ Miata Engine.

So you might as well get all of that from an 01+ Miata Engine
Ahh didn't realize you needed the 01+ oil pan as well.
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