Life after Laser Mags

My buddy just bought a beautiful RV-9a that has an O-320 and Lasar/Slick mags. It runs great but it’s due for the 500hr mag service. Although is still runs great, I don’t want the Lasar to fail and I’m thinking about going back to regular mags. Does anybody know what mags and harnesses would be the right ones to order? I don’t know if I can reuse the current mag gears, or do we need an impulse gear on the Left side. Also I’ve seen some ignition harness that are excessively long, which ones are better sized lengths?

Last.. what’s the market for a used but good Lasar setup with the special timing buzz box?

Tom, does he want to switch to P-Mags? I've had 2 of them on my -4 for a few years now and love them. Cheaper auto Plugs, better starts, 4 knot increase in cruise, among many of the benefits. - Ben

I have also run PMAGs on my last three RVs with great success. He can certainly run one PMAG and one Slick and still have about 90% of the benefit of an electronic ignition, if there is an hesitation of for a new system

Slick mags will replace the LASAR mags. You will reuse gears, spark plugs, and spark plug harness. You MAY need something for Tach signal.

Anyone that can work on Slick mags can due the LASAR 500 hour inspection.

LASAR has fallen out of favor by users due to hig cost of parts. Users like me have picked up used LASAR Systems for pennies on the dollar. I can keep my system running the rest of my life without buying expensive new parts. I would not use LASAR on a new project but will keep it working on my 25-year old airplane.

I am not interested in paying for LASAR parts. They can be sold but you may or may not get what they are worth.

I was thinking regular Slick mags, or Pmags.. if I went to regular Slick mags, I may need a spacer for the Left impulse side, and perhaps the impulse gear? I don’t know yet, I need to take off the cowl to see what’s on the engine now, but I believe the Lasar use the non impulse gear, and no spacer, right?

Another reason for getting rid of the Lasar is because they seem to cause increased CHT. From what I’ve read, most have CHT increased about 30 degrees. I assume this is due to the advance curve. Will the P-mags also have increased CHT? Could I retard the Lasar mags a little to compensate? I don’t like having to throttle back to control CHTs..

Thanks in advance!!

Tom,

Seems like any ignition system that fits in the mag hole and is driven by the accessory drive gears can be retarded by rotating the ignition system so the timing event occurs later. This is commonly done on Pmags by setting them up a bit after TDC rather than right on TDC.

Check my reasoning on this since it's done off the top of my head: Up to a point, advanced timing will:
1. Increase power at higher altitudes and lean mixtures.
2. Decrease EGT a bit since more of the combustion energy goes to producing power.

Some of the electronic ignitions are a bit too aggressive in their timing advance for those who are based at higher altitudes. An advance that starts to kick in at the MP one sees at 5000' is fine for sea level flyers since they are well into cruise climb at 5000'. An airplane based at 5000' or so is still in takeoff mode when the advance over 25* TDC starts to kick in.

I'm running one Lightspeed ignition on my O-360. LOP cruise EGT's are mid 300's. Field elevation is 4234'. On hot days, a 120 KIAS climb speed keeps CHT's below 400. I feel that having to increase the climb speed is good tradeoff for having increased efficiency at cruise. Therefore, I have not changed my base timing.

Taltruda said:

Another reason for getting rid of the Lasar is because they seem to cause increased CHT. From what I’ve read, most have CHT increased about 30 degrees. I assume this is due to the advance curve. Will the P-mags also have increased CHT? Could I retard the Lasar mags a little to compensate? I don’t like having to throttle back to control CHTs..

Click to expand...

I’m having dual PMags installed with my engine rebuild after a prop strike at this year’s AirVenture. I also had some concerns about an increase in CHTs because of the automatic spark advance built into PMags. Those concerns have somewhat been reduced by what I read in the EMag ‘installation and operating manual’ when setting the timing.

“CLOCKING: Set timing with the engine positioned slightly after TDC (1-6 degrees). Greater offsets will produce greater retard (less aggressive advance).

Taltruda said:

I was thinking regular Slick mags, or Pmags.. if I went to regular Slick mags, I may need a spacer for the Left impulse side, and perhaps the impulse gear? I don’t know yet, I need to take off the cowl to see what’s on the engine now, but I believe the Lasar use the non impulse gear, and no spacer, right?


Thanks in advance!!

Click to expand...

They exist both with and without an impulse coupling you will have to take a look.

The last one took off had an impulse with spacer on the left side but I don't know how common an option that was. Would have been a straight swap to a standard impulse mag.

Derek

Implication?

It sounds like we should always aim for less CHT? So if we retard our mags, we get less CHT (and less power), and this makes things right with the world? If 20 degrees reduces CHT, and 15, reduces it more... A rhetorical question! And I think an odd one given how folks feel about engine size

My data point - I have a Lightspeed. Always had it. 2nd is a Bendix. The lightspeed advances once the % power is below 75% (this is a bit of a simplification). I can't say I've seen excessive CHT due to the Lightspeed advance. Whenever I've seen high CHT it was very high ambient temps, break in hours, or extended slow flight in hot weather. I consider high CHT to be over 400.

I have no interest in pulling the Lightspeed (which gives easy starts) and going back to dual mags.

Looks like we have a mag spacer on the left Lasar/slick mag.. does that mean the gear on that mag will fit up to the impulse coupling on a Standard 4373 mag?