Oil Preluber

[dhawker]

Is anyone using an oil-preluber system? If so, what are the pros and cons and what do you think about them? I am considering adding a system like the one from autoenginelube along with some of your oil system mods in my '87 Grandwagoneer.

[Rocky]

That particualr system smells of snake oil to me...
Since oil is a fluid, and fluids can't be compressed, I don't see how any container alone can hold oil under pressure!
Someone correct me if I'm missing something here, but to my knowledge, the only way to supply pressurized oil before startup is with an electrical pump, or with air pressure (either introducing compressed air from a holding tank against a piston or flexible membrane, or via an air bladder within the oil vessel itself.
This system appears to be not much more than an oil resevoir... not a bad thing, but not a pressurized preluber, either.
A true preluber is a good thing to have, since most engine wear occurs on startup, but it'll cost you.

[dhawker]

I was also looking at the system from espperformance. It is the more traditional type (pump oil into engine). But the system from autoenginelube looked interesting .... meaning cheaper ;-) and very simple to setup and install (if it works as advertized). Thanks for the info. Hopefully some of the engineer types will comment as well as to the legitimasy of their claims.

[jeepsr4ever]

The prelubers do work great and the tube is actually pressurised when the engine is running, getting this to work on a amc engine is the tricky part, I still havent figured that one out yet :-|

[dhawker]

According to the website it looks like they attach the cylinder to a tee connector screwed into where the Oil sender unit is. After running the engine for a few minutes the cylinder fills with oil and you add more to the engine to compensate. When the engine turns off the solenoid valve shuts at the cylinder to stop and pressure or oil loss. When you start the system you turn the key just enough to have power without starting the engine and watch the oil pressure light. The solenoid opens and pressurizes the system. The oil pressure light goes off then you continue to start the engine. Seems pretty simple if it works.

[Rocky]

OK, yeah, I've read their pitch, too... but I'd still like someone to explain to me how a cylinder full of oil can pressurize an entire oiling system! Fluids can't be compressed!! The cylinder will only hold one cylinder's volume of oil, no more. How can that oil possibly be introduced into the system and provide pressure to a volume larger than the oil itself???
Air, a gas, can be pressurized. The molecules can be forced to compact into a smaller volume (such as a cylinder) and when it's released, it will expand to fill any space it's released into. If enough air (or any other gas) is compressed into the holding vessel, and the space it's released into is smaller than the volume of that quantity of air at atmospheric pressure, that space will contain "pressurized" air.
...So, how's this work with a fluid?
Again, I may be missing something here...... But I still smell snake oil!!!

[jeepsr4ever]

You are looking at pressure being forced upon the fluid by a spring.....kinetic pressure..Kind of like holding pressure on a syringe and pressing on the tip untill you let go it has kinetic pressure. Does that help?

[Rocky]

Yeah... that helps... It's not that I don't understand the concepts involved.. It's just that this particular device appears to me to be just a cylinder w/ a valve... nothing to store the energy required to produce the pressure.. You're saying there's a spring inside? Does it operate against a piston, or?? If there is a spring or other system (air bladder, etc.) which can be compressed and store the energy, then it's a workable system. If not.....SNAKE OIL!!

[Rocky]

BTW, I checked their site again... No mention of any spring or other device to store the energy required to supply pressure. (Maybe it's their "trade secret" and they don't want to give it away... As if a competitor couldn't just take one of their units apart and see how it works.)
Don't get me wrong... If this thing works, it's a fine idea... I'd put one on my own rig... I just havn't seen an explanation of how the thing works that addresses the physics involved. ... If there is a spring or something, great... If it's just a tank of oil, no matter how much pressure was exerted on it while filling the tank, oil (as a liquid) can't be compressed, so has no way to store that energy.. (Again... am I missing something?)
Anybody actually running one of these things, or, better yet, know for sure what's inside? (MC... you know more about them than they'll divulge on their website??? ...You seen that spring??)

[jeepsr4ever]

Funny you say that, ever since i started making midplates ive dabbled with the idea of a simple preluber.bet i could do it for around 60 bucks and improve the oil pump!... dang maybe i should move this to product ideas

[dhawker]

I would be interested in something like that if you can get it to work. Seems to me that almost all the wear in an engine happens when you first start it up, before the oil has had a chance to make around the block. Seems like pretty cheap insurance if you ask me.

[Rocky]

Hey, MC... Shouldn't take much... a cylinder, piston w/ a good tight seal (maybe multiple O-rings or even a big cup seal), a spring w/ a rate calcualted to be compressible w/ the oil pressure while exerting max possible pressure when released, a good electrically operated valve and a switching mechanism. Were it me doing it, I'd have the thing shut the valve while the oil's still cold and the pressure's higher! ...be able to put that much more pressure back into the system upon startup. A normally closed valve and a pressure switch which feeds power to open the valve from the moment the ignition's turned on until a pre-determined pressure's reached ought to do it. Initially, the valve would open and allow oil to enter the system, then the valve remains open while the engine's started and stays open until the system's pressurized and the resevoir's full.
You could tee into the pressure sender, or better still, make your SS pump plate a little thicker, and drill and tap for a fitting just after the filter output.

Here's the deal... you can have my ideas for free... just toss a unit my way when you got 'em in production! (If you don't, I'm comin after ya... and you don't want that!!)

[Toy Maker]

I can not tell about the "autoenginelube" produce, however the oil accumulators from Moroso or Accusump operate on a floating piston design, where there is air pressure on top of the piston to counteract the pressure of the oil. It is pre-charged with an innitial pressure with a schrader valve by the attached gauge before instalation, then the oil pressure forces the piston against the air to compress the air to store the pressure.
I have a Moroso unit in my Jeep that I installed in the remote cooler/filter circuit that I already had. I chose to wire it to a toggle switch, which I turn on before cranking. As soon as the gauge shows pressure rising, then crank engine. The electric valve is of a type that blocks flow from the accumulator but allows slow reverse bleed flow when the circuit is open. As soon as the engine starts and generates pressure on it's own, I turn off the switch, allowing the reverse flow to refill the accumulator as the engine runs, and leaving it fully charged for the next re-start.
The system could be plumbed into any convenient port after the pump, including the sender port.
I have had it installed for about 5 years with no problems.

[Rocky]

Good simple design. Air makes a fine means of storing the energy needed to exert the pressure upon opening the valve, since it can be compressed. Although its operation is not automatic, the simplicity is a plus.
Is there a determined air pressure that your unit needs to be filled to (in order to give desired oil pressure upon valve opening)? Does air need to be added from time to time?

If the Autoenginelube device works by this principle, it ought to be ok, but they make no mention of any means of pressure storage... which ought to be a primary selling point to anyone who's of a technical nature. (Either they're underestimating their prospective customers... or maybe there's nothing there to talk about..)

[Toy Maker]

The unit must be charged with air to a recomended pressure prior to usage to expel the full capacity of oil in the unit. The engine pressure then charges the unit with oil, further pressurizing the unit to operating presure. The combined pressure feeds the oil into the engine with almost all the capacity available if needed.
So far (knock on wood) I have not had to add air to the unit, although if it was required, it would be very simple. By activating the unit with the engine off, there by draining the unit, the attached gauge would indicate the risidual pressure, and the schrader valve mounted on the top would provide for easy adjustment.

[blmk9999]

Is there any reason you could not use an external electric pump and tap into the milodon external oil system (or something similar, I happen to use the milodon system). The electric pump is manually operated, sucks oil from an existing line right out of the pan, once you have pressure, start the engine and kill the electric pump. Someone could probably create an add on to the amc ignition so that this was an automatic process. Turn the ignition key, electric pump kicks on, oil pressure rises to 20lbs, then the starter kicks in, electric pump kicks off, engine starts and runs on engine oil pump. I'd buy this!

Thanks,

Mark