First of all this is why:

A SH engine is not the best engine to "play" with without real modifications. The engine is limited by timings and other dimensions....

Again: when changing the head clearance you do change the ignition timing which does have an effect on the powerband and max rpm. With spark ignition changing the head clearance the spark will always be on time.

A tight piston will end up in a better performing engine but if it is to tight it will stay with a pinch for a long time giving some resistance reaching top rpm. Some brands like Sirio has a kind of diamond shape piston (the side above the oil rings is tapered and the side under the oil rings is tapered), the side is not realy straight, the corner on the side is on the oil rings and touching the sleeve will get a flat spot taking care of the sealing building up compression. The wider the flat spot the better the sealing and longlivety of the piston.

I also have a Werks B7, but I believe that engine has too much exhaust timing. But if I set it up right,
with the exhaust tract rebuilt, build a phased custom pipe to take advantage of the rotary valve
opening to help the transfer ports on the up stroke. I think I can get it to handle the tight stuff,
and come on the pipe twice down the straights.

I have the SH and other engines that I can play with. #1 is changing the transfer port angles in
order to retain more of the mixture, and work better with a pipe from bdc to transfer port closed.


I would like to sincerely thank the following for their input and wisdom.


Roelof
wingracer
Maximo
Teufel Racing
NitroVein
mxwrench
am
22Racer
thetroll
Anf
ChrisAttebery
sschultz
GNS Racing 86
Gary NJ
Imbue


Thank You very much!


B Mazz

I do not think so.....

I feel as though I should quote Rodney Dangerfield right now.

What I want you to do is get an 1/8th scale buggy together, and try to drive it on the track. I still think you are having a difficult time grasping the true needs of an engine in an off-road r/c car, and until you really see what a car goes through, you will continue to think that all these examples of 2 stroke engines that run wide open all the time have any bearing on why our engines are the way they are. The closest thing to what we have would be 50cc Mx bikes. They have 1 speed, centrifugal clutches, varying levels of traction, and have to work from the moment the clutch engages all the way until the power signs off. I think you will find that a 50cc MX bike engine has a lot of the same design details which you continually question in regards to our little car engines.

I say it again, nothing needs to do what a car engine needs to do, therefore nothing is designed the way a car engine is designed.

Signed,
thetroll

Also, with everything going on during race day, a bit more power at the expense of a more narrow tuning window is the last thing that is desired. There is so much to do with regards to staying ahead of the changing track condition with the suspension setup that nobody would have time to chase the tune of an even more finicky engine. Again, once you see this first hand, I know you will sing a different tune.

A little research I did this winter,see if some applies to you http://www.rctech.net/forum/onroad-n...t-modding.html

Everyone and especially ifuonlyknew:

I know I should look at what has been done before, and build my project based on the current
successful trends. Especially since there has been 20 years, or more of development, and what
I am talking about, might be the same as going back to year 1.

Respectfully

Bill Mazz