SonexBuilders.net

Yes, Art! As I got into the manuals list night I see that the pickup is from the alternator wires. It's been too long to remember. So, the old Kubota may indeed still be good. The bad news is the alternator is probably not as easy of a swap for a new one.

Has anyone had a Jabiru alternator go bad? How difficult to replace?

Thanks,

builderflyer wrote:Are you sure it isn't the alternator itself that failed? If your tachometer takes its feed from one of the two alternator wires as does mine, it may explain why you lost the tachometer as well. Just wondering.

Art,,,,,,,,,,,,,,,,,,,,,,Sonex taildragger #95,,,,,,,,,,,,,,,,,,Jabiru 3300 #261

Kip,

I replaced my Jabiru voltage regulator at 300 hrs, and now use a “Caltric R11-2” reg. Voltage output is higher than the stock Jabiru (Kabuta) reg, and seems to keep the Odyssey battery topped off better.

viewtopic.php?f=8&t=2059&p=30468#p30468

Swapping is easy, and the wires will transfer over to the caltic reg fairly easily. The caltric uses fast-on terminals rather than an OEM connector.

Jeff

Does your alternator have replaceable brushes?

I don't think there are any brushes, Bryan. The alternator seems "integrated" into the flywheel assembly and thus is not an easy component swap.

I'm going to speak with Nick at Jabiru and see what it may be and how long the stock alternators last.

Jeff, my original Kubota may still be up to the task but thanks for the link.

Kip

hi all,
i think the main point here is cooling. we have blast tubes running out the back of our cooling boxes on the jab3300, directed at the coils. one project this winter will be to ‘T’ off the right side tube and have it aimed at the voltage regulator. was also thinking of putting some washers behind the regulator so it will stand off of the fire wall for better cooling. will purchase a extra regulator to keep ready if needed. i did buy the jab alt. from sonex (12 coils if i remember) 20amp. is this what they use in the aerovee also? the alt. can be purchased on the sonex web store under the clearance section.
they were $202 , but recently now $355. Kip when you speak with jab , nick at Arion now?, see how much the alt. is. $.
good luck kip keep us posted.
added: i purchased the alt. a couple yrs ago for a spare. our origional still on. glenn who had the ‘rosie’ red jab sonex a couple yrs ago at osh, on the way home had his alt. fail. he posted on here , i reccommended call sonex , buy one and send overnite mail. he replaced it, not the easiest to get to, but doable. got him home. the other project i want to address is the 2 stock connectors. dont know if thru vibration they loosen up , may need crimping now and then, or better to change out to different connectors or a terminal block? thoughts?
WaiexN143NM
Michael

You can check the alternator by disconnecting it from the regulator and connecting a voltmeter to the alt. Leads and running the engine. Should have 30-40 volts ac at hi rpm. Mine failed at 200 hrs. The first one I got from Ben K was no good, he had to send a second one. That one has been working for about 250 hours now. It can be changed with engine in place(3300). Mine failed over a short time. Charge voltage just got lower.

Thanks for all of the above info.

After some research...
While heat may be an issue, an old, under-performing battery can cause the alternator to work overtime (with heat) to recharge that battery after a start. I am guilty of this as I put off installing a newer, stronger battery over the past year. It was still cranking fine but slow. But ,just two weeks ago it would not crank after a 10 minute flight and being continually topped off with a battery tender. It's probably best to replace the battery every 2-3 years for the sake of the alternator.

To think I was 1000 miles from home a few months ago right on the verge of this! I felt prepared with a spare wheel and tire (that I have never used).

Nick is out of the office today but I'll let you know how the process goes...cost's ect. as I get it fixed.

I find the theories of removing heat from the regulator interesting. Some say they mount them on spacers
so they don't touch the firewall. I made sure I mounted mine on a thick piece of aluminum that is flush
on the firewall. I used transistor heat sink compound between the regulator and alum, and alum to firewall.
Wont the heat be conducted away from the regulator?.....guess I'll find out, lol.


Rick

Speaking of heat and it's proposed effect of coils, regulators, and alternators, I have been monitoring the "under the cowl" temperature for about a year now. My #6 cylinder CHT lead was damaged and disconnected from the cylinder during a flight and left me with a nice inner-cowl ambient temperature display. I've not repaired it so I notice about a 75-80 degree temperature while in cruise flight on an average day. In the summer, after landing, the temperature quickly goes up to about 180F and stays high for quite some time if no air is blowing in the cowl.

Since I just replaced my coils, I began (at least on the hottest days in the South) to put a fan under the engine to blow air up through the lower exhaust channels to cool the engine off quicker. If heat does indeed affect these components, I like to think that I am preventing an extra hour of them "baking" after landing.

I'll add that I use Marvels Mystery Oil too so I may not know what I'm talking about!

Rick524 wrote:I find the theories of removing heat from the regulator interesting. Some say they mount them on spacers
so they don't touch the firewall. I made sure I mounted mine on a thick piece of aluminum that is flush
on the firewall. I used transistor heat sink compound between the regulator and alum, and alum to firewall.
Wont the heat be conducted away from the regulator?.....guess I'll find out, lol.


Rick

Nick has said that the alternator is likely shot because of the tach failure at the same time.

He was a little surprised that the old Kubota was still regulating after all these years.

New alternator stator is about $240.00.

Stay tuned for install notes...