Large coles hit and miss engine

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Wayne j

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Hi everyone, I just bought a large coles hit and miss engine. Been struggling for couple days getting it running. I’ve got the timing the best I can but still fires way too soon before TDC. Does anyone have the plans for this and would share a picture of the cam? This one is a really odd shape so I would like to make sure it’s not my issue. Any help is greatly appreciated!!

Wayne
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Catminer

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Hi Wayne, it's been a lot of years since I built mine but I have the drawings stashed somewhere, I will look
for them.
I will try to get a picture of the cam also, if possible. The engine is mounted in my version of a hit and miss tractor and it may be difficult to get a picture.

Peter
 

Wayne j

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Thank you Catminer for sending me the info I need to confirm Cam is ok. I am new to hit and miss engines and what confuses me is that using this cam with a Buzz coil t it provides spark during many of the 4 strokes except the exhaust cycle. I thought it should only fire once when the engine is TDC on the compression stroke. Anyone’s insight into this would really help. I know there’s lots of knowledgeable people here. Thanks

Wayne
 

Wayne j

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I had the understanding the the buzz coil and the plug fires when the points come into contact NOT when they separate? Am I wrong?
 
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Catminer

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Hi Wayne, So far I have failed in finding the drawings and cannot not get a picture of the cam on my engine.
I will look some more.
This ignition system is for a single spark high tension coil ignition, spark will occur when the points open.
The points closed time (dwell) is the little cutout in the lower right of the cam as you have it pictured.
I use a 6v automotive coil and four D cells or a lantern battery as a power source.

Peter
 

Wayne j

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Thanks Peter MNay sent me what I needed for drawings. The cam is ok. The engine came with a buzz coil. Will that work for this type of engine? Or do I need a single spark high tension coil? I am new to this, I usually work on steam engines.

Wayne
 

Wayne j

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Wayne, a buzz coil will not work with the cam configured as it is. It needs to be a single spark coil.

Peter
Thanks Peter!! That confirms what I was suspecting. Having limited knowledge of these engines I could not get my head around how this could produce a single spark at TDC. It was sparking at too many points in the 4 strokes. Now I just have to figure out how to set up a single spark coil! My hands are really blistered from spinning those wheels on this engine for 2 days trying to get it to run!!!

Wayne
 

Wayne j

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When you use an automotive coil does the negative on coil go through the points and the top connector on the coil go to the spark plug? Thx
 

Catminer

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Correct, the neg terminal on the coil goes to the points. They are a switch to ground. Don't forget to add a capacitor parallel to this part of the circuit.
And the large centre terminal is the high tension lead to the spark plug.
 
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LorenOtto

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Hi everyone, I just bought a large coles hit and miss engine. Been struggling for couple days getting it running. I’ve got the timing the best I can but still fires way too soon before TDC. Does anyone have the plans for this and would share a picture of the cam? This one is a really odd shape so I would like to make sure it’s not my issue. Any help is greatly appreciated!!

WayneView attachment 143098
What a lovely engine. I bought that kit from Coles 40 some years ago. Had fun machining everything, but got tangled up in how to make it run, so put it on a shelf. Hope you have better luck.
 

Wayne j

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Hi Loren, after a lot of messing with this engine I did finally get it to run. Using an Automotive type coil and after a lot of messing with the timing I got a spark at the correct time. The needle valve is quite sensitive but after I started using a rubber wheel in a drill to turn the flywheels over I figured out the needle valve positioning that worked. I also replaced the spark plug. After fine tuning a lot of little things it’s running now. Not perfectly but I’m sure as I keep playing with it, it will get better. Thanks everyone for helping me out with this.

Wayne
 

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