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Check your Slick mags!

Aden Rich

Well Known Member
I recently spoke with the guy who purchased my last RV-6. He called me some time back stating he had issues with the airplane starting. We went through the various items like battery and starting solenoid (all which got replaced). He got 10 years out of a Concorde battery.....!
He still had issues getting the airplane started. It used to fire up on a half of a blade of rotation when it was cold. Now he cranked on it for 15-30 seconds before it lit off. I told him to check his tumbler in the ingnition switch. He replaced that for $12.00. Still no starting. I then told him to disconnect the jumper on the back of the switch that grounds out the right mag so the plane only starts on the impulse mag- 0 degree BTDC. Bang. Fired right up.
He pulls the mags at my recommendation to comply with the 500 hr AD note on the mags and sends them to the repair shop. $650.00 later his mags are back to new. When I called him to see if he got them fixed, he indicated that he did. I asked him what was wrong with the impulse mag. It was shot. The gears were worn down and the bearing was toast! He had been flying around for hours in this condition.......according to the mechanic.
The extra weight of the impulse coupling hanging off the shaft is most likely the problem associated with that mag. There is also some rivets on the coupling to inspect. The right mag was fine but still overhauled.

The jist of this thread is that if you have Slick mags and have not checked your impulse coupling, I would highly suggest you do. Comply with the AD note! You are risking your life and your 80K ariplane on it. All for a few hundred dollars.
Before a bunch of guys chime in here with recommendations of going to electronic ignition I will say this.
They have their little gremlins too. E-mag still recommends a 100hr check on their bearings and shaft for play and wobble. That's a lot of maintenance for not having all these moving parts......
Lightspeed has had their black box issues as well, not to mention that finding all the space to route wiring, breakers, switches and hang black boxes is a chore at best. Put one in on a Rocket........was alot of work....
I don't know about Rose or some of the others so I can't speculate.
Mags have been around for a long time. I don't see them going away in the future. The current cost of the electrionic ignitions and time spent installing them with the current issues they still have don't really amortize out-even with the higher cost of AV gas. I'm not knocking those products, however, we have to compare apples to apples...

Check out the CAFE foundation website. They ran mags against EI and found the mags to be faster. The EI saved on gas.....about .5 gallon an hour. My RV-6 with mags went 214mph at 8K on 9.5gph at 50 dgrees ROP. Not too bad.
If you want economy, I would guess the EI would be a good choice.

Anyways, thread drift there for a moment.......please check your mags out. You just might be suprised.....

I have 4370 and 4373 mags on the RV-6. I have 4370 and 4373 on my current RV-6..

Thanks,
Aden Rich
 
I would urge caution starting on a non-retarded mag. A kick back and broken ring gear teeth can get expensive.
 
Agree

We only did this to trouble shoot the starting problem. Suspected the impulse mag was bad (which it was) and the engine started on the right mag.
Thus the reason for pulling the jumper wire on the ignition. Under normal operation it should only start on the impulse mag were the timing is close to 0 degrees BTDC.


Thanks,
Aden
 
Plus one on the mag service....

The guy I bought my -6 from had a hot start problem. I replaced the carb with no luck. Checked everthing else then pulled the mags and took them in. The impulse coupler was OK but both mags needed overhauled. $478 later and she starts great!!
 
If you want economy, I would guess the EI would be a good choice.

No just learn how to operate the normal one properly. ;) I have a mate with an identical -10 and a light speed, he is not quicker nor less fuel burn when wingtip to wing tip.
 
I have a mate with an identical -10 and a light speed, he is not quicker nor less fuel burn when wingtip to wing tip.

What about 2 Lightspeeds, just asking coz that is what I have.:)
 
They have their little gremlins too. E-mag still recommends a 100hr check on their bearings and shaft for play and wobble. That's a lot of maintenance for not having all these moving parts......
Lightspeed has had their black box issues as well...

....The current cost of the electrionic ignitions and time spent installing them with the current issues they still have don't really amortize out-even with the higher cost of AV gas. I'm not knocking those products, however, we have to compare apples to apples...

Check out the CAFE foundation website. They ran mags against EI and found the mags to be faster. The EI saved on gas.....about .5 gallon an hour. My RV-6 with mags went 214mph at 8K on 9.5gph at 50 dgrees ROP. Not too bad.
If you want economy, I would guess the EI would be a good choice.


I agree that electronic ignition systems have their issues as well. I have had two failures of the Hall Effect sensor on my LS in almost 1000 hours. That said, it makes a strong case for the magnetic pick-up on the ring gear.

However, it has been my experience that the electronic ignition system has paid for itself several times over. A fellow RV-8 buddy of mine and I had this discussion at 35,000' while flying the mighty MD-88 with our airline. I have an RV-8 with an 200 hp IO-360A1A. I burn about 9.3 gal/hr at my typical cruise power setting. I realize that any fuel comparison depends heavily on differences in equipment, conditions, and technique, but after doing this for almost 1000 hours and seven years flying side by side with a lot of RVs and comparing notes, I am very confident that I save about a gallon an hour (or about 10%) over a similar airplane with two magnetos. I burn about 1200-1500 gallons a year. At 1200 gallons, at $5/gal. That's $6000/yr on fuel. So, in theory my LS EI saves me about $600/yr. Not too shabby! I know it's not for everyone, but I'm glad I have it.

BTW, yes it is pretty cool to fly RVs with your buddies and then go fly airliners with them! :)

Jerry Esquenazi
RV-8 N84JE
 
Last summer I had the left impulse coupled mag fail with no early warning signs. Both mags had 491 hours TTSN. I had been flying local sight seeing and had an hour and a half in when I decided to do a touch and go at my home base airport. At about 200' agl with full power in, the engine started to miss and run very rough. I landed with no problem and after de-cowling and pulling all the plugs, the plugs attached to the left mag were all fairly wet. With a trip scheduled the following week, I just ordered a new left mag from AS&S so I never determined what exactly went wrong with the mag and returned it for the core value. I had Aircraft Magneto Services do the 500 hour inspection on the right mag last week. Just a reminder to others that I had no early signs of failure that I expected. Also have your mags inspected by a shop that has the equipment to test the magneto's thoroughly, including heat soaked and spun up. When I had my C-152, the AP/AI did a 500 inspection on the mags during an annual. He opened them up replaced the required parts and adjusted the points and e-gap. That plane was always hard starting for me and that did not help. I pulled the mags and sent them to the place above. Several problems were found and corrected including bad springs in the impulse coupler. EZ starting after that.
 
I have Aden's plane and replaced the mags with dual emags. I fly it at the same fuel burn as before and don't notice any speed difference but it hot/cold starts awesome and runs smoother. I think it makes more power but not really sure as it is difficult to quantify.....AND I LOVE THE PRICE OF AUTO PLUGS COMPARED TO FINE WIRES!!!
 
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