C12 Timing

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NM
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C12 Timing

Hi, just put villiers C12 back together after strip down and replacing oil seals, piston rings, crank bearing and cleaning and painting, thankyou Mr. G. I have fitted electronic module instead of points. Can’t get it to run. I have a spark and ghosting it I’m not getting even a splutter. I’ve just stripped it down and checked cam timing but that’s o.k. The only way I could work out to set ignition timing was to set piton to t.d.c. with dial gauge and then align arrows on armature plate and flywheel. Any ideas or help much appreciated.

wristpin
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By the sounds of it you are

By the sounds of it you are doing everything correctly. Unless I'm using an electronic module as an alternative to replacing a dud condenser I  like to get the engine running on points and condenser and check out that any timing marks are what they are supposed to be. For demo purposes I have extended the wire from the coil to outside the mag and done the same with a wire from the points and condenser. With the two wires joined you are running on the original system ; then separate the wires and attach the module to the coil wire and ground the module's body and you are running "electronic". I've even demmed it with a change over switch and switched from one to the other without missing a beat.

Villiers  usually made in-service resetting of the timing hassle free by setting the engine up exactly in the factory ie correct points gap and BTDC measurement, tightening the flywheel and turning it to TDC and then stamping the setting arrows - saves having to measure the BTDC piston position.    

NM
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Thanks Wristpin.  I’ll have

Thanks Wristpin.  I’ll have another try and go back to points set up to see where I am. I find setting points a bit fiddly and electrics a nightmare.

NM
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Hi, well I’m no better off

Hi, well I’m no better off after spending most of the day trying to get c12 running. Checked timing twice now with points fitted. I think I’m just going round in circles now. The carb is flooding and not sure if the correct float is fitted. It is a float/needle type with no clip and there’s no leaks and it floats when in water.. The fuel isn’t reaching the combustion chamber. I removed the carb from inlet elbow and there is suction and the breather valve is working.

This is the first governed engine I’ve worked on. Governor I think set correctly. Turn governor crank fully clockwise, fit governor lever and connect to carb linkage. Turn governor lever fully clockwise and tighten pinch bolt, the throttle will be wide open. Does the throttle stay wide open until started when the governor gear throws out the sleeve and tries to close throttle.

Thanks

wristpin
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If the ignition etc are

If the ignition etc are correct, I’m guessing that the piston is not creating enough negative pressure in the cylinder for atmospheric pressure to push the mixture through the carb. Test the theory by removing  the plug and dripping a bit of fuel directly into the cylinder . If the spark is happening at the right time and the compression is reasonable you should at least get one firing stroke. If there’s nothing, put s couple of squirts of engine oil into the cylinder first to raise the compression a bit and try again.

Do you know anyone with a leak-down tester ? Performing a leak-down test gives a good assessment of the overall engine condition, valve leakage and piston blow-by etc. More informative than a compression test.

The set-up for the Governor is to turn the shaft fully clockwise, move the lever so that the throttle is fully open and then do up the clamp .

Edit. Should have asked right at the beginning  - after your efforts to start it , is the plug wet ?

NM
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Thanks Wristpin. The plug is

Thanks Wristpin. The plug is dry so no fuel being drawn into cylinder, but won’t even splutter with ghosting. I’ll try another spark plug, these are short reach as plug is directly over inlet valve, strip carb and probably get new float, needle and seating. I’d have thought that even if carb’s flooding it should still draw fuel but it isn’t. I’ll try and borrow a leak down tester if I can.

 I’m pretty certain there’s negative pressure in cylinder on induction stroke as when a finger is placed over inlet elbow and engine rotated you can feel the suction and it leaves an impression on end of finger.

 

wristpin
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Plug. The C12 manual shows

Plug. The C12 manual shows the plug as. Champion RL85. R for resistor, L for 1/2” reach .  So if your “short reach “ equates to 1/2” it is correct but if it is 3/8” , you need to find a longer one. I wouldn’t be too concerned about the resistor bit. (NGK B4H)

Out of interest, when you fitted the new rings, did you pop them into the bore and check the size of the end gaps ? I can’t find a figure for the recommended gaps but by measuring the gaps for the new rings between a midway position in the bore and a relatively unworn position at the bottom of the bore below where the rings run will give an indication of the state of wear.

Ghosting. In a lifetime of dabbling with engines from 10cc to 27 litres, I’ve never heard that term - please enlighten me.

NM
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Thanks Wristpin, the plug I

Thanks Wristpin, the plug I got is a 1/2” reach. I have a RL86C plug which is for the electronic ignition but will try that one. The mechanical ignition points gap says .020” and the electronic version says .030/.035”. I have tried both settings but that makes no difference.

The MK10 through 15 manual gives piston ring end gaps and I did check them. They were towards the smaller gap specified and consistent down the bore.

I probably heard the term ghosting in the mid 80’s regarding adding a little fuel directly into the cylinder and have used it ever since. I have no idea where the saying came from and having just googled the term it seems more to do with online dating.

 

 

hillsider
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In the situation you are in I

In the situation you are in I find it better to squirt maintenance spray directly into the carb air inlet rather than dropping petrol into the plug hole, I find that if an engine is going to run it will usually fire on the spray for a short while, if you are careful you might even keep it going longer by further squirts of spray. 

The spay that I am using currently is GT 85 but other sprays may work, I think it may depend upon the type of propellant used in the can, WD40 is one that does not seem to work.

If the engine can be run in this way you then know you have a carb / fuel problem.

Have you by any chance tried a second spark plug - just in case you have a dud?

NM
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Thanks Hillsider, I tried

Thanks Hillsider, I tried another plug and spraying carb cleaner in manifold but to no avail. Found a donor engine in the end and got that running and swapped points, coil and flywheel, siba recoil fitted as these seem more abundant and started second go without tipping fuel in the chamber. Needs a bit of tuning on carb side re: governor and tick over but so at least it starts now.

Thanks for all the help Nick

Chris G
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Nick, assume you will go back

Nick, assume you will go back to the original engine at some point, that would irritate me, but good to walk away sometimes and come back

NM
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Hi Chris, hope you’re keeping

Hi Chris, hope you’re keeping well and had a good Christmas.

I was a bit irritated to put it mildly among other things but i thought I better put my **** ** right

I have got the original engine running with the points set up from the donor engine. With hindsight maybe should of run the original engine before stripping it down but it seemed in a proper state. I can now try and sort out what is wrong with the ignition set up that won’t work by swapping one bit at a time on the donor engine.

        

   

Chris G
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Hi Nick, happy new year!

Hi Nick, happy new year!

That sounds a good approach to fnd the issue!

Could always bring it to the OLC meet in May and run a competition to find the common denominator !

Cheers

Chris

 

NM
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Hi Chris. I think the common

Hi Chris. I think the common denominator is probably operator error.

Does the meet in May allow stationary (in this case totally inert) engines?