I've recently seen the Merlin plug clamp and the available head buttons on Ebay. While curious, I wasn't in a rush to try these. Lately, larger models and a few contests have been the top priority. I set out today with a few 1/2a's. Its been quite a while since I flew some of them and thats what I really enjoy about this hobby. Each model has its own different engine with different characteristics. One in particular has a modified sure start on it. I had a bronze bushing installed in the crankcase. The downside to this engine is that it never really came alive like some of my others. I figured I could add a high compression head for more power but the price of them makes them more valuable to my tee dee's. While at Brodak's I picked up a 3 pk of head buttons and the clamp for about $15.00. I tried it on the sure start and discovered it was overcompressed while trying to start it. I added 1 gasket, still no success. I then added one more and the engine ran but seemed to start sagging a bit. I then added an additional one and it settled in quite nicely. I finally settled on 4 total. I'm glad to see that I'm getting more rather than less compression. This combined with a 5x3 APC and 35% made for a terrific 1/2 a day. The engine didn't skip a beat. Typically 35% hammers the plug to death in a limited amount of flights. I was quite shocked at the durability of the plug. For those looking for an inexpensive hop up this plug just may be for you. Ken

          I went to the field once again this weekend to blow the cobwebs off of the 1/2 a's. This weekend didn't go as well as last weekend. I did discover something that raised some concern. In my last post regarding the Merlin plug, I thought the plug would interchange with the Norvel, Ap head retainer. This in fact is not the case. Although, I did have a Glo Bee clamp and now I'm not sure which one is in hand. For certain, I did have the Norvel button in my hand which I waffled trying to run it in a Tee Dee which was overcompressed. I tried to switch to the newer Merlin plug when I noticed its diameter was slightly larger. I figured no big deal I'll just use the clamp which was supplied with the Melin plug. Thats when I realized I left it at home. Either way,  for the small dollar amount Merlin does provide their head clamp. Ken

As a comment, I always ran a bunch of copper gaskets on my Norvel 1/2 A engines with the Norvel plugs. Since the Merlin is a copy of the Norvel plug (giving a similar combustion chamber), I guess I am not surprised that engines like more gaskets, especially if you are running the high nitro.