http://www.vincentfurniture.com/photos/subaru/oilpumpinnards/oil1.jpg

http://www.vincentfurniture.com/photos/subaru/oilpumpinnards/oil2.jpg

http://www.vincentfurniture.com/photos/subaru/oilpumpinnards/oil3.jpg

http://www.vincentfurniture.com/photos/subaru/oilpumpinnards/oil4.jpg

And that little piece at the end of the spring can, and has been known to stick.

Just out of curiosity, has anyone measured the stock side clearence on the georotor and the case (depth of case cavity, minus thickness of the rotor).

Is the georotor internal rotor the same thickness as the outer rotor?

One way to improve pump effeciency would be to reduce that side clearence if it is excessively wide.
Bad news is if you go too far it could bind up the pump and kill the engine.

Second possiblity would be to get the georotor pieces and case anti friction coated and detail the outlet port so it has a clean radiused entry rather than a sharp corner.

Larry

NewB Question!


Which is the inlet and the outlet? looks like the outlet on the left side....which would move the pressure relief and bypass that to the inlet side?

http://www.vincentfurniture.com/photos/subaru/oilpumpinnards/oil4.jpg

wow, i never knew it was that simple...

JW what oil pump is that stock, cosworth, etc...

JW what oil pump is that stock, cosworth, etc...

My understanding is that the cosworth is just a stocker that's been honed, and the bypass spring shimmed.

My understanding is that the cosworth is just a stocker that's been honed, and the bypass spring shimmed.

While it may be honed and shimmed, it has another little secret in it too ;)

stock

Thanks

Whats the other lil secret.....???:confused:

from what ive heard, the stock oil pumps dont feed the engine enough oil. is that true and if so whats a good upgrade? is cosworth's "secret" worth buying?

I took my new 12mm pump apart and did some porting. The service manual I have is for a 1991 legacy which is the motor I'm building. I looked at the manual to get torque specs and noticed that it recommends you, "inscribe alignment marks on the inner and outer rotor so that they can be replaced to their original positions during reassembly." I did not do this but there are marks on the rotors as in the above pictures. The diagrams in my service manual don't have these marks. Do I use these marks to align the rotors? Are these marks a design change that makes inscribing your own alignment marks unnecessary?

One other question. I removed the two large bolts from the bottom of the pump so I could get a better view during porting. They were sealed with something but it the workshop manual there is no mention of what to use. I think that is because there is no need to remove them during normal service. What should I use to reseal these bolts? Thanks in advance for any advice.

The design of a georotor pump causes the inner rotor to slowly walk around the the outer rotor as it runs. So their relationship will not stay the same with respect to each other. I suspect they want to make sure the two rotors are placed in the pump facing the same way (same side to the front of the pump for example) and so the postion of the inner rotor is phased properly so it will fit on the crankshaft when you put it back.

I don't think I would worry about it much as long as you place the rotors back in the pump so they both have the same side up as they had when they came out.

For the seal on the plugs I would suggest the same sealing compound you use for the cases and the plugs in the cases would work. Just be careful not to use too much so you don't have any lumps of it floating around inside the pump. I would only put it on the plugs (and sparingly) so that none of the sealant gets squeezed into the inside of the pump as you put it back together.


Larry

Thanks Larry. One thing I thought was interesting... I felt the same way about the rotors but I did a little experiment. I coated them in oil and put them back in the housing with the marks lining up at the 6 o'clock position. then I rotated it many many times and sure enough, the marks realigned and at the 6 0'clock position. I think there is something to aligning the rotors but I'm thinking it is more important on a pump that has seen a lot of RPMs where the rotors wear evenly. On a new pump I think I'll be fine. On the plugs, I'll try a little three bond 1215 which is what the manual calls for when mating the pump to the block. Thanks again for the insight.