thats good to know, ill have to check them out. i bought a tap so i could thread some gears myself, as i already mentioned, the electric motor pinions, and iirc on my fs40 ntc3 i machined and threaded a gear from a savage transmission, it was a 29 or 31 tooth, something like that. later i bought a die so i could thread the clutchbells for the xo-1. iirc the thread is 12mm x 0.5 pitch.

i bought an engine yesterday. i went with an os fs52s. its gonna be a week or 2 before i have it, but in the mean time i can finish the 2 speed up and maybe make an intake manifold.

If you happen to be around your stuff, could you verify that thread size/pitch for me?
You have no idea how hard I searched for that information online and I could not find it anywhere.

The threaded pinions were my first choice in gearing options actually.
I suppose the main reason I want to machine my own gears is simply because I enjoy the machining. Also, I'd be able to cut essentially a single thick gear, then slice it up into several individual pinions or spur gears, so I would have a lot of identical gears for future replacements.

Thanks for the info guys.

i can confirm for you the hpi bell/gears are m12 x 0.5 pitch. i bought the tap and die on ebay years ago, was the only place i could find them.

i just finished machining and threading the 2 speed input gears from a savage transmission. the 18/23 tooth combo gives me a pretty good gear ratio to start out with.

i finished up the 2 speed tonight.






even looks like ill be able to run all 4 brake discs, i just need to get another drive cup that matches the front one. im still amazed the hpi drive cups with the ofna brake discs. and the way ive done it i should be able to swap the 2 speed out for the center diff with nothing more than sliding the motor back slightly.

That's amazing!
What all did you make? The shaft and the gears themselves?
If so, what material, and are they hardened?

Very cool.

i only made the shaft itself. its just steel, nothing special. i didnt harden it, i may do that yet. in the past i havent had an issue without hardening a shaft like this.

Gotcha. I've never paid attention to whether or not the shafts are hardened from factory. I'd assume so for the sake of the one way bearing that rides on it.
I do have one sitting around, I suppose I could take a file to it and see.

they are hardened from the factory. it would be ideal to harden it, but ive only got a propane torch and that wont get it hot enough. id need to get some map gas to heat it hot enough to properly harden it.

What type of steel is it? Ive had good luck with my propane torch hardening some clutch bells. I got them glowing bright in a bed of coal (for extra carbon) and dunked in water after maybe 10 minutes.
Literally every part of the process was totally arbitrary and non-scientific but it worked.

its likely just 1018, but i honestly dont know, i made it out of what i had in my metal bin. doing it in the bed of coal was likely what allowed you to get it glowing, ive never been able to get steel red hot with a propane torch. last time i hardened something i did it with oxy acetelene and did an oil quench. after that the part was heated back up to a dull red and allowed to air cool, this takes some of the brittleness out of the material.

Yeah, I did not temper those clutch bells. No chipped teeth, but, they were meshed with plastic spur gears. I only hardened them as an experiment after all.

I'm looking forward to working more on my project. I need to figure out a reliable starting method. The four stroker sits too high on the Bullet's chassis to use a bump starter.
I may just machine a larger diameter flywheel, as I can't think of any other GOOD ideas.
I did consider a belt driven starter mechanism. I beleive boats use them or something.

starting problems are what plagued my 1/8 gasser projects. i was building a savage octane before hpi released theirs, i was also using a 15cc engine, its was from evolution. i tried building a gear drive starter setup for it to run with a drill and it kept breaking it. i dont know how many hours and designs i went through, i ended up scrapping that project because i only managed to get it running for a total of 5 minutes. thats when i put it into the buggy figuring bump starting would work. ended up burning up one of my starter boxes because of it. lesson learned on that, dont go into a project unless you know how your gonna get it started before hand lol.

looking at the bullet you shouldnt have much of an issue making bump starting work. may just need a larger diameter flywheel.

Oohhh so the guy who put the Evo in the savage was you! I saw that thread back when I was just starting the project.
I also have a gasser Savage... although I cheated by using the Go .28 gasser! Fantastic engines. If Losi used this engine in their 1/8 gas models instead of the rod-snapping SH .31 engine, they would have had a runaway success I think.

Anywho, I'll go with a larger flywheel. I'll just try to make it a little thicker on the edges so it doesn't easily slice through the starter wheels.

yea that was me. i really wish i could have made it work, or even just got the engine running. even mounted on the bench i have a hell of a time trying to get that thing to spin over, makes me wonder how airplane guys get them started.

i really wish the gassers turned out better than they did. 1/8 scale gassers could have been what was needed to pull some interest back from the electrics. seems hpi and losi just got into a war of who could release it first, and the end result result was they both were terrible. had they refined them more they could have been game changing, but seems they will be another half developed thing that goes by the wayside, just like our treasured 4 strokes.

Definitely true. I guess technically the Octane is still around. Really neither are discontinued.
Also, HPI hasn't said the Octane V2 is cancelled or anything...
There might be hope yet.
I mean the concept is do-able. Go engines is no longer around but I'm telling you, their gas .28 has been great for me. It just starts and runs and keeps running.
Unfortunately the flywheel nut loosened on one (I have two) and tore up the pinned crankshaft (no collet) but I can fix that easily when I get time.

But, the thumper project comes first. I re-drew the plans for the chassis. I needed to extend it because the Bullet is 1/10 scale..
However I want it a little longer still so I can fit short wheelbase T-Maxx size bodies.