mt12 crankshaft to nova rs12s5
 

i broke my nova s5 crankshaft, can the mt12 crankshaft fit into it?

I believe you can. The timings on the crank window of the MT12 crankshaft would be different though...

meaning....., i have to adjust the needles butr will it run and idle?

I would not know if you can idle the engine with the MT12 crank at all. I think this you would need to try out yourself or wait for people like Dennis (Motorman) to answer or from people who have actually tried it. Why not give it a try yourself? Maybe it will be for worse or even better in terms of performance if you can get it to start. Who knows...

But still, I'd reckon you retune the carb needles from the start.

And yes, before you install the crank and restart the engine, make sure the internals are clean. If you can, check and see if crnakshaft can turn nicely on the 2 bearings in the engine to see if they are properly aligned.

well the only thing to know is to try, thanks for the tips.:)

You should not have any problems. Providing your engine is not the newer NS5 engine. I have an MT, MT turbo, CX and RS the cranks are all mixed up to the extent that I can't remember which is which...never had a problem.:nod:

Cool. Just that I remembered Dennis (Motorman) mentioning that the crank window timings of the long rod (MT12) and short rod engines were different...

Yeah, the NS12 engines have larger crankshaft diameter (11.5 mm). If you can get the older RS12 internal bearing with 11 mm inner diameter, you may install that in the crankcase and use the older 11 mm crankshafts on the NS12... Just a thought.:sweat:

you are right! they fit perfectly fine and no binding issue, very smooth. But I haven't tried starting the engine, will do it this weekend. I might have issues on its idling/timing as IntialD mentioned, wel I hope not. I will update you guys on its outcome. Thanks for the help.

your timing will be close

Oh D one small problem with going to an 11 mm bearing on an NS. Think about it for a minute>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> >>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> >>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>Oh the light came on didn't it>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> >>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> >>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>The case still has an 11.5 MM hole in it
so the crank won't seal. Small detail. Gotcha LOL

:lol: :lol: :lol: You're the man Dennis ! :nod:

Ummm, I don't get what you mean... The NS inner bearing is 11.5x21x5 while the normal RS12 bearing is 11x21x5. If I use the RS12 crankshaft and replace the 11.5x21x5 bearing with the 11x21x5 bearing in the NS12 crankcase, wouldn't that work?

mt12 crank to nova s5
 

motorman,
going back, i'm no expert in nitro engines, please make it simple. so in short i can't use the mt12 crank to my nova s5?

If it is a RS12s5 you can. If its the NS12 you cant.


What Dennis is talking about (correct me if I am wrong Dennis) is the part of the block between the bearings.

The part where the carb window is, and that the crank spins in. It is bored to a fly shit over 11mm on the RS, and a bee's dick over 11.5mm on the NS.

So, regardless of the fact that you coule change the bearings, if you were to put a 11mm crank, into an NS (11.5mm hole) you will have a 0.5mm gap. Well... 0.25 all the way around the diameter of the crank. This wouldnt be a problem except for the carb opening. The crankcase will never seal at the carb window.

///edit///

The 11.5mm crank would also not work in the 11mm blocks either as it wont fit in the block, due to the crank hole diameter, regardless of bearing size.

Re: mt12 crank to nova s5
 

He said you can but the timings will be slighly different.

sparksy, thanks for the explanation ! :nod: Now I get it. Clear as mud.:lol:

thanks for all the replies, i've learned a lot, i will test and will let you know the results. glad i have the rs12s5.:nod: :)