Verifying the AeroVee Secondary Ignition Timing

[Spaceman]

Actually now that you mention it, the pitot cover was on! Weird. I'll add that to the list of things to scratch my head about.

[Spaceman]

I bet there's condensation or something in my static lines. I had the ports taped over for like half a year while I was gone so I wouldn't be surprised if moisture appeared and never made it back out. I'll check that next time. But anyway this is an ignition timing thread!

[Spaceman]

OK I am dumb. When I did the timing light test the other day and took that video, the light was attached to the primary ignition plug wire! So I wasn't really actually checking anything. I went back today and checked it again, and also did my run-up with the mixture much leaner. I don't remember where it was last time but I have a feeling it was pretty rich. This time I pulled the mixture out until the RPMs started to drop, then pushed it back in just a bit. Now my RPM drops are more like 100 RPM on primary only, but still about 200 on secondary only. I checked the correct plug this time with the timing light, and it looked right to me but I think I will try adjusting it a little bit more.

[pfhoeycfi]

Any guides on how to setup and use a timing light on the Aerovee?

I bought this timing light from Harbor Freight:
https://www.harborfreight.com/timing-li ... 40963.html

It has a stupid feature that lets you adjust when the light fires. I recommend duct taping it to zero, else you will bump it and wonder what in the heck is going on.

Did you have good results with this light or would you, or anybody else, recommend something different?

peter

[Bryan Cotton]

I'm happy with the light. Just duct tape the adjustment feature.

[XenosN42]

Any guides on how to setup and use a timing light on the Aerovee?

I bought this timing light from Harbor Freight:
https://www.harborfreight.com/timing-li ... 40963.html

It has a stupid feature that lets you adjust when the light fires. I recommend duct taping it to zero, else you will bump it and wonder what in the heck is going on.

Did you have good results with this light or would you, or anybody else, recommend something different?

peter

I've been able to successfully setup 3 AeroVee engines without using timing lights. I did the initial secondary timing as per the manual. Then I verified it in flight using the procedure shown here. https://www.youtube.com/watch?v=bMWfEA8s8so

Whichever method you choose will probably provide good results. But, in my opinion using a timing light is just more work to get to the same place.

[flyingbear]

Ihave tried, unsuccessfully, to get me secondary timing to stay where I put it.
I can get it set so there is virually no RPM drop on elec ig only but then when I put the cowl on the go to fly it , it runs TERRIBLY. What could be causing erratic timing changes??????
GlenB

[XenosN42]

I have tried, unsuccessfully, to get me secondary timing to stay where I put it.
I can get it set so there is virtually no RPM drop on elec ig only but then when I put the cowl on the go to fly it , it runs TERRIBLY. What could be causing erratic timing changes??????
GlenB

IMO the only way to really check the secondary ignition timing is in the air running at or near cruise RPM. If you have an MGL, Garmin, Dynon, GRT, Advanced Flight Systems, or Electronics International EFIS the 'Flight Data Viewer' tool can help. https://jasflyer.com/ Even if you don't the techniques described in this video may be of help https://youtu.be/bMWfEA8s8so

[GraemeSmith]

Based on a recent Mike Busch Webinar

I just tried the Equal EGT Rise method. With a thoroughly warmed engine - at 1,800rpm - you don't worry about the actual drop value (within reason), as long as the mags drop equally with virtually no difference between them when dropped. The EGT's should rise approx 100F per mag - the important part being virtually no difference between the rises. Once dialed in I was getting 75rpm drops per mag. And 80F rise per mag.

Seemed to get me an extra 100rpm static once I had it dialed in. Finding ideal mixture (lean for best power) at takeoff is a bit more precise to find.

Fuel consumption - 4 US gph leaned at 2,950-3,000rpm

[pfhoeycfi]

I'm getting my first feel for verifying the secondary ignition on the aerovee turbo. Perhaps someone can make sense of what I'm looking at. The turbo manual says the primary fires at 28 BTDC and the secondary at 18. It also says that when the primary is shutoff there will be a small drop in rpm, when the secondary is shut off there should be no drop in rpm. At about 1800 rpm when I shut off the primary I get the slight drop in rpm. However, when I shut off the secondary I get on average a 50 + rpm drop. The engine seems smooth with both on or just the secondary on but markedly rougher with just the primary on. I didn't get temps...next time.

I should mention...I verified the aeroinjector slider travel from closed to full open and I get the full 90 deg on the mixture arm. I get almost no change in rpm while pulling the mixture out and the engine quits just before the stop. I've leaned 3/4 of a turn on the needle from the prescribed initial start point.

Any thoughts would be appreciated...

Got the AWC btw, slowly and carefully getting ready to fly.
Thank you

peter