What a fantastic couple of engines. To have both of the prototypes running and together, what a great achievement. It's a pleasure watching you guys solving problems with great skill aand engineering genius. Can't wait for the next installment....
How do you reckon Ivan and John don't have an idea ? Go read up on ivan's history! I wouldn't mind betting what he has forgotten about cars and engineering would amount to more than most people's knolage
It is inspirational to see people show some love for the older technology and giving them a new chapter. These engine could never have been given a better home than with you fellows.
How. Wonderful in this day and age to see two fantastic engineers working and making the parts you need takes me back to when I was a mechanic working on proper cars love your videos
Always a pleasure to watch you two working together. What a teaser at the end! I'm looking forward to hearing the two stroke fire up. Best wishes, Dean at Retromeccanica, Oxfordshire.
A true insight into how things use to be done on a daily basis, in days gone by. Still relevant in todays world but only a small minority of people (like you) are able to put the Dark Art into practice. See you all in the next one. 👍👍
I was told about the Puch twin piston engine when an apprentice, but have not seen a twin piston engine till now, thank you!! And I have never seem the wax trick with the rings - thanks again!
I've used (and made) sleeves from cast iron pipe to compress the rings, they have a slot that the narrowest bit of the conrod will just pass through after they're past the bottom skirt of the piston. Easy peasy. Also have quite old Honda factory tool ring pliers, sort of a reverse gyno speculum for want of a better description.
Very happy to find you again. I expect Shed Racing will become my new favorite RU-vid channel. Take off like a rocket and I will hang on for the ride !!
I would be very surprised if it was not designed to utilise ducted fan cooling. So you need the tinwork to accommodate that. If you are not going to cover up those beautiful castings (and who would blame you) you will probably need a heavier duty fan than the one we have just seen. I would recommend that it blows air over the engine, rather than pulling it away, and is aimed at the exhaust side. If it's like most two strokes, you will get very little (if any) notice of seizure.
Many of the comments are pointing out the exhaust system as being faulty and they are certainly correct as how the system now stands it certainly is not ideal, but I’m not sure that it’s causing the severe issue which you’re seeing. As a note - I worked as a mechanic for a Yamaha and Bridgestone dealership in the two stroke days. We on occasion would work on older bikes. This specifically referring to twin cylinder two stroke engines fifteen years or so years old. A twin cylinder weak point was the crankshaft center seal which isolates the two crank chambers from each other. As one piston is coming down on its crankcase compression stroke the other is moving up on its intake stroke. Any air leakage between the two would result in a very sick engine. I’d be surprised, considering the age of the Puch if that crank center seal is still doing its job. Bridgestone had a problem with center seals in the early 70s, resulting in a good bit of warranty work. Often the older Yamaha bikes were not worth the potential repair bill. The symptoms which you’re seeing are hauntingly familiar. Unfortunately the repair is not simple. The crank will need a press for disassembly and reassembly, and it will then go on centers for alignment with a hammer. If your engine were mine, I’d rig up an adapter plate for the carb flange and apply a few pounds of air pressure to the crank chambers checking for air leakage one crank chamber to the other. If that’s ok, fingers crossed, move on to ignition timing. If you’re lucky and have a timing spec given in so many mm piston movement before TDC, this can be easily done with a dial indicator through the spark plug hole. If the spec is given in degrees before TDC, you’ll have to go through the whole exercise of finding crankshaft rotational TDC and then using a degree wheel. Timing is critical. I would then remove the present exhaust piping and jet the carb for what I guessed as a bit too lean. As far as simply running, a 2 stroke is much more tolerant of a lean mixture than a rich. However a caution, it will run hot on the lean mixture if put under load. With these three criteria met, a serviceable crank center seal, proper ignition timing, and a leanish mixture; the engine should operate adequately for the display stand purpose. The engine will run with open exhaust ports but it will sound like two chainsaws running side by side. A chainsaw operates with near an open exhaust port. Everyone is absolutely correct in regards to the tuned exhaust advantages and this would definitely apply if the engine were to be installed in an auto and to expect any performance. For your display purpose, I would lean towards sound control. The tuned expansion chamber system will split eardrums. I would try Y’ing each cylinder’s exhaust ports together and then through a small glass pack type muffler. A Y And a muffler for each cylinder pair. One last thought and it’s something which I would occasionally run into. We used to build and tune 2 strokes for racing. Now and again we would get an engine where an amateur had taken a Dremel grinder to the internal cylinder and piston porting in hopes of more horsepower. In general not a successful outcome. Expertly done, these modifications can be successful, but now the matching expansion chamber exhaust is critically important and most gains will be in the higher RPM ranges. It’s an art. Hopefully, your engine’s porting has not been altered. This is the sort of project when success is finally achieved; one wipes one’s forehead and exclaims, “Well that was certainly an adventure!” Good Luck
Can't help thinking that if this engine had been developed then the cylinders would have been split from the crankcase as is common in most motorcycle engines. This would then allow standard ring clamps to be used.
Neat little engine. I really like your just make it work approach using sound engineering practice. I am applying the same thinking to my own project. Allen Millyard is another just build it type I find inspiring. I don't have quite as much experience but watching things like this really helps.
Wow! Ivan and John, it's really looking good for a successful running of the Puch. Fabulous work from you both, not a lot of talking, just getting on with the job, great. Can't wait for the next installment. ✅
I am by no means criticising but when I make piston rings i split them and expand them round a suitable bit of bar as a mandrel and heat them on this bit of bar, they will cool slower and it ensures uniform expansion. I have seen it where after stretching they are oval. Just food for thought. Amazing video
Not a subject taxing my brain daily, but I'm surprised you wouldn't just saw a suitable gap in a circular ring to give correct circumference when inserted in the bore.
That's just the way I make my rings albeit for much smaller bores, the engine is looking really good. Two cylinder version of my old Puch motorcycle. 👍
I watched the video where you were unable to get the 2 stroke mini engine running. This engine is exactly the same as the 1942 Trojan engine, and it needs to be supercharged. The 2 cylinder banks needs to be isolated from each other for crank case pressure and the 1926-28 Trojan engine is started by a directed injection of fuel into the cylinder. I recommend that you read up on the 1928 & 1942 Trojan engines You fit the pistons into the engine with spring steel clips like trouser bicycle clips and when the piston is in you slide it right down the piston and just slip it off the conrod Hope this is of some help.
Ricardo produced superficially simular two stroke engines when he started his engine business. He used the slave cylinder at the rear to compress the charge for the power cylinder at the front so he could use plain bearings for the crankshaft they were reliable and powerful engines. Initially he sold these engines to power his partners cars to start with. When that venrure failed Ricardo kept his business going by selling these engines to fishermen to fit into small south coast trawlers which enabled these trawlers to leave harbour and catch fish when the tide was against them ..
Would like to have seen some evidence of oil being used in the build. Two strokes don't appreciate being turned over with all the bearings and cylinder walls dry.
I love to see this modern technology used. CAD (Cardboard Aided Design) the cheapest and easiest way to get it right first time if you know what you're doing!
Exhaust piston is leading right? Just asking, cos you complained about it spitting back..... ;) also, the central crank seal, it does seal?? It had better.
This is an absolutely awesome RU-vid channel! Even better than Ivan's previous one. Interesting things to watch every time. The only small downside is the sounds. It is difficult to get the word out. Especially when my mother tongue is not English. If you could get some kind of microphones for these gentlemen.
My poor old brain in a turmoil over this engine, I remember my dad telling me about an MV bike engine being banned for racing as the center cylinder of three acted as a super charger obviously this not the case with this engine, why does it need dual exhaust ports? the extra crank case capacity I assume is compensated for by both pistons moving together which I assume increases induction and therefore pressure to the first cylinder and that the first cylinder acts not just as a pump but also a form of valve for the second power cylinder,seems to me a lot of extra weight and bulk and engineering are the power gains that great?
As Jusb 1066 says, I suspect the dual ports were developed for more efficient scavenging, much in the way that two smaller valves are more efficient than one huge one in a four stroke head. Two stroke tuning is a very black art, and this engine was developed before Walter Kaaden had shown the world expansion chamber exhaust systems, and that knowledge developed from his work with ram jets during WW2.
Id like to hear the reasoning vehindfthis design, any advantages, disadvantages why are they not popular? That would be freaky. To pull a head off the first time not knowing, thinking and expecting two pistons, but find a extra pair of pistons hiding in your engine!!😆
No, I don't get it. The hot grease in the piston ring grooves. What is that?? UPDATE! Now I know it. Glue the piston ring down with wax!! An idea innovative idea! Sorry it didn't work.
I love the project of bringing it back to life but just can't help wondering why anyone would think this is a good engine design. Just more complexity to make a whole extra cylinder do just what the underside of a regular 2T piston does. Plus the significant extra machining.
These Ehrlich engines were trying to improve two stroke efficiency in a world that hadn't been shown expansion chamber exhausts, because the good Mr Kaaden played those cards very close to his chest for some while.
Put a zip tie around each ring. Then as each one goes in to the bore it will push it off the ring, then cut it off the piston and move in to the next one. Simples.
Did you really need to go to the hospital for a "stressed" ECG i'd have thought if they followed you to the petrol station next time you filled up they'd get a good "stressed" result ----- lol
