SonexBuilders.net

I know that the AeroVee is a tremendously powerful engine, but to blow out 2 plugs in less than 30 hours seems extreme. Attached should be a movie of my plug. You can see the marks from the exhaust gases blowing by the insulator. Also the insulator is loose. This came from my #4 plug on the bottom. The first one was my #3 on top. the plugs are torqued to 22 foot lbs. The plugs are the ones specked by Sonex. Is anyone else having this problem? Has anyone specked a different plug? What were the results?

Thanks
Tom

I can not attach the movie. It just show how far the insulator moves. It will move back and forth so the electrode with touch the ground and the insluator will spin completely around.

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What type of socket setup are you using to torque them? Is it possible that with a long extension you might be a little crooked and cracking the insulator? Also try to not use one of those spark plug sockets with the rubber in it. The rubber grabs the end of the insulator and if you tweak the socket a little off center you can crack it.

Keith

Thanks for the input. I use deep socket no extension. When were the specs changed to 12 foot lbs.??

Tom

Rev. P
02/28/12
Added top-mounted oil cooler installation details.
Revised Revision Log format.
Removed specific fuel system installation details and referenced the airframe
plans for this detail.
Removed fuel and oil system specific shopping lists.
Reduced Spark Plug torque value from 22 ft. lbs. to 12 ft. lbs.

What Bolts and or other hardware is needed for mounting top oil cooler??
Thanks

Two (2)AN4-27 and One (1) AN4-23 a couple -4 washers and a -4 nut. But, I believe this is supplied by Sonex when you buy the top oil cooler mount kit.

Geary is correct. Sonex also includes the instructions, but the builder needs to source and provide the top mount oil cooler (which is also called out in the instructions). Go to pages 53-54 of the AeroVee manual for reference.

http://www.aeroconversions.com/support/ ... Manual.pdf

Sonex1414 wrote:Thanks for the input. I use deep socket no extension. When were the specs changed to 12 foot lbs.??

Tom

I snapped a plug off in the head torquing to specs. I went online to all the VW web sites and everyone said not to torque that much. Just seat the plug and give it a little extra. Nothing scientific, just firm. It's worked really well for me and I don't get scared tightening the plugs.

mike.smith wrote:

Sonex1414 wrote:Thanks for the input. I use deep socket no extension. When were the specs changed to 12 foot lbs.??

Tom

I snapped a plug off in the head torquing to specs. I went online to all the VW web sites and everyone said not to torque that much. Just seat the plug and give it a little extra. Nothing scientific, just firm. It's worked really well for me and I don't get scared tightening the plugs.

I'm glad to see this come up. I have a GM Corvair manual and they give 15-20 foot lbs. Not to argue with the experts but that's just crazy. These are not lug nuts on a diesel truck. Best advice for us Corvair driver's was 7-10 foot pounds. I generally use 100 inch pounds which is a bit over 8 foot pounds (8.3). Run them a bit and recheck the torque. I have never had one come loose. I always use a trace of anti-seize and be sure not to get it on the end or the insulator.

I agree with you that firm is enough. When using a new sealing washer you can feel when it has finished setting and then a little snug and you're done. The Aerovee plug thread is longer than what I use so maybe 12 foot pounds is OK but that still seems like too much to me.

Just one old man's opinion ...

Dale
N319WF