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Old 02-20-2004, 04:11 PM   #361
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Default MT12rs

Dino,

The other day at a local championchip race I had trouble starting my engine. After several Glow plugs being burt w/o making an entire lap, I decided to retire my car for the day. Later I let my freind who has more experience w/ engines than I take it apart and revise it. It seems that the Comrod bushing broke causing damage to the piston, the sleeve had a minor scratch. The rest of the engine was fine. My friend found a piston from a RB engine that he had lying around that fit well and pinched well still, and we then matched a comrod from a Novamega sx12re. For the moment the engine has worked fine, but only has 2 tanks since the repare.

Is there anything I should be concerned about w/ this repair, or can I expect the motor to continue running well. This motor is aprox 1 gallon old. How long do you think I can expect it to last. I run Blue Thunder 30% and live in Puerto Rico.
The engine block and crank shaft look OK.

Thanks,
Havy
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Old 02-20-2004, 05:03 PM   #362
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Default Re: MT12rs

Quote:
Originally posted by havy
Dino,

.................. My friend found a piston from a RB engine that he had lying around that fit well and pinched well still, and we then matched a conrod from a Novamega sx12re. For the moment the engine has worked fine, but only has 2 tanks since the repare.

Is there anything I should be concerned about w/ this repair, or can I expect the motor to continue running well.....

Thanks,
Havy
I thought the STS MT12RS was a long conrod engine, just like the Mugen MT12, if so, did you check that conrod lenght was the same with the Novamega's??? I think the Novamega SX12RE is a short conrod engine. If that is the case, your engine is running way under compressed, unless your STS is not MT and is RS, than you can expect good performance.

AFM
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Old 02-20-2004, 09:31 PM   #363
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yes it is the RS edition, hand modded, the comrod was checked w/ the STS comrod to make sure it matched. It is the MT12 RS....threaded shaft. We looked at the Mugen's comrod but it was longer than the STS one.....I don't quite know if this is supposed to be but yes, it was the same size... Thanks for your input.

I was told that the diff between the RS3 and the MT12RS was the crank shaft, threaded vs. SG. Just in case I am running less shims on this custom version, decreased from .06 to .03. For the moment it seems to be performing well....hope it maintains this performance.

Thanks again,
havy
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Old 02-22-2004, 02:38 AM   #364
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Default Stupid tuning question

I am sure this is a silly tuning question:

Problem is, I can go full throttle / idle no worries but if I use 40% throttle engine revs, then starts to bog down (flodding) then coughs a bit then stops. Where am I going wrong?

Pipe is THS pipe on LD3.

(I have a feeling someone is going to say try longer pressure line? hehehe)

Last edited by au_Nightmare; 02-22-2004 at 02:56 AM.
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Old 02-22-2004, 03:16 PM   #365
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I am by no means an authority in engine tuning and really am curious if this could not be a rich low end neddle setting???

havy
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Old 02-22-2004, 03:45 PM   #366
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Thats what I would of said but if I lean out LSN the engine starts to sing and pinch fuel line engine cuts out too fast so I have LSN where engine runs for a few seconds then revs up and cuts out when fuel line is pinched.
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Old 02-22-2004, 06:07 PM   #367
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Default Re: Stupid tuning question

Quote:
Originally posted by au_Nightmare
I am sure this is a silly tuning question:

Problem is, I can go full throttle / idle no worries but if I use 40% throttle engine revs, then starts to bog down (flodding) then coughs a bit then stops. Where am I going wrong?

Pipe is THS pipe on LD3.

(I have a feeling someone is going to say try longer pressure line? hehehe)
This is a midrange tuning issue. Our little nitro motors really are not made to run well with these types of throttle settings (carb design issue). Most of them run quite rough when the low speed needle is just about to completely unseat from the spraybar since this is not really a position used very often in racing.

I am not familiar enough with the STS yet to answer this question fully. Playing with the mid range needle may resolve this issue somewhat, but it may well be an issue related to the design and shape of the end of the low speed needle.
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Old 02-22-2004, 10:44 PM   #368
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Hey Dino is my crank and rod. With you yet???


Just was wondering what was going on with it??
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Old 02-23-2004, 03:42 AM   #369
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Hi,

Can someone tell me what in general how many turns out is the HSN and LSN on the Dragon5? I don't need it to be exact, just want some kind of reference.

TIA
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Old 02-23-2004, 03:57 AM   #370
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Quote:
Originally posted by Joehwee
Hi,

Can someone tell me what in general how many turns out is the HSN and LSN on the Dragon5? I don't need it to be exact, just want some kind of reference.

TIA
Hi,

Someone had the same question before, Dino gave these factory settings for D5:

Mid Range needle - Flush with the housing.
Low Speed needle - 4 Turns out.
High Speed needle - 4 Turns out.

Last edited by GUNPOWDER; 02-24-2004 at 10:40 PM.
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Old 02-23-2004, 11:38 AM   #371
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Quote:
Originally posted by stefan
Dino,

I have lapped my piston before I broke the engine in and had no crankshaft problems so far.

But i think you should probably re-think your tolerance between the piston and sleeve, since two liters of fuel is a real pain in the behind.
Dear Stefan,

When we produce a p/s set with more tolerance,people complain about not lasting enough. When we produce a p/s set with less tolerance,people complain about it is a real pain to break-in. Sometimes there is no end story....
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Old 02-23-2004, 11:56 AM   #372
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Default Re: MT12rs

Quote:
Originally posted by havy
Dino,

The other day at a local championchip race I had trouble starting my engine. After several Glow plugs being burt w/o making an entire lap, I decided to retire my car for the day. Later I let my freind who has more experience w/ engines than I take it apart and revise it. It seems that the Comrod bushing broke causing damage to the piston, the sleeve had a minor scratch. The rest of the engine was fine. My friend found a piston from a RB engine that he had lying around that fit well and pinched well still, and we then matched a comrod from a Novamega sx12re. For the moment the engine has worked fine, but only has 2 tanks since the repare.

Is there anything I should be concerned about w/ this repair, or can I expect the motor to continue running well. This motor is aprox 1 gallon old. How long do you think I can expect it to last. I run Blue Thunder 30% and live in Puerto Rico.
The engine block and crank shaft look OK.

Thanks,
Havy
Dear Havy,

When your engine runs fine before but start to have some odd condition, like burn plug;hard to adjust;easy to cut out...ect. You must stop your engine right now and looking for where is wrong. Sometimes it always some parts has problem. When I meet this situation,I will put a white tissue outside of the tail pipe. Let the smoke spray on it and open the throttle a bit. If you find any impurity,that means your engine has some part fault. I will open this engine and check it carefully.

If your mixed engine work fine,congrats. If it will have some problems,when you start it at the first time you will know. But you better to check the compression,if the head shims are too much or not enough.
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Old 02-23-2004, 11:59 AM   #373
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Default Re: Re: MT12rs

Quote:
Originally posted by afm
I thought the STS MT12RS was a long conrod engine, just like the Mugen MT12, if so, did you check that conrod lenght was the same with the Novamega's??? I think the Novamega SX12RE is a short conrod engine. If that is the case, your engine is running way under compressed, unless your STS is not MT and is RS, than you can expect good performance.

AFM
Thanks AFM.

All STS .12 engines are short rod. And almost all parts can be exchanged with each other.
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Old 02-23-2004, 12:03 PM   #374
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Default Re: Stupid tuning question

Quote:
Originally posted by au_Nightmare
I am sure this is a silly tuning question:

Problem is, I can go full throttle / idle no worries but if I use 40% throttle engine revs, then starts to bog down (flodding) then coughs a bit then stops. Where am I going wrong?

Pipe is THS pipe on LD3.

(I have a feeling someone is going to say try longer pressure line? hehehe)
Try hotter plug to advance the ignition timing.
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Old 02-23-2004, 12:06 PM   #375
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Quote:
Originally posted by Thunder racer
Hey Dino is my crank and rod. With you yet???
Just was wondering what was going on with it??
Haven't got it yet. I'm waiting for them.....Don't worry.
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