Ive recently decided to start modifying some nitro engines. Ive read many great articles on the subject and talked to a few people who do it themselves but still have questions.
1. If I knife-edge the piston rod how do I balance out the crank? Is it just a guesstimation of how much you took off the rod, you need to take about that much off the other side of the crank?
2. Im also A little worried about scavenging the ports. I dont want to mess up engine timing and negate all the work I did to the engine. Is there a fool-proof way of figuring how much to scavenge from the ports without a timing error? A link to an in depth article would be nice if possible.

I have many other questions that I cant think of right now so Ill be coming back here to keep posting questions.

P.S. To anyone that wants to modify nitro engines but thinks its part their capabilities, It isnt. Its not rocket science. Its all about how fast the fuel/air can pass through the engine. Make it pass through faster and your engine will be faster.

i think you should leave this to the pros. it takes a lot of experience to be able to do this. you have to learn from your mistakes ect. Most likely you first moded engine wont turn out as good as you plan.

No matter what you do, don't touch the exhaust port.
Here's a 3-page article all about engine porting & timing
http://www.rcnitro.com/rn/articles/engine_timing.asp


here's a link about porting & polishing
http://www.nitrorc.com/mods/engines/...ngine_mods.htm

Another with more/better pictures:
http://www.nitrorc.com/mods/engines/trx15mod.html


Don't touch the exhaust port! Modifying the exhaust port requires some very precise equipment to measure & change the various angles involved. The connecting rod / crankshaft mods also require a certain amount of equipment + knowledge to avoid screwing up. Best bet is to see if you can find someone local (through the forum) who's done this before. I've been reading up on this too & it doesn't seem very tough. Good Luck!

I just got done with my first one. I havent read the link yet about the exhaust port but The sleeve and the crank case did not match up well at all so I took alot out of the case to match the port on the sleeve. I bored out a smoother more tapered outlet on the crank, also smoothed out the inlet on the crank. I really shreaded the intake ports, didnt do very well on these but hopefully I didnt mess it up to bad. Im sending it out to a freind that does this professionally so he can polish everything out and hopefully fix anything I did wrong. I didnt have the correct bits, I know I HAVE to get a good set if I ever want to do this again lol. Aside from a couple mistakes I can say Im not worried about doing it again, just not on a nice novarossi or something.