Bob Shores Eagle Hit/Miss Engine Build Thread

[ErichKeane]

I found a couple of Florida AME threads with some suggestions about testing compression (which seems fine), and adjusting the carb, which I did. Still not even a pop.

I've put a good 30+ hours into trying to get this stupid thing running, so I give up. I am just not a good enough Machinist for this project.

I found a box for it that I can hide away on a shelf so I'll only be reminded of it occasionally...

Thanks to all who paid attention and commented and liked this thread. I hope you all had fun here!

For now, it's on to other projects. So this one is done

 

[tq60]

Is it sparking under compression?

Common problem with weak spark is compression in the cylinder increases the amount of voltage required to jump the gap.

So after first confirming timing is correct unscrew plug to where it is just in, allowing air to vent resulting in minimal compression.

****do you have good compression?

You need fuel, air compression and spark...

With plug passing air you should now be able to place a drop of fuel in the carb and when spinning crank cause ignition.

3 volts may not be enough primary voltage to output suitable output voltage to start a spark or current to sustain a spark

Sent from my SAMSUNG-SM-G930A using Tapatalk

 

[tq60]

Is it sparking under compression?

Common problem with weak spark is compression in the cylinder increases the amount of voltage required to jump the gap.

So after first confirming timing is correct unscrew plug to where it is just in, allowing air to vent resulting in minimal compression.

****do you have good compression?

You need fuel, air compression and spark...

With plug passing air you should now be able to place a drop of fuel in the carb and when spinning crank cause ignition.

3 volts may not be enough primary voltage to output suitable output voltage to start a spark or current to sustain a spark

Sent from my SAMSUNG-SM-G930A using Tapatalk

 

[ErichKeane]

Is it sparking under compression?

Common problem with weak spark is compression in the cylinder increases the amount of voltage required to jump the gap.

So after first confirming timing is correct unscrew plug to where it is just in, allowing air to vent resulting in minimal compression.

I don't know. I had spark every other way, and I shrunk the gap way down figuring it would make jumping the gap easier. Still nothing.

****do you have good compression?
You need fuel, air compression and spark...

With plug passing air you should now be able to place a drop of fuel in the carb and when spinning crank cause ignition.

3 volts may not be enough primary voltage to output suitable output voltage to start a spark or current to sustain a spark

Sent from my SAMSUNG-SM-G930A using Tapatalk

I'm sure i don't have 'great' compression, but it seems like I have at least a decent amount... I'm not running 3v, the 3v supplies the ignition coil, which I think is way more than that. I've got 6v batteries coming that I guess I could try too, but I thought it would be controlled by the microchip.

 

[tq60]

The coil steps up the volts by huge ratio so every volt more on input makes many more output.

Current is reduced by same ratio as ohm's law is what it is.

So 3 volts on small batteries mean small voltage with limited current.

6 volts would double the input voltage and the available current also greatly increases.

For the coil to work the primary windings need to be saturated so the collapsing magnetic field crosses secondary windings causing the induced voltage.

This voltage charges the magnetic field of secondary that then collapse across the primary.

The capacitor completes the current path to allow the coil to "ring"

If voltage or current too low no saturation

Sent from my SAMSUNG-SM-G930A using Tapatalk

 

[BGHansen]

I found a couple of Florida AME threads with some suggestions about testing compression (which seems fine), and adjusting the carb, which I did. Still not even a pop.

I've put a good 30+ hours into trying to get this stupid thing running, so I give up. I am just not a good enough Machinist for this project.

I found a box for it that I can hide away on a shelf so I'll only be reminded of it occasionally...

Thanks to all who paid attention and commented and liked this thread. I hope you all had fun here!

For now, it's on to other projects. So this one is done

View attachment 334278

Sorry to read about your troubles. Probably best to give it a rest for a few days and collect your thoughts. I have to disagree with your assessment of your machining skills; sure look top-notch from what I've seen.

Could you turn a round that fits into the spark plug hole and drill it out? Basically extend the hole in the head to a tube you can get your finger on to check compression?

I'm not an engine guy, so kind of asking, why is compression important? Isn't it a measure of how well the piston rings are sealing to the cylinder wall? Gasoline is pretty explosive when in vapor, your piston at TDC will go in the other direction in a hurry if you've got fuel vapor in the combustion chamber and it sees a spark. Naturally, if you had a drilled hole in the head, you'd blow expanding exhaust gases out the hole. I can't imagine from your build that you have that much pressure loss.

Maybe try pulling the plug and blow out the combustion chamber. Then spin the engine, swab above the piston with a Q-tip and see if there's fuel there?

Someone else mentioned it, but did you lay the plug on the side of the head and turn the engine over and look for spark?

It's fuel, air and spark, so one of those three are frustrating us all from seeing a video of your engine running.

I can't tell you the number of times I cussed out my "blankenty blank" Massey 35 tractor. I couldn't get the dang thing to start. I ended up replacing the starter solenoid which was bad, and the ignition switch (measured a volt drop across feed to the coil. Still didn't fire. Ended up pulling EVERY electrical connection and cleaned them all. FINALLY got it to start. I spent a few months on it, but finally got it going. I admit to considering more than once to punch a hole with our Case 580 backhoe and bury the "blankety blank" Massey 35. Persistence finally paid off.

You'll be successful but I understand the frustration. Best to just walk away for a bit and lose the emotion and work the problem when you're calm.

Good luck and keep your chin up!

Bruce

 

[ErichKeane]

Sorry to read about your troubles. Probably best to give it a rest for a few days and collect your thoughts. I have to disagree with your assessment of your machining skills; sure look top-notch from what I've seen.

Could you turn a round that fits into the spark plug hole and drill it out? Basically extend the hole in the head to a tube you can get your finger on to check compression?

I'm not an engine guy, so kind of asking, why is compression important? Isn't it a measure of how well the piston rings are sealing to the cylinder wall? Gasoline is pretty explosive when in vapor, your piston at TDC will go in the other direction in a hurry if you've got fuel vapor in the combustion chamber and it sees a spark. Naturally, if you had a drilled hole in the head, you'd blow expanding exhaust gases out the hole. I can't imagine from your build that you have that much pressure loss.

Maybe try pulling the plug and blow out the combustion chamber. Then spin the engine, swab above the piston with a Q-tip and see if there's fuel there?

Someone else mentioned it, but did you lay the plug on the side of the head and turn the engine over and look for spark?

It's fuel, air and spark, so one of those three are frustrating us all from seeing a video of your engine running.

I can't tell you the number of times I cussed out my "blankenty blank" Massey 35 tractor. I couldn't get the dang thing to start. I ended up replacing the starter solenoid which was bad, and the ignition switch (measured a volt drop across feed to the coil. Still didn't fire. Ended up pulling EVERY electrical connection and cleaned them all. FINALLY got it to start. I spent a few months on it, but finally got it going. I admit to considering more than once to punch a hole with our Case 580 backhoe and bury the "blankety blank" Massey 35. Persistence finally paid off.

You'll be successful but I understand the frustration. Best to just walk away for a bit and lose the emotion and work the problem when you're calm.

Good luck and keep your chin up!

Bruce

I HEAR compression I think, so I thought I was close enough. That plug adapter thing is a good idea, maybe if I end up getting back into it, I'll check that!

I get fuel when I pull the head off, so I think it is working alright?

As far as spark, I've seen spark in and out of the head (without compression, just the bolts backed off enough I can see it).

Just feels like I've tried everything and have no ideas, besides trying a better battery pack (coming tomorrow), but not sure how motivated I am anymore

 

[BGHansen]

I HEAR compression I think, so I thought I was close enough. That plug adapter thing is a good idea, maybe if I end up getting back into it, I'll check that!

I get fuel when I pull the head off, so I think it is working alright?

As far as spark, I've seen spark in and out of the head (without compression, just the bolts backed off enough I can see it).

Just feels like I've tried everything and have no ideas, besides trying a better battery pack (coming tomorrow), but not sure how motivated I am anymore

If you've got fuel in the combustion chamber and it's not firing, sure sounds like ignition problems.

I bought something called "Hot Spark" conversion for my Massey 35 which changed it from points and condenser to a modern (as of 40+ years ago) high energy ignition module. Big thing was the change from around 15,000 volts going to the plug to 100,000. I'd lay a plug on the block and in the sunlight imagine I was seeing a spark. After the conversion, no doubt it was sparking.

Doubling your voltage will give you quite a bit more spark. We're all rooting for you!

Bruce

 

[Flyinfool]

OK, another silly question, but it has to be asked.
When you are spinning this up with your drill trying to start it, Are you spinning it at an RPM that is turning off the ignition by getting into the "Miss" part waiting for it to slow down before the next "hit", be sure that you are not spinning fast enough to get into the "Miss" zone. Can you rig a temporary light bulb or LED to the primary side of the ignition so that you can see the points opening and closing and the primary side being told to make a spark while you are spinning it.

Yes I am grasping at straws here. None of us have the blood, sweat and tears into this engine that you do, but we are all just as anxious to see it running as you are.

 

[ErichKeane]

OK, another silly question, but it has to be asked.
When you are spinning this up with your drill trying to start it, Are you spinning it at an RPM that is turning off the ignition by getting into the "Miss" part waiting for it to slow down before the next "hit", be sure that you are not spinning fast enough to get into the "Miss" zone. Can you rig a temporary light bulb or LED to the primary side of the ignition so that you can see the points opening and closing and the primary side being told to make a spark while you are spinning it.

Yes I am grasping at straws here. None of us have the blood, sweat and tears into this engine that you do, but we are all just as anxious to see it running as you are.

The ignition has a light on it that was definitely turning on/off. I tried a vast range of speeds with the drill. I'd also disabled the 'miss' capability while I was working (I just pulled the actuator arm away, since it got in the way a few times).