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Barry

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Posts posted by Barry

  1. 1 hour ago, Kent Ashton said:

    Been for sale for a couple years and posted May 6 at $40K.   No pics in the ad.  Seller only wants to speak to "serious buyers".  Maybe that's why he isn't selling.  Can you imagine a used car lot with a sign "serious buyers only"?   Jeesh.

     

    It's not just aircraft sellers. A lot of ignorant people trying to sell something with little description and no pictures. It always amazes me.

  2. On 8/23/2022 at 12:05 PM, Kent Ashton said:

    SPARKPLUGS - I have not had a spark plug blow out but others have.  A recent post on the Cozy list described an 18 mm adapter + 14 mm auto plug blew out of an IO-360--top one in pic1.  His other adapter had cracked threads.  I have used adapters with 14mm plugs as well as 18mm Autolite 386 plugs and 18mm Bosch M8ACO.  Never had any problem with any of them but the adapters are a bit fiddly and I can't tell any performance difference between the 14mm and the 18mm.  Using 386s at the moment.  It seems that the 18mm was mostly developed for tractors.  They are cheap enough that you can toss them every year or so.

    I looked at some scrap cylinders I have as well as a new Superior Millenium and they all have very few threads in the sparkplug holes--about 5 threads (pic 2).  An 18mm Autolite 386 has a 1/2" reach and it only has about 5 threads too so I suppose it is a good match (pic 3).   An aircraft plug has about 6 threads with the copper washer used (pic 4, an REM38, electrode removed). 

    None of them stick very far into the cylinder (pic 5).  You can buy Autolite 388s with a 9/16" reach but they do not seem necessary.

    Lightspeed says torque the insert to 25 ft-lbs and the 14mm plugs to 15 ftl-bs,  Lycoming torques 18mm aircraft plugs to 35 ft-lbs.  I gather some brass inserts are of higher quality than others.  Don't know which, though.

    With inserts or 18mm A/C plugs I keep a string of copper washers handy and anneal them after a couple uses.  Get them cherry-red and allow them to air cool which softens them.  Somewhere I read to use copper anti-seize on sparkplugs and don't get the anti-seize on the business-end of the plug.

    I do not know if heat-range is very critical in these old low RPM, low compression engines.  If your plugs are fouling it can be lead, oil, or carbon.  Lead must be blasted off with a machine, carbon can be removed by a lean runup and running lean when able.  Oil, you can't do much about except refresh your cylinders.

    Reasons why a plug might blow out?  I'm guessing old, beat-up inserts, improper torque or maybe an old copper washer which does not seal as well

    IMG_0726 2.jpg

    Hole.jpg

    Screen Shot 2022-08-22 at 5.53.39 PM.png

    A:Cplug.png

    Hole2.png

    I have always used Champion spark plug anti seize for aircraft on my race car spark plugs with aluminum heads, and also on my street cars. I've never had a problem. My bottle of anti seize must be 25 years old now...

  3. Gotcha. I always assume that vacuum lines will get gasoline vapor at some point, which will eventually return to a liquid state IMO. On cars anyway. Same thing should be true of aviation engines I *think*. 

    That is pretty small at 0.079 ID. The 3/16 is 0.111 and the 1/4 is 0.15, which I'm sure you already know. I like the nylaflow hose for many things. Tough and durable, and holds its shape very well. I use a lot of the 3/8's in industrial applications.

  4. The rule of thumb we have used in industrial electronics, ground the shield on the source end for DC signals, and both ends for AC. When you have DC that is pulsed at higher frequency (encoders for example) the "guidelines" get murky. For high frequency encoders we have done it both ways, with good results either way.

    The why is complex...

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