R/C Tech Forums

Go Back   R/C Tech Forums > General Forums > Nitro On-Road > Onroad Nitro Engine Zone

Reply
 
Thread Tools Search this Thread
Old 05-14-2004, 12:02 AM   #1
Tech Adept
 
Join Date: Sep 2001
Posts: 197
Trader Rating: 10 (100%+)
Default NSR crankshaft nonconcentric

The induction hole of my NSR crankshaft is not concentric. You can see that as I turn the crank the hole is not centered and wobbles.

The vid is 1.3 megs

http://image.gotdns.com/nonconcentric.mov
boom is offline   Reply With Quote
Old 05-14-2004, 12:41 AM   #2
Tech Elite
 
AMGRacer's Avatar
 
Join Date: Oct 2001
Location: Brisbane, Australia
Posts: 3,939
Default

Its fine, the hole is elongated at the bottom due to the crankshaft "turbo" port. I personally have never seen one like this from the factory, has it been modified?
AMGRacer is offline   Reply With Quote
Old 05-14-2004, 01:01 AM   #3
Tech Adept
 
Join Date: Sep 2001
Posts: 197
Trader Rating: 10 (100%+)
Default

No it has not been modified. The engine definitely runs fine though.....

To clarify, the entire hollow cylinder is off axis, not just the hole. It's hard to see because it is so dark.
boom is offline   Reply With Quote
Old 05-14-2004, 10:57 AM   #4
Registered User
 
OB42TC3's Avatar
 
Join Date: Nov 2001
Location: Columbus, OH
Posts: 417
Default

It is supposed to be like that; forget why but I do remember the local engine guru telling me about all the things he does to his engines and that was one of them.
OB42TC3 is offline   Reply With Quote
Old 05-15-2004, 07:34 PM   #5
Tech Elite
 
AMGRacer's Avatar
 
Join Date: Oct 2001
Location: Brisbane, Australia
Posts: 3,939
Default

Quote:
Originally posted by boom
No it has not been modified. The engine definitely runs fine though.....

To clarify, the entire hollow cylinder is off axis, not just the hole. It's hard to see because it is so dark.
All the Novas I have seen have a sharp edge on the channel unlike this one. Might be the latest itteration of the NS crank. Novarossi is changing crank design all the time. I have had three different types of cranks in RS12 motors.
AMGRacer is offline   Reply With Quote
Old 05-19-2004, 07:26 PM   #6
Tech Elite
 
rcfoolz's Avatar
 
Join Date: Sep 2003
Posts: 3,327
Trader Rating: 22 (100%+)
Send a message via Yahoo to rcfoolz
Default

the crank in the RR12 L3 is the same way. Does anybody know where to find a piston and sleeve for the RR12 L3 though?
__________________
Am I going back racing?...Hmmm.. Not anytime soon... But soon enough.
rcfoolz is offline   Reply With Quote
Old 05-20-2004, 12:02 AM   #7
Tech Rookie
 
Join Date: Aug 2003
Location: nor cal
Posts: 6
Send a message via AIM to JoshA
Default

just a guess. if the hole is not concentric and offset towards the crank pin then maybe it's a way of balancing the piston/rod combo. my 2 cents.
JoshA is offline   Reply With Quote
Old 05-25-2004, 10:24 PM   #8
Tech Regular
 
boner's Avatar
 
Join Date: Oct 2001
Posts: 343
Trader Rating: 3 (100%+)
Default

NSR is milled the same way... non concentric
boner is offline   Reply With Quote
Old 06-04-2004, 10:42 PM   #9
Tech Addict
 
Bivens's Avatar
 
Join Date: Nov 2003
Location: Knoxville, TN
Posts: 679
Default Sirio also

Just over-bored the center of the shaft in a Sirio .12....it was off-center as well........Not anymore...but it's x-sectional area is now 133% what it used to be.........now it's time for the hand work.....
Bivens is offline   Reply With Quote
Old 06-04-2004, 11:18 PM   #10
Tech Fanatic
 
teammpp's Avatar
 
Join Date: Mar 2004
Location: Northern Ireland
Posts: 894
Default

Its all to do with fluid dynamics and how the fuel mixture moves through the shaft and into the ports. Fluid moving through a rotating cylinder swirls like a tornado and so by making the bore non-concentric it allows the flow to work with the crank.
teammpp is offline   Reply With Quote
Reply

Similar Threads
Thread Thread Starter Forum Replies Last Post
HPI F4.1 Crankshaft marvs777 R/C Items: Wanted to Buy 0 12-22-2007 02:29 AM
JP FX3 CRANKSHAFT rchopeless Australia Wanted to Buy 0 01-01-2007 03:47 PM
rb x12 SG crankshaft cmain R/C Items: Wanted to Buy 0 06-24-2006 08:46 AM
os crankshaft webinjected Nitro On-Road 0 02-06-2005 03:13 AM
crankshaft TRF_TG10R Nitro On-Road 1 06-14-2003 10:51 PM



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off



All times are GMT -7. It is currently 01:27 AM.


Powered By: vBulletin v3.9.2.1
Privacy Policy | Terms of Use | Advertise Content © 2001-2011 RCTech.net