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Old 10-10-2008, 07:52 AM   #1
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What do people actually do to nitro motors when they say it's been modified??

Would it be easy enough to do it yourself with just a roto-tool and a bit of know how??

And once done is it really that noticable?
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Old 10-10-2008, 09:45 AM   #2
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Quote:
Originally Posted by freestyles View Post
What do people actually do to nitro motors when they say it's been modified??

Would it be easy enough to do it yourself with just a roto-tool and a bit of know how??

And once done is it really that noticable?

This is my modified engine, can you tell the difference...?...

If you did correct modification, you can tell the performance is much better than original.



















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Old 10-10-2008, 11:27 AM   #3
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What do people actually do to nitro motors when they say it's been modified??
They Write "Tuned by....." on the cooling head.

This will help you:
http://www.rctech.net/forum/exclusiv...o-engines.html
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Old 10-10-2008, 03:52 PM   #4
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The problem with modifying an engine is knowing what to mod., how much to mod. it, and when to stop. I had an os tz .12 that I simply copied what I saw on other professionally modified motors. I took it one step at a time. I started with the head button mod where you cut grooves on the inside of the head to direct the fuel air mixture toward the glow plug. This gave a noticeable improvement in performance and had little affect on fuel mileage. The next mod. was the crank scoop. This had very little affect on performance and the fuel mileage was slightly down. The next mod was putting tear drops in the sleeve and this was the worst mod for this motor. It had no affect on performance and took fuel mileage from 5+ minutes a tank to 4.5 The motor was now useless because the mileage was terrible. But, the piston/sleeve are cheap so I replaced them.

The thing you have to know is that these results only apply to my motor. Since all motors are different, you have to know what certain mods will do to certain motors. It can be an expensive experiment when you don't know what you're doing (like me ) So i've learned to leave the modding to the people that can afford to do it. Plus they can test them and use actual measurements and CNC machines (some even have dynos) to do it right.

If you really want a modded motor, look at which modders win the big races at big tracks. See if their motors got good mileage or were the guys pitting early with a splash and go at the end while everyone else was making 5min. Do your homework since these motors are expensive to begin with and paying a modifier usually isn't cheap. Hope that helps.
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Old 10-15-2008, 03:12 AM   #5
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The problem with modifying an engine is knowing what to mod., how much to mod. it, and when to stop. I had an os tz .12 that I simply copied what I saw on other professionally modified motors. I took it one step at a time. I started with the head button mod where you cut grooves on the inside of the head to direct the fuel air mixture toward the glow plug. This gave a noticeable improvement in performance and had little affect on fuel mileage. The next mod. was the crank scoop. This had very little affect on performance and the fuel mileage was slightly down. The next mod was putting tear drops in the sleeve and this was the worst mod for this motor. It had no affect on performance and took fuel mileage from 5+ minutes a tank to 4.5 The motor was now useless because the mileage was terrible. But, the piston/sleeve are cheap so I replaced them.

The thing you have to know is that these results only apply to my motor. Since all motors are different, you have to know what certain mods will do to certain motors. It can be an expensive experiment when you don't know what you're doing (like me ) So i've learned to leave the modding to the people that can afford to do it. Plus they can test them and use actual measurements and CNC machines (some even have dynos) to do it right.

If you really want a modded motor, look at which modders win the big races at big tracks. See if their motors got good mileage or were the guys pitting early with a splash and go at the end while everyone else was making 5min. Do your homework since these motors are expensive to begin with and paying a modifier usually isn't cheap. Hope that helps.


I have an O.S 12 TZ but cause i don't know what i'm doing i don't want to ruin it. Have you got any pics of your modded TZ so i can copy those head button grooves. Will this work with a turbo button head??
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Old 10-15-2008, 04:09 AM   #6
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I have an O.S 12 TZ but cause i don't know what i'm doing i don't want to ruin it. Have you got any pics of your modded TZ so i can copy those head button grooves. Will this work with a turbo button head??
Search the internet for "singh grooves", lots of info about how and why.

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Old 10-15-2008, 08:17 AM   #7
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Yes, this is the first mod I did to my tz and like I said, noticeable improvement in power and no loss of fuel mileage. I also did this same mod to a .28 motor that came in my RTR 1:8 buggy with the same results.
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Old 10-15-2008, 12:54 PM   #8
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Largest gain is going to come from timing. This is something you do only when you know what you are doing. Timing can be changed from crank, or sleeve, in either case, you have to know exactly how much and where. Unless you have lots of money, equipment, and patients, you're better off leaving it to the modders that know what they are doing.
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Old 11-03-2008, 02:38 AM   #9
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Someone once said to me that the glow plugs determine engine timming. For example a motor with an RB 5 plug will have different timming to the same motor with an RB 7 plug in it. Could anyone shed any light on the subject for me please.
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Old 11-03-2008, 04:03 AM   #10
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Thats ignition timing.... The roug timinh is set by the headshims and finetuned by the glowplug. A colder plug will give a slight later ignition which can give a tiny bit higer rpm and a warmer plug will give a early ignition which will give a tiny bit more bottom power. But running a 5 in a .21 high end competition engine which does have a high compression can result in broken plugs.

Finally this is only done as correction to the outside weather.

A tiny change to the cranktiming will do more than you will get with changing ignition. Inlet and exhaust timing are the things to change to get more out of it.
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Old 11-03-2008, 07:04 AM   #11
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Thats ignition timing.... The roug timinh is set by the headshims and finetuned by the glowplug. A colder plug will give a slight later ignition which can give a tiny bit higer rpm and a warmer plug will give a early ignition which will give a tiny bit more bottom power. But running a 5 in a .21 high end competition engine which does have a high compression can result in broken plugs.

Finally this is only done as correction to the outside weather.

A tiny change to the cranktiming will do more than you will get with changing ignition. Inlet and exhaust timing are the things to change to get more out of it.
Gee and i'm running a RB 5 in my STS .30 at the moment, should i use a 6 or 7 instead?
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