Thanks SlobbaTech.


Here's some of my other motors for comparison.

S7:

• INDUCTION—open 43 degrees ABDC (above bottom dead center); close 54 degrees ATDC (at top dead center); duration 191 degrees.

• EXHAUST—open 85 degrees BBDC (below bottom dead center); close 85 degrees ABDC; duration 170 degrees.

• TRANSFERS—open 65 degrees BBDC; close 65 degrees ABDC; duration 130 degrees.


C5:

• INDUCTION—open 45 degrees ABDC (above bottom dead center); close 62 degrees ATDC (at top dead center); duration 197 degrees.

• EXHAUST—open 92 degrees BBDC (below bottom dead center); close 92 degrees ABDC; duration 182 degrees.

• TRANSFERS—open 65 degrees BBDC; close 65 degrees ABDC; duration 130 degrees

it seems like I could either widen the opening in the crank or widen the case to achieve different induction timings, which is the right way, the HPI is pretty restricted where it goes into the crank opening.

dont cut the crank up 2 much, uther wize it will bust.......
people have busted cranks cuz they modded em 2 much..;)

You should grind on the crank over the case b/c you don't want to risk losing the seal around the crank in that area. When the cranks broke by the induction port I think it was mainly due to the edge of the hole being too square or sharp edged, so all the stress was located in the weakest spot where if the corner was radiused more would be stronger. Also making sure the intake ports on sleev all open at same time instead of one side sooner than other will make more power then also making sure all the ports open straight or square instead of from one end to the other or however. On .21's though you have to be careful with if the ports open square or tapered from one side or center out b/c the ports are bigger than on .12's and the piston can catch on them, especially exhaust port.

hey folks haven't heard from anybody in a while...got a ? though

Just want to know.....has anybody tried using large duration numbers for induction on a .12 engine..like 220, 230, 240. If so did you like the results?

My max on a .12 is 218 degrees. It's a monster, but thirsty

Hmm....I was wondering I got a NS12 5 port I was thinking of trying 220 and boring the crank out a little more. Not really worried about fuel economy because I will only mess around on the track with it. An X12 (RB or Mugen) will be my legal race engine.

Stefan care to share any open or closing #'s :sneaky:

Hey all iv never modded any engines in my life and was just wondering What you are talking about when you say 200,220,230 degrees. how are you working out the Degrees and the degrees of What?

Can you plz let me know. Becasue i got no idea.

Thanks:)

When modifying the engines we bolt a 360deg protractor onto the engine to get a reference. The figures stated are numbers relating to when the ports open and close and how long they stay open as in regards to a full turn of the protractor from the piston being at either the Top Dead Center or Bottom Dead Center.

here's a very good guide on the basics of timing.

http://www.rcnitro.com/rn/articles/engine_timing.asp

Piston clean up
 

Has any one ever poslished the buildup out the top of they piston before. I thinking that by doing a poslish I might get better glow plug life plus keep the Temp down. The Motor is a TMaxx 2.5...

:)

Is it possible to convert a Ns12s3 to a turbo head?
- Dust

impossible to convert a standard head button to a turbo head button, but you can always pop a S5 head button on the S3.

hello Ed

My sleeve is distorted a little bit and I took it to a local mechanical place where they do the grinding. Does the sleeve has to be re-chromed? How oo I get the roundness of the sleeve back to the original shape?
The guy said I need to pay for a set of holder/clamp to do the grinding?
Which method do you use, honing or grinding?