Bob Shores Eagle Hit/Miss Engine Build Thread

OK, another silly question. Does the new electronic ignition take a second to charge up? As in if the motor goes to "Miss" does it cut power of just delay the points breaking contact? Some electronics do not come to life right away at power up?
 
Flyinfool said:
OK, another silly question. Does the new electronic ignition take a second to charge up? As in if the motor goes to "Miss" does it cut power of just delay the points breaking contact? Some electronics do not come to life right away at power up?
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It doesn't seem to take any time. The motor itself doesn't cut ignition to cause the 'miss' on this engine though, it only fails to open the exhaust valve.
 
rdean said:
I don't know if you have seen these tips from Bob Shores but they may help.

Ray
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Based on his test, I don't have great compression (10-15 seconds or so? but I didnt do it with fuel in the cylinder) but since the rings haven't worn in, it seems like thats still pretty good. I'm using a normal paper gasket material (1/32, so the right size at least...), but it seems to seal?

I DO think I have a mediocre fit from my valve-stems to the head. The valve faces themselves have pretty good fit, but I've basically lapped for a ton of time now (I thought it was a problem at one point), that a bit of air leaks through around the stem.

Either way, I'd expect to get SOME bit of firing...
 
FWIW, I picked up some 6v (highest rated for my ignition) NiMH batteries and gave it a shot. Mine meaured out closer to 7 volts, but blinked the light all the same. However, no change still :/

I DID find the motor has a bit of a distinc 'goose honk' through the carb though, which is odd..
 
Is the honk during the intake stroke or the compression stroke?
Compression stroke would indicate that the intake valve is leaking, during the intake stroke would indicate that the intake valve spring may be to strong.
 
I'm not sure! I cannot imagine it is too strong of a spring through, ive chopped it down a whole bunch, it barely keeps the valve closed.
Flyinfool said:
Is the honk during the intake stroke or the compression stroke?
Compression stroke would indicate that the intake valve is leaking, during the intake stroke would indicate that the intake valve spring may be to strong.
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As bobshore explained on his website the intake spring needs to be just enough to keep the valve from falling into the cylinder. It is the engines compression that holds the valve closed. The intake valve acts more like a check valve. It is the vacuum as the piston is moving down that uses atmospheric air pressure to open the valve and fill the cylinder.
 
If you think the valves may be leaking then you can make a test plate. I used a scrap piece of 0.500 thick aluminum with a pocket cut out for the valves and spark plug on one side and a fitting for shop air on the other. Bolt your head to the plate and listen for the leaks.
I also found that valve grinding compound that you get from the auto parts store is too course for finish lapping. I used a copper polish paste that seems to work well.

The paper head gasket is just fine as that is what I use on my engines.

The valve guides are not a problem at this time as they will not keep your engine from firing but may influence how it runs later after starting.

Ray
 
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