Hi Tim.

I followed that link you gave on page 2 regarding the Suntec model A pump mods you've devised. Let me ask a couple questions in case I missed anything.

I think I need to do the following steps:
1. Permanently remove the filter screen and top plate as well as the pressure diaphragm and its spring.
2. Fabricate and install a new top plate from 1/4 inch aluminum or steel (with no oil passages or diaphragm pocket).

I also think I will need to drill out the 1/8" diameter high pressure oil passageways to a larger diameter to allow higher flow. Maybe 1/4" or 3/8" will work okay. Since I haven't really seen these oil passages except in my minds eye, I'm wondering if you might be able to describe their location a little more. I wish you had a web cam so I could actually see all your mods.

The way you described the function of the pressure diaphragm in the stack of plates, I'm not sure if it somehow modulates output pressure in coordination with the bypass valve? It sounded like initial oil pressure overcame the spring resistance against the back of the diaphragm until it blocked the center diaphragm oriface in the top plate, then oil pressure would increase sharply. Once oil pressure increased enough, the oil would push back the bypass plunger before oil could leave the pump head and enter the lines.

Did I read that correctly? I always thought that bypass valves bled fluid from the pressure side of the gears back to the suction side. Does this one function differently, or did I misunderstand? It seems that this plunger valve is meant to guarantee downline pressure rather than limit it. Perhaps it somehow does both jobs.

Will I need to remove or modify the bypass valve in order to allow oil to flow out of the pump? Since I'm adding one or two external check valves to act as bypass valves I don't really NEED any internal valves, right?

I was also wondering about the rubber "cone valve" that Suntec uses in one of the high pressure passages to retain pressure on the positive pressure side of the pump when the gears stop spinning (it is removable from outside you said). I've heard of biodiesel eating weaker rubers, but I always thought that veggie was okay with natural rubbers. Lately I've read somewhere that veggie can eat rubber as well as biodiesel, only slower. Have you heard about this? Has anyone else? Would it be a safer bet to just remove the rubber cone valve, or is that likely to be necessary?

I just thought of another question for you, Tim:

When you did the flow test and came up with 11 gph at 1600 rpm, was that for a 1725 rpm rated pump or a 3450 rpm rated pump?

The difference in tooth width on the spur gears might help out if you switch from your 3450 to your 1725.

Pump mods --

Yes , you need to permanantly remove the pressure diaphragm and spring located under the outer layer of the inner pump stack.

You can remove the strainer entierly but I prefer to replace the stock fuel oil strainer with a used oil strainer, still gives plenty of flow but the strainer will catch anything that might jamb up the gears.

there are several ways to re-route the flow that originally went to the diaphragm bypass valve. I initially made a new solid top layer plate, this blocked off the bypass flow holes so the pump would output oil no matter how slow it was turned, worked but took a bit of fabrication, Perkhouse simply removed the diaphragm and spring and made a new teflon gasket with only the 3 mounting screw holes, he reused the original outer top layer, workes fine also.

Both these allow the pump to output oil at slow speed but do nothing to improve the flow.

I now remove the top layer completely, tap the two appropriate holes in the 2nd layer, and screw 1/8 inch long set screws into them as plugs, then drill a 1/4 inch hole directly over the suction side of the gears. This allows the pump to putput oil at any speed and also improves flow by allowing a large opening directly to the suction side of the gears. By removing the top plate completely it also gives over another 1/4 inch of space for oil to freely flow directly through the strainer to the new inlet hole to the gears.

Welder -- You read everything correctly, your conclusion is correct if we were taking the oil out of the "burner nozzle" output, we dont, that outlet gets plugged, we take the oil from the "guage" output on top of the pump. This outlet has full pressure and the full flow from the gears is available there.

The bypass pressure plunger does two things, at low pressure it is pushed up against a small hole in the back of the burner outlet by it's spring, this keeps that outlet plugged til full pressure is reached. Once full pressure is reached the pressure plunger moves back to spill the excess oil back to the suction side, the movement of the plunger also opens the burner outlet to a limited flow of fuel, limited, but enough for the burner.

No modifications need be made to the pressure bypass.

Once the oil passages are drilled out the cone valve will no longer have a seat to operate against so will simply be removed. The FE pump had the cone valve installed up until about a week ago, been working just fine for the last year flowing hot oil, the cone valve was still working fine as a pressure check valve. For veg it can be removed or left in place unless you drill out the passage. the come valve spring is VERY weak, the cone valve does not hinder flow any as far as I can tell. Biodiesel would probably destroy the rubber tip though. I don't really see any need for this check valve in a lift pump setup?

The 11 G/H flow rate was from the 3450 rated pump with the smallest gears, turning at 1600 RPM with the stock passageways but with the cone valve removed. Based on this I calculate the 1725 rated pump with the wider gears will flow about 18 G/H but have not yet confirmed this with a test.

The following picture is of the unmodified pump with the cover and strainer removed.

end_view_of_pump_stack_-_cover_removed.jpg (3 KB, 61 downloads)

This is a side view of the pump with the cover removed but the new used oil strainer in place, it also shows the location of the cover plug for the cone valve.

used_oil_strainer,_cone_valve_cover_removed.jpg (7 KB, 60 downloads)

Same view but without the strainer installed.

rectangular_oil_inlet_and_cone_cover_plug.jpg (6 KB, 48 downloads)

This shows the outer side of the second layer of the pump stack and the location of the two holes that need to be tapped and plugged. The upper hole originally flowed oil directly from the gears out in to the diaphragm bypass chamber, the lower hole is where the bypassed oir flowed out of the diaphragm chamber.

pluged_hole_locations.jpg (6 KB, 48 downloads)

This is a view of the inside side of the unmodified second layer of the pump, you can see the rectangular oil passage on the right. The holes have already been plugged in this picture. Note the somewhat hard to see crescent shaped filler section mounted on this layer, the crescent goes between the inner and outer gears and the oil is carried along on both it's inner and outer surface.

inside_view_of_stock_second_layer.jpg (4 KB, 38 downloads)

this is the same view of the inside side of the second layer with the new 1/4 inch oil inlet hole located.

plugs_installed,_new_oil_inlet_located.jpg (4 KB, 35 downloads)

This is the same view with the new oil hole and the plugs installed.

new_oil_inlet_hole.jpg (4 KB, 33 downloads)

This is the outside view of the pump stack with the modified second layer installed, the gears are clearly visable.

modified_second_layer_installed.jpg (7 KB, 29 downloads)

This view shows the actual gear layer.

gears_located_in_pump.jpg (4 KB, 41 downloads)

main shaft of pump.

pump_shaft_and_gear.jpg (4 KB, 41 downloads)

this is the location of the verious in/out oil holes in the pump body and a flow diagram of the oil through the pump.

Unfortunatly, the oil passages behind these holes are NOT at 90 deg angles to the surface of the pump. This will make it a bit difficult to drill them larger and will likely end up with some bits being broaken as the pump body will have to be held by hand to align the drill bits with the holes. I have yet to try this but intend to sometime this week. The largest that I think these passages can be drilled out to is probably 3/16 inch, anything bigger and the sections of the pump would no longer seal over the entire surface of the holes.

The smallest passage is located at the tip of the cone valve, it is .120 in diameter, drilling these passages out to 3/16 will increase the area by 2.44 times, should flow at least some amount more oil ?

pump_body_oil_flow.jpg (8 KB, 43 downloads)

this shows the side of the gear layer that contacts the cast iron body of the pump. The passage indicated also has to be increased in size to match the drilled out passages, will be a bit of a challenge but hopefully a Dremmel tool will work for the prototype. The material is a very fine grain cast steel and the part is investmant cast, it machines and files very well, a milling machine with a small rotary table would make short work of opening up this passage.

oil_passage_in_gear_layer.jpg (5 KB, 29 downloads)

Hi Tim.

It looks like you DO own a webcam after all!!!
Nice Pics. Thanks for the clarity this gives.

In your second to last post (1:28 AM), you said that the pump body would need to be held by hand to align the bits with the holes. Won't this thing snug up in a workholder on a drillpress or even in a bench vise?

After seeing inside this thing, I realised that it's actually a gearotor style gear pump, not a spur gear style. For some reason, I assumed that it used spur gears, not a gear in a gear.

I'm excited to see what flow rate your 1725 RPM unit will do after the mods while spinning at 1600 RPM.

One of the easiest ways to drive a burner pump is to just use an old discarded oil burner, Just strip off everything (including the blower) just leaving the housing, pump coupler and motor.

If you are using a different motor, you can make a mounting plate to adapt the new motor to the housing.

I am using a 160RPM gear motor to drive my Webster pump as a metering pump in my WVO burner.

im thinking of trying this one

Facet Posi-Flo

Hi Ron.

This thread is actually about on board lift pumps to feed veggie to diesel engines, not oil burners.

I can see how you might have been confused since Tim and I have filled the last few pages of this thread with talk about his Suntec pump mods and his mods are known on this forum for oil burner application.

Hi Blacksheep.

Any idea what the max temp of that little Facet pump is?

quote:

Originally posted by welder:
Any idea what the max temp of that little Facet pump is?

I dont know, Facet website does not say.

but i went ahead and bought a Carter P4070 pump and im going to try it.

quote:

Originally posted by welder:
Hi Ron.

This thread is actually about on board lift pumps to feed veggie to diesel engines, not oil burners.

I can see how you might have been confused since Tim and I have filled the last few pages of this thread with talk about his Suntec pump mods and his mods are known on this forum for oil burner application.

Hi welder,

I have used DC motors adapted to the gutted housing for mobile use.