maoy

hey, I remember somebody posted an article on sealing air leaks and asked the moderators not to delete it. I'm having air leaks problem now, I was wondering if anyone can help me out. Greatly appreciated.

RcSuCkA

hey guys. i remember about 4 months ago i ported my epic .18 big bore nitro engine using this article and another magazine article similar to this one as a guideline. i did a really careful job and made minor cuts to the sleeve so that i wouldnt ruin it since they dont make the engine anymore. when i completed i took the thing out for a run but it seemed as if it were slower but that was probaly because it was in need of tuning. well, just for fun i put the car to a dead stop and let off at WOT and it turned out the thing broke off 3 teeth from the second gear. ever since that i havent ran it, but im pretty sure it made a difference

SAVAGEJIM

LOL, I too have torn up a drivetrain piece from modding my engines. I have to Axial .28RR Spec1 engines that I modded, very mildly though. I slapped both engine into one Savage and ran it. Wheelies at just about any speed is possible. One day, I was doing some hard pulls, and the output shaft in my tranny's reverse module gave out. It could not handle the torque load of the two modded engines.

RcSuCkA

holy sh** you have 2 modded engines on a savage? hahha you had that coming

SAVAGEJIM

Yeah, I did. Even if I didnt mod my RRs, they would have shorn that shaft anyways.

gabbonator

check out my job with this gxr-15 . my first attempt and on an unheard of model to boot.( damn kyosho ) ANYWAYS i rounded the air entry thingy on the crankshaft, rounded the connecting rod and cut fangs etc on the sleeve. made some minor nicks on the sleeve by accident but nothing serious.
im thinking of making universal dogbones cause they keep falling out. maybe do a tutorial on it.

iexion

Im honestly still a bit confused on which part of modding is for timing because i dont want to tuch the timing at all. Like most of the modded sleeves i've seen there is just a small triangular "groove" that has been drimmel'd out from the (or a) boost port.

I guess i should ask the right question first before i know where im going with it

Do you, or is it common to make a groove into the main intake port. i have a steady hand and im confident on using a drimmel but my main concern is what is a good starting depth, length, width and angle a beginning modder start with. I recall someone mentioning when they first modded there engine, it broke because the modd made the engine overheat. I guess thats my only real worry about modds to the sleeve other then losing power.

Anywho. The sleeve is from a Mach .26SS engine (the project)
The black marks on the sleeve are just marked in so i can get an idea if this looks about right to start with

SAVAGEJIM

As for cutting the little "fangs" or flow channels into the lateral intake ports, yes, that is standard practice of every engine modder out there.

As for modding the timng profile of an engine, I wrote this thread and also gave formulae on how to calculate what the timing profile is and how far you need to cut to get to a desired timing profile.

http://www.rcuniverse.com/forum/m_59...tm.htm#5995115

My first post is the instructional post on how to manipulate the induction timing, and in post #16, I posted how to calculate the sleeve timing profiles.

Codeblack

here ya go dude: http://www.savage-central.com/module...wtopic&t=54465

Codeblack

I also did a few mods lately. I got the sleeve ported, got the conrod "sharpened" modded the engine block and the crank. no pics of engine block yet.

iexion

Well i did some light modding to my M26SS sleeve and crank. I smoothed out the cranks "ridges" and made a small "fang" to each side of the boost ports. To cut the story short. I cant really say how much of a gain the engine has because not only has it been modded, the engine is also waking up to "a new world". And what i mean by this is the engine was ran only stock with stock parts before i got alum clutch shoes and then switch to my axial engine.

So now the engine is using a losi HT pipe, max life alum clutch shoes, o'donnell race fuel, and bit of changed gearing. Also taking into consideration the engine had around a gallon maybe more ran thru it. When i started it up, it didnt take much tuning and once i got up to temps and a good tune.... [X(] the truck about did a back flip in the street. I cant say how powerful the Mach 26ss engine is but im sure it wasn't anything close to that out of the factory... is it possible to get this much of a power gain from some slight modding? (regardless is hop-ups to make the engine work better)

when i get some time i'll take out the sleeve and post pics my moddings

As it stands for now,with both engines using the same set up (Pipe, shoes, gearing, air filter etc) My now modded M26SS is hands down more powerful then my stock Axial .28 Spec 1s. The axial engine does has around 3 gallons thru it or so but it can still pull wheelies like it did right out of the box. [&:]

SAVAGEJIM

The Axial Spec1S (.28ci and .32ci) are great candidates for modding, especially as for their timing profiles are concerned. Aside from the typical flochannel cuts, tubo scallops, switching out bearings, etc, the Spec1 engines could really see some performance gains just by advancing the timing profiles. With a racing profile, I bet these engines could keep up with a refined racing engine. Also, the advantage of modding it yourself is that you can eliminate sharp edges and areas of turbulent flow, where even racing engines from the factory still have some areas of improvement.

iexion

After seeing how my m26ss did wint a slight bit of "adjusting", i want to shoot for my axial engine also but the only thing i want to be sure of is how much to an 8 port engine? i have yet to see anyone mod anything more then a 3 port so im a bit sketchy[sm=72_72.gif]

I not saying the power of an Axial .28 spc 1s is not as good as the m26ss, hell in stock form i almost sold the m26 after i got my .28 but lucky i kept it so i could learn something

iexion

here's the sleeve for my .28 spec 1s

Codeblack

Hey j_blaze, wana guess which engine my modded parts came from?

Codeblack

isnt it a bad idea to round the crank intake hole edges? Whenever I mod my cranks I sharpen them...

gabbonator

well i was reading a thing that reccommended it. http://www.e-maxximumrc.com/html/nitro_motor_mod.html
still works. the added power has killed my gears. also when i stop it by plugging the exhaust, it wont start again and the pull start makes a weird sound. if i pull the head off and take out the plug, put it all back, it goes away. ill see how i go tomorrow and instead ill stop it by pinching. the fuel is wayyy old.(over a year) so im suspicious that thats the problem. surely rounding that part of the crankshaft would help the air flow into the crankcase better without the added corners.

iexion

After some slight modding to the axial engine

drift*king

Hi all I was looking to buy a new motor for my RS4-3 but then seen this other then runnig N02 the motor is un-modded its a nitro star .15 anyone port this motor or mod it. If so is it worth it? Im good with die cuting and have a good hand for this type of stuff but never modded a nitro motor should I pull mine and try it or just scrap it and buy a better motor and go from there?

JB COMP

I have a question about when people cut out a part of the sleeve, by the main boost port. what do they use to cut, a cut-off wheel, or a carbide cutter?

drift*king

dont take this the wrong way but read the first post--tools you will need and the rest of it you will want to read to.

JB COMP

I have all 12 pages I just don't recall anywhere that it tell about what I'm talking about.

Heres a picture of what I'm talking about

drift*king

Your post asked what to cut it with and in the first post it tells you what you will need to do all the mods that cut in to the sleeve now they dont tell you how to do the mod your talking about but you will need the same tools to do it. I think the cut-off wheel will take to much to fast so go with the carbide bit in a rotary tool at a slow speed and take it slow as to not take to much out of the bottom of the sleeve.

JB COMP

I said cut out a part of the sleeve. I guess I should have said cut a piece out of the sleeve, or a notch.

in the picture it looks like a cut-off wheel, but it being brass a cut-off wheel would probably get cloged up.

but I have both a hi-speed roto carbide cutter and a cut-off wheel. Thanks for the help.

Codeblack

Seems like a pretty cheap engine, meaning it should be very raw and simple on the inside, so you should see significant performance boost when modded.

I did the same with cxp.15, it was really worth the effort.