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Old 02-12-2006, 06:15 PM   #961
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Hi guys, I have one TZ 3 port and I want more power. Talking with some friends they suggest to take out 1 shim from the inner gasket, the thicker one. Does anybody heard about this? Im running fuel with 20% like the instruction sheet said, to use this configuration I think will have to use 16% nitro fuel, correct?
Thanks!
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Old 02-12-2006, 06:48 PM   #962
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You can try different pipe or manifold
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Old 02-12-2006, 07:14 PM   #963
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I agree with Dani you should try different pipes before you start risking your motor and taking shims out, but if it comes down to it and you want to take one out you should start with the smallest one as that will do the least in terms of power and motor compression.

With the fuel to tell you the truth i have used 16% with all my motors and then i had to use 20% because we had no 16 in stock and i did not notice any difference in power at all.

So it would be better to run 16 since obviously its less nitro content but most rules in events state max 16% nitro anyway so if you run 20 then enter in a event and have to go back to 16 you will have to re-tune engine and everything for it which can be a pain if it gives you grief.
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Old 02-12-2006, 08:15 PM   #964
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Quote:
Originally Posted by Kyosho3PKRacer
With the fuel to tell you the truth i have used 16% with all my motors and then i had to use 20% because we had no 16 in stock and i did not notice any difference in power at all.

.
I agree totally....i`d tried both 16% and 20% nitro content in a RB V12 i was racing and really couldnt tell any difference.
The TZ has 2 shims.....one is 0.1mm the other 0.2mm......if you really have to take shims out, then the 0.1mm would be the first port of call.
Again, as mentioned previously, I`d also be trying different pipes to get more power......or also consider experimenting with gearing....the TZ makes plenty of torque so different gearing is a good option to explore.
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Old 02-12-2006, 08:31 PM   #965
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I would also suggest not to mess with the engine's settings. Changing shims will modify the engine greatly. Like AndyT said, you could try to use taller gears, TZ has no problem in moving large gears.
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Old 02-14-2006, 04:51 PM   #966
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Different shim thickness goes with differnt nitro content in the fuel. I won't mess around with the shim unless you are going to run with a fuel with different nitro content. But, few percentages in nitro content probably won't make too big of a differnece in power.

If you want more speed, I would change the P/S to 5 ports.
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Old 02-14-2006, 06:37 PM   #967
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Taking the shim out for me is a cheap way to improve the performance. I dont want to spend $70 in a new pipe, I cant
Here the rule is very simple. Any nitro % is allowed, but I prefer to run with 16% or 20% because is cheaper.
PS. 5 port is not allowed Im curious! lol I will test without the thicker shim 0.1mm after I tell you guys about the result
Thanks
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Old 02-14-2006, 07:48 PM   #968
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Default more speed ?

send your engine to uriah murnam to get modified

then you will be saying "guys i have too much speed" hehe
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Old 02-15-2006, 12:25 AM   #969
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Taking the 0.1mm shim out will increase the power at the bottom end greatly. It will also help to reduce the engine temp. The danger is that you will get pre ignition and ruin the pistion and maybe the liner.

The engine already has good bottom end as its a long stroke engine. I would take out the shim and run a taller gear.

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Old 02-15-2006, 12:40 AM   #970
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Quote:
Originally Posted by jeff1
Hi guys, I have one TZ 3 port and I want more power. Talking with some friends they suggest to take out 1 shim from the inner gasket, the thicker one. Does anybody heard about this? Im running fuel with 20% like the instruction sheet said, to use this configuration I think will have to use 16% nitro fuel, correct?
Thanks!
Are you good at tuning your own motor? if not you might want to get some help from someone at your local track who is a master tuner of nitro engines, that is what I did and the motor was ballistic without messing with the shims.
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Old 02-15-2006, 05:43 AM   #971
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Default Engine head shimming

This is what master engine tuner Dennis Richey has to say about head shimming. I hope it clears up the issue with people trying to find the proper head clearance.

Engine Shim Tuning
By Dennis Richey


Experience dictates that just by lowering the head (more compression) you gain more power especially in lower rpm range, idle quality can suffer, but the engine also runs cooler . Also, that a higher head (less compression) will increase top rpm speed on bigger tracks.
A decrease in head shims (an increase in compression ratio) will increase torque because as the compression ratio goes higher, the actual ignition timing occurs sooner. However there is a point of diminishing returns where detonation occurs or engine temps can soar, and if this happens a colder plug can help.
A colder plug will also increase torque, except in the instance of a colder plug the ignition is slowed until a greater point of compression build occurs.
When you increase head shims (a decrease in compression), top end is enhanced as the ignition timing is retarded and occurs later. Generally a hotter plug is needed to advance the ignition cycle so that timing does not occur to late in the cycle, but at this point you end up over leaning the engine to get it to rev properly and the engine life will suffer dramatically.

On a .12 engine we would only advise going 0.10mm over or under 0.46mm, so that is 0.36mm or 0.56mm of total head clearance at sea level.
Generally on a .12 engine 0.10mm will change the compression ratio about 3/4 to 1 point..

We should also state that the comments with regards to plugs and head shimming are when both are used together. Used alone a hotter plug will rev harder and a colder plug will make more torque.

One last comment. never assume that the head shim that is on the engine is the actual head clearance. In many cases you will find that the engine actually has 0.20mm to 0.15mm without any head shim. Novarossi's have 0.20mm without one, and the factory installs a 0.30mm shim, giving the engine 0.50mm stock head clearance. This has not always been the case but 99% of the time it is. When in doubt measure the head button register and the piston to the top of the liner at top dead center and subtract, to determine proper shim. This is the only way to really know.


AFM
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Old 02-16-2006, 02:00 AM   #972
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Thanks AFM for the info. I never really knew what shiming a motor was all about, with that explaination I learn a lot, thats why I like rctech so much plenty of info. to learn when your a novice also your able to pass on what you learn to next beginner.
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Old 02-16-2006, 10:38 AM   #973
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my friend has a tz 5p, when he lease from full throtal, the engine rev at a somewhat higher pitch for few second before going down to idle, can anyone tell me what happend?
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Old 02-16-2006, 12:06 PM   #974
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Seems that the idle speed needle is too high. Do this, start the engine, warm it up. Let it sit at idle speed. And begin to open the idle needle until it reaches a very low speed. This happened to me on my TZ. Coming out of the straight, the engine felt that it didnt went to idle speed quickly and stayed reved up.
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Old 02-16-2006, 05:17 PM   #975
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they call that "getting up on the pipe". it indeed does have to do with the idle screw, it's too rich, so the engine will maintain a high rpm for a moment then die down because a shot of fuel was injected into the carb. leaning the idle should fix it, because it's shooting less fuel in.
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