JV Puleo

My 1910 Mitchell "parts car" project

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Posted (edited)

Joe, I just noticed that you are in close quarters with this lathe with the red brick wall nearly against your 4 jaw chuck.  Space must be a premium in your shop.  Is your pump, now in the test mode, building much heat in the circulated oil?

Al

Edited by alsfarms
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The bricks are an optical illusion. The lathe is about 2 ft. from the wall. It is tight behind it but that was intentional. My shop is crowded enough so that I'm sworn off any more big machines. Some of the smaller ones, like the valve grinder, are on casters so I can roll them out of the way when not in use...I haven't used that one for two or three years so taking up bench space with it would be a waste.

 

The pump is generating very little heat. It's slightly warm to the touch after running for hours. By the end of the week, I should have about 20 hours running so it is probably time to open it up and take a look. So far, there has been no change in the oil flow. If all is well, the next step is to set up the entire oiling system on the test rig with the lines going to a "dummy" crankshaft. If that is ok, I'll continue to run it until I have a good 40-45 hours. At that point, I will probably feel some confidence in its performance. I have no way to test it with hot oil so I'll have to make some allowance for that.

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Just a thought Joe, would a lower viscosity oil be equivalent to using hot oil? I seem to remember reading somewhere that the oil in an engine does more for cooling the engine than the water in the cooling system.

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I think so. I'd intended to run 10W30 n the engine but the test oil is 15W40...mostly because it was the cheapest.

 

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You could run lower viscosity oil, but that won't help with testing hot running, i.e. the effect of tolerance changes. What about a little water heater of some kind in the oil reservoir?

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I was thinking of a cheap electric hotplate set at the lowest temperature.

 

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The pump ran for 7 hours today...still no noticeable change in output.

I threaded the body of the cap...

 

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Then went on the end. These pieces of flat stock are too thick and too big but they were the only flat stock I have that is big enough to do the job. I drilled and reamed them 7/16", the hole size for a 1/4" NPT plug. I have to put a hole in the center because I've no other way to hold them when threading.

 

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Unfortunately, I didn't have a fixture to hold those pieces that set up for a 7/16 hole so I had to interrupt the job to make one. This is an old piece of line shafting.

 

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Turned down and threaded 7/16-14. It would have been easier to thread if I'd taken it out of the lathe but by doing it in the lathe I am assured that the round section is perfectly concentric with the lathe spindle.

 

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Turning the pieces from square to round is a pain in the neck but I've no other way of getting two pieces of uniform thickness.

 

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I actually finished this part of the job today but I'll wait until tomorrow to thread them. There are two of them because making two is the same work as making one and I will need another for the oil filler cap which has the same thread.

 

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The work goes on...... and on.... and on......  That spells progress!

Al

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Posted (edited)

Once the cap ends were the proper diameter, I threaded them and tried them in the cap.

 

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Then put soldering flux on the threads and set it up on my camp stove for soldering,

 

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After it had cooled, I set it up in the lathe screwed to the fixture I'd made earlier. At this point, I don't even remember what I made it for but it is the correct thread.

 

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I turned the end flat and threaded it for 1/4 NPT. This cap will get a plug. The thread size was determined by the oil filler cap, which I haven't made yet but will have a breather valve with that thread screwed in.

 

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I then turned the diameter and knurled the cap without removing it from the fixture. Here it is screwed on to the end of the valve.

 

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This is a very simple valve. It consists of a spring-loaded plunger that should be pushed back, thereby letting excess oil return to the sump. The plunger is a piece of 5/8 ground stock which fits perfectly in the 5/8 reamed bore of the valve. In order to make sure the end of the plunger is perfectly flat, I surface ground it.

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And there is it. I still need to calculate the spring rate - which may be a guess and will need some experimentation to get right but this leaves me with only the oil filler tube to make.

 

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Edited by JV Puleo (see edit history)
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After I was done with this, a way of making the pressure adjustable came to me. I'll fit the cap with a little adjustment screw that can compress the spring and increase pressure. All I have to do is make sure the spring isn't too stiff, to begin with.

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Posted (edited)

Very timely post, JV. The engine which I'm currently working on was completely stripped down 50 years ago, and put into boxes. Among the components I have found some parts of the pressure relief valve, but no plunger.

 

The spring I found appears to be about right, and the adjustment has quite a long travel. The seat is a flat bottomed bronze insert in the main oil gallery. I have been picturing a flat topped piston type of plunger, with a guide shaft running inside the spring, into the adjuster. Very similar to the one you have just made. I don't have a surface grinder, and was leaning toward a face mill, then finishing on the flat plate with fine wet and dry. 

 

The car does have an oil pressure guage, of sorts, which is a help. A Malivert guage, which simply shows white for oil pressure, and red for none. I will probably hook up a graduated guage on start-up, although what pressure it should run is an unknown. It is a 1926 Metallurgique engine.

 

Edit. I have just found wear marks on the outside face of the spring, so I doubt that it was the original item. Tension feels about correct though. 

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Edited by Bush Mechanic (see edit history)
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That is really interesting. I appreciate knowing my design is similar to a real one. I think your plan for the plunger is fine. I might put a tiny bit of grinding paste on the end and lap it against its seat. I doubt these have to be absolutely airtight.

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The pump had now run for 20 hours so, first thing Monday. I took it apart to check the inside and finish one last piece.

 

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I needed to insert the dowel pins that locate the pump body in perfect alignment with the top and bottom plates. They have to be tight in the pump body but a slip fit in the end plates because one thing you cannot do is pry them apart since they rely on their lapped surfaces to seal. I opened up the holes in the plates a tiny bit with an expansion reamer, just enough to allow the pins to slip in and out freely.

 

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I also gave the surfaces a final lap on the lapping plate then reassembled the pump with the dowel pins in place.

 

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I also changed the oil so it would be completely clean and restarted the test rig. The oil is clean but appears to be picking up some air bubbles which are discoloring it for these photos.

 

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While it was running I went back to the pressure relief valve. I need a lock nut for the adjusting screw, one that can be hand tightened. The thread size is 1/4-28 - selected because I happen to have a thumb screw saved from a printing press I scrapped about 35 years ago. This is 1" brass bar in the lathe.

 

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Making this presents a bit of a problem because the knurling tool places tremendous pressure on the piece...to much for a 1/4" screw to take without bending. So, I drilled and tapped the end of the brass bar for the thread then used the cutoff tool to put a deep groove in it.

 

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I then knurled the piece while it still was connected.

 

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When that was done, I finished cutting it off. This went really well although it was the second time I'd done it. I managed to get the threads slightly crooked the first time and decided, with all this effort, it had to be right. Here it is on the adjustment screw. I still have to modify the cap to receive it but a trip to the local hardware store didn't turn up the right pipe plug so I'll have to order that.

 

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How have I not seen this project earlier? I just spent an hour catching up on the work--very impressive! Beautiful machine work, Joe. I'll be following along carefully.

 

 

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Thanks. I'm flattered but I think it's easily missed by someone who hands are as full as yours must be with that Lincoln.

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Posted (edited)

I have one last major piece to make for the oiling system, the oil filler tube with a line incorporated to return excess oil to the sump. Here's the problem...

The crankcase has this boss on the front left side. It looks as if it was plugged and I don't know if this was original to the car (although it looks as if it was) or if it was done later. This is the location PM Heldt recommends for an oil filler but my engine, as far as I can tell, just had a pipe fitting screwed into the left side. It was very crude and when I got the car all that was there was a rusty street elbow. I've put a crankcase breather in that hole and plan to move the filler to the front using this place to mount it. I made a filler tube earlier but I'm changing it to incorporate the return line.

 

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But, screwing pieces directly into this old - and fairly soft aluminum is a very poor idea, something that was known and appreciated at the time. Nevertheless, Mitchell did it all the time and I've several places where steel screws have solidified in place, never to be unscrewed. The correct way to do this was to insert a brass or bronze sleeve which was probably held in place with some sort of hardening varnish. I am trying to do that everywhere I can but in this case the available space is limited. My feeling is that I can insert a sleeve of a maximum diameter of 1". But, I still need to be able to screw in the oil filler. Until I am certain my sleeve will work, I can't make the filler tube should the dimensions have to be changed.

 

A 1" long piece of 1" brass bar... I drilled this and reamed it to 3/4" so that it would fit on one of my expanding arbors.

 

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When that was done, I threaded the outside 1"-20. Ordinarily I would never use such a fine thread in old aluminum but in this case, the only purpose of the thread is to lock the sleeve in place. I will probably use locktite on the threads or I may use their method and use something like Gasolia hardening pipe varnish. I failed to take a picture because while doing this the line returning the oil to the saucepan on my test rig jumped out and dumped about half a gallon of oil on the floor. When the outside was threaded I put it in a collet, drilled it 13/16 and threaded it 7/8-14, the standard 7/8 fine thread. Mathematically this works out so that the bottom of the outside threads and the bottom of the inside threads are about .030 apart so it was critical that everything is straight.

 

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And, it worked. As you can see, the sleeve is very thin but once it is screwed into the crankcase this won't matter. That lump of bronze behind it is going to be a split bearing for a camshaft I'm making for a friend so perhaps I'll work on that tomorrow.

 

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Edited by JV Puleo (see edit history)
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Posted (edited)

 

I took a break today and worked on the bronze camshaft bearing. This is for a friend, largely to repair what I am certain edinmas would (rightly) refer to as hack work. I won't go into the details, but the only way I can think of to repair it is to cut off the old one and replace it. But, in order to do that, it has to be in two pieces. I've never made one of these but I will have to for the Mitchell so this is good practice. The bronze stock was turned round oversize and two flats milled on it. These are for alignment. It's impossible to take something round out of the machine and put it back in exactly the same place unless you have some reference surface.

 

I calculated the position of the cap screws that will hold it together. Using a center-cutting end mill, I put a flat where each screw goes. As soon as the flat was milled I changed the collet and put a center hole there. By doing them one at the time I've eliminated any chance of them being even a tiny bit off.

 

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I then drilled holes the size for the tap through the entire piece. I did this in the little drill press because I wanted to be able to "feel" the drill and because if I do it in the milling machine it is extremely tedious to crank the table down to clear the chips. By drilling all the holes in the piece before it is split I'm assured that all for will align perfectly.

 

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And here is the piece with the holes in place. The next step is to mill the ends but I forgot that drawing so I put this aside and went on to the oil filler tube.

 

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This is the same brass stock used to make the nuts but in this case, I'm incorporating the "nut" in the piece. The first step was to drill and ream to 5/8" - the finished inside diameter.

 

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Then I turned down the end that will screw into the crankcase to .875 for the 7/8-14 thread and undercut it at the end. I suspect this is going to be tricky to thread because I have to get the threading tool quite close to the "nut" portion.

 

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Most of the other end will be turned to 1" diameter but I got to this point at 4 PM and decided I'd had enough for the day.

Edited by JV Puleo (see edit history)
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Various bits and pieces came in at the end of the day but this morning, before I went to work on them I finished turning the oil filler tube. Here it is with both diameters turned. I will now have to thread them but that is a "first thing in the norming" job.

 

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With the spring in hand, I shortened the plunger so all the pieces fit in the housing.

 

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Then finished the cap. I cut the thread deeper so that the 1/4 NPT plug would go in as far as it could then drilled and tapped it 1/4-28. The plug went in a bit too far so I had to trim the inside surface as well.

 

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At this point, I discovered that the thumbscrew I intended to use didn't fit the threads correctly - why I'm not sure but the printing press it came from was probably as old as this car is and it may be that the parts weren't as precisely made as we'd expect today. In the end, I gave up trying to modify it... I can make a thumbscrew if I have to but for the moment I don't even know how this will work so I'll leave it unti I've had a chance to test everything. Here's the relief valve assembled... I suspect the spring may be too stiff but only a test will demonstrate that.

 

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Before I go home I'll set up the next operation on the camshaft bearing but I'll wait until the morning to do the milling.

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Joe, I am most anxious to see the results of your home made pressure control valve and how it performs in a controlled test environment.  I need to build a pressure control valve that I can use to control pressure down from 70 PSI to about 2 to 5 PSI.

Good work by the way!

Al

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Posted (edited)

I'm anxious to see it work as well...and a bit afraid it won't. But, if it doesn't, I'll just keep plugging away at it until it does work.

I've been putting off polishing the intake manifold elbows - mostly because I don't like polishing but I'll have to do it shortly because, in order to test the oiling system, I have to finish the oil manifold and in order to do that I have to be certain that the oil lines will not conflict with the intake.

 

I did come up with a way to make a new thumbscrew last night so perhaps I'll try that this afternoon.

 

What is your application and where does it fit?

 

jp

Edited by JV Puleo (see edit history)
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I had an unusually productive day today... I started by making a threading gage for the 7/8-14 thread that will screw into the crankcase. I could have used a nut for this if I had one. Its made from a bushing that came out of my milling machine. It had been badly damaged taking the machine apart. I made a new one it but seemed "too good to throw away" so it has been on the shelf for about 3 years.

 

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I used the same tap I used on the brass liner that will screw into the crankcase. I should knurl the end but couldn't think of a way to hold it securely enough.

 

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I then drilled the oil holes that line up with the banjo fitting and cut the oil groove.

 

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Then changed the lathe over to threading and cut the threads on both sides.

 

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This is the finished piece.

 

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And this is how it goes together, with the threaded sleeve on the bottom end. I still have to make the cap.

 

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The threads look really good.  Threading is something I need a lot more practice on.  Unfortunately I'm usually pressed for time and I can use a tap or die to get the job done so I wimp out and do so. 

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I am afraid to say that I to often 'wimp out' cutting threads using the lathe, I tend to use a tap and die, in case I mess up the part I that I have just spent time machining. I am getting more and more confidence the more I read Joe's posts. The posts and chatting with Joe on his visit to the UK have helped me no end. At least I now use my milling machine and big lathe rather than just looking at them!

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It is always daunting to spend hours making a part and then worry about ruining it in the threading but I get that feeling with every complicated part no matter what the last step is. It took me quite a while to get comfortable with single-point threading. It's definitely one of those skills that take practice but I think I've only ruined one part. The early threading projects took much longer than they would now but they still came out functional. More important, it's a skill that makes a world of difference in what you can actually make, especially in my case because I don't know how to weld.

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