Engine Runs Hot-Need Suggestions

[mvivion]

I started with LASAR mags on my RV8 in '03, and I had overheating problems. They have a very aggressive advance curve. After all the usual baffle etc. changes, I switched to Lightspeed and my troubles went away.

And, the winner is ^^^!

The mechanic who installed this thing installed an "On/Off" switch in the system. Today, after carefully re-reading the Flight Manual Supplement, I fired up and went flying....with the On/Off switch selected to the "Off" position. First interesting factoid: With the switch off, according to the FM Supplement, you cannot start the engine. Period. With the switch (and circuit breaker to be certain) powered off, engine fired right up. Factoid two: Ever since the temps increased significantly, the engine has had really rough starts. Starts fine, but shakes like a dog shitting peach pits. With the LASAR Off, MUCH smoother start up and it idled right away at 800 rpm. A clue.

Took off climbed at full rich and leveled at 6500 msl (7500 DA-cool day). leaned as normal, pull till it pops, richen up to ~ 9.1 GPH on the fuel flow at 2350 and 21 inches. Waited for CHTs to stabilize, and voila! Three cylinders were very close to 360 (358, 356, 355, 338). Energized the circuit breaker, then turned the LASAR switch to "ON", and waited. Fuel flow did not change noticeably. Within a few minutes, three of the CHTs were over 400, the fourth was 385. That was all I needed to see, so turned the system off again.

Out of curiosity, I leaned to 75 ROP at the above noted power setting, using the "Lean Find" feature on the EDM 900. Fuel flows came out to 9.1....as expected.

According to the FM Supplement for the LASAR, CHTs may increase as much as 20 degrees. Mine increase 40 degrees, so I'm assuming the system needs to be reset, OR there's something out of whack. The Supplement is quite clear that the engine cannot be started with the LASAR system off, but this one started fine. Which suggests there may be something wrong with the unit. Unit is no longer in production, different company owns it and by accounts on the interweb, support is minimal.

So, the next question is "What now?". The FM Supplement is quite clear that if the system fails, the mags "work just like conventional mags". So, I'm assuming it's perfectly safe to fly it with the system off. Is that legal? I'll talk to the Mechanic here and see if he'll collar the circuit breaker and log the system inop. I can take the bulb out of the Amber "warning light" which informs the pilot the system has failed......


If not that, I'm assuming it's time to change to conventional mags, or some other flavor of E-Mag. Suggestions?

MTV

 

[skywagon8a]

Bingo Mike! This one is for certificated airplanes: https://www.surefly.aero

 

[wireweinie]

It most likely starts because they installed a left mag with an impulse coupling. Champion Aerospace called this their 'Bush Kit'. It allows you to hand prop with a dead battery.

Web

 

[supercrow]

I have the Sure fly on my left mag, and have been very pleased with it

 

[mvivion]

It most likely starts because they installed a left mag with an impulse coupling. Champion Aerospace called this their 'Bush Kit'. It allows you to hand prop with a dead battery.

Web

Maybe, but the installation instructions say remove any impulse couplings. And the supplement clearly states engine will not start with the unit off or disabled. Doesn’t say will be hard to start……but, who knows.

MTV

 

[DENNY]

If you are going to change mags just get a set of Bendix and be done with with all that yuppie pilot stuff.:lol:
DENNY

 

[wireweinie]

Maybe, but the installation instructions say remove any impulse couplings. And the supplement clearly states engine will not start with the unit off or disabled. Doesn’t say will be hard to start……but, who knows.

MTV

Pull it through and listen for the impulse coupling. When I installed them, I always recommended the 'bush kit' specifically for hand propping. It's per instructions and 100% legal, just requires a different part number for the left mag assembly.

 

[MainlandCub]

Did the plane speed up when you switched the LASAR on? If not and there's no difference in fuel flow, what's the point in having it?


Andrew.

And, the winner is ^^^!

The mechanic who installed this thing installed an "On/Off" switch in the system. Today, after carefully re-reading the Flight Manual Supplement, I fired up and went flying....with the On/Off switch selected to the "Off" position. First interesting factoid: With the switch off, according to the FM Supplement, you cannot start the engine. Period. With the switch (and circuit breaker to be certain) powered off, engine fired right up. Factoid two: Ever since the temps increased significantly, the engine has had really rough starts. Starts fine, but shakes like a dog shitting peach pits. With the LASAR Off, MUCH smoother start up and it idled right away at 800 rpm. A clue.

Took off climbed at full rich and leveled at 6500 msl (7500 DA-cool day). leaned as normal, pull till it pops, richen up to ~ 9.1 GPH on the fuel flow at 2350 and 21 inches. Waited for CHTs to stabilize, and voila! Three cylinders were very close to 360 (358, 356, 355, 338). Energized the circuit breaker, then turned the LASAR switch to "ON", and waited. Fuel flow did not change noticeably. Within a few minutes, three of the CHTs were over 400, the fourth was 385. That was all I needed to see, so turned the system off again.

Out of curiosity, I leaned to 75 ROP at the above noted power setting, using the "Lean Find" feature on the EDM 900. Fuel flows came out to 9.1....as expected.

According to the FM Supplement for the LASAR, CHTs may increase as much as 20 degrees. Mine increase 40 degrees, so I'm assuming the system needs to be reset, OR there's something out of whack. The Supplement is quite clear that the engine cannot be started with the LASAR system off, but this one started fine. Which suggests there may be something wrong with the unit. Unit is no longer in production, different company owns it and by accounts on the interweb, support is minimal.

So, the next question is "What now?". The FM Supplement is quite clear that if the system fails, the mags "work just like conventional mags". So, I'm assuming it's perfectly safe to fly it with the system off. Is that legal? I'll talk to the Mechanic here and see if he'll collar the circuit breaker and log the system inop. I can take the bulb out of the Amber "warning light" which informs the pilot the system has failed......


If not that, I'm assuming it's time to change to conventional mags, or some other flavor of E-Mag. Suggestions?

MTV

 

[FatCub300]

mags and plugs

Mike,
probably gonna start a fight here...but, I had those same mags on my Husky years ago...they were installed quietly by a previous owner. Mine would also start with the switch in the off position. One thing I found after a lot of trial and error, was that the LASARs REALLY like the fine wire plugs, not the massive electrodes. Things got much better and cooling presented a 30 degree delta after switching plugs. After owning the plane three years, one mag catastrophically destroyed itself during a runup at my farm strip, which I was thankful for, as the day before I was a weeks walk away from home by air and they displayed no difficulties on that flight.

The problem then went away entirely and cooling further improved when I installed a brand new set of Bendix mags with new harnesses for $3400.

The moral to all aviation problems is: Spending more money to undue your problems, almost always works...unless it doesn't.

I hope that helps.


Steve.

Did the plane speed up when you switched the LASAR on? If not and there's no difference in fuel flow, what's the point in having it?


Andrew.

 

[mvivion]

Thanks, Steve, that’s interesting information. At the moment, I’m just operating the plane with the EI selected off, till my mechanic and I decide the best solution.

Interesting devices, these. Obvoiously a few folks thought they were a good idea.

MTV

 

[skywagon8a]

Thanks, Steve, that’s interesting information. At the moment, I’m just operating the plane with the EI selected off, till my mechanic and I decide the best solution.

Interesting devices, these. Obvoiously a few folks thought they were a good idea.

MTV

At the time of their introduction, there weren't any other electronic ignition systems available. They were just an initial attempt which received the FAA's blessing. At the time, even the automotive electronics were nowhere near the quality they are today.

 

[FatCub300]

I meant to say also...I have put a Surefly mag on my left mag on my 520 on the Fat Cub and have been running it for the last year with fine wire plugs...I run this engine with an MA4-5 carb setup the same as P ponk's. I've never had an engine start so easily, be as lean-able, or run as smoothly, even with the Bendix mag on the right shut off. I do notice about 25 degrees hotter, which I attribute to the Surefly advancing the timing particularly at lower power, leaned operations up about 8000msl.

I guess the technology does have a place, I'm still learning to use it properly!!

Have a great day,

Steve

 

[skywagon8a]

.