-Crash-

I just got in from testing the mod work.

I did not touch the sleeve at this time well, OK I smoothed the port openings a little. I could not take it, they are squire edges for gosh sake. lol

anyway, I did what you suggested with the crank, I removed approx. .02 mm from the closing side of the crank.

I also smoothed the internal journal then polished it back up

The sleeve got a quick cleaning on buff wheel careful not to over do it at all

Results: wow, I love you RcTech

This mill is sick, 212 degrees, it revs up allot faster, similar to the 28 RR spec 1
the power band is beautiful. more testing will tell what it did to mileage but, this thing rocks.

as of now I will not be going back in to finish the porting, it doesn't need it.

thanks to all who helped me do this.

Dan

here is a slide show of the mod work , enjoy guys.



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Roelof

Well, this is only simple handtuning to get more but not the max out of it. The real secret is with the modders you are using machinery and other tools to alter the timing to a real known spec in numbers.

-Crash-

hello again

Roelof, Im back again. lol

Your advise on the axial I modded went incredibly well.

(here is a video of the axial I modded http://www.youtube.com/watch?v=cQzYelFf3JM ) tell me what ya think

I have another little monster Im working on. It a surefire .32 R

The sleeve is already worked over from the factory pretty well.

the crank is where I think the most gains will provide.

I was considering removing .2mm from the closeing side as describe here in your thread.

do you have any other suggestions for this one:?

thanks again

Roelof

The engine on the vid runs great but I can not see how it was before. I can imagine it did improve the performance, wheelies all the way.

As I did mention changing the timing (and sharpening the edge) does a lot. I did play with making a bigger venturi in the airintake of the carb and making the whole flow smoother but it does not give a lot of improvement.
You can sharpen the under edge of the cilinder so it will take more and better the flow into the channels to the ports and if you want more rpm you can make uper edges of the exhaust port a tiny bit wider

wingracer

iTrader: (24)

Hey Roelof, any suggestions on a degree wheel? I made one years ago but not being a machinist it was rather crude and not very accurate. I really need something a little more professional if you know what I mean.

Roelof

Last I downloaded one, I have to find out the best way to set it up but I know how to inovate so that will become OK.
http://www.tavia.com/free_degree_wheel.html

Problem with a degree wheel is that there are still some factors in which you can not directly say how far you can go, that is a bit of trial and error. Thats why you 1st have to go no further than lets say 0.4mm and then you can try to take off 0.1mm in steps to give it a try on the track. If you go over the limit the engine will be critical to adjust on the low speed needle. So far I did see some tenths of a mm is more than enough to gain enough performance, the price of most racing engines is not worth to find the limits because there is no way back.....

-Crash-

thanks again

here is a link to the pics of the stock parts & I started to round the bottom edge of cylinder
http://s519.photobucket.com/albums/u354/crash357/

Cowboy

iTrader: (5)

Here are some real number for ya

inlet opens 145 degrees btdc
inlet closes 65 degrees atdc
exhaust opens 92 degrees atdc
transfers opens 118 degrees atdc

This makes a real good off road motor
if you want on road you can do

inlet same as above
exhaust opens 90 degrees atdc
transfers open 117 degrees atdc

freestyles

iTrader: (14)

Very interesting stuff. I would like to have a play around with an old motor i have but i have no car to put it in, what could i do to load the motor up on a make shift break in bench that i will make???

mc_chofo

Hello actually this info actually helped me out to understand more about modding engines. the thing is that i just bought a novarossi 3sct, and i want to make it just like the tunned version or even better, i don't want to make my way to that point too hard. i was thinking about doing some milling kind of drops on the piston sleeve, opening the upper part of the exhaust port 1mm each side, and at last i'm planning to remove those 2mm on the crankshaft hole of the side that closes. ´cause i don't what to screw the engine, does any of you know what i should do exactly to this nova 3sct to turn it into the tunned version? or what i shouldn't do to it to avoid screwing it?

i really appreciate your help.

stefan

Please don't.
You got a wonderful engine there, that will have gobs of power if your pipe and clutch is correct.

All the changes you mentioned above are guess work. You can not measure crank timing in mm, also, opening the exhaust by 1mm will give you approx. 15 ° timing change, which is way too much. If you are opening the exhaust port 1 mm to each side, your piston will catch the edge and your engine will be toast. The exhaust port on the 12-3 is very complex and works well as it is.

You cannot transfer any of the measurments, you might have read here to any type of engine. Below they are talking about .28 engines.

Leave it alone and be happy, or send it to someone like Murnan and get some reliable power.

Roelof

Yes, that is an awesome engine which do not need any mods, for sure if you are no toplevel driver. If you want to get some improvement you can smoothen the flow.

mc_chofo

Hi i appreciate your comments really, but i do want to modd this engine, not extreme gain power, i just want to gain those .04hp that the tunned version has. i did not bought the tunned version 'cause i didn't found it. so this is exactly what i'm planning to do, suggestions or comments are wellcome.

the piston sleeve that i show it's not from the 3sct it's from a mega mf12, but i show it just to show my plans, my plans are, opening the inlet port a little, or maybe the exhaust port, like 1mm each side horizontal or .5mm horizontal(not vertial) in order to gain some power and maybe some rpms. i'm planning to do that only on the crome part, not touching the crome, but if you look it from outside you will see a wider port.
the fangs that i plan to do, are short and wide like the ones that i show here. i'm planning to smoth the lower lip of exhaust and inlet ports a little.
and finally i'm planning to smooth and polish the fang of the crank like the tunned version is. i will not touch the inlet port of the crank unless you suggest it.

stefan

As I said before, leave that exhaust port alone. It's one of the great improvements Novarossi made on the Plus engines and it works great, due to his roof like shape.

Also, leave the crank inlet alone unless you have a degree wheel. If you do, change it to 30° ABDC - 65° ATDC (total of 215°)

mc_chofo

Hi stefan, i do have a degree wheel, thanks for the advice, but do you know exactly what does make the difference in power between the nova 3sct and the tunned version?. i was also planning to mod the crankshaft by making it closing 2 degrees later.