Comparing Magnetos

mlw450802 · #1 03-28-2006, 08:28 AM

I was looking at the engine descriptions in the plans and noticed that an 0-320 D2B is the same as an 0-320 D2A excepting it has "retard breaker" magnetos.

Would one of you knowledgeable types tell me what the difference is (in the magnetos) and why would you choose one over the other?

Thanks in advance,

-mike

RScott · #2 03-28-2006, 09:00 PM

I am not one of those knowledgeable types, but since no one else has replied, here goes: Maybe it means it has impulse couplers? They retard the spark at startup & give a hotter spark in the process.

osxuser · #3 03-28-2006, 09:39 PM

Nope, impulse couplers would be the 'normal' D2A, I THINK the retard breaker mags are the 'shower of sparks' style mags, but I could be wrong. In any event it shouldn't matter, just buy a impulse mag for the left and throw EI for the right

.

mahlon_r · #4 03-29-2006, 05:14 AM

Retard breaker mags are shower of sparks type mags. This system requires the installation of a shower of sparks vibrator and associated wiring in the airframe, in order to supply a retarded spark for engine starting purposes.
Good Luck,
Mahlon
"The opinions and information provided in this and all of my posts are hopefully helpful to you. Please use the information provided responsibly and at you own risk."

BruceMe · #5 03-29-2006, 05:26 AM

Yup, I just installed my SoS system last night... It makes a nice growling sound. Should make great sparks.

My system came with the engine. If I had a bare-core, I'd install pmags. But becaues they are there, and it's a prooven system, I think it may stay in my bird for a while.

Bob Nuckolls wrote a great article... You can find it here:

http://www.google.com/url?sa=U&start...rks.pdf&e=9797

jbDC9 · #6 03-29-2006, 06:50 AM

Speaking of articles, in this month's issue (April) of "Light Plane Maintenance" there's one that 'splains everything there is to know about the SOS/vibrator Retard Breaker system.

A subscription is kinda pricey, but they have lotsa good info that should come in handy for maintaining an RV once it's up and flying.

http://www.lightplane-maintenance.com/

mlw450802 · #7 03-29-2006, 07:06 AM

Thanks everybody,
I now know ONE more thing about these engines.

-mike