Anybody Know the Difference in Zenoah G23 Primary Coils ??

[Gyan]

I have a grey one & a red one. (the coil that goes around the flywheel) Is there a difference between the two? I somehow doubt it but I have to ask.

[TargetG]

Yes the coils are the same I have work with a lot of zenoah motors for cars and boats.

LG

[cbergen]

They are different. The timing is slightly different between the two.

The red one is what normally comes with heli engines, the gray coil is typical of airplane engines.

In actual use, I doubt you will feel much difference between the two.

[Gyan]

Thanks for the responses. Is there a placve where the actual specs are available?

[bigrcr]

Chris is correct. The red coil (normally found in the heli version) has a higher timing than the grey coil....How much, I am not sure but I think it is only a couple of degrees. I ahve heard it suggested that the grey is 28 before and the red is 30, but I cannot confirm the actual amount.

Later,

[Gyan]

Thanks for the responses. Why is the 30 degree better for helicopter usage? Do you or anyone know?

[bigrcr]

The higher timing raises performance to a point. Like Chris said, I doubt it you will see much of a difference. Interestingly though, if you live at high altitude and/or have detonation or mild overheating problems the grey coil may help with the slightly lower timing.

Later,

[Tom Fiddler]

I think it has to do with the fact that the Plane engine turns a prop about 9000 rpm.
Since we turn the Heli engines faster than that. we need more "lead"
Just a theory

[Gyan]

Ahhh Tom; You finally added the piece to the puzzle I needed ! Faster RPM means of course faster piston speed. That 2 degrees is needed so the spark has enough time to create a proper burn & explosion. A 28 degree BTC is slightly closer to the top so would not allow a complete burn, thereby allowing unburnt gases to cool the engine a little more. Although it would be hard to measure a 2 degree difference, @ 12,000 RPM !