J2BD vs. J2B

[navajoflyer]

Any thoughts on converting the Chieftain from the J2BD engine to the J2B? 

[Tim Glubaskas]

We are in the process of beginning to convert our fleet

We currently use Aero Recip for our overhauls (J2BD) but will send them through Lycoming for the conversions since they do it for 'free'
Our first J2B is built-up on our QEC stand and about ready to go on

Frontier/Haagland/Ravn - whichever does their PA31-350 aircraft have been using them with good result for a while, though we will be using Slick Mags vs the Bendix Mags they use

[navajoflyer]

Thanks, we have decided to go ahead and convert our aircraft to the J2B engines. We just put two engines on one of our Chieftains and are getting ready for a third engine right now. We are using all Lycoming engines since they will take the J2BD cores with no up charge and we are only about 4 hours away from the factory. We are using the Slick mags that Lycoming puts on, and haven't had any problems so far.

[Tim Glubaskas]

Great - we are in the process of putting on our first

Glad to hear the slicks have been working fine as we have chosen to use them also

[Tim Glubaskas]

Oh - noticed it took me a while to respond to your first as I wasn't loggin on enough during the spool up for a busy season

If you ever have an issue to discuss, please feel free to contact me/us

Tim
907-474-3583
Warbelow's/Air Arctic

[roger]

We have used both the Slicks and the Bendix 1200 and have had issues with each. Slicks when paired with the OEM starting vibrator had some real issues with having enough spark to start a cold engine, and both types we've had issues of cam follower wear most often on the retard points resulting in no spark on start. Just FYI.
Nice things about Slicks are they take up a little less space and if you have a multi-type fleet all the repair parts are the same as any other Slick magneto. In general though it seems the 1200s are a slightly more robust magneto.

[navajoflyer]

We now have 1200 hours between the three J2B engines we are running on our Chieftains. All three engines have the slick mags. We have changed two right mags and one left mag. These mags were all warrantied by Lycoming so I couldn't tear them down to see exactly what went wrong, but the two right mags acted like the distributor blocks were bad, and the left mag ran great you just couldn't get the engine started so that was undoubtedly a retard point problem.

[roger]

We have a pair of -J2Bs with ~1700 hours on them. First ~500 was with slick mags, I think we pulled one for a retard breaker problem, and we had repeated cold starting issues using the OEM starting vibrator. Now ~1200 hours on Bendix 1200s, and with this latest round I think we're at about 50% removal rate before reaching 500 hour inspections. Had maybe 3 we pulled for point problems (I think 2 of those we just reset the points in the field and reinstalled, my memory is a little fuzzy on it), and now 3 within 50 hours of eachother for bad distributors (loose bushing in the distributor leading to contact between towers and finger). The first one was a catastrophic failure, mag lost a couple teeth and jumped time leading to rough running and high temps. Other 2 we caught visually while we had mags off to do a dual hyd pump change (that's another story). SDRs on file for the 3 most recent ones. Overall not real impressed with either magneto option on these engines. We send mags out to a repair station every 500 hours too so it's not like we're neglecting them.

[navajoflyer]

We have had some starting issues with the slick mags, but they are not consistent. I have two engines that start great and one that will hardly start at all sometimes. I am using the Bendix starting vibrator but I'm going to try a Slick start on one engine to see if it makes a significant difference.

[roger]

That's exactly what we had. Left motor was fine, but right motor required a special touch unless it was nice and warm.   
I don't know about the turbo motors, but we ran slick starts on 6 IO540s (Cherokee 6s) and they were superb other than after ~4000 hours or so they would "wear out" and cause intermittent left magneto problems.

[Tim Glubaskas]

We have 6 engines on so far that are J2B with slicks - haven't experienced any issues to this point.

Where are you all getting your mags overhauled? Are you sending them out for the 500 as exchange or is someone doing the work?

[roger]

We are having Merrill Field Instruments do the work.

[roger]

Update on this-
I just got off the phone with the folks at Aircraft Magneto Service down south and this is what they had to say:
1. The 1200 series mag is the best one there is in both performance and reliability.
2. Our distributor problems vibration related. We need to do a dynamic balance on the props, and they also recommend replacing the rubber drive bushings on the mags every time a magneto is off.

I'll buy that, for 2 reasons. First, the engine that we had the worst of the magneto issues on is the one that got stuck at a gravel strip and took some pretty good prop nicks powering out. Second, last time I had this problem repeatedly (4 years or so ago) I replaced drive bushings and the problem went away. I think we're going to stay with the Bendixs and let you guys know what we find out.

[navajoflyer]

Update on Slick Mags

I put Slick Start on the right engine of one our Chieftains and it made a huge difference, especially on hot starts. If you are going to use this system on a twin, Champion requires a slick start on each engine rather than just installing one in place of the Bendix vibrator. This is because the unit draws more current than the starter toggle switch in the Navajo can handle. I mounted ours just behind the firewall on the inboard part of the nacalle on the right engine. When I do the left engine I'll most likely mount it on the outboard side of the nacelle. I picked the power up off the starter terminal. The instruction say to get the power off the starter side of the starter solenoid as close as practical to the solenoid. Since the unit operates on either 12 or 24 volts it seems to me that the voltage at the starter is still more than sufficient. This makes the installation much simpler than running wiring from the starter solenoids. Took about 1.5 hours total

[Tim Glubaskas]

Interesting info on the Slick Start -

We have yet to have any issues on the 5 J2Bs we have installed but we will continue to monitor

Thanks for the information