SAVAGEJIM

Here is a sample of one of the diagrams I will be presenting in my essay. Of course, this is one of many pics I will use in calculating just the induction timing.

shesha

SavageJim you considered righting a book ? I'll endorse it

paddy4511

ive been after this walkthrough for a while ive got a kyosho GP 1/10 gx.15 engine.I broke the con rod last week not to sure how :lol: (dougnuts)so ive replace the conron and gave a knife edge then i notice the exhaust manifold was 1/4 closed from the weld they did so i ground that out but i would like to port the sleve and this looks good so i'll let you know how i get on lots of usefull info here but i think i'll get another crank before trying that mod so as not to rush.


heres my first attemp at the conrod.

and my sleeve has the ports open i didn't do this but is there a way to mod it furtner?

I would like to mod the crank allso if any body has a walk through

rocco212

The photos on the first page are not displaying. I remember seeing something else about porting the sleeve but can't seem to find it now. Can someone post a link?

Thanks

JB COMP

I'll be modding my old Force 26 when I get it back from Ray for a pinch. I'll be doing the ports only, but I'm woundering how do you how what to do to the crank when modding?

bluesilver

G'Day, I am keen to see this essay on timming.

If by grinding the intake and boost ports do you need to fix the timming at all?

By adjusting the timming are you just talking about grinding more of the top of the ports? As this is the only way that i can think of adjusting the timming.

Any updates to it yet?

SAVAGEJIM

I am so sorry, I have been piddling around and really have forgotten about that project. But since you guys have brought your interest in crank timing, I will finish it. I will also read through what I have and shorten it; hopefully to simplify it.

Krixxer

Yes please finish it up. I can't wait to start blowing things up myself.

Does anyone have any good info to read about porting etc. . I can't seem to find much info online or in books

Danno123

My Feedback: (3)

This is a pretty good read!!

http://www.e-maxximumrc.com/html/nitro_motor_mod.html

bluesilver

Thanks, I am interested to see how you can ajust the timming.

hpi apollo

i dont know if this has been posted before but i had a noticable increase in power when i did this

Anthoop

Ooo not seen that before Hpi Apollo,did you compensate for the decreased compression ratio?How are the slots orientated,with the transfers or exhaust/boost ports?Any idea what it does?

j_blaze

apollo, wouldn't that just make the compression chamber a little bigger, kinda make a 21 into a 22? I'm not sure, I'm very new to all this.

hpi apollo

well when you are able to force more fuel into the chamber that automatically raises the compression by a tad, that little bit of volume doesnt really do much, but what it does is add better flow and a good flamefront

bluesilver

I have seen this done before. They normally put a small cross through the button. Sort of like an X . They asy the idea is it gives you as more efficient burn.

I personally wouldn't have put that big of a gouge in the button, Just a sort of like a deep scatch I think is all that is needed.

But if it works like that then well done. If you have any spare buttons you could try the sratch method and see if it improves it or not..

hpi apollo

there is no reason to do an X, that just makes flow worse, you have flow going from the intake to the exhaust which is what i did, an X serves no purpose because you have gouges going the other way and causing unwanted turbulence

SManMTB

Until someone comes up with a dyno comparison and a real technical description to what this would do I consider it snake-oil.
The squish band (the almost flat part around the edge of the combustion cahmber) and the physics involved there is a huge factor when it comes to how the engine performs.
I did see someone making three small cuts in the head and showed a dyno comparison too. Maybe it was a magazine doing it.

You decreased the compression ratio by quite a lot with those big cuts.

hpi apollo

Consider this, when you can cram more into the chamber than before then you raise compression just a tad, those gouges did not remove much material at all, and i promise that those gouges are not as deep as they look, i agree they do look very deep from that pic. The power differenced that i experienced was very noticable and not just in my head because i was finally able to top out my mt2 in my yard on the fairly high gearing that it had, it got up and topped out much faster than before, i was surprised.

Anthoop

I'm not being funny with you Hpi Apollo but when you increase the volume of the combustion chamber then your decreasing the compression ratio.

Hutch-e-bee

And when you decrease the compression ratio the 'bang' is reduced meaning less power. If you felt it had more power then thats cool but the facts say it should have less.

hpi apollo

yes i know when you increase volume of the chamber that compression decreases, those gouge channels were not extremely deep and like i said, when you mod sleeves you can cram more air/fuel in there, automatically raising compression by a tad, even if the compression went down as you are saying, i still gained power

Anthoop

hpi apollo please.The compression ratio has nothing to do with the amount of fuel in the cylinder when the engine is running!The compression ratio is the ratio between the volume of the cylinder when the piston is at BDC, and the volume when the piston is at TDC.
Edit:Please do not take offence.

SManMTB

^^^^

What he said.

hpi apollo

my bad, i see what you are saying, what i mean to say was it raises the pressure inside if you can cram more in, having more to compress, i confused myself, anyways, compression may be a tad lower but there is more in there, it helped, i know it did, you can say it wont but until you try it then dont shoot it down

bluesilver

How is the essay coming along? Still very interested to see it.