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Old 01-03-2011, 07:55 PM   #1
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Exclamation Port and polishing..

Hi i was wondering if porting and polishing your nitro engine worth or no?
just curious because im about to send my novarossi and lrp to get port and polish all around from top to bottom?
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Old 01-03-2011, 08:22 PM   #2
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Hi i was wondering if porting and polishing your nitro engine worth or no?
just curious because im about to send my novarossi and lrp to get port and polish all around from top to bottom?
If its not an RTR engine, then it isn't worth it unless its for free!

Best way to improve performance is through timing changes in the crank and the sleeve ports.
There are a few around here that do this, myself included:
Colt4G63 - AB Mods
Grinder - Murnan Modified Motors
and others.

These two are the best of the best IMO, but to each there own.
They have proven work and can consistently repeat their work, whereas I can only get that engine into the "sweet" area.
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Old 01-04-2011, 02:42 AM   #3
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Hi i was wondering if porting and polishing your nitro engine worth or no?
just curious because im about to send my novarossi and lrp to get port and polish all around from top to bottom?
Its normally not worth the effort to polish up the motor. Whatever the gain in flow would be, will be negated by poorer quality of atomized fuel. All those rough surfaces help keep the fuel suspended in the air charge going to the combustion chamber.

Now for some port/timing, there is acouple of threads that can show you some basic stuff that could improve a budget motor.

Shawn.
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Old 01-04-2011, 06:23 PM   #4
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Its normally not worth the effort to polish up the motor. Whatever the gain in flow would be, will be negated by poorer quality of atomized fuel. All those rough surfaces help keep the fuel suspended in the air charge going to the combustion chamber.

Shawn.
This is not correct, rough surfaces do nothing to suspend fuel in the incoming fuel charge. Air acts and reacts as water does (just thinner) rough surfaces causes air to slow. By removing the rough surface you not only increase the amount of air that can flow but you speed it up as well.
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Old 01-04-2011, 06:41 PM   #5
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I think in a four stroke yes but in a 2 stroke it doesn't make a difference. but that is just an opinion.
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Old 01-04-2011, 09:43 PM   #6
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I know for a fact that it will definitely benefit a major production/RTR engine, it showed fantastic results in my TRX 3.3 engine - In order to just hit second gear I had to lean it a full turn, otherwise it was just blubbering.

For more race-orientated engines and other .12 engines, the improvement is minimal. You might gain some flow benefits because there is a smoother path to follow - if done correctly - but that is something you can do yourself easily.

What you do want to do is port-match your engine block with the ports - make then all flush with each other. This is one thing that will improve the engine, but not as much as timing changes. Changing timings require pretty precise calculations if you know how to do that, and you would need to experiment with multiple engine sleeve to know how far you can go, what kind of power change did changing "port X" timing do and so forth - not easy and not cheap.

Thats why, if you want your high-end engine to be somewhat 'unique' and better than the other engines (same type) you would send it to somebody that has the knowledge and right timings for that engine, that's why when I got my JLR Evo3, i had it modified by AB Mods because he knew where to change what, and that same type of engine got the ISC speed record in whatever category it was in (.12 smallblock I think) I would go to Murnan Modified (Grinder here on RCTech) but I dont need my engine modified, yet, and he is a fair bit more expensive that people like AB Mods (Colt4G63) and Clockworks racing. Everybody has there way and price.
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Old 01-04-2011, 11:52 PM   #7
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You can polish the crankshaft, piston head ( polish the top section only ), conrod and backplate.

Clean engine = better performance and better looking too.

You must not polish the side or inside, big no no. ( minor polishing on sleeve's outer body is okay, but do it not often. )

You understand what i mean.
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Old 01-05-2011, 09:07 PM   #8
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If you want, I can do the porting and polishing for free, just pay for postage to and from me.
Depending how it is internally, I'll even port-match it for you. Just a free heads-up
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Old 01-06-2011, 03:32 AM   #9
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dj are you a modifier now?
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Old 01-06-2011, 04:32 AM   #10
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dj are you a modifier now?
i just think he likes to write up a good story or 4 ....
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Old 01-06-2011, 05:41 AM   #11
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Anyone can modify an engine. Polishing is a waste of time, tiny changes on a crankshaft will do so much more and anyone can add 1 or 2 degree timing which is safe to do, even with the fastest .21 onroad engines.

If you are afraid to change timings than you can always add a shimm under the edge of the sleeve to raise it a tiny bit which can be easy undone and otherwise some flowing (rounding all sharp edges of the compleete flow) will give a more stable running engine which does react faster and does reach a tiny bit more rpm.
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Old 01-08-2011, 08:41 AM   #12
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Anyone can modify an engine. Polishing is a waste of time, tiny changes on a crankshaft will do so much more and anyone can add 1 or 2 degree timing which is safe to do, even with the fastest .21 onroad engines.

If you are afraid to change timings than you can always add a shimm under the edge of the sleeve to raise it a tiny bit which can be easy undone and otherwise some flowing (rounding all sharp edges of the compleete flow) will give a more stable running engine which does react faster and does reach a tiny bit more rpm.
were do u add the shim? to raise the timing and is it a head shim u use?
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Old 01-08-2011, 09:10 AM   #13
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were do u add the shim? to raise the timing and is it a head shim u use?
You add the shim between the liner and the crankcase under the lip of the liner.

We used to make them ourself from a headshim for a .26 for example, but since recently they are available through capricorn.

http://www.capricornrc.com/capricorn...d_product=1320

http://www.capricornrc.com/capricorn...d_product=1319

For the amount of shims you add below the liner you have to take out the same amount of headshims to keep the squish/compression the same.

These shims are also available for .12 engines.
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Old 01-08-2011, 09:48 AM   #14
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dj are you a modifier now?
Hahaha, is that sarcastic?
Ive been modifying for a little while now, with no negative results having no dyno to use
I haven't done many, but the ones I did turned out to be just what they wanted to get out of it.

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i just think he likes to write up a good story or 4 ....
Errrmmm, is that a good thing or bad thing?? O.O
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Old 01-09-2011, 04:00 AM   #15
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first you must learn to run in properly these engines then you can modify yours and espacially others engines.
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