SonexBuilders.net

Looks really nice!

For those using AN 1/4 NPT fittings (nipples, elbows) for the fuel line are you using a 4 or 6 tube size.

Thanks in advance for your answers.

David

I used AN6 lines from Jegs. I believe the Sonex instructions call for the -6 size.

Just my own experience...

Thanks Michael.

Hello All,

Over the past few weeks, I've been overhauling AeroVee #0631 to fix a low oil pressure issue. This involved completly disassembling the engine and replacing the crank, all bearings, and replacing the oil pump. I'm also using this opportunity to change the compression up to 8 to 1 (it was 7 to 1), making all new pushrods, and swapping the bottom mounted oil cooler with the new Onex style top mounted cooler. At this point I'm around 80% done and only need to work on some baffling upgrades and final assembly before it's ready to go.



As I was working on the engine today, a special visitor stopped by.



Mark Waldron flew his Sonex over for a visit and to inspect the progress on my engine. This was the first time I've had the chance to see Mark's airplane, and it looks like he has a great looking Sonex! Mark was the celebrity of the day at my airport, with lots of people asking questions about his airplane as well as the differences between Mark's Sonex and my Waiex. Both are polished and attract lots of attention!

Unfortunately I couldn't stay long so after watching Mark depart, I had to call it quits before finishing my engine. Hopefully I can get it finished later this week.

One more shot of Mark's great looking Sonex:

Mike,
I had a good time looking over your shoulder as you worked on the Aerovee, thanks for your patience with my questions.
Folks from Texas may recognize that yellow-and-metal plane as Sonex 1230, built by Jay Gibbs. I'm enjoying the plane a lot and it flies great. I expect it may beg to go back to Dallas when the Ohio winter arrives.

Hi Mike,

When you get your top mounted oil cooler up and running, please let us know how it compares to the bottom mounter filter. I have all the parts for the top mounted one, but I'm still on the fence as to whether or not I'll use it.

Also, regarding your oil pressure issue, what symptoms did you have that lead to such a significant overhaul. My friend's AeroVee powered Sonex is having an oil pressure issue where the oil pressure is fine for about 10 minutes, but then drops off completely. My thought is that it may be the rear-relief valve sticking...but maybe its something more serious like the bearings and seals like you experienced.

I will do that Frank. Primarily I'm switching to the top mounted system for two reasons. First, it will make oil changes easier and perhaps a little quicker. I will also not need to worry about the flexible oil lines running to the cooler that, on my airplane, made some contact with my cowling. Second, the turbo AeroVee has the top mounted system and I'm hoping to add that once it's for sale.

As for my oil pressure issue...first, I take responsibility by running my oil at low pressures for the first few hours as a result of putting a gasket on the oil pump cover plate when I installed it. My fault but it took the 0.004" max clearance and made it much bigger. Combined with that was a crappy VDO electronic pressure sender unit that was never accurate, so I didn't have a good idea what my oil pressure was for the first several hours. Needless to say, it was way too low and now I paid for it. My fault...

The issue I have is similar to your friends. When the air temps in Ohio were cold and my oil only got up to around 120 degrees, my pressure was great (50-60 psi). Once summer hit and my oil temps got up in the 180-190 range, that pressure dropped to 30-35 psi. I installed a variable tension spring adjuster system on the rear oil pressure galley and that raised my initial startup pressure, but it was ineffective once the oil got warm. Regardless of how high it was at startup, it always fell to around 30-35 psi in cruise. My crank bearings weren't terrible but there was a lot of wear once I took the engine apart. I certainly learned my lesson and plan on being much more careful from here on out!

Thanks Mike,

I appreciate the insight into the oil pressure issue...it looks like the lesson is pretty clear here...once I get my AeroVee up and running in a few months, I'm going to be pretty diligent regarding my oil pressure.

Regarding the oil cooler, I'm also real interested in the Turbo...so, thanks for the heads up... I will likely move forward with my top mounted filter. What modifications (if any) are you going to do to your cowl air inlets? I'm assuming that you are going to close off the old lower oil filter cowl inlet.

Yeah Frank, your thoughts on really watching oil pressure is a good one. One of the tricks I learned was that, when you assemble the oil pump, make sure you fill the entire pump (after you install the pump gears) cavity with white lithium grease. The instructions say to coat the gears as you install them...do that and then fill the rest of the spaces inside the pump with more grease. This will help prime the pump so you will get pressure when you turn the engine over.

Otherwise, like you said, just keep a close eye on things as you start test running the engine and you'll be fine. Most of the oil pressure issues I've heard about seem to stem from pilot/builder errors.

As for the lower inlet, to be honest I'm not quite sure what to do. One the factory Waiex, they put the cooler on the top and simply closed up the lower inlet. Their claim is that there's plenty of airflow through the main cowling inlets. I think it looks nice that way, but I've read different people indicate that the VW case needs some kind of airflow across the bottom of the block so I'm tempted to leave the inlet there. Actually, my plan at this point is to leave the inlet there, and eventually add a small size LED landing light to shine through that space, but I'm still debating. I may send Kerry an email to make sure it's okay to fill in that space. We will see...