An easy way to time the electronic ignition?
Posted: Mon May 04, 2015 11:32 pm
by kevinh
Hi ya’ll,
So I’m thinking ahead a bit to setting the timing on the secondary ignition. I’m still a long way from that on my plane, but I’ve read the aerovee assembly manual and many build logs. It seems that a fair number of folks fought high CHT problems while they iteratively made small adjustments on the secondary timing.
Has anyone ever tried just using an oscilloscope to measure the spark timing directly? It seems like doing this on the ground would be easy-cheesy if you have access to a modern digital scope. Just a loop of wire around the top and bottom plug wires of one cylinder + a capacitor and a resistor to protect the scope. Then you can see the two sparks in time and adjust (on the ground without needing long engine runs or flight) until the sparks line up. It sounds like a <15 min operation with the right setup.
Am I making some mistake here? If not, this is probably what I’ll end up doing when I reach that point.
There are some good enough scopes in the $200 range but I bet most EAA clubs have at least one member with access to one (and the knowledge on how to use it).
Re: An easy way to time the electronic ignition?
Posted: Tue May 05, 2015 12:44 am
by wlarson861
I used a timing light to set my ignition. Running at 1500 rpm it was dialed in perfectly. At altitude I did the ignition test and shut off the mag ignition and watched the temps climb. On landing I retarded the advance and after a few trys got the cht to come into line. The timing light just does not work at the low rpm but it gets you close. An oscilloscope would probably be the same. But what the hell give it a go and report back…anything that works is a step forward!!
Re: An easy way to time the electronic ignition?
Posted: Tue May 05, 2015 11:52 am
by nwyooper
I just timed mine as per the AeroVee manual and it worked and works fine-I have never changed it. I get no change in RPM’s on ignition check and no CHT problems. Runs great with either ignition and both.
Loren
Onex 33
Re: An easy way to time the electronic ignition?
Posted: Tue May 05, 2015 4:53 pm
by radfordc
Loren, just for fun try switching the electronic ignition off and run on just the mags for 20-30 min and see if you notice any CHT change. My engine would run about 10 degrees cooler on just the mags.
Re: An easy way to time the electronic ignition?
Posted: Wed May 06, 2015 2:45 am
by kevinh
Thanks for the good advice. I’ll report back when I try it (in twoish years ;-))
Re: An easy way to time the electronic ignition?
Posted: Wed May 06, 2015 8:30 am
by Gripdana
I’m a little late on this. I agree with Loren. I followed the Aerovee and Aeroinjector manual and found the entire process to be very easy to do. I have the same results.
Re: An easy way to time the electronic ignition?
Posted: Thu May 07, 2015 12:14 am
by nwyooper
Will try that radfordc and let you know. On another electronic issue, when I turn my prop by hand, I can hear a little click in 360 rotation. The number of clicks equals the number of magnets in the alternator stator. I also get a little electric hum at idle that goes away as soon as rpms are increased. Alternator works fine and I have a pretty good size electric load. My friend Mark (Onex 35) has the older stator that was supplied by Jabiru via Sonex (open windings) and I eneded up with a stator(encased windings) from Sonex’s new supplier. Just wondering if anyone else has noticed that and what kind of windings in your stator.
Re: An easy way to time the electronic ignition?
Posted: Thu May 07, 2015 8:38 am
by radfordc
Seems a while back someone else talked about hearing a “click” like that. Turned out to be loose screws allowing the stator assembly to move.
Re: An easy way to time the electronic ignition?
Posted: Thu May 07, 2015 9:43 am
by nwyooper
4 screws in mine and they are tight-thanks radfordc
Re: An easy way to time the electronic ignition?
Posted: Thu May 07, 2015 4:29 pm
by RodgerC
They may well be tight because they have bottomed out in their tapped blind holes…That was the case for me
When I experienced exactly the same symptoms you have described…I had to through drill and retap the threads…Might be worth a close inspection.
Re: An easy way to time the electronic ignition?
Posted: Thu May 07, 2015 10:11 pm
by nwyooper
What kind of stator do you have Rodger?? Do you have open windings or are they covered? Sonex Tech said they have 2 different types. I tried moving the stator last time I had it apart and it did not seem loose. I will check closer to see if they are bottomed out. Thanks for the tip.
Loren
Re: An easy way to time the electronic ignition?
Posted: Fri May 08, 2015 3:26 am
by RodgerC
I have the 20 AMP stator that is “cast” in either epoxy or phenolic. There is an Aeroconversions service bulletin that deals with with topic. I.e. Through drilling the blind holes. It was issued a day or two after I discussed my issue with tech support. The stator may appear tight, but those magnets are very strong.
Re: An easy way to time the electronic ignition?
Posted: Fri May 08, 2015 11:10 pm
by nwyooper
I Believe they are phenolic. I have the same thing so I suspect that maybe my holes do need to be drilled through. Missed that bulletin. Thanks Rodger.
Re: An easy way to time the electronic ignition?
Posted: Sat May 09, 2015 12:11 am
by nwyooper
Just read the service bulletin. I received my engine after 1/1/12 so that bulletin should not apply. That is why I didn’t look at it. Would not be surprised to find same problem you had anyway Rodger.
Re: An easy way to time the electronic ignition?
Posted: Sat May 09, 2015 6:30 am
by RodgerC
I won’t be surprised if you find that is your problem…In any case, checking it out will be a worthwhile investment of 2 hours
Re: An easy way to time the electronic ignition?
Posted: Mon May 25, 2015 1:39 am
by nwyooper
All 4 holes were drilled and tapped all the way through but two holes were full of the white sealant that is on the ignition trigger modules so it had the same effect as not being drilled. Initially I thought the allen head cap screws were too long because when I removed the ignition modules and tightened the cap screws, I saw a protrusion from the hole. That sealant was very hard to get out of those threads. Additionally some phenolic material was removed from the back side of the stator to provide clearance by whoever does that for Sonex. The problem there was that the phenolic wasn’t removed close enough to where the leads come out of the windings. That excess material prevented metal to metal contact between the plate and stator in one spot resulting in part of the looseness. Along with the cap screws bottoming out, it wa
qs a double whammy. Got that all fixed-no more clicking or electronic hum-then I found a defective spark plug. It is always something!
Re: An easy way to time the electronic ignition?
Posted: Mon May 25, 2015 2:55 am
by RodgerC
I feel your pain…But good to get them tightened down before some real damage occurs.