Continental A-65 Spark Plug Insert

[SteveR]

I have a spark plug that is siezed to its insert (the insert spins when I try to remove the spark plug). I've been told there is supposed to be a pin in the insert that keeps it from rotating in the cylinder head. What I'm wondering is what will likely be required to properly fix it? I've asked a couple of A&Ps about it and they didn't even know these engines had inserts. What is the typical R&R for this? Remove the insert, check & clean the threads, install a new one & insert the pin? Or could it require cylinder removal? I'm just trying to figure out what to expect.

This is actually an A-75, but I believe this will be identical to the A-65.

[NY86]

Re: Continental A-65 Spark Plug Insert

The inserts are (were?) available in oversizes. It's an interference fit, not threaded. You have to heat the cylinder and drive it in, much like a valve guide.

[GLB]

Re: Continental A-65 Spark Plug Insert

AS an Od A&P I have seen this a few times, the insert / bushing is threaded in, it is what is called an interference fit (another words is a tight fit) over sized inserts are available from Preffered Airparts or Fresno Airparts ,I believe. Screw out the old one clean the threads install the new you may need to heat the head to screw in the new bushing use locktite 680 and repin the bushing with a brass pin made from brazing rod.
GB

[high time cub]

Re: Continental A-65 Spark Plug Insert

http://www.joea.com/phpBB2/viewtopic.php?t=1389&highlight=spark+plug+bushing

[M Towsley]

Re: Continental A-65 Spark Plug Insert

Steve,

This happened during the prebuy inspection on my L-2 and the owner had to remove the cylinder to have the insert repinned. At least that was what I was told, and I have a copy of the receipt around here somewhere for the work.

[Ragwing nut]

Re: Continental A-65 Spark Plug Insert

You will have to remove the cylinder to do the job. I would suggest sending to a shop that can properly heat the cylinder to reinstall the bushing correctly. Oh, and make sure you don't let the A&P who didn't know the engine has inserts work on your engine if you can help it.

Mike

[GLB]

Re: Continental A-65 Spark Plug Insert

The cylinder does not have to be removed to replace the bushing, this is not rocket science to do this repair, maybe to the most fun job but simple. The old bushing is screwed out the threads are cleaned up the spark plug bos area can be heated with a hand help propane torch and the new bushing screwed in place with Locktite 680 torqued to 30 ft lbs and let the locktite set up before removing the old plug used to torque the bushing, be sure to have the piston at TDC. If you remove the cylinder and send it to a cylinder shop you may as well buy another cylinder as it will probably cost the same or less. I know from experience that the cylinder doesn't have to be removed.
The fact that the A&P didn't know about the bushing is not surprising, lets face it these engines are 60 years old and have not been in front line operation for 30+ years, A&P's that have 20 years experience may only see a couple of these engines a year, thus if he is willing to work on the problem why not then the will be another A&P the has experience with this problem, which is not a big problem cause in also 40 years I have only came across it about 3 or 4 times. For the most part these bushing were only used on the Cont. 65-75-85 & 90's after that SS Helicoils were used.
This is why spark plugs always need antiseize and a torque wrench when being install.
GB

[SteveR]

Re: Continental A-65 Spark Plug Insert

Thanks guys, that is some really good information, I appreciate it.