Honda 390 Ign

Jimbo

You can fool some of the people some of the time
What effect does coil air gap have on the ignition timing?
 
There are a couple of different coils used on the 390 platform, Jimbo.
Of the oem variety, the polarity is reversed on at least two of them.
The coils also have a built in advance that changes (similar to the pvl coils you're familiar with) above a certain rpm (2000 if I remember correctly.)

The air gap of the stock coil doesn't seem to take away much timing at all. We've opened them waaaay up like is popular on the clone stuff now, and really didn't see much (very small retard) change using a timing light.

If you're able to use an aftermarket flywheel, then by all means do so...the flywheels on these engines are way overkill, even for the heavy stock rotating assembly.

Hope that helps.


-----
Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Cutz
www.CarlsonMotorsports.com
Carlson Motorsports on Facebook
30 years of service to the karting industry
Linden, IN
765-339-4407
bcarlson@CarlsonMotorsports.com
 
On earlier OEM style coils you will see a wider gap retard the timing more in the upper RPMs than a narrower gap, but you will also see a reduction in magnet drag when using a Billet flywheel with rare earth magnet. These two combined will improve power in smaller, stocker style CC engines where every tenth of a HP means something, but you wont see much of a change with a big block.
 
There are a couple of different coils used on the 390 platform, Jimbo.
Of the oem variety, the polarity is reversed on at least two of them.
The coils also have a built in advance that changes (similar to the pvl coils you're familiar with) above a certain rpm (2000 if I remember correctly.)

The air gap of the stock coil doesn't seem to take away much timing at all. We've opened them waaaay up like is popular on the clone stuff now, and really didn't see much (very small retard) change using a timing light.

If you're able to use an aftermarket flywheel, then by all means do so...the flywheels on these engines are way overkill, even for the heavy stock rotating assembly.

Hope that helps.


-----
Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Cutz
www.CarlsonMotorsports.com
Carlson Motorsports on Facebook
30 years of service to the karting industry
Linden, IN
765-339-4407
bcarlson@CarlsonMotorsports.com
what about putting a PVL on a 390, is it worth it?
 
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