I got a square bore Enya 5224 engine in a box o’ stuff from the hobby shop earlier this year.  The engine was not what I was after, and I didn’t really look at it when I bought the box that came with a great deal on a Champion tether car.  The Enya was in pretty sad shape, covered in dust and looking pathetic, but I decided to spruce it up yesterday.  I took it apart and it was very clean inside, with no evidence of abuse with a little carbon on the piston head.  So I oiled it up and put it back together.  Compression is pretty good.  It was missing the venturi and prop washer and nut.  I ordered the new aluminum venturi and the washer/nut from shtterman on eBay to finish her up.  But I have questions:

1)   I’d like to replace the phillips head screws with socket head cap screws, but I don’t have anything on hand.  My caliper says the screws are 3.5mm, so I don’t know if I can source them locally.  Does anyone know a good source of socket head screws for this engine?
2)   It came with two glow plugs loose in the box, so I don’t know if they were being used with the engine.  I know it’s almost impossible to tell from the picture, but below is a pic of the two plugs.   One is an idlebar plug.  Neither has any marking on it I can work from.  Any ideas?
3)   I have O.S #8 plugs and a Fox Long R/C idlebar plug in my spares box.  Would one of these be good to try on the Enya?  If not, what would be the recommended plug?  I’d guess a good choice would be an Enya #3, but I don’t know a source for these.
4)   I was going to try an APC 9x6 or 9x5 prop on the engine.  What would Y’all recommend for props?
5)   Any other quick tips for this engine?




Thanks for your attention,
Mark

Just as an FYI on early Enya screws, I've got a list with some extra info at http://sceptreflight.com/Model%20Engine%20Tests/Enya%20Screws.html

           Mark, the Fox plug could also be the Super Stunt plug. These were somewhat short lived. They actually worked pretty good. I dislike Fox plugs due to various reasons but they were marketed as Super Hot or Super Stunt I can't quite remember. I owned 3 of them and I do recall they were black. One thing about Enya's, they have a strong dislike for too much oil. It will run, it might be a bit ragged or it will just shut off like someone threw a switch.  The instruction sheet calls for 20% oil. Determining if it's broken in is also important.  I have seen many of these while they looked used, they were essentially new inside. Make certain the front of the case doesn't come loose or the engine will instantly shut off.

1)   I’d like to replace the phillips head screws with socket head cap screws, but I don’t have anything on hand.  My caliper says the screws are 3.5mm, so I don’t know if I can source them locally.  Does anyone know a good source of socket head screws for this engine?
2)   It came with two glow plugs loose in the box, so I don’t know if they were being used with the engine.  I know it’s almost impossible to tell from the picture, but below is a pic of the two plugs.   One is an idlebar plug.  Neither has any marking on it I can work from.  Any ideas?
3)   I have O.S #8 plugs and a Fox Long R/C idlebar plug in my spares box.  Would one of these be good to try on the Enya?  If not, what would be the recommended plug?  I’d guess a good choice would be an Enya #3, but I don’t know a source for these.
4)   I was going to try an APC 9x6 or 9x5 prop on the engine.  What would Y’all recommend for props?
5)   Any other quick tips for this engine?




Thanks for your attention,
Mark

Mark
You can get the  3 x 06 pitch screws  from  Micro Fastners , and  the  Merlin  2004  plugs will work well in that engine  also the  Glo Devil  #300

Randy

Are the phillips screws in good shape? If so, they really don't need replacing. They are probably JIS (Japanese Industrial Standard) screws. With a JIS screwdriver they can be tightened easily but with a standard phillips screwdriver they can be difficult to remove or tighten. Another possible issue is the head. 5224 engines typically came with a low and high compression head and no head gasket.  Check to see which one you have, for stunt you want the low compression version. Shtterman may be able to help you with identifying which one you have... and sell you a low compression one if your's is the high compression version.