BlaCkPlaGUE

To start off, I have an S4, and my OMP was leaking bad, it needs a new O-ring.

But anyways, I pulled if off tonight and had a real good look at it and cleaned it up as best I could.
As I was cleaning it, I was extremley curious as to how this thing worked, it seemed like a simple enoughe thing, I was wondering how strong the pump is inside that pushes the oil out, and was also wondering if there were any parts that could wear.

I took the whole thing apart, everything, all thats left is a shell for the parts.

I've found out one thing, the OMP isn't a pump at all, this took me like 10 minutes of figuring out, I kept on looking at where the oil came from, and how it was pulled into the chamber that the control rod connects too...
The OMP simply 'directs' oil at specific intervals into the banjo fittings that lead to the oil injectors! The oil is pushed through the OMP only by the oil pressure from the rest of the engine!

When that pin moves, it slowly (very slowly) turns a gear that is actually a rod that is hollow with holes that will eventually line up with the banjo bolt chambers. While the rod turns from the engine mechanism, there is a point in wich it comes to that the holes in the bolt itself line up with the banjo bolt chambers, and thats when the oil comes out. Once It turns some more, it seals off these areas until the next revolution comes around, preventing oil from going into the lines, and thus the engine all the time.

When the control arm pushes down from the TB, it pushes a neat little 'cam' very similar to those found in a piston engine, into a position that extends this distribution shaft (what I talked about earlier).
When the shaft is pushed in, it somehow allows more oil into the banjo bolt chambers... this part I havent figured out becuase I cant see inside of the OMP housing and see how it lines up with the chambers, etc...


So, basically. This part will practically never fail becuase the parts inside really don't move all that much, as in they don't pump oil, they just 'direct' it. If your oil is really dirty then I can very well see that it would gum up the small little chambers and cause a few issues with oil movement, but when I took mine apart, it was pretty clean, even though my engine oil hasnt been changed in over a year. (previous owner)

If your having issues with your OMP, as in its not putting out any oil, then its one of two problems.

The inside chambers are clogged up, and you'll need to pull it completley apart and give the housing a nice bath in degreaser.

or

You have a severe oil pressure issue inside of the front cover (front of engine) as in, theres no oil pressure going to the OMP.

Anyways, thats about it. I think I'll draw a digram of how it works if you guys want me too, its good information becuase cleaning this part is ideal, the cost of replacing it is like 200$ I think

thx for your time.

bingoboy

and the S5 one does the same thing, but it uses an electrical stepping motor instead.

BlaCkPlaGUE

Cool, I guess thats why the S5 ones fail, cause the motor is not gonna last more than 10 years at best.
I guess the S5 block doesn't incorporate the gear that drives an S4 oil pump right? it just mounts on the engine to allow oil to come in, and the electrical motor replaces the gear of the S4 block. Why would they do that? was it really such an improvement to goto an electrical drive from a built in mechanical one thats driven by the engine itself?
I guess it was...


I put it all back together. The hardest thing to get back on was that ******* spring for the lever! took me like 15 minutes!

coldfire

iTrader: (1)

the S5 electric 'pump' has the advantage of being ECU controlled and is therefore able to inject a more accurate amount of oil, and also use less oil. although you then have a greater risk of failure...although i can safely say that there are many more things that will fail before that does

uRizen

iTrader: (2)

Cool, thanks for the info. I'm about to pull mine off to clean 'er out and replace the lines. is there any advice you could give on removal and reinstallation? Where can you get the o-rings as well? I know alot of the hardware stores around here have ones for sinks and all that, but do you think they'd have the proper size and type for the OMP?

pontious

It is a pretty odd shape, I would doubt it.. I took mine off some time ago, and never looked back (I premix )

ilike2eatricers

The oring is more like an oval ring. You may also need the metal gasket for the lines that go on the omp itself (looks like an X shap with 4 cicles, just look at how the lines are arranged). May also need new copper orings.