Omar

iTrader: (15)

I just started getting interested in engine modifacations i have seen a couple of people doing the engine modifacation to the crank and other places. i just wanted to know if anyone could point me in the right direction(how to's)(and do not's) Websites and pictures will be very helpful, thanx

EdwardN

iTrader: (1)

I will try to get web links for you where you can find very valuble info to understand engine, will posted later.

dino.tw

Read R/C Car Action February 2004.There is some information.

WheelNut

iTrader: (5)

Goto the RCzone on rccaraction website and talk to "MaverickRacer" He's very, very knowledgable (sp?) about modifying nitro engines. He also mods engines for alot of people and apparently is very good.

modellor

The first thing to do before starting modding is to learn what actually happens inside an engine and what characteristic each modification has.

This link is a favourite with a lot of people to learn more about engines and modding. It is primarily about RC boats but the same principles are applied to cars also.

http://rcboat.com/past.htm

There is no point watching someone modding an engine and then trying to recreate what they did. For one you dont really know why you made the change and that particular change may not suit your requirements. Different changes can be needed for different tracks (depending on whether you just need out and out speed, really low end punch or a mixture of both).

EdwardN

iTrader: (1)

Agree with Modeller. If you will just copy what people does, you will be always "chasing the tail" It is much better to understand how engines are designed and build, what is impacting their beheyvior, what events are following each others and then try to improve one or other thing in chain of events.
Here is web links will help you in some way:
http://www.bmaps.net/info/pipes.html
This is one of my favorit article and without understanding this events you can't do any modding-poilishing and porting will not make anydiffernce: http://www.control-line-team.de/moto...echnik_en.html
http://members.bellatlantic.net/~vze2p5sj/engine4.htm
http://rcboat.com/anttech.htm
http://www.rc-sa.co.za/engine.htm
http://geocities.com/CapeCanaveral/G...67man_pipe.htm
I hope these web links will help you and some other guys to understand engine's designs and find your way to work with engines.
Good luck in modding and if you have questions please feel free to ask, I will be happy to help.
Edward

Omar

iTrader: (15)

thanx for all your responses very!!!!!!!!!!!!!!!!!!!Helpful!!!!!!!!!

theRED5

Those were very detailed articles on boat engines, and combat airplane engines, but where are the ones about CAR engines? Specifically on tuned pipes and stuff on cars.

stefan

It's not about cars, planes or boats, it's about how engines in general work.

Once you understand that you can come up with the mods you need.

IronMan

I'm still learning the trick of the trade and would like to share any information that I can find thru the internet .Hopefully someone who understand better can help to explain certain topics.OK I start with crankshaft balance .

Some notes on crank balance:

If you want to get fussy, and allow for the port being moved, balance on a "wheel" type balancer. This can even help on a stock type crank. (see some of the Russian engines, .15 size for examples). The amount of counterbalance needs to be in the 50~65% range of the weight of the piston,wrist-pin,(ring, if used) and 1/2 the weight of the rod. To test this, measure the weight of the reciprocating parts on a good gram scale, and make up bob-weights in this amount to add to the crankpin, before you put it on the balancer.The crankpin should "stop" at the 12 O'clock position. On a single cylinder engine: If you add weight to the counterbalance, or lighten the reciprocating weight. you DECREASE the PRIMARY shaking imbalance (vertical= Cyl. bore axis), and INCREASE the SECONDARY imbalance (crosswise= across the lugs).
For this reason, IT'S IMPOSSIBLE to balance a single Cylinder engine, without a secondary Balance shaft, as used in some auto engines. Adding weights (heavy slugs) to the counterbalance is done to change the resonant frequency at which you get a "Harmonic" or strong vibration level. You want this at a lower than full rpm number. Most of the ST X-40's used in Formula-1 Pylon and Fast Rat had cranks that needed this changed to resonate in the high-teens (RPM). Sometimes you could see the engine "shake" in this range, on the test stand. I never put a strobe light on one to see what one would look like while running. If the engine is balanced to "resonate" at full RPM, IT USUALLY COMES APART

Again some one might be able to eleborate this further.
Thanks

EdwardN

iTrader: (1)

I am 100% agree with Stefan. What is the difference between RC cars engines and other type engines. Actualy nothing. Every application required adjustment of varibles ( timing, balancing, pipe length etc). General principals are totaly the same.
In Pipe wise, just can tell you, in air modeling and boating is use single period resonance tuned pipe and in RC cars ( due to the car's sizes) it is two period ( two cycle), means you need to devide all varibles in half ( lenght etc). Single cycle pipe is much more efficient and when pipe kicks in it sounds as exploded "bomb". I have tryed my boat's .15 pipe on car -it was amesing, but it was hanging out of body like cucumber ( 6 inches) and it is totaly illigal. LOL, but was working realy great.
But because it is, two period pipes, we need to take to concidiration-wave is loosing its power on second return ( when most charge happened), so our goal is to save power of that second return wave as much as possible. If it is loose it will not be that efficient.
So here is thing to think about ( and make experiments).

EdwardN

iTrader: (1)

Hey very interesting point. Somewhere of the beginning of my present here in forum I mentioned about dynamic balance ( but someone call me irrogant idiot for it). This is what about. In many cases we just think about static balance ( when we work with engine on working table) try to weighing piston wrist pin and conrod. But when engine is working specialy at high RPM we have place dynamic balance, when wight are shifting from one position to other. In my opinion there can be real solution to get rid of unbalnce and made balance perfect. but there is ways to decrease it a lot.
Here in your post is mentioning some Russian engines with uncommon design of the shaft, it is absolutly tru. We can move some part of engine to one or other side which will help us to fight with this problem. On my new upcomming engine, I am using this trik- I have moved induction port to one of the side. We did it always in the past, no one Russian engine has induction port on the center. This design been use sometimes from mid 1980's
It is impossible to use the same way of improvement on existing common RC cars engines ( one of the point why I decided to make my own device). I am not saying existing engines are bad, I just think about this problem differently.

IronMan

Thanks TG for your response.You mentioned that you move the induction port to one of the side.Then the transfer and exhaust port timing position do you change that too in relation to your induction port design/position.

EdwardN

iTrader: (1)

I moved induction port to one of the side, I did it phisicaly, but induction timing stays where it is designed to be-opening and closing. about timing on exhaust and transfer-I always do alter them to my numbers.
Phisical position and timing-I can move port in any way, but still can keep timing on induction even as stock existing engines. Just dreaming-if I have space under the car for carb-it will be almost ideal situation, but unfortunately we don't have room under car.

IronMan

Your explaination here reminds me of this OS engine.Unlike most engine now which the piston stroke is in the vertical manner.The OS LD(LayDown) piston stroke moves horizontaly.The carb is on top of crankcase.My point is I believe the induction port position of this engine is different.I have one of this engine and will open it up to confirm.Have you seen this engine or any comments from you?