The Creation

of

Engine Number Four

Click here to to to Part Two

(Electronic Governor)

Having nothing better to do, I decided to build an engine using some small engine parts and scraps from other projects.  I'm going to see if I can make a runnable engine without the use of CAD for design.  I'll just make sketches when I need to work out dimensions.  This could end up being The Mother of All Engine Disasters!

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27 December 2010:

The start of the project consists of gathering some likely looking stuff on the bench and looking at it for a while.  The crankshaft (shown below after being carved on) was machined for ball bearings mains.

Some of the raw materials.

The first thing that jumps out is the big cast iron gear.  That thing's been sitting around for several years and I figure it's just begging to be a flywheel.  After I get a hub bushing made, I will just barely be able to get it in the mill so I can machine off the teeth and clean it up.  It'll be a kind of skinny wheel but the diameter helps.

Modified crankshaft and camshaft.

I'm not sure where the original engine parts came from.  The block, flywheel, carb, head, etc. are long gone.  One thing I did notice is that the part have virtually no wear.  There's not even any scuffing on the piston skirt and the rings look new.

 

I may or may not use the original rod.  It's kinda short to suit me but, with the original piston and rings, it would make the job easier.  Note that I turned the lobes off of the camshaft.  I may make an eccentric to operate the exhaust valve (I'm still a-thinkin' on that feature).  Oh, yes, the little end bearing on the camshaft isn't on crooked, it's a self aligning ball bearing out of some long-forgotten machine.

 

So far, I haven't quite decided whether it's going to be water or air cooled.  Air cooling sounds nice but if I use the piston from the original engine the parts came from, the piece of cast iron tubing won't have a lot of meat on it for fins.  I also haven't figured out whether it's going to be vertical or horizontal, "L" head, "F" head or Overhead.

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30 December 2010:

I've whittled some steel in the last couple of days and have a good start on the engine frame.

  

Bottom plate, ends and sides squared-up.                                                 End plate main bearing boring.

The base and ends are of 1/2" steel.  The side plates are of 1/8" steel.  

 

To machine the end plates, I laid them together with spacers between them and squared them up on the mill.  This ensures that everything is in line.  If I properly locate the bolt holes in the base plate and the end plates, everything will fit properly.  The reason I put a space between the end plates is that one of the cam bearings is smaller than the other and I didn't want to un-set everything to do the larger bore.

  

Engine frame, crank and camshaft laid in place to check fit.

The last thing I did today was to lay the crankshaft and camshaft into the end plates then lay the whole works together to check fits.  So far, so good except that I now see that I should have made the base plate about an inch longer.  There's not going to be much space for mounting bolt holes.

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1 January 2011:

I didn't get much done today.  I had to make new bushings for the guide wheels on my (free!) el-cheapo bandsaw.

 

After I finished that, I flycut the bottom plate.  At first, I thought the plate was flat enough but after taking a skimming cut, I found that it needed to have almost 0.030" taken off of the surface for it to be flat.

Work product for New Year's Day 2011.

With the bottom plate still in the mill, I've dyed the areas where holes will be drilled.  I will do a fairly accurate layout but will depend on the mill to get the holes in as close as possible to the correct places.  The holes in the base plate must align with those I will drill in the end plates.  To make sure everything lines-up, I will put a couple of 1/8" steel dowels in each end where they mount to the base.

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2 January 2011:

The base and ends are now joined.  I still have the side plates and top (cylinder mounting) plate to do.

  

Crankcase side of base plate.                                                                          Bottom side of base plate.

I used the mill to lay out the holes for the end plate bolts and dowel pins.  You can see the dowel pins on the left-hand photo.  The oil drain hole was drilled and tapped for a 1/8 NPT pipe plug.  Fitting the 1/8" X 1/2" dowels worked fine.  The base plate was drilled 1/8", 1/4" deep and the pins were a press fit.

  

Flywheel side together.                                                                     Frame test assembled for fit..

The end plates were drilled and tapped for 10-32 socket head machine screws and the dowel pin holes were drilled 1/8", 3/8" deep then finished with a well oiled 1/8" reamer.  This gives a nice slip fit of the pins in the end plates.

 

The engine mounting holes were drilled 1/4".  Because the bolts are so close to the side plates, I will mill off one side of the bolt heads so they are against the side plate.  The nuts and washers will go underneath.  Works for me.

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3 January 2011:

I didn't get a lot done today but did get the side plates drilled and the angle brackets that seal the bottom of the sides done.  I've got to finish the tapping.

         

Angle bracket and side plate in place.                                               Side plate in test fit.             

The top plate for the crankcase will locate the cylinder and the side plates will bolt to the top plate through the top three holes in the sides.

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8 January 2011:

Today, I cut the top plate out of 1/2" steel and did the finishing, drilling and tapping for mounting bolts.  The rough cut out of a bigger piece of stock took a while using my bandsaw!

   

     Cylinder temporarily set on crankcase.                                                          Beginning boring the cylinder hole.

I plan to turn the O.D. of the cylinder (originally 3.5" O.D.) to where it will slip into a 2.9" bore in the top plate.  There will be a step and the length of the step will be determined after the the location of the piston skirt at the bottom of the stroke is determined.  

 

The jury's still out on how I'll attach the cylinder to the top plate but I would like to see if I can get by without welding anything on the main parts.  I suppose I could use a number of #10-32 screws through the top plate, threaded into the bottom of the cylinder.

 

I will figure the length of the cylinder after I've got the crankshaft and rod permanently in place.  Once I have the piston hung, I can make measurements to determine the height of the cylinder to give about a 5:1 compression ratio.

 

The piston is 2.620" so I'll make the cylinder bore around 2.625" (the original cylinder material I.D. is 2.5").

 

I'm still undecided as to the valve arrangement.  I would like to use an "F" head configuration with the exhaust below the intake valve.  To do that, I'd need to make a cage for the intake valve.  I've got a lot to think about.

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9 January 2011:

The top plate is bored and the cylinder is coming along.

   

       Turning the step in the cylinder.                                                   Cylinder ready for pressing into top plate.

I calculated the cylinder length after measuring the piston height and stroke.  The cylinder was cut to length for a compression ratio of 5:1.

 

It was then chucked in the lathe and indicated true then the step was turned to the calculated depth.  As you can see, I made a lot of stink in the shop turning this diameter.  Chatter was a real problem until I got the speed, tool angle and feed rate set.  I ended up taking many 0.005" cuts!  Most of the afternoon was taken up doing the step.  You will notice that I've made a ring compression chamfer to make it easier to put it back together when fiddling with the cylinder/piston.

 

The step diameter was turned for a press fit of the cylinder onto the top plate. 

Pressing cylinder into top plate.

After all was done, I found that my fit was not as tight as I thought it would be.  It only took about 1,500 lbs to press the cylinder home.  I think I'm going to tack weld the cylinder to the top plate on the inside so it won't show.  I could decide to put a bunch of 8-32 machine screws into the cylinder from beneath to hold it.  I haven't decided.

   

Cylinder assembled to top plate.                                                                     Engine Number Four so far.

Next, I've got to bore the cylinder to fit the piston.  I hope I haven't gotten myself into a corner here.  I'm ass-u-ming that I can fit the top plate/cylinder into the mill and use the boring head to do this.

 

The method of cooling hasn't been settled on.  I may first try turning a bunch of fins on the cylinder and have a small fan for pushing air.  I also could make a water jacket.

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11 January 2011:

A couple of days ago, I snapped a drive belt on my little lathe and decided to take an AC current transformer and meter out of "retirement" and put 'em back to work.

Load measuring meter.

What I did was to put the meter in the motor hot lead.  The more power I use, the higher the motor load amps go so I ought to, after a bit of use, be able to figure out when I'm really straining the poor l'il thing.  What I did find out is that the motor on the imported lathe isn't a real efficiency champ.  Here it is shown running without load and drawing about 16 amps!  The white box just behind the motor switch contains the old Weston current transformer and the meter is mounted on a piece of surplus fake wood flooring........  Classy!

And now, back to our riveting commentary..................

I wasn't sure the cylinder was pressed tight enough to keep it from going "walkabout".  After thinking on it for a day, I decided that the prudent approach to making sure the cylinder stayed on the top plate was to resort to the "belt and suspenders" rule of engineering.    

Belt and suspenders.

In the time I had left after hooking up and mounting the motor load meter, I drilled and tapped eight 10-32 screws into the base of the cylinder.  That should do it! 

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12 January 2011:

Most of the day was spent figuring out how to bore the cylinder to fit the piston.  The first "awshoot" occurred when I had it all set up on the mill and found that the boring head was bigger than the bore and the longest bar I had was about two inches too short.

 

After a bit of head scratching, I decided to bite the bullet and make a boring tool holder for the lathe that was long enough to do the cylinder.

The new boring bar.

Rooting around in my junkbox found the main shaft for an air conditioner compressor.  It's made of high-quality cast iron and I figured that, being cast, it would not be as resonant as a hunk of steel.  I had a carbide tool bit with a 1/4" shank so I drilled a slanted 0.312" hole in the big part then filed it square enough to securely mount the tool with a setscrew.  The diameter of the shaft is 0.750" so I had to make another boring bar holder. to go with it.

  

       The cylinder on the face plate.                                                             Setup on the lathe.        

On the right is the boring bar holder, made from a nice hunk of steel I picked up at the scrap yard.  I now wish I'd gotten a lot more of those pieces (1.5" thick by 3" wide by 5" long).  They were cutouts from something and there was a pile of 'em there.  I'm sure all the rest have gone to China by now.

 

It was a kind of Rube Goldberg lash up to get the cylinder mounted on the face plate.  I had to use a bunch of spacers to get the bottom of the cylinder to clear the face plate then clamped it up just snug.  After I put the face plate on the lathe spindle, I indicated and banged on it until it was within 0.001" of true.

 

Since I had some serious digging to to in the front yard, I had to quit early but not until I made a test cut and found that the tool chatters something awful.  I think there's too little clearance, causing a very wide cut.  The tool is shaped fine for going forward but, since I only had one tool bit that would work and it faced so the lathe has to turn in reverse, it cuts on the trailing edge of the tool.

 

It's kind of interesting to turn something in reverse.  Because the leadscrew also turns backwards, the carriage moves from left to right, meaning that I have to put the tool all the way in the bore, adjust for cutting depth then bore from the "end" to the "beginning".

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13 January 2011:

Today, I got to try a couple of things I'd heard about.  One of them was using lead on a boring bar to minimize chatter.  I think the theory is that it adds mass and, since lead is very un-resonant (doesn't ring), it keeps harmonic vibrations damped.  It worked!

  

Method of damping chatter.                                                              Honing the cylinder.

First, to minimize the chatter, I ground more clearance on the tool bit and made the tip radius smaller.  This worked better but there was still some chatter.  I then tried adding lead to the tool.  Since the only lead I had was solder, I wrapped several feet of it around the boring bar.  Surprisingly, the chatter just about entirely disappeared.

 

After boring the cylinder to give 0.005" skirt clearance, I then honed the last thousandth out of the bore.  This also cleaned the tool marks from the finish.

Piston fit.

The piston is 2.618" in diameter and the cylinder is 2.624".  I figure about 0.003" skirt clearance per inch of bore would require about 0.007+ of clearance but, since I plan to run the engine slow and break it in carefully, I should be able to get away with a thousandth less.

 

Having nothing better to do with my time and wanting to remove the scale from the hot rolled steel and make the engine look better, I flycut the front and back of the engine.  This brings up the second thing I'd heard somewhere.  I was told that if you use carbide tooling, you can really crank up the surface speed and that will give a slicker finish.

 

Low speed (360 RPM) flycutting.                                                    High speed (1,200 RPM) flycutting.

On the flywheel side, I was running the flycutter at 360 RPM and, even using cutting oil, the finish wasn't exceptional.  When I turned the engine over to do the off-side, I decided to at least do the first cuts at 1,200 RPM.  WOW! the finish was a lot better even though I was flycutting dry at a high enough speed to be throwing sparks off the work as you can see in the right-hand photo.

Showing the "slick" side of the engine.

Since I was on a roll and time was running out for the day's work, I didn't try oil on the surface for the high-speed cutting.  Also, I didn't want to smoke up the shop at the end of the day.

 

Before fitting the crankshaft and making the bearing retainer plates, I'm going to disassemble the engine frame and mill a shallow slot in the base in line with the rod big end.  This will make a trough for oil, allowing sufficient oiling for when the engine is not dead level.

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15 January 2011:

The side plates are slicked up and the crank, camshaft and ringed piston are assembled.

   

Engine Number Four partially assembled.

As you can see in the left-hand photo, I've milled a trough in the bottom plate.  A dipper will be made for one bolt of the rod that will throw oil all over the inside (I hope) of the engine with wild abandon.

 

One other "aw-shoot" occurred when I started to assemble things.  Seems I ass-u-med the crankshaft would be centered between the mains.  Wrong!  The timing gear offsets the crankshaft by it's thickness.  This necessitated shifting the crankshaft and boring a recess in the gear-side end plate for the cam gear.  As you can see in the right-hand photo, the crank and cam bearings are proud of the flywheel end plate by about 0.200".  They are inset the same amount on the off-side.  I will be making bearing retainer plates and will use the retainers to position the bearings.

 

Because this engine is being designed "on the fly", I will most likely be cutting off the camshaft stub once I get the cam and the timing/tach wheel done.

 

It now looks like I'm going to be making the engine water cooled.  I've also been thinking about the controls.  I've been considering a magnetic tach wheel, sensed by a Hall Effect transistor.  This will operate a charge pump and filter that will be one input of an operational amplifier.  The other input will be a variable reference voltage to set the speed.  

 

Now, I need to come up with a small 12 volt gear motor to operate the throttle.  I thought briefly about a voice coil type actuator and may consider the head positioner from a junked hard drive.

 

I've also been thinking of a simple electronic way to make the ignition timing automatic, based on RPM.  

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16 January 2011:

It doesn't look like much got done today but I did get the dipper made for the rod and got the flywheel side cover plate/bearing retainer done.

   

              Connecting rod dipper.                                                                Flywheel side side cover.

The dipper was no problem, just a piece of 16 gauge sheet metal drilled for a rod bolt and formed to get at the oil.  

 

The side cover was something else.  Because the main and cam bearings are proud of the face, I had to bore the plate to the proper depth to give some side play.  This took the rest of the time I had for it today.  Note that I've drilled and tapped four 10-32 holes in the cover plate.  These holes are for mounting of the cam follower.  The other two holes are where I've got a couple of 1/8" dowel pins to keep the plate located.  I painted the plate because it is very thin at the cam bearing and flycutting would have possibly made it cut through.

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17 January 2011:

Today, I got the off-flywheel end bearing retainer plate and bearing spacers made and put on.

   

Off-flywheel bearing retainer and spacers.                                                         Retainer on engine.       

I made the retainer out of 1/8" steel because it didn't have to do anything but cover the end of the engine and keep the bearing spacers from falling out.

 

Tomorrow, I'll make a breather and oil check elbow and I can then button-up the crankcase.

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18 January 2011:

I'm hoping I've gotten it buttoned-up.  In other words, I hope I haven't done anything stoopid and will have to take it back apart.

 

                     Parts of the breather.                                                  Scientific engineering test of breather.     

The oil check was easy.  Just a 1/8" NPT brass street ell and a brass plug.  No biggie.

 

The oil fill/breather was made of a 1/2" NPT street ell, a nipple and a cast iron cap.  It is a simple check valve arrangement.  Once the engine is running, if it drools out of the breather, I may have to add some coarse steel wool to catch the oil vapor.

]

Engine buttoned-up with oil check and breather.

The last thing I did today was to make a couple of skids so I could put the drain plug in.

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19 January 2011:

The flywheel is well on it's way to being done.  The raw flywheel is a cast iron gear from a deceased boat lift.

Raw materials for flywheel.

First, I mounted the gear in the mill and flycut the hub until it was even with the rim of the gear.  Then I bored the piece of 3/4" hot rolled steel for a press fit of the piece of shafting into it.  After welding the shafting to the 3/4" piece, I chucked it up and faced both sides of the steel plate.

 

After the plate was true to the O.D. of the shafting (the hub now), I turned the O.D of the plate until it was a press fit into the gear.  Now, I suppose you could call it a flywheel.  The last operation of the day was to bore the hub to fit the crankshaft of the engine.

Semi-finished flywheel.

I still have to drill two setscrews into the hub then put the whole works  up in the mill and turn off the gear teeth.  If  you look carefully, you'll see that I had to grind some of the teeth off in order to center the flywheel in the mill for the hub boring.  I may have to grind down the rest of the teeth in order to be able to turn the O.D. of the flywheel true.

 

I think I'll slap a coat of paint on the web of the wheel before mounting it up in the mill to take the teeth off.  That way, I can clean up the paint slop from the hub and rim.

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22 January 2011:

Yesterday, I finished the flywheel.  

Flywheel in place and head raw material.

Now, I think that since it is going to be just a bit on the tricky side I'd better use the CAD to design the head and water jacket.  It will be water cooled and I'm going to try to drill the head for some water flow, having the outlet in the center of the head.  The material I will use for the head is the hunk of ductile cast iron I've got sitting beside the engine.

 

The water jacket will be made of a piece of schedule 40 4" steel pipe.  My first thought is to use "O" rings in grooves to seal the jacket from the head and bottom plate.  An "O" ring will also seal around the cylinder at the base.  The top of the cylinder will be "deckless" and the head gasket will be made of 0.0156" copper sheet.

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23 January 2011:

I did a little CAD on the head and started on the water jacket parts.

        

Preliminary CAD of cylinder, water  jacket and head.                                 Starting on bottom cylinder plate.                        

As you can see in the drawing, the water jacket-to-head and the bottom jacket plate-to-jacket are to be sealed with Buna N "O" rings, the whole thing held down by the head bolts. 

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24 January 2011:

Geez, Louise!  Making the bottom jacket plate took nearly all day!  I found out just how difficult it is to turn a 1/4" deep groove in the face of a steel plate.

   

              Top of bottom jacket plate                                   Bottom of bottom jacket plate                 Cylinder head cut from stock.

It's going to be interesting to see how the water jacket idea works.

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25 January 2011:

Today, I got started on the head.

   

The head with outside machined.                                               The head in place.

Most of the time was spent cleaning up the cast iron and making the "O" ring groove for the top of the water jacket.  I found that making the groove is a lot easier in cast iron!

 

The head gasket is roughed-in, made from some scrap 0.0156" copper sheet.  Once the McMaster order comes in, I'll have the piece of pipe to make the water jacket, the head bolts and the "O" rings to seal the jacket.

 

Rooting in my junk box turned-up a couple of 7/8" valves from some long forgotten lawn mower engine.  I'll see if these look all right for the application.  Actually, I could use 1.00" valves but I don't have any lying around.

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26 January 2011:

Yesterday afternoon, the pipe for the water jacket, the head bolts and the "O" rings arrived.

    

     Water jacket in place.                                     Head in place on jacket.

It again took some doing to get rid of chatter marks on the O.D. of the water jacket but with some very fine cuts, a file and some sandpaper, it's decent.

 

You'll also notice I've made a shaft stub for the exhaust cam and the timing magnets.

 

The project will now "rest" for a few days so I can catch-up on other things around here.

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30 January 2011:

I went into CAD and made a template for the layout of the head bolts and cooling holes.

Drill template in place and center punched.

Since I don't have a way to accurately lay out the holes with the mill, I made a 1:1 plot of the top of the head and taped it into position on the top surface of the head as accurately as I could.  I center punched the spark plug location and the eight head bolts.  (I've made another template for the valve side of the head and the valve seats, ports and guide bores will be done from that side.)

 

I then drilled two of the head bolt holes with a #21 drill which is the tap drill size for 10-32 machine screws.  I mounted the head and, after very carefully aligning it, I used the #21 bit through the head to center punch those two holes.  The head was removed and those two holes were drilled and tapped.  All of the bolt holes in the head were then drilled with a #9 drill which is the clearance size for 10-32.  

 

After punching the first two bolt holes into the head gasket, I put the gasket in position and bolted the head down with the two bolts and snugged them up.  I put the engine with the head in place in the drill press and used the #9 bit to spot drill the other six holes.

 

The head was then removed and the remaining #21 holes were drilled and tapped into the cylinder.  Doing it this way ensures that any slight mis-location of the holes wouldn't affect the fit.

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31 January 2011:

I've got the valve ports to the combustion chamber and the intake port done.

The semi-finished head.

Still to be done to the head are the cooling passages, spark plug hole, water outlet and the exhaust port.  Then it's time to button this part up.  The mixer is the one I built for the spark ignition version of The Homebrew Hvid.  Since I've converted that engine back to HVID and will use it for display, all the spark ignition parts are recyclable.

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1 February 2011:

The exhaust port is done, the spark plug hole is done and I've got a good start on the cooling passages in the head.

  

Center punching vertical cooling passages.                                                 Drilling vertical cooling passages,

Again, I used a 1:1 CAD plot as a template for center punching the vertical cooling passage holes.  

 

In the right-hand photo above, the female 3/8" NPT is the water outlet connection.  There is a 3/8" hole that goes from there almost to the other side of the head, across the top as shown in the template in the left-hand photo.  On each side, three of the vertical holes intersect with the 3/8" hole.   The way the coolant flows is from the bottom of the water jacket, past the cylinder, up through the head and to the outlet.

 

The vertical holes will, as well as I can, be milled so they connect at least partway to the top of the head.  This is not optimal because air/vapor will be trapped above where the holes connect but it is the best I can do with what I've got.

 

What remains to be done is to connect the vertical holes, press in the 1/2" NPT exhaust pipe stub, make the valve guides and lap the valves.

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2 February 2011:

After having tried to use a small milling cutter to remove the material from between the vertical cooling holes, I had to resort to the old "elbow grease" method.

 

      Removing material from between vertical holes.                                        Valves in place, water inlet started.  

It took a couple of hours of sawing to get the vertical cooling holes connected in the head.

 

I made valve guides from brass and seated the valves.  The little 10mm spark plug is WAY down in a bore in the head so it can be close to the combustion chamber.

 

I goofed at the end of the day and, instead of drilling and tapping for 3/8 NPT pipe for the water inlet in the jacket, I drilled it for 1/2 NPT so had to go ahead and tap it for the 1/2" pipe.  I'll figure out how to reduce it to 3/8".

 

Tomorrow, I think I will get the top end assembled and sealed up.  I've gotta remember to put oil in it.  It would be a definite "aw-shoot" if I were to get it running with no oil!

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3 February 2011:

The first thing that was done today was to make a concentric 1/2" NPT to 3/8" NPT reducer to cancel my "aw-shoot" of yesterday.

 

            Boring the I.D. of the 1/2" pipe stub.                                  Tapping the 1/2" pipe stub to make reducer.

Since I save nearly everything, I had the threaded end of a piece of 1/2" pipe so I simply bored it out so I could "bottom" a 3/8" NPT pipe tap in it and, voila', instant reducer.

 

          Blue gasket compound on deck prior to installing head.                            It's beginning to look like an engine.

With the head and water jacket done, I assembled them.  Since the head gasket is made from 1/64th" copper sheet, I needed a little "insurance" against leaks so I put a light coat of blue gasket compound on both the deck and the head.  After torquing the bolts, the engine has compression and there are no leakage sounds out of the water jacket outlet.  So far, so good.  The muffler is one I made for The Homebrew Hvid but replaced with a better one.

 

Oh, yes - I filled the crankcase with oil to eliminate another "aw-shoot" down the road.

 

The next item of business was to make the cam follower and guide.

Cam follower finished.

I had some scraps of 5/8" cast aluminum plate that I pieced together for the cam follower guide.  The follower itself is made from a piece of 1/2" leadloy steel bar stock.  First, I milled 0.050" off of two opposite sides and milled 0.025" off of the other two opposite sides.  This gave four flats for it to ride in the milled slot in the aluminum plate.  The roller is another small ball bearing out of something or other.  Once the slot and cover are done, that part will be finished.  

 

The ignition sensor(s) will be mounted on the aluminum plate somehow and a magnet wheel will be made to go on the camshaft outboard of the cam.  My thoughts now concerning the automatic advance are toward either using one magnet and two sensors or one large magnet and one sensor.  

 

One the one magnet/one sensor idea, I can trigger the ignition on the following edge of the magnet for retarded (slow) timing and trigger on the leading edge for advanced timing (fast).  It shouldn't be a biggie to come up with a circuit that senses crankshaft speed and switches from lagging edge to leading edge as the speed increases beyond a set-point.

 

I'm also thinking of trying to use a head actuator from a hard drive for the throttle control.  I think, if the actuator has enough muscle, I can use the tachometer signal and drive a charge pump to make a voltage that is proportional to crankshaft speed.  This signal can be fed to one input of an operational amplifier.  A reference voltage can be varied on the other input of the opamp to determine throttle operation.  A gain potentiometer can be used to set the sensitivity.  It -should- work ...... says here in the fine print.

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4 February 2011:

Lots of fiddly bits today.

   

Cam follower exploded view.                              Follower partially assembled.                                      Follower on engine.    

There were a lot of details to work out.  The follower assembly was milled with enough clearance around the follower to allow for brass strips to act as bearings.  It took a bit of fiddling to get everything to fit and the final fit was just a bit too tight so I made a paper shim for the brass top cover/slide bearing.  It is still a little on the draggy side but, due to the surface finish wearing off, it will soon fit fine.

 

I did some measuring on the cam lobe and, as it is, there is only 0.085 lift.  I figure I need a lift of 0.125" with 0.010" tappet clearance, so I will have to mill the minor diameter.  To do this, I have to make a jig for the mill.  I will have to leave the jig in the mill after machining the base diameter because I will have to modify the dwell angle.  I plan to do this by the "It looks about right" method.   I figure the exhaust valve should begin opening at about 140 degrees ATDC and close at about 5 degrees ATDC. 

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6 February 2011:

A friend was down from Kentucky and we spent a few hours machining the cam.  

Setting degree tape to TDC on rim of flywheel,

It now has a lift of 0.125" with 0.005" tappet clearance.  The duration ended up being 215 degrees from the point of zero clearance on opening to zero clearance on closing.  

 

I calculated the circumference of the flywheel and used CAD to make a "degree tape" which I taped to the wheel.  I'm sure some of you nitpickers noticed the printer caused the tape to come out 3-1/2 degrees off.  Zero is right on, TDC being found using the dial indicator on the piston.  The high-tech super accurate indicator extender is a 1/4" drive extension.  Using the degree tape, we ended up with the exhaust valve starting to open at 150 degrees ATDC and closing at 9 degrees (with the 3-1/2 degree correction) ATDC.  We figured that it was plenty close enough. 

 

Next up is the rocker arm and pushrod.  After getting the basic ignition magnet and sensor done, I'll be close to making smoke. 

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7 February 2011:

Have you ever had one of those days ......... ?  Well, I did!

 
DAG NABBIT!

                            Cracked rocker arm                                                          Preparing to cut out the second one.         

Most of the day was spent sketching the rocker arm, laying it out and doing the machining.  The bushing could be pushed halfway into the bore in the rocker by hand and it only needed a slight push to seat it.  Instead of doing what my instinct told me to do and use the vise to carefully push it home, I decided to use my 10 ton hydraulic press.  Everything was fine until I looked and thought that I could get it seated really well with juuusssstttt a little more pressure.  POP!  Now it's back to the beginning.

 

The bushing is made from a short end of brass bar stock I had.  To finish it, all I had to take off the length was 0.050".  The rocker will ride in the dowel pin which I can cut to length in the lathe using a carbide bit.  It will be pressed into the rocker stand and I'll make a press-on ring to hold the rocker on the shaft.

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11 February 2011:

This time I was a little more careful.  

 

                                     The second rocker arm.                                                      Rocker arm, stand and pushrod finished.

After making another rocker arm and fitting the bushing to the dowel pin, I made the rocker stand.  It is two pieces of 1/4" steel that are held down by two head bolts.  The rocker shaft is pressed into the upright of the stand and the upright is held to the rocker base by two flat head 8-32 screws countersunk into the bottom of the base.  

 

The pushrod is part of a display rack that has been the donor of several parts.  I think I may take the rocker off and do a little filing to knock off the sharp edges and make the stand blend-in more.

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12 February 2011:

Moving right along, the ignition is finished enough so I can use one of my solid-state modules for testing.

   

   Left to right - magnet disc, hub, swaging tool.                              Swaging the disc hub.                       Selecting magnet. 

The ignition timing disc is made from some left-over 0.062" printed circuit board material.  The hub was bored to fit the camshaft and the outside diameter of the hub is turned for about 0.070" to about 0.100" larger than the bore.  The center hole of the disc is a thousandth of an inch or so larger than this diameter.  

 

A 60 degree swaging tool was made.  The disc was set on the diameter step with a little loktite applied.  The assembly was then placed in the press and, using the swaging tool, the diameter was expanded, locking the disc securely onto the hub.  

 

In order to determine what size magnet was needed to have the sensor sense the leading edge at about 20 degrees BTDC and the lagging edge at about 5 degrees ATDC, magnets were taped to the disc and tried.  After trying three incrementally smaller magnets, a good match was obtained with a rare-earth magnet that was 0.150" in diameter.  This magnet was then glued to the disc, the sensor cabled-up with a mini-DIN connector that mates with the ignition module.

   

                  Raw materials for tank.                                             Filler neck sawed off.                        Tank with filler neck.

Next was making a fuel line and the fuel tank.  The tank is made from a piece of 3" copper pipe from somewhere.  The filler neck is made from a piece of a dead water faucet assembly.  The filler neck piece was sawed-off the faucet and screwed into a piece of 1/2" NPT pipe.  The whole works was chucked in the lathe and it was cleaned up.

 

To make the neck fit the curve of the tank, I put the neck in the mill and, using the largest end mill I had (3/4"), I cut a partial diameter on the lower end perpendicular to the neck.  The plug was then screwed into the neck and the neck was placed on a piece of galvanized 3" pipe and was hammered to fit the pipe.  A little filing and some solder and the neck is in place.

 

Tomorrow, I'll make and solder the ends to the tank and add the outlet pipe.  Then, I think I'll use some of the big copper wire (seen in the left-hand photo, above) to make the mounting.  The mixer has a check valve so the tank will be placed aside the engine a little below the mixer.

 

At that point, all that has to be done is to make a spark plug wire, add gasoline and see if it will make smoke.  If it does run, it won't run very well because the timing will be retarded to 5 degrees ATDC.  After I get the cooling tank set-up and run it some, I will design the automatic spark advance circuit.  It will use a tach signal generated by a slotted disk on the crankshaft to determine at what RPM the ignition will switch from the lagging edge of the magnet to the leading edge.

 

I plan to make a video of the first attempt to start the engine and I will publish it on my YouTube account (my handle there is "Enginecoot").  Now that I've told the world that I intend to make a video, the engine will probably refuse to run.

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13 February 2011:

Today, I finished the fuel tank and made the spark plug wire.

 

Making tank ends.                                                                                     Swaging the end caps.

I've found that the hardest part of making tank ends is to get them to fit inside the tank body snugly enough to stay put while soldering.  Since the copper pipe I'm making the body out of is 2-1/8" I.D. and I had some heavy pipe, one piece which fit loosely inside the other and both just right for the caps, I decided to make a swaging punch and die.  As you can see, after cutting the end caps about 0.150" oversize, they were each centered over the end of the big pipe and the smaller pipe centered over the copper.  Then I let the press do it's work.  I will admit that, had the pipes been a little closer fit, there wouldn't have been the wavy places in the caps.  

 

End cap in place, ready for soldering.                                                      Cleaning up the mess.

The body and the end caps were buttered-up with my favorite soldering paste, "Nokorode", which has been around for ages.  Then the caps were pushed into the body of the tank and solder was sweated into the joints.

 

After cleaning up the solder goobers on the ends, it was ready for the mounting bracket.  After fiddling around making the first bracket, I decided that the tank would be fine with one bracket made from the heavy wire I was using. 

Engine with fuel tank, ready for first try at starting.

The tank was mounted to the engine and the fuel line was plumbed.  The ignition wire was made out of a piece of high voltage cable removed from a long-dead 'puter monitor and the spark plug connector was from an old set of wires taken from my long-gone Allis-Chalmers WD-45 tractor.

 

I guess I could be cruel and not tell you if it ran or not but I will say that the test was a qualified success.  Here's the video.

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14 February 2011:

Today, the engine ran.  I belted a motor to it and added a cooling tank.  After motoring it for about ten minutes to loosen it up, I turned on the ignition and opened the needle valve.  With some fiddling with the flutter choke and mixture, it began running fine.

Running under it's own power!

It ran so well after adjusting the mixture, I let it run at idle with an occasional blip for a full tank of gasoline (about an hour).  I've made another video of it running today. 

Here's a flick.

I started working on the throttle servo and governor.  Experimentation proved that an old hard drive head positioning voice coil assembly will do nicely for the actuator.  That will follow in the second part.

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Click here to to to Part Two

(Electronic Governor)

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BOY!  This is fun!

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