intermixing cy/zenoah parts, is it really all the same?

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Sharkey

Sharkey

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right now im screwing together a motor for my onroad car. i started with a cy26, now putting a zenoah g230 head on it. ive done some measuring and checking things out and decided to see how close to factory spec the ignition timing is. stock spec is 30 degrees BTDC (before top dead center), + or - 1 degree. turns out on a zenoah g230 i checked it was dead on 30 degrees. my cy26, dead stock comes up at 28 degrees, not too far off, but far enough. ive now got the motor partly screwed together, cy bottom end, crank, flywheel, zenoah g230 top end. ignition timing comes out at 23 degrees. play around a little, double and triple check my degree wheel and tdc marks, everything is correct. try a g230rc flywheel, timing is now 26 degrees. add in a zenoah coil to the mix, adds another 3 degrees for a total of 29 degrees.

zenoah flywheel- 3 degrees more advance
zenoah coil- 3 degrees more advance
zenoah head- 6 degrees less advance

just tossing this combo together would net me way less timing than needed. now say i was doing it the other way around, zenoah bottom end with cy head, in theory that would give a total of 36 degrees, far too much timing.

the end result: sure it all bolts together, and it will run, but is it actually right? ill leave that open for discussion
 
in the past i,ve run a mish mash of all three brands zen, cy, and k,m and never had a problem, its only when i,ve run a comlete c,y or zen they have gone pop,lol
 
hi sharky, ive had a 23cc zenoah in my marder,but put a cy bb kit on it, so zenoah bottom, cy top,no issues in the last 7 months, i ive not gone lightly on it either,
 
with ignition timing on anything you wont always end up with a noticable problem, however with the timing being off you will lose power and efficiency. too much timing can create knock that potentially can damage an engine. im not trying to say it doesn't work, clearly you can toss the parts together and it will run, its been done many times. what im getting at is the stuff isnt the same, cy and zenoah parts are different enough. im kind of stunned nobody has seen this before, however i guess im the only one to throw a timing light on one of these motors
 
Sharkey said:
with ignition timing on anything you wont always end up with a noticable problem, however with the timing being off you will lose power and efficiency. too much timing can create knock that potentially can damage an engine. im not trying to say it doesn't work, clearly you can toss the parts together and it will run, its been done many times. what im getting at is the stuff isnt the same, cy and zenoah parts are different enough. im kind of stunned nobody has seen this before, however i guess im the only one to throw a timing light on one of these motors
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What are you using as a timing mark? A degree wheel or something?

Only noticeable difference I have seen between Zen and CY is on the cases CY has bigger openings for the transfer ports. So if using a Zen gasket on CY case you need to trim it and if desired you might want to match the case and cylinder.
 
Best to use degree wheel and piston stop and splitting diference each way to find the exact TDC with pointer arraigned and set to 0 TDC then using a timing light on the degree wheel while the engine is actually running so you can see for certain where the actual point of ignition is occurring. These coils have electronic induced ignition advance programmed into them so using magnets and armature as firing points will not be very accurate especially whan mixing and matching coils and flywheels.
 
im using a degree wheel and a dial indicator to get top dead center. i don't have the motor running, that will come later, however im spinning the motor over with an electric impact gun at roughly 2000rpm, doing that i get a rock solid view of the degree wheel. i know my method works, using the same method on a stock zenoah g230rc i come up with exactly 30 degrees timing, just what zenoah claims it is.
 
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