RETROL 16cc Horizontaler 4-Takt Diesel Stationärmotor Modell Wassergekühlter Verbrennungsmotor D16

This is my first diesel engine and what a learning experience! Let me share some thoughts and offer a little advice. First, if you own the G2, I highly recommend purchasing the G3 upgrade. Well worth it as it eliminates a few complexities of the G2 injector. I installed it with no instructions as I could not find any. Look at all the parts included and you'll figure it out. You will need one more long bolt for the new cylinder head. The new fuel injector is awesome, simple and a marvel of micro engineering. You will need to learn what adjustments are changed and where those adjustments are located. Watch the videos on the user guide and follow the procedure on cam timing. This engine was quite a challenge. Including the three cams, exhaust, Intake and fuel pump, I counted an additional two more. The fuel pump mounting block height and most importantly, the fuel volume adjustment. That small nut on the top of the fuel pump height limiter. The advice on one of the videos was to set it so the fuel pump piston clears the suction orifice no more than .5 mm. At that starting point I noticed quite a bit of fuel dripping from the exhaust. I turned the nut clockwise almost a full turn in 1/4 turn increments to reduce the amount of fuel going to the injector. Be patient and it will make a significant difference in how well your diesel runs.

I received the engine in reasonable condition, but with a few problems:

The circlip on the governor arm shaft was missing and the pin on the governor arm that engaged with the governor was loose. I installed a spare circlip and fastened the pin with high strength thread locking compound. The pin on the starter drive fell out every time I used it so I also fastened this pin with high strength thread locking compound. I straightened up the external plumbing to get a neater appearance. Eventually I do plan to replace the (ugly) line from the pump to the injector for appearance reasons. This will be done with 4mm copper tubing and brass compression ferrules from Amazon. I obtained 4mm tubing with 1mm wall thickness and this also might seal better than thinner tubing.

After priming the injector line, I got the engine started using a heat gun and controlling the governor manually. Once running it became obvious that the injection cam was advanced too far since there was heavy knocking. I reset the cam by trial and error (approximately 7 degrees advanced with reference to the crank pin) and got the engine running quite well, but still with manual governor control. Note: small changes in injection advance from optimum can make a big difference so experimentation is in order. For example, there is more leakage than I would like from the injector line and this may require more ignition advance.

I shortened the governor spring by about 70% and it was still too weak. I installed a stiffer spring I had lying around was finally able to obtain automatic governor control (see video). I am still looking for a better spring...

Once the injection timing was “optimized” the engine started much more easily (but still needed prewarming with the heat gun) and responded to different governor settings by speeding up and slowing down as expected and was mostly free of diesel knock. With incorrect advance (too much or too little), the engine only ran at one governor setting and speed. A minor glitch during my experiments was that the hinge pin on the governor arm fell out. I replaced it with a 2 mm screw that actually threaded into a tapped hole in the governor arm, and for extra security, I locked the screw in place with a nut.

From the video soot and oil can be seen spraying from the exhaust stack. I will put a drain fitting in the bottom to prevent unburned fuel from accumulating in the stack which should keep things much cleaner.

Note that there is a “gasoline” can in the backgrounds of the video. It is actually an empty container I filled with diesel flue to create a local diesel supply.

The builder's long journey to get this right for market is complete and now it's up to each hobby engineer to adjust the injection timing, the governor, even the injector pressure just like Rudolf Diesel did on his early machines. Like those vintage machines, expect some smoke and mess. I was involved with a pre-release red model and the builder fixed all my concerns for the 2025 green model. If this was an easy task to achieve, I guess there would be more working model diesel's available. It's not easy to build...and it's quite something to add to my collection. I did not get mine from Stirlingkit but you should get this from Stirlingkit as a reputable supplier - syudy the videos first to see if it's for you. I will get this running better with time and tweaking as the builder hopes for us to enjoy, with more time than he can put into testing each one. But, my released Green 2025 version ran great first time as you can see!