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LASAR Ignition System Removal - Which Slick's now?

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VF84Sluggo

Well Known Member
The LASAR system in my new-to-me RV-4 is dead. Toast. Inop. When I bought the plane, I didn't know anything about the LASAR system, so with the cockpit switch "on" I assumed (my mistake) that the system was working. Well, it hasn't been working at all, and now the mags are failing.

After talking it over with someone very familiar with the defunct LASAR system, we've decided to remove it totally and go with a standard Slick setup. Question is, which mags to use?

The engine is a Lycoming IO-360-B1B. The Slick/Champion table shows 4347 Left, 4370 Right, for this engine. However, according to a shop in Atlanta that I also consulted with, they installed in an RV with this exact same engine make/model mag #'s 4373 and 4370 that was having its LASAR system removed.

So, that agrees the Slick/Champion table for 4370 on the right. But which for the left? 4373, or 4347 (per the table)? The installed LASAR mags are 4771 on the left, 4775 on the right.

I reached out to Slick/Champion, but they are unresponsive.

Any help is appreciated!

PS I'm in FL. This plane was located in the Seattle area. I used a pre-buy guy in the Portland, OR (that holds himself out as knowledgeable). Had he actually DONE what he said he was gonna do, ie a full systems check and a run-up, AND PROVIDED THE SERVICE THAT I PAID FOR (his lame excuse for not doing a run-up was that the plane was blocked in by another airplane and couldn't get it out of the hangar; I don't think he ever even turned the master switch on...pathetic...avoid this guy...but to be clear, I paid him in full, kept MY end of the deal) he might have discovered that this LASAR system was failed. The amber light passes press-to-test, but never illuminates. The system is dead.

I flew this plane from Washington state to Florida in the back-up mode! No wonder these mags are failing. I'd also corresponded with a tech rep at Pro Aero Aviation, as they still have some support for LASAR. The rep was amazed the mags have lasted as long as they did, and didn't fail on the trip. The LASAR-modified Slicks were NEVER intended to be run for that many hours in back-up mode.

Again, I'll accept responsibility for not doing my homework on the LASAR system. Should have known what to expect on initial power-up and the mag check on run-up. I'd have known, then, that I should be seeing illumination of the amber light, that that is normal, and correct.

And as far as that pre-buy guy, like in "Animal House", hey, I f*cked up, I trusted him. I'd have never done the deal with a failed ignition system. Now I'm spending a few thousand to correct this. AVOID THIS GUY!
 
Lasar mag

I have had great results with Pmag. On first flight I had a standard mag on the left and Pmag on the right. After 10 years, I removed the standard mag and installed a Pmag on the left as well.
 
I have had great results with Pmag. On first flight I had a standard mag on the left and Pmag on the right. After 10 years, I removed the standard mag and installed a Pmag on the left as well.

+1. Install dual pMags and end the pain. They have been flawless for 12+ years and 1000+ hours on my first RV, and just about to hit 200 hours on my new RV-8. The six cylinder pMag has been flying for over a year on my old RV-10 and has provided significant gains in cruise efficiency. The new RV-10 will sport dual six cylinder pMags.

Carl
 
Thanks for the input. I'll take a look at it.

Although, I have talked with folks that don't recommend electronic ignition systems. Or, say if you're gonna do it, do both. Don't do just one side: the "spark" on the fixed advance mag is firing after the electronic one, and is not doing much, if any, good.
 
Look at the back of your engine.
The basic physical difference is if you have a spacer on the Left side or not.
-If your Left mag mount looks like the Right mag mount and does NOT have a spacer collar - you need the 4347 mag - which is a Retard Breaker mag and the distance from the flange to the gears are same distance as the Right mag.
-If there is a spacer collar between the old Lasar unit and the accessory cover on the Left side, than you need the 4373 mag as the impulse gear makes the distance to the drive gear longer on that mag.
 
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Look at the back of your engine.
The basic physical difference is if you have a spacer on the Left side or not.
-If your Left mag mount looks like the Right mag mount and does NOT have a spacer collar - you need the 4347 mag - which is a Retard Breaker mag and the distance from the flange to the gears are same distance as the Right mag.
-If there is a spacer collar between the old Lasar unit and the accessory cover on the Left side, than you need the 4373 mag as the impulse gear makes the distance to the drive gear longer on that mag.

My first guess was the 4373 mag but looks like Ralph was faster at the keyboard.

I looked up Lycoming recommendations in Service Instruction 1443R and found 4347 listed for the IO-360-B2B engine.

Without me doing more research, I would do what Ralph suggests. IF no spacer, then the 4347 mag would be the one you need. Since the engine is in an EXPERIMENTAL airplane, it could have had a mag and spacer swap that need the 4373 mag or no spacer and need the 4347 mag.

LASAR mags come in sensor and non-sensor versions with long and short shafts. Long and short shaft versions take into account if there is a mag spacer or no mag spacer. In other words, there are 4 possible LASAR mags part numbers on your airplane. IF the engine was converted to LASAR, Ralph's instructions are correct in the need to check what you have and not just use what the Service Instruction suggests.
 
This just gets more confusing:

After reaching out to ProAero, I was told the difference between the 4347 and 4373 is that the 4347 is shower-of-sparks, 4373 has an impulse coupler. Otherwise, they said either mag will work just fine. The ProAero rep did say that since the LASAR is setup to start on both mags, he recommends two 4373 mags.

My ignition switch is a Bendix, with "OFF/R/L/BOTH" positions, and a separate spring-loaded guarded starter toggle switch.

As I get an education on all this, I have been starting in "BOTH" with no kickbacks or other issues. Don't know if the starter switch is wired to ground a mag when the starter is engaged.

Interesting oddity: This RV-4 has LASAR mag 4775 on the right, 4771 on the left. The ProAero rep said that is backwards. Well, I know for SURE its a 4775 on the right. Can't see the dataplate on the left, but some notes I found do say a 4771 is on the left. So, if my start wiring is setup to ground a mag on start, is it the left one? WTF? Perhaps just going with two 4373's, as the ProAero rep suggested, would make all this moot.

Regardless, no WAY am I going to go with a shower-of-sparks, and have to install a "vibrator." YGBSM. So, I can at least rule OUT the 4347.
 
Note your plane is an EXPERIMENTAL and the engine could have been set up any which way the builder could fit it in.

Hence - my suggestion still stands. Look at the back of the engine. See if there is a spacer collar between the mag & accessory cover.
I looked up the B1B engine in the Lycoming Parts Manual & if configured to original Lycoming spec, there should be no spacer collar on it. If you eventually go the 4373/4370 route, you will have to get the collar & longer mounting studs if it isn't already there for the impulse coupled mag.
 
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Since you are starting from scratch:

If you buy new legacy magnetos please consider Bendix type over Slicks. Both are certified but the Bendix type are built much better. I have done quite a few 500 hour inspections and would certainly trust a Bendix much more than a Slick. So, I would go for a set of Bendix (or TCM, CMI, or whatever they are called now) "compact" magnetos. I don't mind conventional mags but consider Slicks on a new Lycoming a temporary set up and replace them at the first 500 hour inspection with a good old bulletproof Bendix or one of the more modern digital ignitions.

If you are willing to try something more modern I would encourage you to look at a set of dual P-mags. I run those on my RV-8 and am very happy with them. Remind your buddies giving advice that the P-Mags generate their own electricity internally as a failsafe backup if the power fails, at which point they emulate a conventional magneto in so far as not needing external power.

If you aren't comfortable going with all electronic ignition at this point then consider one CMI/Bendix and one SureFly electronic magneto. The reason to mix a SureFly with a mag is that the SureFly is totally dependent on external power so the conventional mag is a backup. A dual SureFly set up would require a secondary battery and electrical system at which point it gets complicated. Which means silly since there are P-Mags available without this type of backup scheme.

You have a lot of options starting from zero.

Also, your ignition switch has two terminals that can be jumpered with a wire to ground one magneto during start in case there is only one impulse coupler. So it grounds the non-impulse mag to avoid kickback. You may or may not have this jumper in place but if you go with dual electronic ignition or dual impulse mags check to see if you have this jumper and if so remove the jumper so you have all the spark available at start.
 
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Note your plane is an EXPERIMENTAL and the engine could have been set up any which way the builder could fit it in.

Hence - my suggestion still stands. Look at the back of the engine. See if there is a spacer collar between the mag & accessory cover.
I looked up the B1B engine in the Lycoming Parts Manual & if configured to original Lycoming spec, there should be no spacer collar on it. If you eventually go the 4373/4370 route, you will have to get the collar & longer mounting studs if it isn't already there for the impulse coupled mag.
Thanks Ralph. I give it a close look tomorrow.
 
Thanks for the input. I'll take a look at it.

Although, I have talked with folks that don't recommend electronic ignition systems. Or, say if you're gonna do it, do both. Don't do just one side: the "spark" on the fixed advance mag is firing after the electronic one, and is not doing much, if any, good.

I have to disagree. The idea of one traditional mag and an electronic one is that the magneto doesn’t need ships power so if your charging system fails you can still fly. Not necessarily an issue for a pmag but it is for other systems.

The traditional mag is mostly there as a backup. The spark is so much hotter from the EI that you don’t really need the 2nd plug. There is virtually no mag drop during runup with EI.
 
Laser to pmag

My Lasar system failed. Did a lot of alternative investigation and decided on dual Pmags. Easy to install great customer support. Very easy to time, both at once. Gained about gph and no issues starting. And spark plugs are a lot less costly.
And for doubters, if they weren’t reliable, why is lycoming putting them on?
 
Regardless, no WAY am I going to go with a shower-of-sparks, and have to install a "vibrator." YGBSM. So, I can at least rule OUT the 4347.

No one does this anymore. You buy a ‘Slickstart’ module to feed the retard mag. It’s all solid state, no mechanical vibrator.
 
I don't know why someone starting from scratch in 2021 would choose a 1930s-design magneto over P-Mags.

- mark
 
SOL Now that’s a blast from the past, Ivan’s first RV, but I digress...... My RV6 engine new out of Vans came with Laser Ignition. When it completely died (they all did) I went with dual LightSpeed Plasma3, had a dual battery set up and it was faultless and still going strong when sold after 1600hrs. However now I think SureFly is definitely worth consideration, it’s all electric but with no scheduled maintenance and a TBO of 2000hours plus and recommended by Lycoming it’d be hard to go past. With Experimental a dual SureFly setup would be the go I think. Cheers from Western Australia
 
I went through this in March when my right mag went bad. I was able to get two re-maned slick mags for less than the price of one P-mag, from a local pilot supply store in one day. I was 600 miles from home. I fly around 50 hours a year and the extra cost for p-mag performance just didn't add up for me. The front end load was hard to justify for me. two grand buys a lot of av-gas. I have 4370 and 4373 on my o-360.
 
This just gets more confusing:

After reaching out to ProAero, I was told the difference between the 4347 and 4373 is that the 4347 is shower-of-sparks, 4373 has an impulse coupler. Otherwise, they said either mag will work just fine. The ProAero rep did say that since the LASAR is setup to start on both mags, he recommends two 4373 mags.

My ignition switch is a Bendix, with "OFF/R/L/BOTH" positions, and a separate spring-loaded guarded starter toggle switch.

As I get an education on all this, I have been starting in "BOTH" with no kickbacks or other issues. Don't know if the starter switch is wired to ground a mag when the starter is engaged.

Interesting oddity: This RV-4 has LASAR mag 4775 on the right, 4771 on the left. The ProAero rep said that is backwards. Well, I know for SURE its a 4775 on the right. Can't see the dataplate on the left, but some notes I found do say a 4771 is on the left. So, if my start wiring is setup to ground a mag on start, is it the left one? WTF? Perhaps just going with two 4373's, as the ProAero rep suggested, would make all this moot.

Regardless, no WAY am I going to go with a shower-of-sparks, and have to install a "vibrator." YGBSM. So, I can at least rule OUT the 4347.

Just looked up the LASAR mag model number in SL1-96H. Section 3 has this table.

Screen Shot 2021-07-16 at 8.52.33 AM.png

I have a 4771 mag on the LEFT of my airplane and can tell you that it requires the spacer. That tells me that if you have the 4771 mag installed, you also have longer studs and spacer so the 4373 impulse mag will be required.

4775 is a LASAR sensor mag and has an electrical connector that has two additional contacts than the non-sensor mag.

Someone suggested that you use Bendix mags. If you look up the Type Certificate Data Sheet for your engine model, it has the Lycoming approved Bendix mags listed. As you know, Bendix mags weigh more than Slick mags and use a difference ignition harness.
 
I think Jliltd (post 10) summed it it very well.

I don't know why someone starting from scratch in 2021 would choose a 1930s-design magneto over P-Mags.

I used a number of combinations of ignitions in the first 9 years of flying my plane: Slick- Lightspeed; Dual Lightspeed; Lightspeed + Pmag; Dual Pmag.

The Lightspeeds were good until they failed and a lot more complexity compared to Mags. Pmags were good but they require 100 hr or Annual inspections and I never liked the electrical connectors on the Pmag.

When I replaced my O-360 with a high compression Titan IO-370, I went with Dual Bendix Mags and Fine Wire plugs.

I've been running the IO-370 for 2.5 years. It runs great and starts easily. I check the timing and plugs during my Annual. I love the simplicity compared to the electronic ignition. I may not be getting every last ounce of performance but I plan to stick with my Bendix mags for the foreseeable future.
 
After the hassles and SB's on the Slick impulse mags I replaced the left Slick (impulse coupler) mag with a SureFly system and left the Slick on the right. Works perfectly, simple install, better starts and the SureFly needs no attention or service between engine overhauls
 
The subject of the thread is, which Slicks to use after LASAR removal.

So, for anyone else that might be considering a similar thing - which Slicks, NOT which electronic ignition system - based on a recommendation from a great source, I'm going with dual 4373's on my Lycoming IO-360-B1B. The LASAR system was set up to start on both mags, and this will be the case with 4373's, as they have the impulse coupling.

For what it's worth, I had Slicks on my Lycoming O-360 powered Marquart Charger and Lycoming O-320 powered RV-3. Worked great, not a bit of trouble.

Thread closed.
 
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