Vertical hit and miss engine

[doubletop]

I am now in that "post building slump" that always follows a successful build.

Brian

I know what you mean for me its always a bit of an anti-climax when the project is completed and there’s not much else to do apart from the odd tweak here and there. More a case of the journey than the destination.

In my professional life, as a project manager, I had the same emotion when a project went live. There’d be people jumping up and down wanting some sort of celebration that the job was complete and more importantly it did what it set out to do. What did they expect to happen? For me it was more looking forward to the next challenge.

Pete

[doubletop]

Brian

A thought on this load test.

Use a gallon, or more water container and fix a hose into the container inlet. Turn the water tap on to trickle feed progressively fill the container as you lower and raise it on the manual clutch. At some point the engine will stall and you’ll be able to work out the max power using formula Zephyrin provided.

Alternatively, you could just add another pint from a jug each time the container was lowered.

Pete

[Brian Rupnow]

Here she is boys, my mother 99 years old today. That handsome (slimmer) fellow with her is myself, turned 73 in July. Drove up north and had a little birthday party at the senior citizens manor where she lives. Good time was had by all, my back is sore--driving 400 kilometres will do that.

[MJM460]

Congratulations to you both.  A remarkable achievement.

And both look good for a few more years yet.  Must be something in the invigorating climate you guys have.

For your back, I suggest taking the drive with breaks every hour and a half, and get out and walk around the car or further each break.  Takes surprisingly little time, and I find I arrive fresher.  It’s a routine that keeps me going for our trips that in recent years have been over ten thousand km.  As packing up in the morning to leave takes at least as much out of me as some of the driving, I often stop after the first hour.  It also helps me to see a little more of the places I travel through.

MJM460

[Brian Rupnow]

I'm in thinking cap mode this afternoon. As the engine sets right now, there are only two ways to adjust the speed at which the engine kicks in and out of "hit and miss" mode. One is by changing the weight of the governor balls, and the other is by changing the strength of that light green spring on the vertical cam shaft. I think the governor balls are very close to the correct weight right now. The light green spring is a real pig to change, requiring almost complete disassembly of the cam shaft and brackets. However--If I were to add a third factor into this, I believe I could fine tune the kicking in and out of "hit and miss" mode. The way the engine works right now is that once the engine reaches a certain speed, centrifugal force makes the balls fly outward away from the cam-shaft (as it is shown in the model). The cams on top of the governor arms force the grey governor thimble upwards, compressing the light green spring and in turn makes the dark blue "hit and miss lever" rotate and end up underneath the rocker arm, which prevents the exhaust valve from closing. It works great, but I have no control over when this happens. If I were to make the yellow bracket which bolts in place with two of the head bolts, then I could tap a hole in it, and add the bronze colored adjustment screw and lock nut. The spring from a ball point pen would be Loctited to the bronze threaded adjustment screw, and the other end would bear against the dark blue "hit and miss lever". Any pressure applied to the "hit and miss lever" by the spring would counteract the force applied by the light green governor spring. This should give me the ability to fine tune the rpm at which the engine kicks in and out of "hit and miss" mode.

[gbritnell]

Brian,
On most governors the main control is at the governor assembly itself, meaning the weights and primary spring should be set to operate for a given rpm. Any secondary spring control is just for overriding the main setting to increase  the engine speed. It's true that both work in conjunction with each other but trying to make adjustments on both simultaneously is like chasing your tail, you never catch up.
Being an old hot rodder you should know that to solve an engine problem you only make one change at a time.
gbritnell

[gbritnell]

Brian,
If I'm looking at your model correctly, above the governor spool (gray) there is a spring (green). This spring in conjunction with the governor weights would be the primary control of the lock-out lever (dark blue) When the governor spins the centrifugal force of the weights is modulated by the spring (green)
The lock-out lever is moved to the right to go under the rocker arm to prevent it from operating. Now you are adding another spring (orange) which by the picture I assume is a compression spring. If this is the case then this is where you're having a problem. The orange spring should be an expansion spring to override the primary control, thus increasing the engine speed. As you back off on the orange control control knob thus lessening the the spring pressure the engine would go into the 'miss' cycle sooner.
This is how the governor on a lawnmower engine operates. The governor which is preset is connected to the carburetor with a mechanical link. When you want to increase the engine speed you move the control lever which is connected to the governor lever with a cable and a spring. As you move the lever farther toward the high speed position you are adding more pressure on the secondary spring which is overriding the governor mechanism (weights and spring)
gbritnell

[gbritnell]

Brian,
Here's what I would do. Remove the orange spring and adjust the green spring until you get the engine to run at it's slowest speed (approximately) Now instead of having the threaded rod screwed into the tan bracket drill out the bracket so the threaded rod will slide through it. Now thread the knob so that when it rotates it will move the rod laterally. Drill the inner end of the threaded rod to accept the loop of an expansion spring. Drill a hole in the lock-out lever to hold the other end of the spring. Now by turning the knob you put more tension on the spring which will override the governor mechanism.
gbritnell

[Brian Rupnow]

George--I hear ya. As I said in my first post about the governor, that light spring is a real bear to remove. I'm going to try my method first, because it requires no disassembly of the original engine. If it doesn't work, I'm only out a couple of hours of my time, which isn't all that valuable these days.---Brian

[gbritnell]

 Brian,
Here's the question. How slow do you want the engine to run? Apparently with the setup the way that it is your desire is to have it run/miss cycle slower. If that's the case then here's the next question, how slow will the engine run (miss cycle) before the speed of the engine isn't enough to restart itself. With the engine having good compression at some point the flywheel won't have enough inertia to go over compression and restart. Before you add or modify to the engine here's what you can do. Start the engine, manually override the lockout lever until the engine slows down more than the governor will allow. At some point when you feel that this is where you want the engine to be spinning at release the lockout lever and see if the engine will restart. Keep experimenting until you get the engine to run as slow as possible and will restart. If you find that it will run quite a bit slower than it currently runs then make up your adjustment mechanism. This will add to the pressure on the lockout lever and slow the engine down. Keep in mind that by backing off the adjustment knob will only allow the engine to run as it is currently configured. You won't be able to make it run faster. Not a problem is that's not your desire.
gbritnell

[Brian Rupnow]

It works!!!  I have attached a still picture and a video showing my "fine tuning adjustment screw" that affects the rpm at which the engine kicks in and out of hit and miss mode.
<a href="https://www.youtube.com/watch?v=y5I-vitFqUI" target="_blank">http://www.youtube.com/watch?v=y5I-vitFqUI</a>

[Brian Rupnow]

I've never had a real problem getting engines to run fast. I like my engines to run slow, and it takes more fiddling to get them to run slow than fast. In a perfect world, I'd like the hit and miss engines to fire once, then coast for seven or eight revolutions, then repeat. I have came to the conclusion that although Viton rings seal extremely well, the penalty for using them is that they create more drag on the piston than cast iron rings. This drag has a rather dramatic effect on how many coast cycles a hit and miss engine will have before it hits again. This engine has a pair of cast iron rings that  purchased, and it does seem to have an improved coast cycle. The only thing wrong with having them run as slow as I like is that they lose the ability to take over and keep running when a load is applied.

[Brian Rupnow]

George B--I greatly appreciate that you look at my posts and offer up advise. I am in awe of your knowledge and talent. Thank you for offering help. ---Brian Rupnow

[Brian Rupnow]

The people who have purchased this engine plan set will be interested in details of this fine tuning adjustment for the hit and miss function. Rather than email every individual, I will post it here.

[gbritnell]

Brian,
I am posting this only as a suggestion of what I would do. I respect all the time and thought that goes into building your engines and mechanisms so I trust you don't take this as criticism in any way.
When you posed the question about trying to control the engine speed I offered up a suggestion and explanation of what could be done. You replied that you would have to take the cam drive assembly apart to change out the spring and you felt like it was too much work. Part of this hobby is the experimentation phase where you design something to the best of your ability and then tweek it in until it works as close to what you had originally thought it should be.
In designing, drawing and building my flathead engine I have at least 2,500 hours. A lot of this was making new heads to alter the compression, a new intake manifold to solve the fuel delivery problems , numerous changes to the distributor to solve the burned out Hall transistors. I did all the extra work because I, and I repeat I, wasn't happy with the outcome.
I would have liked to see you change out the spring, even several times, to achieve your desired goal and then make up the mechanism you devised to increase the speed as it would have been used on a 1:1 engine.
Thanks for presenting us with another very nice build.
gbritnell