Wright j-5 "1/4 scale" almost done!

[Smartmove]

Hi!
Here is video of my Wright J-5 "1/4 scale" from the drawing by K.E.Olsryd. It's 90% finished. Need to make the tube for the pushrod. Also want to make a new distributor like the one on the drawing with cables that have steel mesh as noise isolator outside. It's very easy to start and run well at low and high RPM. Had problems with the ignition sensor. Was quickly destroyed. Moved the minus pole to the ignition to the distributor housing, hasn't broken anything after that.
Also a video showing what happend if you have bad isolation between the sparkplug cap and sparkplug, and how i fix the problem on my very cheape DIY caps.
Regards Gunnar!

 

[kuhncw]

Very nice work. Sounds good.

Chuck

 

[ninefinger]

Excellent work, maybe even inspire me to get off my but and do something with the J-5 castings I have aging in my workshop!

 

[GreenTwin]

Nice work !
Very impressive and large engine.
.

 

[Smartmove]

Hi!
Thank to all of you for nice words. It was realy nice to get it to run since this was my first multicylinder and second sparkignition engine.
To ninfinger. I have done som reconstructions compared to the original drawing. I changed the oiltank, make tha camring in one pice and the camwheel a littelbit different. I also made some changes on the shaft for the impellar. If you are interested i can send you drawing of the changes i have made.

 

[petertha]

Fantastic! I would be interested to learn more details of your ignition system (module/coil, distributer, leads, plugs...) & the modifications you did in the 2nd video that suppressed the wayward sparks.

 

[ninefinger]

I would very much like to see the drawing changes. I'm always looking at what improvements can be made, either to the method of manufacture or the design itself,

Regards,

Mike

 

[Smartmove]

Hi!

The ignition system i use is a LS2 smart coil, a modifyed drive circut by 74sprint. Powered with 3s lipo battery.



The ignition wire is "5mm HT Ignition Lead Cable - Wire Core Silicon Black" from The Green Sparkplug in UK. The sparkplug caps is mad of round bullet connector. I removed the oringinale plastic isolation bend the top an solder the ignition cable in. Put some layer of heatshrink tube over it.

The solution for the wayward sparks is a pice of silcone tube made for model airplane engine. What's inportent is that you dont make them to long so they make too mutch preasure against the metallic part of the sparkplug. If you get to mutch preasure on the tupe you make a small airgap between the ceramic and the tube and the spark find the way between the tube and the ceramics. The cilicone have a wery cod electrical isolation.
In the beginning i have big problem with my hallsensor. I run maybe one tank an when i try to start again the sensor was broken. I then make another wire, for the negative pole in the ignition system, from the socket for the distributor cap and close to the battery. I still also have one directly to the crankcase. After this modification i haven't broken any sensor.
One problem with the LS2 coil is that it fire automaticly after , i think it's 8ms, if it haven't got any signal from the controller circut. So i used ø3mm magnets, the drawing say ø5mm, to be sure that i don't get preignition to early on low RPM. I haven't done the matematichs but i can run it down to 800 rpm and up to 4500 rpm. I like better to see engine run on low than high rpm.

I hope I have made myself understood as English is not my language.