SonexBuilders.net

Hello All, From the builder, I purchased his Sonex with the AeroVee 2.0 engine. I started the condition inspection last month. (June 2024) I have been addressing several issues. Installed bigger 500-5 main and 6 inch tailwheel tires.
Turning my attention to the engine, I learned a very important lesson. Remove intake manifold before screwing around with the upper spark plugs.
So, here is the thing. I am going to repair my stripped out threads with a Time-Sert. In the mean time I have ordered two new heads and I plan to install those and save my old ones as spares.
Have you ever heard the saying "Don't fix it if it isn't broke"? I am tempted to "fix" all 8 spark plug holes, even if 7 are still good. What do you guys think. It will be a winter project as I tend to procrastinate some.
Thanks

Yes, and the exhaust manifold holes also (at least on the turbo).

Hi Art! when I built my engine, s/n 870, I did indeed timesert all plugs, and have had no problems or concerns since. the stripped hole should clean up and be ready for the timesert tap and installation tool. Of course follow the directions. you should have a good set of heads afterwards!

After hearing the horror stories, I had planned to timesert all 8 holes at rebuild (or sooner if needed). But here I am, 270 hours, and all the plug holes are fine. The #3 and #1 valves & seats, not so much. So I don't think it is a have-to item, but if it makes you feel better then go for it.

I am horrified that I got my nomenclature mixed up. In my original post to this thread I said, "Remove intake manifold before screwing around with the upper spark plugs". What I meant to say was, "Remove Intake Elbows before screwing around with the upper spark plugs". I apologize to anyone that thought I was referring to the actual "Y" shaped intake manifold tubing that runs from the AeroCarb to each of the two intake elbows.

I was studying up on the cylinder head installation when I realized my mistake. Next time I will use a much more technical description like "little red thingy that sits on top of the cylinder head". :)

Please be careful removing and reinstalling the intake elbows. I don’t recommend you remove them while removing the top spark plugs. Each time you remove and reinstall the intake elbows you create the risk of an induction air leak that will lead to a cylinder running lean and therefore hotter than it should. Just be careful with the spark plug installation. Make sure you properly seat them, screw them in initially with your fingers, make sure they are not cross threaded before you apply torque with a socket. If you have to put a time sert in later it is easy to do. I would not do all of the spark plug holes as time serts because there is not much distance from the bottom and top plugs to the valve ports. If you end up taking too much material out when prepping the time sert hole, you may end up too close to the valve ports and then you will likely get a crack.

Jake

On my airplane I either have to remove the elbows or the baffles to get the top plugs. My elbows have been off a zillion times. I have not found it to be a big deal.