I picked up a NIB AME 0.49 (C/L version) and a NIB Big Mig 0.61 R/C engine. I assume that the Jan venturi will be a bolt on conversion for the Big Mig and that should be a good stunt engine. How does one tame down the AME 0.49. I understand that they are screamers and need lots of skill plus pressure feed to work as they should in normal guise? Can one just reduce compression and maybe sleeve down the venturi to get them to handle in a more civilised way?
  I have not checked yet, but I understand that the early ones used the Freedom head, which is not compatible with the Merlin / Cox / Galbreath heads. Just hope I don't have these, otherwise a bargain suddenly becomes an expensive paperweight!

Regards,

Andrew.

Hello Bill,
Thanks for the information on heads. The 0.49 has what would appear to be standard size fins, the 0.61 has much larger fins so I presume this is the Revlite cylinder with the hard anodised aluminium cylinder. The 0.49 would be the earlier ABC setup or have I got that one wrong? Looks like a close examination is called for!

Thanks for your help,

Andrew.

Thank you Kenneth,
That has saved me from a heart attack! I will try the link to Norvel and see if I can get an NVA. I seem to remember that you had a go at taming an AME 0.49. I may be wrong , I usually am, but if so, did you ever figure out how to tame the little critter down?
  I have also just taken the head off the AME 0.49, it looks like a cox head. However when I tried to screw down an AP Wasp glow button retainer onto the AME, the threads bound up after a couple of turns....... The AP thread is the same as the Cox as far as I am aware. So why am I having this binding problem? I don't want to force anything.

Regards,

Andrew.

          Andrew, there are a few things you may need to do to run that AME. For starters, I don't know which version you have. If it has the aluminum venturi assembly, the top screen and cover can be removed. The intake is quite large for running that engine using suction ( tank setup). You just may be able to choke the venturi down using fuel tubing. Place the tubing into the venturi and let friction hold it in place and put the cover/screen back on. Make sure the tubing isn't going to get caught in the crank cut out. The spraybar is on the backside of the venturi therefore requiring a notch into the fuel tubing allowing fuel to get into the center of the tubing. You could also add more head shims as needed. You may be able to just prop with a 2 pitch or 2.5. I have some Big Mig's that actually run like some of my AME's. You could use Cox glow plugs such as the standard  the 1702 high comp is going to make it run on the same level as the stock Norvel. Keep the nitro in the 10% range using the Cox standard. Merlin plugs are going to raise your compression considerably. I find it very normal to use up to 6 shims while using the Merlin plugs. Does the engine have a muffler? If so I recommend it due to the fact the muffler pressure will assure your run is consistent while the added heat and exhaust restriction will keep the performance down a touch. I would certainly experiment with props. You may find a wide range of engine runs using different props. A Cox 5x3 black has a extreme difference than a APC 5x3. When I do certain things to engines, I try not to modify them in a way that isn't non-revervisble. This is why I suggested fuel tubing, brass tubing can be inserted as well but may need to be epoxied into place. Ken

        Andrew, I would still try the Nelson Galbreath head. It just may take several shims to get the engine to run to your liking. I've had a few problems using the Merlin plugs. I do like the plugs, but I find them to really overcompress the engine. This may be just the head shape of the plug. My plugs have a red insulator. Xenalook sells a blue plug as well. I would have to say the different colors indicate different heat ranges. No one has been able to confirm which is which and Merlin hasn't responded to any of my e-mails. I suggested the Cox standard, I believe it may be the 305 plug due to it being ready to go. It wouldn't take but 1-2 shims to try this plug. Another alternative may be to try a glow plug adapter such as the one Norvel makes or Mecoa. A few other make this conversion as well so that you can run standard glow plugs. I've found these adapters to work, its just the performance falls off a bit. It may be worth just trying as is. The bigger problem with the AME is that it was designed around either using backplate pressure or a bladder. Ken

        Andrew , using a bladder is very simple once you have some of the basic understandings. For 1/2A engines I use low pressure surgical tubing. A very fine needle valve is a must. The stock needle assemblies generally don't work using bladders. A smaller syringe works better due to the piston being smaller. You just don't have to push as hard to fill. Using 1/2A this typically isn't a big deal, but when you get into larger engines requiring 3oz's or more it can be hard to fill. I personally use a line clip for a pinch off device. This probably answers your question on what happens when you open the needle. Once the bladder is filled I hold the inboard tip high and purge out any air that is left inside from filling. You simply do this by undoing the line clip on the tubing and the air/fuel spits out. Initially, I point the venturi to the ground and open the line clip once again and allow the fuel to start flowing. I generally watch the fuel and adjust the needle until the drips or droplets are about 1" apart. I know now the engine is ready for starting. A few drops on the piston and battery hooked up its time to give her a flip. Once the engine revs up a bit undo the line clip and let the fuel in and its off to the races. Now if the engine doesn't initially start and you left the fuel line open well you just flooded the case. This is where it can be a pain. At this point position the cylinder to the sky and try and flip and burn out the flood. Once the flood is cleared it involves the procedures like I explained . Very simple though and nothing difficult about it. It just involves practice and knowing your equipment. Ken

Andrew, not to worry! The AME will run on muffler pressure just fine.
 If you want to try different things go in this order:
1.  Muffler pressure
2. Bladder pressure  use soft bladder material and the norvel needle will work just fine, keep the spray bar hole clean! By this i mean if it sets for a couple of weeks just blow it out with an air hose to clear out any gunk.
3. Backplate pressure   What a pain, good luck if you decide to try this! Do not, Do not, Do not open up the size of the hole in a pressure backplate.
You may have an early version with the smaller head and glow plug, if you do , my experience is that they are a cooler plug and prone to flooding.
The merlin head and plug should do just fine on your .049, i would start out with a good break in by hand with the head removed using light oil and then run a few ounces on the bench with no head shims, add them if necessary but i don't think you will need any. My preference is omega 25% fuel, it is a synthetic and castor blend. My choice of props is the good ol cox 5x3 and the apc 6x2 or 5.5x2.  Good luck, i think you will be fine.  Ray