Hart-Parr 30-60
Semi-Replica Engine
Part Two
The Fiddly Bits, Flywheel And Getting It Running.

8 April 2012: I removed the McVickerish engine from the 2009-1/2 Algore Edition Hybrid Hoyt-Clagwell tractor and have set the 30-60 engine on the chassis to work on the fit.  I have to work out the relationship of the engine to the alternator so the belt will fit.  I will probably use the dummy flywheel for this.

Engine set in approximate position on chassis.
For the testing, I will use the radiator that's already on the tractor.  If everything works out and I decide to scrap the "Hybrid" stuff, I'll relocate the alternator to below the engine so I can construct a Hart-Parr-like exhaust and radiator box.  If I decide to scrap the "Plough-by-wire" feature, I can dispense with the alternator and the large battery and just use one of my solid-state ignitions on it.  We'll see.
9 April 2012:
Here's the flywheel blank.

The flywheel blank.
The flywheel is to be made from a 2" long (!) hunk of 10+" diameter gray cast iron bar stock.  The waterjet cutting will only be done to remove the material from between the spokes.  In order to save money, I'll do the rest of the carving.
11 April 2012:
The flywheel's back from the waterjet shop.

Semi-finished flywheel.
What I need to do with the flywheel is, first, bore for the shaft.  Then, I'll make a mandrel to mount it in the mill so I can clean-up the O.D.  Alternatively, I can make a mandrel for the rotary table and use a carbide insert flycutter to do the job.  I'll consider the latter because I can get most of the dirty work done with that, then mount the wheel in the spindle of the mill and do the O.D. last before broaching the keyway.

I have been busy in the meantime.  The engine's now bolted to the chassis.  The float valve in the mixer tested out okay so the mixer's now mounted and I'm presently working on a shut-off valve for the fuel tank (I never trust a float carb in a gravity system).

Then, it looks like all I have to do is make-up an ignition module and wire the plugs to the distributor and I should be ready to make smoke.  Who knows when that'll be.
12 April 2012:
After getting the fuel system sorted out, I tackled the flywheel.

Test fit on crankshaft.

Mandrel made, showing collet.

Mandrel and collet in place.

Cleaning the O.D. of the flywheel.
Note in the upper left photo that the crankshaft isn't long enough get to the end of the flywheel hub.  It'll be closer to the end after the sides are faced.  In order to get enough length on that end of the crankshaft, I would have had to purchase a larger blank.  As well as being expensive, the additional length would have made machining the crank more difficult.  I'll take that into consideration when I broach the hub for the gib key.

After boring the hub of the flywheel for a slip fit on the crankshaft, I made a mandrel put of 1.500 shafting that is 1.000"(-) on one end and 1.9" long.  There's a 1/4" long
1.500" diameter in the middle of the mandrel to fit the bore of the flywheel.  I've drilled and tapped for 1/2-20 so I can use a bolt and washer to firmly hold the flywheel on the mandrel. The other end of the mandrel is turned to 0.875" to fit into the collet that will go in the quill of the mill.

It's kind of kludgy but turning the wheel in the mill does work, although the finish isn't perfect.  Part of the trouble with the finish on the O.D. is chill areas of the blank where, I guess, uneven cooling when it was poured caused differences in the hardness of the gray iron.

Tomorrow, using the same technique, I will face the flywheel and will see if  it's practical to use this method to relieve the thickness of the spokes.

13 April 2012:
The flywheel's moving right along.

Beginning the relieving operation.

Depth achieved with the flycutter.

Removing excess material.

Using ball end mill to finish hub.

Milling radius at ends of spokes.

One side of flywheel nearly finished.
The first thing I did today was to set the turning tool in the vise so I could face the bottom side of the flywheel to make it perpendicular to the axis of the hub bore.  Pretty early on I found out that the tool wanted to chatter no matter how I ground it or positioned it.  Although I finally got it to where there was a decent finish, I decided to use the new flycutter I bought for this job.. The wheel was removed from the collet and the mandrel was removed from the wheel.

The last job I did on the rotary table used a piece of 1" bar stock as a pilot, just the right fit for the bore of the flywheel.  It is threaded for a 1/2-20 clamping bolt.  I used a bastard file to remove the excess material adjacent to the bore of the hub (which couldn't be accessed with the turning tool) so it would lay flat on the rotary table.  
The wheel was then bolted to the rotary table. Using the flycutter with cast iron carbide cutters made pretty fast work of removing the bulk of the material although, as you can see, it was only possible to make a slope-sided cut.

After removing material to the desired depth, I used a carbide roughing mill to remove the rest of the material.  I then used a 1/4" ball-end carbide milling cutter to finish the hub at the root of the spokes.  This cutter gives a 1/8" radius.

Using a 1/2" carbide milling cutter (matching the radius of the spoke ends where they join the rim), I cleaned-up the inside of the rim.  This didn't turn out as nice as I thought it would, mainly due to inexperience of the operator.  Close enough, though.

I again used the 1/4" ball end cutter to finish the ends of the spokes where they join the rim.

The next to last operation was to again mount the flycutter and use it to clean-up the end of the hub, finishing it 0.050" below the rim at the maximum width.  Finally, I used the flycutter to chamfer the hub and the O.D. of the flywheel.

This part of the work went a bit faster than I thought it would so I should be finished with the flywheel, including broaching the keyway, with another day's work.
17 April 2012:
After a few days pause, the flywheel's done.

Flywheel on engine.
The only comments I need to make about the flywheel are:
- It's the most expensive single part on the engine.
- I had to machine 0.175" off of the hub width in order for the shaft to come to the end of the hub.
- When I broached the keyway, I had planned to take a last "swipe" at it with an 0.020" shim at the outside end to give it the gib taper but, after the last straight swipe, the keyway was so close to a good fit, I didn't want to chance getting it too loose.  The key knocked in just less than a half-inch shy of fully seated.

Tomorrow, I'll start on the ignition circuit and the plug wiring.  After that's finished, it should be time to see if it makes smoke.

Stay tuned.
18 April 2012:
I got the ignition circuit designed and assembled.  I will test/debug it tomorrow.  Again, I'm using a magnet and Hall-Effect sensor to trigger the coil.

Ignition circuit, ready for testing.
This is a relatively simple arrangement, using a hex CMOS inverting Schmitt-Trigger chip to do the timing and rudimentary logic functions.  I have also used one of the Schmitt Triggers to construct a simple rev limiter.  If the governor belt breaks, the engine runs away and I'm not close to shut it off, it could damage itself and/or injure someone.  The rev limiter will kill the ignition if the speed exceeds a setpoint.  After the engine slows to a safe speed, the ignition is turned back on.  In effect, it sounds like a hit-and-miss.

The coil is made for a two cylinder opposed engine that fires both plugs at the same time.  Since this is an inline 2-banger, I can't use that arrangement.  What I've done is to make a sort of distributor that shorts out the plug that shouldn't be firing.  Each high voltage wire goes through the distributor and on to the plug. This worked like a champ on the Edwards "coffee can" magneto I built.

Depending on how the ignition tests out (new designs usually don't work when first tried), I may attempt to make smoke tomorrow. 
19 April 2012:
Well .......  Today, I got the ignition debugged and working.  Then I got the spark plug wires made-up.  Then I pushed it out into the driveway.  Then I cranked it over a couple of times and it made smoke.  The only problem is that the smoke leaked out of the ignition board so I've got to re-visit it.  

My theory is that, because of the large battery, there's enough energy in the back EMF from the coil switching off to fry the internal protection diode in the output transistor.  I may try making-up a small choke using a ferrite bead and a few turns of wire.  This can be connected between the coil and the drain of the MOSFET.

Maybe tomorrow.
20 April 2012:
After doing a little tweaking on the ignition circuit and replacing the transistor with a new one, filled with smoke and ready to go, the engine ran for the first time.

As usual, with home-made engines, I need to tweak a few things.  First, the intake valve springs need to be changed so the valves close more firmly.  I believe there's some blowback at the start of the compression stroke and this makes me have to run it with a lot of choke.

Then, the governor needs a bit of tweaking.  Craig Andersen, who is an expert on Hart-Parr 30-60 tractors corrected me on the governor operation.  I thought that one cylinder was supposed to latch out at just a little higher RPM than the other one.  That's how I had the latches set so I changed them to Craig's suggestion.  Now the latches don't work right and the engine doesn't want to latch out reliably.  I did run the engine for a few minutes even with the latch-up and valve problems to try to get the rings to seat a little.  Testing stopped when the governor belt broke.

Here's a video of yesterday's first attempt and today's successful start.
In case you're interested in electrogeek stuff, here's the schematic of the successful ignition circuit.

This circuit uses a MC14584BCP hex inverting C-MOS Schmitt trigger I.C. to drive an IRF840 MOSFET transistor.  In the original design, the 0.33 microfarad,  640 volt capacitor was across the coil.  I think this arrangement caused the internal diode in the MOSFET to short due to a high energy spike generated when the transistor turned off.  Placing the capacitor across the MOSFET has the same effect except that instead of a parallel resonant circuit, it's now a series resonant circuit.

In operation, the first Schmitt trigger simply isolates the output of the Hall sensor and filters any stray glitches from the line.  The output of the first Schmitt trigger is used to form a differentiated pulse that is squared-up by the second Schmitt trigger.  This 0.8 millisecond pulse goes to the MOSFET to drive the coil.  The rev limiter is simply a pulse stretcher that clamps the inputs to the parallel Schmitt trigger drivers of the MOSFET high.  If the output of the pulse stretcher is still high (it hasn't timed-out) when the next ignition pulse comes through, it is not allowed to pull-down the inputs of the driver Schmitt triggers, thus inhibiting the ignition if the interval between trigger pulses is too short (RPM excessive).

One of the things I like about C-MOS technology is that its outputs are naturally current limiting.  This allows stuff like driving the LED without having to use a current limiting resistor.  The current output is limited to between 10 and 20 milliamps, ideal for an LED.

Now, is that explanation really more than you wanted to know? .......    I thought so.
21 April 2012:
Today, I got about two hours of running time, off and on.  The tinkering phase of these projects is hard on my arms and shoulders because of all the cranking.

Made a new governor belt and continued the fiddling.  I tightened up the flat spring that serves both the intake and exhaust valves.  That helped a little with the blowback out the mixer but it's still there.  I now believe it's because of the cam timing.  While running the engine, it began getting sorrier and sorrier until it would just barely run.  While checking the problem out, I found that both cams had slipped almost 90 degrees (retarded!).  No wonder it was sorry.

After setting the cams again, the engine ran much better but still had the blowback at the mixer.  I know what the problem is.  The cam profiles are ground so that if the exhaust valves are opening at about 30 degrees BBDC, the overlap occurs early.  This makes the intake valve open before the piston has quite reached the top of the stroke.  If I adjust the cams so the overlap occurs right at TDC, the exhaust will be opening closer to BDC but the blowback problem should be solved.

I'm putting off fiddling with the mixer until I've got the cam timing sorted out.  The mixer has to have a lot of choke in order for the engine to run half-way decently.  I believe that's caused by the cam timing blowback.

I also think I may not need a water pump.  After a long run with the spark retarded, the water temperature barely got up to 130F.
22 April 2012:
I changed the cam timing so the exhaust valve opens at about BDC.  The exhaust valve closes at TDC.  That makes the intake valve open a little after TDC.   The intake valve now closes just a shade past BDC.

I also worked on the #2 latch which is the one that was making the valve slam shut.

The modified #2 exhaust latch.
The reason for the clacking is that the rocker and latch rounded off where they met when latching-up  The rounding made the rocker fall off the latch before the cam lobe had relieved the pressure on it.  The fix was to make a hard latch using a piece of hacksaw blade ground to a knife edge.  This works better but I still get the occasional snap.  The most likely fix will be to make a hard mating surface on the rocker that has an angle that will hold the latch in place until the cam releases the pressure.

Anyway, with the new cam timing, the engine runs better but I still need to mess with the mixer.  Even without it blowing back into the mixer, I still have to run with a little choke on and the needle almost all the way out.  I think I need to fit a smaller venturi.  

Here's today's video of it running better.  You can hear the occasional "clack" as the #2 exhaust valve snaps shut.

23 April 2012:
Today, I got the #2 latch sorted out and did some work on the mixer.

Making smaller venturi insert for mixer.
After getting the cam timing sorted out, I attacked the problem of the mixer needing a lot of choke.  The fix was to make a brass insert that pressed into the choke end of the mixer bore, running almost to the needle valve.  There is a small hole drilled into the side of the insert to let any fuel drain if trapped between the bores.  The insert reduces the bore from 1/2" to 1/4".  While I was at it, I increased the size of the jet from 0.040" (#60 drill) to 0.0465 (#56 drill).   When put back on the engine, the decreased venturi size and increased jet size allowed the engine to run with no choke and there was some adjustment range of the needle.  

Improved #2 latch.

Cam secured to shaft with taper pin.
The modification on the #2 latch involved making a blade and striker from hacksaw blade.  I used the Dremel disc to make a "V" notch in the striker right at the end of the rocker arm so the blade would have something to engage with so it wouldn't "fall off" of the rocker and allow the valve to snap shut.  This fix almost completely eliminates the snapping.

The other day when I changed the cam timing, I noticed that the setscrews had left slip marks on the cam shaft. The fix would have been to double-up on the setscrews or drill and ream for taper pins.  I chose the taper pins because if I have to disassemble the cam shaft for any reason, it will be simple to get it back in time since the sprocket is also keyed to the shaft.  I'll just have to remember to witness mark the sprockets and count chain links between the marks.

After finishing up, I ran the engine, checking the mixer and latch mods.  It seems that I'm on the right track but another problem cropped up when I belted-up the alternator and put a load on the engine.  After a minute or so of running under a moderate load, it would sorry-out and quit.  At one point, I couldn't get it to hit a lick after it quit.  In desperation, I removed a spark plug and cleaned it in solvent (it was sooty, I figure, from all the running on choke).  I put it back in and the engine readily started and ran nicely on one cylinder.  The other plug was also sooty and fouled.

I think the problem of the engine sorrying-out may be caused by fuel starvation.  I raised the gas tank about two inches and the problem seemed to be less severe.  Next time I'm fiddling with it, I'll make a couple of temporary 4" spacers and see if the problem improves.

There is another thing that could be causing the engine to do this.  It could be that the plugs, when warmed-up (running under load) are breaking-down.  Now that would be a real problem.  The design of the engine makes it necessary to use 10mm spark plugs which are prone to fouling.  If the design causes the plugs to foul and I can't find hotter range plugs, I've got a problem because there's no room for larger spark plugs.  The only possible fix for this problem is to re-design the ignition for higher energy.  That doesn't appeal to me and I hope the sorrying-out problem can be solved with fuel system changes.
29 April 2012:
Okey dokey.  After a pause, I've gotten a little done.  I took off the mixer and found that the reason I couldn't adjust the fuel mixture 'til it was lean enough for the engine to not smoke.  The needle seat was off-center.  I made a new needle guide and seat and now it runs better although it still sorrys out at times when under load.  I adjusted the exhaust lash to 0.010" but that didn't solve the problem.  The engine ran better so I lowered the gas tank to where it originally was. After I did this, the engine ran the same so I guess it's getting enough fuel.

I probably need to again disassemble the mixer and enlarge the venturi from 0.250".  This should give a little more power.  Presently, I can run the engine fine with no choke at all.  I'll also probably increase the energy of the ignition by increasing the "on" time of the coil.  

All in all, today, I ran the engine another hour or so.  It seems to be burning a little less oil and breather smoke is a little less than before.  Maybe after more run time, it will quit the smoking.  If it doesn't, I can always add that second compression ring.
2 May 2012:
For the last couple of days, I've been fiddling with the mixer venturi insert.  A couple of days ago, I reamed it out to 0.296".  Today, I removed the insert just for fun and found that the engine doesn't want to run with no necking-down of the throat of the mixer.  Before I put the insert back in, I reamed it out to 0.328".  It runs a little better and I'll probably leave it at that.

After having increased the ignition energy, the engine would only run on one cylinder.  This is due to the rev limiter not liking the increased length of the coil driving pulse.  After fooling around with some component values I thought I had it fixed but the engine would hardly run.  My fix for the time being was to remove the I.C. and bend-up pin 6 (see schematic) which disabled the rev limiter.  

Maximum ignition advance was found to be a bit too much so I retarded the rotor.  I haven't degreed it to see where it actually is but the engine starts and runs fine.  At full retard, it hits almost all the time (and barks) and at full advance, it runs like an itsy-bitsy Hart-Parr.

Piddling with fuel tank height didn't solve the sorrying-out problem but, increasing the float level did help a lot.  I can now run the engine at full load for several minutes without having it get sorry.  

Here's a video of today's run.
3 May 2012:
I had a little time today so I worked on the #1 rocker arm governor latch.

Latch arm modification.

Rocker arm modification.

Everything back together.
The #1 exhaust valve snapping shut when the latch disengaged seems to be caused by rounding on the edge of the rocker and the latch.  This was expected because neither part is hardened.

The fix was to grind pieces of a hacksaw blade (very hard steel) to fit both the rocker arm and the latch.  The piece on the latch was ground with a knife edge which engages with a groove in the piece on the rocker arm.  When I ran the engine, it snapped less often but still does it occasionally.  I think I may remove the piece on the rocker and more carefully grind the groove deeper to see if I can eliminate the snapping altogether.

One fun part was drilling holes in the hacksaw blade steel.  I used one of the small 0.040" carbide drills I used to use for drilling fiberglass printed circuit boards.  Once the small holes were drilled, I used a larger carbide bit to enlarge the holes for 2-56 screw.  Kind of fiddly but it got the job done.

I again drove the 2009-3/4 Algore Edition Green Hybrid Hoyt-Clagwell around the neighborhood to put more time on the engine.  I loaded the engine until it fired continuously, running it that way for about 30 minutes of the hour-long exercise.  There's very little oil smoke out the exhaust now and the breather smoke is less than it was right after the engine was started.  There's about four hours of running time on it now and I don't know how long it will take to seat the compression rings until it doesn't smoke out the breather.

I can always get a couple more compression rings and put them on the vacant grooves in the pistons.
31 May 2012:
Approximately 10 hours of running time has accrued and the hard starting and falling on it's face at low RPM still exists.  I've noticed that the engine still has low compression and the smoking out of the breather hasn't gone away completely.  This leads me to believe that the problem is due to not having the second compression rings so I went ahead and ordered the two additional compression rings.  We'll see how it runs after they arrive and I get them installed.
4 June 2012:
I got the rings in the engine a couple of days ago and have about two hours on the engine since then.  It does start a bit better and doesn't smoke as much out of the breather.  Today, while I was riding around the neighborhood, it started misfiring on one cylinder and making a strange "gulp"ing sound and quit running.  I had a look and found that one of the dual purpose leaf springs had broken.  These springs are both intake and exhaust valve springs and serve as a way to hold the intakes closed harder when the exhaust valves are latched.

Broken valve spring.
I think that, due to this little problem and the unavailability of suitable leaf spring material, I'm going to convert it to regular coil valve springs for all valves.  That will mean removing the cam and rocker arm assemblies to get at the parts.  Also, I can eliminate the "hairpin" springs.  Before I do anything, I'll think about it some more.
6 June 2012:
To be able to properly fix the problem, I had to pull the head.  This also gave me a chance to de-carbon and check out the valves and de-carbon the combustion chamber.  The carbon was very greasy probably due to the oil pumping the engine did early-on.

Broken valve spring.

"New" valve springs.
I never really liked the dual purpose valve springs so I just used some springs found in my spring collection.  The head was replaced and everything hooked back up and it got about another hour of test running.  I don't know if it's running a whole lot better than it was but at least I don't have to worry about the "iffy" springs.  

Also, the intake springs are strong enough so they don't get sucked open when their cylinders are locked out but are weak enough so the hairsprings can force them open.  It might not be Hart-Parr but, in my opinion, it's a better arrangement.

The next thing on the agenda is to fiddle with the mixer to find out why it runs rich under load but leans-out when idling.  It could have something to do with the size of the venturi or the float level ........  There's hardly anything else it could be.

Oh, yes - after about three hours of run time on the new rings, the engine has noticeably better compression and less breather smoke.  It's still slobbering some oil out of the breather but I think that's because of an imperfect breather system.
8 June 2012:
I finally decided to not be such a cheapskate so I got a new camera/camcorder combo.  Here's a photo of the new valve spring arrangement.

Big difference, eh?
Then, there's the new High-Def movie:

Now, that IS a difference!!
20 June 2012:
A small update here.

There was a small water leak in the jacket where it joins with the crankcase header.  I had a brainstorm and decided that plain cornstarch would seal it without needing to grind out the area and re-weld it.  I added a few tablespoons of starch and ran the engine a couple of hours to get it warmed-up really well then let it rest overnight.  If anything, the starch made it leak worse.  When I drained the water, I found that I'd made a small batch of very thin rust pudding and, no, I didn't taste it.  I tase enough rust as it is.  After re-welding and repainting, the leak is now gone.

After a couple or three more hours of running, the engine is starting easier and making more power.  Yesterday, I got it to start cold from a quarter turn on the crank so things are looking up.  My power test is to see just when I can get it into high-gear, high range and it's beginning to be able to (just) pull itself on level pavement.  It's no powerhouse but it does pretty well.
6 July 2012:
The 10 mm spark plugs continued to foul, having sooty carbon deposits.  I've gotten the fuel mixture within control but the plugs still foul out after about an hour of running.  What I've been doing is to soak them in solvent (mineral spirits) then using a long bristled brush (NOT a wire brush!), poked up the plug cavity to remove the carbon.  I finished by blowing out the solvent.
This would get the plugs to fire but still, after about an hour, they'd foul again.  I tried reducing the gap from 0.028" to 0.018" in steps, thinking the smaller gap would not allow the voltage to build-up to a point where the carbon could cause a misfire.  I really couldn't tell a difference in the period between cleanings with the various gap settings.

For years, I've heard that a fouled plug can be de-carbonized by heating it with a torch.  I took two of the fouled plugs and used the Mapp torch on them, getting them hot enough to turn the center insulator from black to the original white.  I put the plugs back in the engine and, not to put too fine a point on it, it ran terribly.  My guess is that the heat cracked the insulators although I cannot see any evidence of it.

Another brainstorm had me into spark plug specifications.  I believe the fouling is caused by two things.  First, the plugs have to fire through a hole to the combustion chamber.  Second, I believe the plugs are to "cold" to self-clean.  The plugs I've been using since the beginning are NGK CM-6's.  I can find no heat range information for these plugs so I went looking and I found an Autolite 4303 that is said to be a "hot" plug.  Luckily, the local auto parts store had some.

To make them run even hotter, they have a 3/4" reach.  To make them work, I made adapters.

The original plug on left, new plug on right.

The adapter and gasket.

The new plug with adapter and gasket.
The adapters were made from some 5/8" bar stock.  All I had to do was cut them to length and drill them for clearance over the plug threads.  The extra gaskets are made from 0.020" copper sheet scraps.

Modified socket.

New plugs in place.
Since the new plugs have a 5/8" hex instead of the 9/16" hex on the old plugs, I had to modify a socket wrench to be able to fit in the depression in the head.

After about an hour.  #1 plug.

After about an hour.  #2 plug.
I ran the engine in the Hoyt-Clagwell 30-60 tractor where it's mounted for about an hour and a half.  There was no apparent misfiring.  I stopped the test run because it is really HOT out there!

The plugs were removed and inspected.  I -think- things are better, at least in the #2 cylinder which fires more often than #1 which was pretty sooty.  I'll run it some more to see if the plugs can self-clean well enough to make the plug change interval tolerable.
10 July 2012:
I've put another couple of hours on the engine with the new plugs and they don't seem to be fouling although, if I idle the engine for any length of time with the spark retarded, it will miss a lick or two then make a "pop" sound and start running normally.  This, I think, is a plug that is intermittently fouling. I'm going to keep running them until one of them refuses to fire at all then see what they look like.

They're sorta getting an acid test because, yesterday, while driving around the neighborhood, the governor belt came unhooked and the engine took-off.  It got pretty fast before I retarded the spark to slow it down, then it was really putting out the oil smoke.  I think the high speed caused the dippers to pick up enough oil to overwhelm the oil rings.  After fixing the belt, oil drooled out of the exhaust pipe joints until I'd run it for about 30 minutes.  The smoke finally cleared and the plugs were still firing okay.

Yesterday, I made a new #1 latch to try to correct the condition where occasionally, one of the rockers will fall off of the latch with a loud "clack".

New #1 cylinder valve latch.
The way this latch is made is to allow the finger to rotate a bit around the piece that goes on the latch shaft (the clamping diameter).  The latch rotates around the pin to the left of the clamping diameter.  There's a spring that holds the latch in the clockwise position in reference to the latch shaft piece.  When the valve is latched and the engine speed decreases, the latch is forced to stay engaged until the governor shaft has turned clockwise enough for the latch to snap clockwise far enough to completely clear it's mating latchpiece on the rocker arm.  The screw and nut are to limit the rotation of the latch.  I may add another screw to the top to give some vernier for tweaking exactly when the it engages in relation to the #2 latch.

If this works well, I may just make another one for #2.  We'll see.
13 August 2012:
After thinking about it for a while, I decided to replace both latches with a simpler design.  

New simpler latches.
The new latches use pieces of 0.025" band saw blades as both the latch and a spring element.  This arrangement allows the latches to compensate a bit by minimizing the snapping back of the rocker arms when they unlatch when the valve is open.  After running it for a couple of hours today, it seems to latch-out better with much less of the snapping.

The latch blades are positioned on the mounting blocks so the blade edge is on the centerline of the latch shaft.  This gives a better geometry to the whole thing.
13 September 2012:
Today I decided to see if running the engine slower while riding around would make it run cooler.  All that did was to take longer to reach a stable temperature which I think is a bit too high.  I'll probably have to add a water pump or change to a horizontal radiator or both.

When I started the engine after rolling it out of the garage, it again had a misfire on #1.  As usual, suspecting an oil fouled plug, I swapped it with a clean one.  The problem persisted so I replaced that plug with the same result.

Eventually, I found out that the problem all along (I think) was not a fouled plug.  What it seems to be is a spark path to ground from the #1 wiper on the distributor rotor to one of the magnets when the engine is first moved from the air conditioned garage into the warm humid air.  I think condensate is forming on the rotor causing the arcs.  This and because there isn't enough space between the magnet and the wiper causes the problem.  The permanent fix will be to make a new and larger diameter rotor that will allow more space between the magnets and the wipers.  Temporarily (or permanently), I've filed some of the wiper off so there's more clearance.

Will I make a new rotor?  I dunno.  Maybe.  Then again, maybe not.  Depends on how the fix works out.
26 September 2012:
Today, I started on the water pump.  I've decided to make it a piston-type pump because I'm a little leery about my ability to make the impellor and curved housing.  The first thing I had to do was to make a new governor pulley with a second groove for the water pump belt.

The new governor/water pump pulley.
While I was about it, I increased the diameter of the governor groove to try to make it a little more sensitive and as an experiment in reducing the occasional "clacking" when a rocker drops-off of the latch.

The water pump will be driven at about 80% of crankshaft speed.  It will have a bore of 0.5" and a stroke of 1", giving it an output of about 0.2 cubic inches per stroke.  This should circulate the water fast enough so the engine will cool better.

Pouring the water sight gauge base out of acrylic.
Since it would be nice to see that the coolant is circulating, I decided to make a sight gauge using a peanut butter jar and lid.  First, I selected a suitable form for the outside.  Then I mixed one batch of the acrylic resin and poured it into the form.  The peanut butter jar lid was floated in the acrylic before it hardened.

After the acrylic had firmed-up sufficiently, I mixed another smaller batch and poured it around the part of the lid that was above the original surface.

The plan is to center the lid in the lathe and turn the housing round (the lid floated off-center when I wasn't looking!).  I'll then face the bottom.

Two holes will be drilled in the housing and tapped for 1/4" pipe.  Copper tubing will be run from the supply side to nearly the top of the jar with a 180 degree bend in it.  I will drill a small hole in the jar as a breather so the coolant will not be sucked in when the engine cools.  To drill the jar, I will chuck a piece of 1/8" copper tubing in the drill press and use valve grinding compound as an abrasive.  I've done this before so I shouldn't break many jars getting it right.  I guess that means I may have to eat a lot of peanut butter.

30 September 2012:
After a break, we're moving right along again.  The sight glass is finished.

Drilling the inlet.

Turning the O.D.

The finished sight glass.
I centered the casting on the lid by reversing the jaws in the chuck and carefully getting it centered.  Until I could get the hole drilled, it wasn't really firmly in the chuck to avoid messing up the threads in the cap.  I drilled all the way through to the center of the cap and tapped the bottom end for 1/4" NPT.

After the hole was drilled and tapped, I could use a piece of 1/2" threaded rod through the spindle to firmly hold on to the assembly.  I faced the bottom and turned the O.D.  After the O.D. was turned. I reversed it and faced the lid side.

A little chamfer and a light going-over with sandpaper has it looking nice.

I have to confess to a really, really bad Aw-Shoot!  While pulling the pulley off last week, I broke it.  I need to remember to loosed the setscrews before I start leaning on the puller!  I didn't remember that I had a setscrew that went through the pulley, threaded in the extension and then went into the keyway.  Result, broken pulley!  Oh, well - McMaster probably appreciates my DOH! days when I buy a second of something to replace the one I buggered-up.

The new pulley came in yesterday and I got it machined and back on the engine today.  Anybody wanna really good deal on a slightly damaged cast iron pulley?
1 October 2012:
The CAD is nearly done so I'm now beginning to make parts.

Main mounting frame.

Cylinder spacer.

The parts so far.
The coolant pump will be mounted to a frame rail of the tractor.  The mounting frame locates the driven pulley, the crankshaft and the cylinder.  The inlet valve is at the bottom of the cylinder and the outlet valve is in an outrigger fitting.  The piston will be made of brass with an oil-filled nylon insert.

After thinking about it, and in order to keep the total height of the pump from being excessive, in order to shorten the connecting rod and keep side thrust on the piston within reason, I've reduced the stroke from 1 inch to 1/2 inch.  The bore is 3/4 inch.  This gives a displacement of 0.221 cubic inches or about five strokes per cubic inch pumped.  Since the pump will be running at about 80% of crankshaft speed, at 500 RPM, the pump will be running at about 400 RPM, pumping about 88 cubic inches per minute.  This has got to be a lot more than the thermosyphon is circulating.

2 October 2012:
Today was a slow day in the shop.  I made the "pulley/crankshaft" and it was a bit complicated.   On yesterday's photos, you can see the hunk of 2.5" aluminum bar stock I cut off to make the part out of.

Boring the off-center hole for the crankpin.

Cutting-off the hardened needle bearing inner race.
After  facing the pulley/crank to length and boring for the crank bearing,  the piece was reversed in the chuck and the belt groove was cut.  Then, the part was taken out of the 3-jaw chuck and , after laying out and center punching the center of the crankpin 0.25" off center, it was put-up in the 4-jaw chuck, centered on the punch mark and bored to 0.748", a tight press fit for the crank pin.

The rod bearing and crankpin came out of a piece of surplus machinery I bought for some sprockets for an earlier project.  The assembly had a really nice hard race and caged needle bearing that I put aside, knowing I'd need it some day.  The crankpin was longer than needed so  I used a cut-off wheel in my handy Dremel, mounted in the lathe, to cut the pin to length.  It took a while but made a nice cut.

Pulley/crank and needle bearing and race.

Semi-finished connecting rod.   
The ball (main) bearing was pressed into the pulley/crank, then the crankpin was given a bit of bearing set Loktite and pressed into the belt side of the pulley/crank.

The part on the agenda was the connecting rod.  I cut out the parts and faced the big end to length.  The rod part is made of 1/8" steel plate.  After laying it out and filing it to fit the big end, it was welded together with my usual sloppy welds.  Next time in the shop, I'll position the rod on the mill, drill the 1/4" wrist pin hole then offset and drill and bore the big end to accept the needle bearing.

Another day or so of work and a trip to the hardware store for 1/4" pipe fittings and it may be ready to mount.
4 October 2012:
The connecting rod is done.  There was a "running design change".  I decided that, instead of simply having the "wrist pin" run on a 1/8" steel pin, I'd use something a little more sophisticated.

Connecting rod small end with ball bearing pressed in.

Partly done cylinder laid-up with other parts.
What I ended-up with was a small ball bearing out of a dead hard drive.  The pin is made out of an 8-32 bolt that has part of it's length turned to .125".  The piston boss is drilled and reamed to 0.125" then one side of the piston boss was threaded for the short length of 8-32 thread left on the bolt adjacent to the head.  In assembly, the rod and piston are lined-up and the modified screw is inserted in the threaded side of the wrist pin boss.  It is then tightened in the threads.  I think it'll work fine.

The cylinder is made of a piece of 2" round LeadLoy bar stock.   It is drilled for the I.D. of 1/4" pipe all the way to near the bottom.  Then it's re-drilled 0.750+ to where the inlet valve seats.  The cylinder is then bored to 1.25 diameter 2" deep.

The cylinder liner is made of 1.250" diameter oil filled cast Nylon rod.  It is bored to 0.75".  After facing it to length, it was drilled to 0.750".  Since Nylon shrinks back a little when drilled, the drilled bore  ended up under 0.750".

I then turned the O.D. of the liner until it was a press fit in the cylinder.  You will note in the right-hand photo above, the liner does not come up to the top of the bore. 

The piston is made of a length of 0.750" steel bar stock.  A slot was milled in the top for the wrist pin as described earlier and the diameter was polished with fine emery paper. 

After pressing the liner into the cylinder it was about 0.010" unersize.  The cylinder with liner was put back in the lathe and the I.D. of the liner was bored  until the piston slips with slight friction.  Actually, if the piston is dropped into the bore, it will only very slowly fall to the bottom due to the slight air leakage between it and the liner.

There will be a cap that has a diameter turned on it that will slip into the cylinder about 0.250" and press against the top of the liner.  The cap will be bolted to the top face of the cylinder.  The bottom of the diameter turned into the cap will have a taper machined that is supposed to apply a squeeze to the top of the cylinder liner to seal against leakage.  This ought to work.
5 October 2012:
The water pump is finished.  All that's left to do is to mount it to the frame and plumb it into the cooling system.

Cylinder nearly finished.

Valve body with ball in place.

Completed pump.

The finishing of the pump and outlet valve body was uneventful.  Turning the pump by hand gives suction on the inlet side and pressure on the outlet side so it ought to move water, especially because it's always flooded.

What I'm going to use for a belt is an "O" ring.  I've got one that -may- work but it's going to be stretched very tight.  Next time I have an order ready, I'll get one that will work better.  For now, I'll go with what I've got.

The next issue I need to address is the mounting of the sight glass.
7 October 2012:
The pump and sight glass are in and working.

Here 'tis with the pump and sight glass working.
Of course, I'd be lying if I tried to tell you that everything worked perfectly right from the beginning.  The pump did work right off the bat and I didn't even need to bleed air out of it.  The coolant flowed past the valves just from the weight of it in the radiator.  After I started the engine, it pumped a good stream.

Soon, though, the pump started knocking and I noticed that it appeared that the piston was sticking at the top and bottom of it's stroke.  I found out that I had the nylon liner fitted juat a bit too snug.  I took the cylinder off and put it in the lathe and bored out about 0.002", giving the piston a fairly loose fit.  I put it back on and filled the system.  It leaked like crazy around the piston!

My first iteration of the design had the cap squashing the nylon liner to make the fit tighter and effect a seal.  After relaxing the fit, no matter how tight I got the cap, it still leaked.   Again, off it came and went back into the lathe.  This time, I turned a taper in the top of the liner.  When I put it back together, I installed packing.  The packing was a ravelled bit of graphite rope that I wrapped with Teflon plumber's tape so it would move freely.  After assembling it, the cap was down tight and the packing was still not really snug.

At first, when I filled the radiator, it seeped a little but I decided to go ahead and run it for a while and see what happened.  After the engine warmed up, the leak slowly stopped.  I'll know tomorrow when it's cooled down whether it will leak again when cold.  If it leaks when cold, I'll remove the screws and lift the cap and add a couple more turns of packing.  At least it works and I put a couple of hours on the engine driving around the neighborhood.  The coolant temperature looks to be about 20 degrees lower so the pump may be the fix for the overheating.

The sight glass leaked a little around the cap so I sealed it with some gray Silicone sealer.  There seems to be a good volume of coolant flowing so the pump must be near the optimum displacement.

I haven't drilled the glass yet and may not do it.  The level of the liquid in the glass rises about 3" when the glass cools off right after shutting it down and I'll see if it goes back down.  If I have to, instead of drilling the glass, I might simply make a small standpipe that is tapped into the base and vented to the atmosphere.  That avoids all the cussing when I try to drill the jar.  I have successfully drilled holes in jars before but there's always going to be a klutzy day when I shatter one.  No sense in tempting fate.

9 October 2012:
Yesterday I fixed the sight glass.

Sight glass with air bleed.
Instead of drilling the jar, I simply made a standpipe out of some 1/8" copper tubing.  You can see it to the right of the water pipe.  I've found that you can make mini-pipe threads for 1/8" copper tubing by using 6-32 taps and dies.  The threads are almost perfect on the tubing and the joints easily make water tight seals.  The hole the pipe screws into goes all the way through the base to the bottom.

Oh, yes - when the engine cooled-down, the water pump seal was seeping a little so I made an "automatic" packing adjuster by selecting an "0" ring and slipping it over the piston.  When the cap is secured, the "0" ring puts a steady pressure on the packing.  So far, so good.

28 October 2012:
I went to a show with the tractor and, after running fine as I drove it into the trailer prior to the show, when I unloaded it, it wouldn't start.  I came to find that the Hall Effect sensor on the rotor had failed.  Since I didn't have the parts or the means to fix it, I borrowed some stiff copper wire and whipped-up a temporary timer that worked well for the day.

After I got back home, I went low-tech for the permanent fix.  Since the Hall sensor was in close proximity to the high voltage, I figured that it failed due to induction.  My fix was to mount a miniature sealed mechanical magnetic reed switch in place of the Hall device.  It works like a champ and doesn't care much about glitches.

After putting a number of hours on the engine, the oil burning increased quite a bit.  Bottom line is that I let it go too long before changing the oil.  I suppose the contaminated oil really wanted to get out of the engine so it sneaked past the rings.  After changing the oil, the smoking was less.  Then I narrowed the dippers on the rods by about a half.  That reduced the smoking even more.  I think if I were to pull the pistons and drill more drain-back holes under the oil rings, it would probably not smoke much at all.

Then, today, I decided to see if I could make the latches stay latched and not snap off with the loud "clack" sound.  What I did was to narrow the pick blades from 0.450" to 0.200".  This seems to help quite a bit but it will still occasionally snap off. 

Narrow pick blades.
Maybe if I narrowed the blades a bit more it would completely go away.  The trade-off is in getting them too narrow and then have them bend due to the force required to hold the valves open.  I just may leave well enough alone.
6 November 2012:
By George, I think I've got it!

Finally, the clacking is gone after three more tries.  This time, I opted to use some of the take-off parts from other unsucessful parts of the engine.

Two views of the new and improved anti-CLACK latches.
What I did was to use two lengths of 0.028" (0.7112mm) music wire.  I was very scientific in choosing that particular diameter.  It's what I had!  I'll try to 'splain how this arrangement works.

The general principle is to make each latch independent of the other so when the engine slows and the governor tries to lift the picks, there is a spring to allow the latch blades stay engaged with the notch in the blades on the rocker until the governor has moved the shaft enough for the picks to come out of the notch cleanly as the cam lifts the rocker arms (with the notches) off of the picks.  The pick blocks are not tightened to the shaft so they can "float on the shaft, only tied to the governor shaft via the music wire.  Since I didn't want to have to make new pick holders, I simply spread the clamping notch then used not-so tight lock screws to "adjust" them until they were a nice slip fit on the shaft.

The two rectangular driving blocks (from a former governor iteration) are tied solidly to the shaft.  As the governor turns the shaft, the force is communicated to the pick blocks via the cantilevered music wires.  The wires are a press fit in the pick blocks and a slip fit in the driving blocks.  (Drilling those #70 holes was tedious!  The #65's in the driving blocks were a lot easier).  The length of the spring determines the amount of force that can be exerted on the picks.  Setscrews in the driving blocks firmly hang onto the springs.

In my first test, I guessed that a distance between the driving blocks and the pick blocks of about a half inch (12mm or so) would be a good place to start.  When running the engine, once I got the picks to engage at very close to the same speed, I found that the latches behaved themselves admirably.  In an hour of running, there was nary a CLACK so I think I may have that particular irritation solved.
13 January 2013:
After thinking about it for a few months, I decided that the compression ratio wasn't high enough and that was causing the engine to underperform.  A couple of days ago, I removed the head and did a little shaving.
My "executive decision" was to remove about 0.062" from the head height above the deck.  Half of that was accomplished by replacing the 0.063" gasket with one made out of 0.031" material.  The rest was gotten by milling 0.030" from the head.  While I was about it, I re-lapped the valves just for insurance although only one exhaust seat showed any problems.

I got the 30-60 back together and
gave it a couple of hours running time.  First, there is a noticeable increase in compression on cranking.  Not enough to pull the crank out of my hand but an increase. Also the engine decidedly runs better now.
Milling the head.
For some reason, it's smoking less from oil getting past the rings.  It still smokes but very little.  Breather smoke is also less.  I have a theory about that.  With higher compression and higher combustion pressure, maybe the rings are pushed harder against the cylinder bore, thus causing better sealing and the lessening of oil loss and blowby.  When I had the head off, I did notice that machining marks are still very visible in the bore.  This is probably the reason it smoked in the first place.

I can now
stay in high gear more of the time but getting shifted into that gear requires slipping the clutch (with the attendant squealing complaint from the clutch belt) until everything catches up.  When starting-off in the lower gears, it is no longer required that the clutch be applied very slowly.  The engine retains torque and doesn't "fall on it's face" when lugged down to a low speed.

Starting may be a little easier with a little less cranking.
Fuel mixture doesn't seem to be as touchy now.  I can run it just a little on the rich side of perfect and it does well at all speeds and loads up to the point where it will inevitably "fall on it's face" and need a lower gear.

There is one additional thing that could be making it run better (?).  After
the milling and thinner gasket, the head is, of course, closer to the crankshaft.  That makes the timing chain more on the slack side, meaning that my tensioning idler has to be adjusted a bit more.  With the tensioning idler in the position it is in, positioning the chain in the same sprocket teeth as before advances the valve timing a bit.  When checking the valve timing, I find that I cannot get a perfect setting.  If I have it timed so the exhaust opens at around BDC (my cam profiles are a bit off), the overlap occurs a bit before TDC.  If I retard the timing by one sprocket tooth, the exhaust opens a little later and the overlap is after TDC. The setting I chose is the former where overlap is early by, maybe 5 degrees.  I find that, when running, I can feel a barely noticeable little "puff" at the air inlet to the mixer at the beginning of the intake stroke.  It's not bad enough to blow fuel out or disrupt normal mixer operation so I'll leave it.  I'd prefer to have the exhaust open closer to the theoretical best point (around 40 degrees before BDC).  I think if it was timed so the exhaust opens after BDC, the overpressure against the rising piston would be detrimental.

As far as operating temperature is concerned, it doesn't seem to be running any warmer (between 120F and 160F or 49C to 71C) so that's good.

Anyway,I think it's about ready for prime time.
17 August 2013:
I've been thinking about it for a while since I milled the head to increase compression.  Today, I removed the pistons and made spacers, creating "high-compression" pistons.  Noted was the fact that, in spite of probably 50 hours of running, the rings are not totally seated.
High compression piston modifications.
After putting the engine back together with the "improved" pistons, I ran it for a while until I got rained-out.  It seems to run better and has noticeably higher compression on cranking.  The rings will have to re-seat before I know for sure if this modification was worth the effort.

Something I noticed when tearing it down is that there was surface rust all over the inside of the crankcase, rods, liners and crankshaft.  I may have to either improve the crankcase ventillation, run the engine up to temperature more often or change the oil more often.

The "catch" magnet also had quite a bit of very fine wear detritius.  Normal?  Maybe???
13 October 2013:
Today I got back to the project for a little fiddling.  I was going to put some more time on the engine to further seat the rings but, before doing that, I decided to make one more of my 10mm to 14mm  spark plug adapters to see how they would work in the engine.  The reason I'm trying it in this engine is that it is an oil pumper and quickly fouls the 10mm plugs.

The adapters are made from 0.850" long piecees of 3/4" bar stock and a couple of the long reach spark plugs.

Since I don't have a 10mm spark plug die, I made the 10mm threaded part of the adapter from the threaded part of the 10mm plugs as you can see below.

Pieces of the adapters.
The 10mm plugs were chucked in the lathe and the threaded portions were turned until they separated from the rest of the plugs.

The adapter blanks were chucked up and the small portions at the 10mm ends were turned for 0.500" to 0.250" diameter.  Then they were drilled through to the 10mm tap size and tapped just deep enough so the threaded portions of the 10mm plugs would bottom out in the threads with about 3/8" extension for screwing into the engine.

The adapters were then reversed in the lathe and the 14mm ends were drilled and bored to a little over 0.500" diameter and about 0.600" deep.  The 14mm ends were tapped using a 14mm spark plug thread chaser.  This was hard to cut threads with but, with some effort, it did a decent job.

Flats were then milled on the adapters so they could be held with a wrench when tightening the plugs.

Since the adapters disappear into the spark plug bores, I first screwed the 14mm plugs into the adapters and tightened them.  The adapters were then screwed into the head of the engine and snugged down.  To service the plugs, the "plan" is to screw out the whole sheebang then seperate the plugs from the adapters.

The adapted spark plugs in place on the engine.
The tractor was then wheeled outside and cranked-up.  Unsurprisingly, it ran fine with the plugs distanced from the combustion chambers through a port, then a 90 degree angle and about 3/4" more distance to the gaps in the plugs.  The plug gaps were first set to 0.040" but I was getting some arcing in the "distributor".  After decreasing the gaps to 0.028", it ran fine with no misfires.

After running it for a while with the timing retarded a bit to make it warm up, I noticed black streaks on my wrists.  Dang!  The dreaded clag-boogers strike again.

The dreaded clag booger.
I think the clag boogers are being blown out of the exhaust as a result of the higher compression making the exhaust run hot enough to dry-out the oily carbon that was deposited when the engine ran with low compression and before the oil control rings were added. 

The clag booger on a shop towel.

Touching the clag booger transfers it on your finger.  Ick!
Clag boogers are not conducive to good community relations when onlookers get them on their skin and clothes.  All it takes is a swipe with your hand and the booger smears itself all over.

After running the engine for over an hour with the spark retarded, it was still spewing a few boogers so I'm probably gonna have to remove and clean the exhaust pipes.  Maybe after that, the problem will go away.
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BOY, This is fun!
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