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1915 Studebaker Oil pump


oakhurst

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This oil pump is a horizontal piston driven off the camshaft.  It sends oil two places. One to the sight gauge on the dash, then to the front of the engine for the timing gear and back to the pan.  The other is back into the pan to fill the "trays" that hold oil for the scoops on the the rods to oil those bearings. We're not getting enough volume of oil.  All passages are clear and tight.  The piston appears to be "tight" enough to it's cylinder to "suck" and Push". but there is an opening in the "dome" of the piston with a spring inside and a hole at 90 degrees emerging on the side of the piston just below the "pad" that rides on the camshaft.  We do not know the purpose of this mechanism inside of the piston.  Is it a check valve?  How does it come apart?  Right now my plan is to enlarge one of the exiting grooves on the piston (similar to those on a normal piston)  and fit an O ring to increase compression.  Is anyone familiar with this pump?

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I have seen a spring loaded valve built into a piston on an old dental compressor, so your comment may be correct about yours.

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I've been looking into my old books for some specific info to help, but ..................

My 1918 Dykes indicates 4 & 6 engines  had gear pumps. Probably not right info for your 1915

 

 

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17 hours ago, oakhurst said:

I'm thinking that this spring loaded valve built into the piston might be to allow some oil to pass through the piston to lube the cylinder and piston itself.

 

I'm not familiar with this pump but it sounds reasonable that the spring loaded valve is there to lubricate the piston as you suggest as well as the camshaft lobe that drives it.  Is the valve working properly and not allowing excess oil to flow through it?  It would seem to me that the valve would be there to allow oil to pass on one stroke and not the return stroke.  Before re-assembly I would make sure it is working properly.

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I agree that this check valve not working properly could be the problem, however we don't really know what it is supposed to do.  It does seem to open and close.  Other than cleaning it thoroughly, there seems to be nothing else to do. It does not come apart without drilling it out.

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I checked them on the main line and they are functioning.  The valve in the piston was confusing but I think I got it loosened up.  WD40 and air pressure.  It seems to move now.  Not sure I understand it, but putting it back tomorrow.

Will keep you posted.

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I enlarged the picture of the motor.

Just wondering about pump posibilities,   oil flow ( spray ) to rods may be a higher pressure, while flow to gage and front of eng may just be a  volume ( low pressure)

 

I sure would like to see your pump and internal parts to see if the flapper valve in piston is a low press buy pass to the gage and front of engine.

Can you take pictures and post them....?

 

Your issue has has intrigued  me.

 

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I am not seeing any pictures.  The pump has two discharge lines.  One goes to the sight gauge on the dash, then back down to the front of the engine to lube the timing gear, then back into the pan.  The other discharge which is getting oil first, dumps back into the pan to fill the "tray" in the pan that hold oil in four dished out areas for the rods to scoop oil for the rod bearings.  That is the complete oil system.  I think the check valve in the piston in the pump is only to keep the pump lubed.  If I knew how to post picture on this site I would be happy to.  If anyone provides an email address i would be happy to send them directly.  My email is  rwendt@sti.net.

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with out seeing actual pictures of your pump and internal parts, I surmise the following:

1. vertical sliding pump piston supplies TWO  levels of oil pressure and volume.

2. a check valve above point where oil is pressure fed to engine rod area and toughs.

3. check valve in lower area to stop oil from leaking back to lower pan

4. not sure of this but the flapper valve in piston head may be a releaf ( vacuum breaker ) so piston can return downward to be able to pump again.

 

How many check valves in your system?  and where ?

 

 

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23 hours ago, oakhurst said:

I checked them on the main line and they are functioning.  The valve in the piston was confusing but I think I got it loosened up.  WD40 and air pressure.  It seems to move now.  Not sure I understand it, but putting it back tomorrow.

Will keep you posted.

Perhaps the valve in the piston is to regulate the oil pressure as revs increase ie it opens and allows some oil to bleed off. It may have been frozen in an open position thereby explaining low volume of oil pumped.

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I hope the pics you sent to me help others.

 

I am just ruminating in my mind:

1. Horizontal pump plunger has spring return to keep contact with cam lobe. this appears to be sealed to block, and likely below level of oil in pan, so any blow may be reduced with oil surrounding it.

2. If no check valve in lower discharge outlet then bulke of oil goes this way toward inner engine and rods to fill troughs.

3. Vertical tube with large round barrel is a pressure dome, this will smooth out the pump pulsations.

 4. little ball bearing is a check ball, to only let small pulses of oil to be pushed up to larger barrel area, to eventually go to gage and then front of engine.

5. If I am somewhat correct so far, then your pump is not a high pressure pump.

6. engine rpm will increase oil flow but a 'slug' pump is basically a volume pump.

 

I have similar type ( not the same ) oil pumps on several engines.  It seems to me the  oil is supplied as make up oil with basic operation coming from the oil in the toughs.

So make sure they are full before running.

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Hit and Miss farm engines have little check balls in lower end of gas line in tank to allow gas to remain up in the gas line to be ready for next intake intake stroke.

Some old outboard motors have similar "check valves" in water intake system to retain flow.

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I sure hope I'm some what right?

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9 hours ago, Hans1 said:

are my arrows correct, to show oil flow?

Hans I would suggest that the line with the "barrel" is the inlet (suction) and the two connections on the other end being the  outlets (delivery) with the brass elbow being the delivery to the sight gauge.

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The picture I sent should have been rotated 180.  The inlet is the single tube below the large round barrel.  the two outlets are at the top, the lower one sending oil back into to pan to fill the dipping trays, and the upper one with the 90 degree elbow goes up to the sight gauge, and then returns to the front of the engine to the timing gear and then pack into the pan.  There is no valve that would change the pressure to either of the two discharge lines.  I pulled the pan, attached everything to it, added 4 quarts of oil and stroked the piston manually.  We did get oil from both discharge fittings. Just not sure of the volume.  The cam lope looks to move the pump piston about 3/8 of an inch.  Will try an put the pan back on in the next few days.  Thanks Hans for posting my pictures,  They did show up in the posting for me. 

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I enjoyed looking into this.

Do you have a picture of piston with "flapper valve" ? before you button it up??

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If your piston is driven by a camshaft lobe, is it single or double lobe.  ( one lob on each side of cam shaft )???

That will help to understand what quantity of oil it is delivering.

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I have an Essex engine with slug pump, it is driven 1/12 engine speed and is not a large pump.

As a volume pump it apparently passes enough oil for a 160 cu in, 60 Hp motor rated over 5000 rpm.

 

Good luck with your motor.

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I get no pictures at all on this forum.  My email is rwendt@sti.net.  I am happy to forward and receive any pictures from my email..  Hans and I have been exchanging info that way.  Any other interested individuals should feel free to contact me.

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Hmmm. I think you have pasted the image plus the instructions for the thumbnail (see my post above: it starts "GetImageThumbnail"). Maybe paste into a photo editor first, then copy it from there? I do that from the 'net. I use a basic editor, Irfanview.

 

A jpg image starts like this

"ÿØÿà JFIF H H  ÿáÿExif" if you look at it in a hexidecimal editor.

Edited by Spinneyhill (see edit history)
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