setzep

While I had the engine out for a oil pan leak fix (turned out to be the damn oil level switch) I figured I would plug off the OMP gallery.

If you plan on doing this I would be very careful about shavings getting in the oil gallerys from drilling/tapping. I removed the front stationary gear for this reason then flushed it out with oil and compressed air.

It's pretty straightforward to do, simply drill and tap. This is a 1/16" SHPP (socket head pipe plug).



I figure I don't need a ~.070" orifice bleeding of oil that could be going to my front bearing if I'm not running a OMP.

setzep

Also, make sure the eshaft is verticle and do not rotate the engine with the stationary gear out.

BLUE TII

Lots of good info as usual in a thread with posty by Lynn. Thanks.



On the front sidehousing to oil pump pick-up it would seem like if you dress both surfaces very flat and use hylomar you would have a better than stock seal to stop sucking in air instead of oil. Hylomar gets more solid w/ oil and heat- make sure don't get it gooped up inside the tube of course and locktite the bolts.



On the oil pump body to front side housing it would seem there is a lot of chance for leakage as there is a wider mounting base for surface inconsistancies and you have high oil pressure at the pump outlet. There is also enough material on the pump body to cut an O-ring groove into the mounting flange. Would this be of any benifit?



As for eliminating sharp edges and 90 deg turns it is really easy to drill out and tap the front side housing oil pump outlet galley where the factory plugged it and put a pipe to -AN fitting there to outlet to the oil cooler. Then plug the front housing oil cooler outlet.



As for front cover gasket, I thought it was pretty much a given to ditch the gasket and use only RTV to get maximum crush on the front cover to front housing oil passage- does this trick not work on the later engines?



I aslo saw that JHB Performance offered a service to dowel this front cover to housing junction so that the O-ring is captured. Very good idea!



For working the front side housing oil pump cavities I found a 1/8" shank carbide burr in a Dremel flex shaft works great. My handle fit inside the oil pump pickup. To really work the edges smooth here and on the oil pump outlet cavity to galley I used the 10" split mandrel in the die grinder (that I made to port my manifolds) and I cut the stiff backed 80 grit into strips at the edge so that when I work it in and out of the galley it really abrades the edge. Then switch out to finer grits and polish away at all the galleys.



As for the notch between the oil pump land pressure cavity to pump shaft that is to force highpressure oil into the oil pump bearing area. The front of the pump gets a flow through from the pressure side into the front cover cavity, but the rear flow is more limited as it would more easily leak out between pump inlet and outlet cavities at the mounting flange than go down into the pump shaft bearing cavity.





Now, we need to start a thread about the oil mods done for flow once the oil is re-introduced to the engine from the oil cooler! I just got done adding the rear e-shaft galley, and porting the e-shaft bearing inlet/outlets to aid flow to the rotor bearings/rotor cavities and a tapping the front housing for the loop line to ease oil flow to the front bearings.



Getting higher pressure is good, but I believe higher total flow can really help drop the oil temps as well.

Cheesy

Ive been looking at this as well, apart from blocking off the pressure bypass and using the drilling in the side of the front iron it may be possible to use a tapered reemer on the front cover and the iron and use a brass compression fitting similar to the one pictured instead of an oring.

[attachment=28310:attachment]

also regarding the phasing of the two stages of the oil pump is it possible to modify the pump so it will be more efficient

Lynn E. Hanover

For the land area mods, I cut the back off of an old pump. Then I can rotate the guts across the upper web and mark off the shape of the cavity formed by the ring and rotor as it captures a slug of oil and moves it to the pressure side of the pump to be squeezed out. Note that once the shape has captured the oil it moves through a few degrees of rotation before the volume is exposed to the pressure cavity.



I ink up the land with a Magic marker and scribe a thin line around the inside of the capture cavity. I then grind in from each side to within a few thousandths of the scribed lines. Keep checking with the cut up pump body to be sure there are a few degrees of rotation left where the high and low pressure sides are still separated. The mission is to remove sharp edges and to do so in an area that will not intrude into the capture volume. If you do make a mistake it will ruin the iron because the pump will not longer work. You can keep it around for a dry sump engine you should have built in the first place.



The notch into the bearing area from the pressure side is to aid in lubricating the rear end of the pump shaft. It is highly loaded and there is no bearing to protect the shaft. It is poor design to have no bearing material running on the shaft.



The reduction in the size of the land area between high pressure and suction will reduce idle and just off idle oil pressure. The width of the land acts as a seal to reduce bleed back to the suction side. Reducing the land increases the bleed back.

Lower oil pressure at idle just is not a factor because there is no load at idle. Any amount of oil is fine. Once the revs spool up the time available for leak back is reduced and it is no longer a factor.



A bit smaller version can be done on the bottom land also but it is much less productive. The job done in the picture is poor because the material removed changed the pump timing as is OK, but it did so at a steep angle that still makes for poor flow. A rounding of the sharp edge of the land is the desired result. Not a massive removal of material. Less is more.



You cannot get oil passages too smooth. Like chrome would be the best. No sharp edges anywhere, ever. there is no point at all to this modification if you are not running 100+ pounds of pressure, and larger bearing clearances.



Poor pump performance as a result of shading, sharp corners, poor pump timing and suction side design faults, tend to cost oil pressure and induce foaming at the end of a long high RPM pull with hot oil (not over 180 please). If you are not having the problem, leave it alone.



Most people are complete after of one or two gears woth of mind numbing accelleration. A racer has to have great pump performance after 45 minutes of mind numbing accelleration in all of the gears and wild eyed high performance braking.



Otherwise the stock system is fine. The pump will be more productive at high speed. Better flow results in higher pressure (assuming a high pressure relief valve is installed). If you premix, you could run the oil straight out the gallery with an "O" ring boss to AN 12 fitting, and block off the "O" ring junction in the front cover with a thick aluminum disc. Just one of many fixes you can do.



When helping the airplane engine guys I suggested puting the pump rotors into index and rounding the corners of the divider plate. Another idea was to remove that divider and shorten another rotor and ring, and make the whole length of the pump into a pump. Seems obvious.



The best answer is to hang a big nasty American V-8 dry sump pump on the side of the engine and forget that little bitty stock pump.



Lynn E. Hanover