SonexBuilders.net

I started my AeroVee yesterday. Its on a Onex that can be seen in that forum. We had spent the last few days changing the cylinders from Nikasil to Steel. Before the start I did the heat gun test on the EGTs and CHTs to make sure they were going to the right place. They read colder as I heated them up. This could be a good solution to Lou's heating issues ;) After reversing the leads (red really is negative) all was ready.

It started right up. The tach was reading about 1000 rpm high and the Oil Pressure was 100. It was smooth and responded well to throttle. I only ran it to about half. It responded to the mixture well at idle and mid throttle. I shut it down after about a minute or so.

After a thorough inspection, the second started was about 15 minutes later. It was nearly the same results. I checked the ignitions and found the secondary (electronic) one wasn't working. The Mag P (grounding) leads were obviously working. I ran it up a little higher and saw 4100 rpm briefly. Oops...This run was probably 1-2 minutes also.

I put it away and went to breakfast. Yeah!! After eating, I got a second wind and decided to do some troubleshooting. I quickly determined the coil leads were going to the wrong plugs. Doah! My hangar neighbor Googled the tach pulse for AeroVee and dove into the MGL Xtreme while I was monkeying with the schematic. He changed that and did something to the Oil Pressure sending unit setup. Friend said he didn't see 0.5 bar on the menu but I was busy and didn't follow up. It was getting hot outside and we decided to run it one more time.

Third start was smooth. Oil Pressure was now 25. I think the setting is still wrong. The tach seemed correct. Full throttle showed 3000. Idle was a bit high around 1300. Everything was smooth. Second ignition worked perfectly. I couldn't notice a change when switching between them at the high idle.

I was super happy. Just enough minor quirks to make it interesting but no show stoppers. Next time out I'll work on Oil Pressure Sending unit to make sure its correct. Turn the idle down. Check timing at higher RPM. Check mixture. I suspect it needs leaned just a bit.

And lastly we somehow missed a MAJOR mistake. There wasn't any oil leaking, anywhere! We pulled the dipstick to confirm there really was oil in it :) We looked everywhere and couldn't find a drop. The hydraulic brakes, which were filled for the first time the day before, were also dry and held the full power run up. The tie strap never became taught. Getting closer....

Congratulations! If you need some oil leaks I have spares I can send you.

Yeah, you can have mine too! Waiting for new heads from Sonex. Found a burnt valve in #3. Hoping that will fix my hot #3 cylinder. Since I pulled the heads, I figured why not pull the engine too. So I did, verified the main seal was dry, (yay), and I believe that I finally found my last 2 oil leaks. Either the lower cylinder bolts on cylinders 1 and 3 or the cylinder bases, I will re-seal all of that before I install the heads. Fingers crossed.

If my problem doesn't resolve itself, I may take you guys up on that :)

Scott,
What did you use to seal the cylinder bases to the case? I tried the recommended Permatex 3H sealer and hated it. Drippy, smelly, hard to clean up, and I did not get a good seal with that stuff.

Lou, It was some red stuff like RTV but I think it was Permatex brand. I keep meaning to take a photo of the tube for you and forget. I'll swing by and get one for you.

I need other help. I'm using a #2 needle. It responds well to mixture at low to mid throttle but not full throttle. I've got it a full turn out from the baseline 1/8 at a time with same results. I can tell the low and middle are getting richer with each adjustment but the top end quits almost immediately as I lean. Jeff used a 2.5 needle. I found one and thought I would try it next. Latest manual indicates they don't use halves anymore. Thoughts?

MGL Xtreme issues. The EGT is SLOW to respond. It takes probably 10 seconds to see any change. Its hard to lean and adjust mixture like this. Any thoughts?

My CHT's were working fine for the first 5 or 6 stars and about 10 minutes of running time. This morning, all of a sudden 1-3 are reading 600-800 while #4 looks normal around 280-300 for the short runs. A temp gun confirms all of them are running about the same. Any MGL users with ideas? RDAC issues are all I can think of.

I am also using a 2 1/2 needle. #2 required too much fiddling for me. I had a #3 in for a while, but went back to 2 1/2 cuz 3 seemed too rich.

I don't know anything about the MGL hardware, sorry.

I borrowed an old school Oil Pressure gage to check my VDO sender. I changed the setting on the MGL and got them to within a few psi of each other. It works out to about 45-50 psi which I'll verify when it runs again.

I put the 2.5 needle in and will report back on those runs.

I was told by a local I should run the RDAC DB9 ground wire to the engine block as it can otherwise give wonky readings. I thought it was grounded well but I may add another one on the next run to see. I also found the main engine ground was loose so maybe that was causing issues.

There is a little bit of oil spray visible on the firewall and an occasional drip from the oil screen cover on the bottom and the valve covers. I snugged them up a bit. I feel much better now that's its leaking somewhere ;) Lou, here is what I put on the base of the cylinders.

Thanks, Scott.