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There are two main areas that need to be cleaned up on the type 4 26mm pump. The outer plate that plugs in is simple to lap. Just pull the steel locating tube out that goes around one stud and lap it.

The hard part is lapping inside the deck of the main pump body. To do this, I will pull all four studs....then go to a machine shop and have a steel plate made...possibly a delrin plate. I have not decided yet. It will have a hole dead center. It will be machiend dead flat on one side and be within .002" of the exact inside diameter of the pump body ledge.....with sides sloped back on the disc so as not to wear the side walls of the body. Then put a mandrel in the hole in the center so I can turn it by hand.
I can apply fine git paper to the bottom flat side...or simply use lapping paste. Lap the two gears elsewhere to make surethey are dead even in height.
With the mandrel and disk...we will only be lapping the inside of the body.

The areas the gear sit into can be lapped smooth with an old gear and a disc or .010 steel shim stock glued to the bottom...with lapping compund underneath.
I don't think it will be that hard. Ray

Clatter wrote:

I have a couple of ideas about how to clean up the bore a bit and tighten the lash on teh gear ends.

Please share!

I just oringed and cleaned up a couple 30mm Mellings...

Has it gotten that bad, to where this is what we must resort to?
Or some other crazy project in the works??

Cast iron makes for some nasty swarf, that's for sure...

Anybody out there go here yet??
http://www.revmasteraviation.com/produc ... /index.htm
Too big, yes, but maybe solve the problem of too much oil instead of too little...
http://www.revmasteraviation.com/produc ... pump/1.htm

The orings are really the ONLY good fix for a cast iron pump, due to the expansion issues. The best fix would be two orings, one just under the flange to eliminate the seepage issue.

One way to deal with "too much pump" would be to add pressure balance grooves, which is basically adding intentional internal leaks in the pump. The grooves in the cover could be tweaked to set the pressure as desired.

Piledriver wrote: One way to deal with "too much pump" would be to add pressure balance grooves, which is basically adding intentional internal leaks in the pump. The grooves in the cover could be tweaked to set the pressure as desired.

You could just use a full flow cover piped back into the case with a small valve in-line to adjust the pressure reduction.

And/or...put a ball check valve in the cover with correct spring tension setting to bleed anything over say...75 psi back to the case. Ray

Ok, I am ready to consider another oil pump. The Wasserboxer holds 4.8 quarts. If I run an HP1 and over fill it, I can probably get 5.5 quarts in the motor. I am thinking of poop canning the dry sump and CB pump, and installing a melling that I have sitting on the counter. Before I spend money for a new Schedeck 30mm or a Bugpack 2 stage, I want to see what kind of oil pressure I can get with the melling at 230 degrees. I also want to see if the oil pressure will stay at 75 pounds at the end of the 1/4. The other scenario is to block the ends of 2 outer pushrods.

Anyways I did not realize that the wasserboxer case holds 4.8 quarts. This is the same as a type 1 with deep sump.

3literboy wrote:Ok, I am ready to consider another oil pump. The Wasserboxer holds 4.8 quarts. If I run an HP1 and over fill it, I can probably get 5.5 quarts in the motor. I am thinking of poop canning the dry sump and CB pump, and installing a melling that I have sitting on the counter. Before I spend money for a new Schedeck 30mm or a Bugpack 2 stage, I want to see what kind of oil pressure I can get with the melling at 230 degrees. I also want to see if the oil pressure will stay at 75 pounds at the end of the 1/4. The other scenario is to block the ends of 2 outer pushrods.

Anyways I did not realize that the wasserboxer case holds 4.8 quarts. This is the same as a type 1 with deep sump.

Yep, that's why we were all kinda wondering WTF you needed a deep sump

Unfortunately the Melling fits so badly and is ~zero expansion, so oringing is basically required.

I just used one on a throw together 1800 build (scrape the floor) pump dual oringed, with balance grooves, and set for std chevy end play, (really tight)

This is an experiment, as the Mellings are infamous for super high/blow filters/plugs off pressure cold (iron holds tight tolerances) and ~no oil pressure hot, due to sloppy case fit, esp due to the expansion difference.
Mellings are generally not recommended for this reason.

I'm hoping the pressure balance grooves and oring combo will tame max pressure and hold hot.
(Probably be next week before it fires due to work)

If you are looking at that sort of coin, check with Jake and see if he is selling his billet pumps.

...OTOH, More oil may not be the solution.
Read the PCV threads for an idea or three, and.. what ARE you doing for a cooler?
(and have you tried the larger fitting on the pump inlet?, and using a full flow cover as the outlet?)

The trick may be not just not letting your oil get HOT.