crankshaft NR

[XtremeRcBoats]

I've got a NR T21-7M and the ramp at the inlet of the crankshaft came loose, I found small parts in the case. I tried to get the ramp out, and after that i found more harder stuff.

Can I run it without the ramp and the harder stuff? Is the harder stuff needed for the structural strength of the shaft or can i run it without with less performance? I've got a race this weekend and can't get a new shaft before that time.

After I get a new crankshaft, what is the best way to preserve the ramp? I normally clean the engine with WD-40 and then flush it with ATF oil.

Thanks,

 

[steve wood]

you don't need the ramp.clean it out good.don't use wd-40,that will attack the ramp material

 

[D-7]

Paul, you have mail

cleaning - pure methanol, after this "after run oil" (modeltechnic)

 

[Ian Inverarity]

Personally I wouldnt buy a new crank. I remove the ramp from all my Nova's and they run fine!

 

[XtremeRcBoats]

ok thanks a lot for the info, wasn't sure if I could run it. Then I'll remove the ramp including the stuff behind it, and then i can run this weekend

Frank, thanks for the mail.

 

[Blackout]

Does the 5-port NR come with a ramped crank shaft? What about an O.S. XM outboard? I use WD-40 all the time, but I always make sure it's all spun out of the engine too.

 

[RodneyPierce]

Craig, no and no. I know for a fact that the OS does not. And Im about 90% sure the 5 port doesnt either.

 

[Blackout]

Craig, no and no. I know for a fact that the OS does not. And Im about 90% sure the 5 port doesnt either.

Good to know, thanks!

 

[aaron alberico]

The 5 and 7 port motors don't come with silicone

In crank..

Regards Aaron

 

[RodneyPierce]

there's your answer for sure. I didnt think so.

 

[XtremeRcBoats]

hmm than my T21-7M is starting to look more and more as a 35plus21? The reason i thought it as a T21-7M was because the cooling head said so.

I ordered a new head button from Frank Orlic and that didn't fit either. He told me the sleeve was from a 35plus21. So maybe the crankshaft is also from a 35plus21. What diameter crankshaft is in the 35plus21, 14 or 14,5mm?

 

[aaron alberico]

Only 14.5mm version as the silicone in the crank...

Regards Aaron

 

[Blackout]

hmm than my T21-7M is starting to look more and more as a 35plus21? The reason i thought it as a T21-7M was because the cooling head said so.

I ordered a new head button from Frank Orlic and that didn't fit either. He told me the sleeve was from a 35plus21. So maybe the crankshaft is also from a 35plus21. What diameter crankshaft is in the 35plus21, 14 or 14,5mm?

Is this a used engine? Maybe the previous owner ramped the crankshaft himself....

 

[XtremeRcBoats]

Craig your where right. I bought it used and the previous owner did his own mods, see pictures below. The ramp was made from black stuff. I removed it all and bought the silicone stuf Frank suggested to me. As you can see in the last picture he removed a lot of material from the crank.

Now also got a new cooling head from Frank Orlic and backplate.

 

[steve wood]

Craig your where right. I bought it used and the previous owner did his own mods, see pictures below. The ramp was made from black stuff. I removed it all and bought the silicone stuf Frank suggested to me. As you can see in the last picture he removed a lot of material from the crank.

Now also got a new cooling head from Frank Orlic and backplate.

i don't see where the crank has any mods,aside from maybe a little polishing

 

[RodneyPierce]

Looks to me like they opened up the turbo a little bit, and maybe a little on the counter balance weight. But the induction timing looks to be untouched.

 

[David Murany]

Is that a stock rod? It doesnt loook bushed from the picture which is surprising.

 

[Martin Hamilton]

Couple of things, the rod needs turning 180 degrees so the oil hole is facing shaft induction passage + that looks like someone has fitted an Axe Rossi con rod.

 

[XtremeRcBoats]

Martin, thanks for the comment I'll have a look at it. What do you think about the sleeve, is this from a T21-7M?

 

[RodneyPierce]

yes, as is the crank. I dont think that rod is from a rossi either, I think its stock to the motor. Everything you have there looks to be a stock T21-7M in my opinion. Someone just did some polish work on it.