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Weasel Engine Water & bio ethanol diesel conversions.

29/09/2026

PJI development is going well with the little 50cc stroker. This is the largest prop we have for this engine and it’s pulling it to around 7.7K. There’s much more to come, squish needs to be significantly tighter, however we need to liquid cool the head first. For a given load we have reduced fuel burn from 1289g/hr to 974g/hr, this is still too high. The increased engine output is now starting to break things. If you look at the prop boss, you can see it moving around, this is because the prop loads have exceeded the capacity of the angular contact ball race that isolates the engine from prop thrust. Yes, I know, prop guard! We are only performing short runs at the moment and need access to the engine, as soon as this phase is finished and we go onto endurance runs then it will be run in a full cage.

The final element to our Micro power project is fuel delivery. We wanted to know if the fuel vaporiser that we develope...
24/08/2026

The final element to our Micro power project is fuel delivery. We wanted to know if the fuel vaporiser that we developed for the converted four-stroke engine would work on a reed valve-two stroke. The vaporiser relies on inlet port reversion and we weren’t sure there would be enough with the reed valves being so close and it being 50cc…..Turns out there is, so we need to make a scaled down version. If you look closely at the two photos you can just see the difference when the vaporiser fires, the fuel mist is that fine! Why bother? The engine picked up 400 RPM on less fuel……

10/08/2026

The first part of the video is of this 211cc Diesel in its original form with a 3Kw load….and plenty of smoke! The second is after conversion to E10 petrol and Pulse-Jet Ignition with a 4.5Kw load. At this stage we are using a carburettor instead of my normal vaporiser as we can connect it to the diesel governor system via a cable. This should prevent us having to look in the next county for failed engine parts should we have a load bank failure! 💥😂

The engine is now clean, new bearings etc and modified for Pulse-Jet Ignition and port delivery of fuel. E5/10 petrol t...
30/07/2026

The engine is now clean, new bearings etc and modified for Pulse-Jet Ignition and port delivery of fuel. E5/10 petrol to start with, then over to ethanol and water. Max RPM was 3.5k continuous and a peak of 3.8k, we are now going for a lean burn unit running at up to 6k RPM peak.

This is the std 211cc Chinese Yanmar clone diesel engine that we use. This is running as the manufacturer intended on ...
20/07/2026

This is the std 211cc Chinese Yanmar clone diesel engine that we use. This is running as the manufacturer intended on direct injection diesel and compression ignition. The load bank is three 1Kw bulbs. You can clearly hear….and see 💨💨the strain as the load is increased 1Kw at a time. The engine has run for around 2hrs in total. Ok, there is an element of running in, but the blow by on the piston surprised me…but did account for the state of the oil.

16/06/2026

Initial testing of our “in development” 10mm PJI units. Idle and low load are the hardest to get correct, this is because with the throttle closed there is little compression to fill the pre-chamber. This is where our asymmetric design really comes into play. The keener among you will notice the oil leak from the oil pressure gauge. The rattle is the handle of the engine stand. Onto the engine Dyno next for some more exciting testing!………

We had an excellent day yesterday at the University of Lincoln, where Theo presented his thesis on the effects of pre-ch...
27/05/2026

We had an excellent day yesterday at the University of Lincoln, where Theo presented his thesis on the effects of pre-chamber port geometry on main chamber combustion. With a few tweaks his CFD predictions closely matched reality. The first graph is the CFD prediction of pressure oscillation and the second is as measured using a Kistler pressure transducer. The green line is a standard spark plug and the yellow is the PJI. Spark timing and AFR were left the same. The vertical line shows peak pressure position on the standard spark plug. Retarding the ignition for PJI would make two differences, the first is that peak pressure position would be realigned and the second is that the initial hit of the PJI would be stronger due to the increase in fill time. The difference in this case is around 7 degrees of crank rotation. One other interesting observation, each CFD compression and power stroke took over 20 hours of processing time, the Kistler probe had significantly less time @ 4k RPM!

This is the basic kit of parts that allows you to convert the Yanmar diesel engine, or its Chinese counterparts, into th...
25/05/2026

This is the basic kit of parts that allows you to convert the Yanmar diesel engine, or its Chinese counterparts, into this clean burning engine. It will run on gasoline or gasoline and ethanol blends all the way to straight ethanol. The RPM/power is controlled by fuel alone, this preserves volumetric efficiency unlike most spark ignited engines. In the picture we have a high output ignition system with automatic dwell control, vacuum fuel pump, fuel vaporiser(a carburettor can also be used, as can fuel injection), machined piston and of course, our Pulse-Jet Ignition pre-chamber assembly. If anyone is interested in building one of these high efficiency engine then please contact me via the website. www.pulse-jetignition.co.uk

This is the cylinder head from the LC 17:1 CR engine. One of the advantages to two strokes and having oil in your fuel,...
14/05/2026

This is the cylinder head from the LC 17:1 CR engine.

One of the advantages to two strokes and having oil in your fuel, is that you can see exactly where the Pulse-Jet is firing.

This was the silly experiment that started Pulse-Jet Ignition over 20 years ago, and is here to please all of those comm...
05/05/2026

This was the silly experiment that started Pulse-Jet Ignition over 20 years ago, and is here to please all of those comments saying that our engines aren’t Pulse-jets!. They are quite correct, however what delivers the ignition is! The first part of the video is in slow motion and reverts to real time at the end.

Theo, under the watchful eye of Prof Ron from the University of Lincoln and myself have been working to hone in on the specifics. Theo has created a 3D CFD (computational fluid dynamics) model to predict flows, temperature and velocities. The predictions generated were then tested against those measured on the test engine. To give you an idea on the detail of this project, each simulation took over 20hrs of computer time to run one compression and ignition cycle!

The paper will be on our website once published, http://www.pulse-jetignition.co.uk To give you an idea, the project showed that at 4k RPM the PJI insert had five peaks in mass flow and velocity on each spark event until it ran the pre and main chamber out of fuel.

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Unit 13a @ 97A East Road
Sleaford
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