Gear Pump

[Brian Rupnow]

Everything is done and all buttoned up. I have to make up a gasket yet, and I want to make it from the thinnest possible material. I searched all over town today and nobody carries the really thin Teflon gasket material that Gail in New Mexico always recommends. My business card stock is .010" thick. Ordinary printer paper is .003" to .004" thick, but it is too fragile. I will root around a bit and find something for a gasket, then make up a pulley, and we'll try this thing out!!

[SHOPGUY]

Brian
Back in the day when we rebuilt Detroit Diesel fuel pumps we used a gasket that was like cellophane.  As I recall they were red in colour and you had to be careful not to tear them.  American Bosch just lapped the two surfaces on their fuel pump on the PSB pump.
Neat project.
Ernie J 

[Brian Rupnow]

 I ended up using a .007" piece of oil treated light cardboard as a gasket. I have tried the pump out using the mill to power it, but the test was inconclusive. I will make a proper set-up tomorrow and run it off my side valve engine. I didn't have a 3/16" steel ball for the check valve---the balls I had that I thought were 3/16 turned out to be 7/32" diameter, so I ordered some 3/16" balls and they will be here tomorrow. Preliminary indications are that the pump will not lift oil up from a lower elevation, but I will know better tomorrow. EDIT--I just realized as I posted this that my test today was probably inconclusive because the 1/16" diameter hole thru the pump body for the ball retainer rod was open--the rod hasn't been installed yet!!!

[Brian Rupnow]

Things are looking up!!! I plugged the 1/16" hole and retried the pump. The vessel full of oil was 4" below the pump, and I started the pump dry, with no prime. It sucked the oil up from the vessel, and then was able to pump it 24" vertically (that's all the tubing I had). It is sucking air somewhere, because I am using clear tubing and I can see a lot of air bubbles entrained in the oil coming out of the discharge side of the pump. However, the pump does work. I don't know yet how good or how consistently, but it does indeed work.---More tomorrow.

[b.lindsey]

Congrats Brian!  What kind of speed were you running it at?

Bill

[Dave Otto]

In this picture you can see the inlet and outlet tubes finished to size and Loctited into place, the plugs Loctited into the back side of the main pump body to prevent any oil drip from potentially sneaking past the shafts on that side, and in the other picture you can see the scuff marks on the inside of the cover plate, from "running in" the gears on my mill.

Not only have you made a pump; you have created Dykem Man!

Dave

[b.lindsey]

I missed that completely, but now that you mention it....

Bill

[Brian Rupnow]

Not very fast Bill. The vice wasn't really tightened up on the pump body--it was just there to keep the pump from rotating. The speed readout on my mill has never worked from the second week I bought it, but I estimate about 150 to 200 rpm. I was afraid to run it any faster than that in case everything went "sideways". I will have a much better idea of what speed it runs at when I get a more permanent set-up driven by my side valve engine.

[Brian Rupnow]

Dave--That's funny as Hell. I never noticed that either.---Brian

[b.lindsey]

Brian, that sounds like really good performance for a relative slow rpm. And not priming it either!!  Pretty impressive.

Bill

[philjoe5]

Fantastic Brian.  Nice work.  I'll wait for your complete plans, though I'll need to modify them some.  But the build log details all the critical stuff and I thank you for that

Cheers,
Phil

[Brian Rupnow]

This is what I hope to put together today for a test rig driven by my side valve engine.

[Alan Haisley]

I hope you can find where that "air suck" is coming from. This is such a great project. I wonder if a more uniform gasket material would help? Or perhaps lapping a bit where the gasket goes.   

Alan

[Brian Rupnow]

Alan--I submerged the whole thing in a pail of water, plugged the end of one tube and "blew my guts out" on the other tube. The only bubbles I seen were a few around the #6 flat head screw that holds the o-ring retainer plate on. I will give it a dab of sealer on the threads.---Brian

[b.lindsey]

Any chance it could be nothing more than cavitation?

Bill