Single Turbo RX-7's Questions about all aspects of single turbo setups.

Rotor weight , Picking correct counter weight

Thread Tools
 
Search this Thread
 
Old 06-22-22, 07:18 PM
  #1  
Junior Member
Thread Starter
iTrader: (2)
 
Mikesfd's Avatar
 
Join Date: Jul 2018
Location: Wi
Posts: 36
Likes: 0
Received 2 Likes on 1 Post
Rotor weight , Picking correct counter weight

Put used auto counterweight and Mcloed rst clutch and flywheel on my fd , in higher revs it seams unbalanced and not smooth . How do I know what weight the counter weight needs to be ? Ft rotor is 4321 grams and rear 4353 grams don’t know what (rotor code) that is
Old 06-22-22, 08:14 PM
  #2  
Rotary Freak

 
billyboy's Avatar
 
Join Date: Jun 2005
Location: sydney
Posts: 1,533
Received 261 Likes on 199 Posts
Counterweights are only modified by the balancer.
Old 06-22-22, 08:31 PM
  #3  
Junior Member
Thread Starter
iTrader: (2)
 
Mikesfd's Avatar
 
Join Date: Jul 2018
Location: Wi
Posts: 36
Likes: 0
Received 2 Likes on 1 Post
Originally Posted by billyboy
Counterweights are only modified by the balancer.
ive heard that there is abcd code rotors and also counter weights to match those weights factory . How is one to put a aftermarket clutch/flywheel on with the correct weight counter weight without disassemble the motor to keep it balanced without vibrating ?
Old 06-22-22, 08:37 PM
  #4  
10000 RPM Lane

iTrader: (2)
 
TeamRX8's Avatar
 
Join Date: Oct 2006
Location: on the rev limiter
Posts: 2,468
Received 844 Likes on 577 Posts

The following users liked this post:
fc3s-ty (06-23-22)
Old 06-22-22, 08:38 PM
  #5  
Junior Member
Thread Starter
iTrader: (2)
 
Mikesfd's Avatar
 
Join Date: Jul 2018
Location: Wi
Posts: 36
Likes: 0
Received 2 Likes on 1 Post
Originally Posted by TeamRX8
thanks very helpful …… glad your here
Old 06-23-22, 12:31 AM
  #6  
10000 RPM Lane

iTrader: (2)
 
TeamRX8's Avatar
 
Join Date: Oct 2006
Location: on the rev limiter
Posts: 2,468
Received 844 Likes on 577 Posts
same to you gotta love the interwebz

all those “letter” rotors use the same counterweights. You’ll get the same half-crap balance the engine came with from Mazda. Not only is there a wide variance with the letters, but the cw’s too. Mazda’s version of Russian roulette so to speak.

the correct way to do it is to have the entire rotating assembly microbalanced properly, a highly under-appreciated service imo; Rob Dahm’s opinion be dahmed …
.
The following users liked this post:
fc3s-ty (06-23-22)
Old 06-23-22, 04:57 PM
  #7  
Rotary Freak

 
billyboy's Avatar
 
Join Date: Jun 2005
Location: sydney
Posts: 1,533
Received 261 Likes on 199 Posts
Originally Posted by Mikesfd
ive heard that there is abcd code rotors and also counter weights to match those weights factory . How is one to put a aftermarket clutch/flywheel on with the correct weight counter weight without disassemble the motor to keep it balanced without vibrating ?
Without the front counterweight included in the mix too, it wouldn't be a balanced assembly anyway, if rear counterweights were available like that.

You could spin up the clutch and flywheel assembly for a hail mary. Not familiar with the brand, but unless they're made by gronks, shouldn't be like the bad old days of imbalance.
Old 06-24-22, 08:49 AM
  #8  
Full Member
iTrader: (1)
 
Monika's Avatar
 
Join Date: Jun 2017
Location: Canada
Posts: 59
Received 4 Likes on 4 Posts
My rotating assy is balanced and lightened. quite a lot of machining was done. But smooth as butter all the way up.
Old 08-05-22, 09:34 AM
  #9  
Racing Rotary Since 1983

iTrader: (6)
 
Howard Coleman's Avatar
 
Join Date: Oct 2001
Location: Hiawassee, Georgia
Posts: 6,097
Received 519 Likes on 289 Posts
"Mcleod RST clutch" awesome

if you are really having a balance issue it is probably something other than your rotor weights or the CW.

imbalance says hello on an exponential basis w RPM. if you are running near 9000 and above a lot i suggest a dynamic balance.


as to rotor weight... i don't look at rotor coding... i have found rotors 50+ grams apart with the adjoining letters. 50 grams is too much.

of course ideally it would be great if they matched. when the motor gets running the rotors take on lots of oil and probably differing amounts resulting in differing weights. your 30 grams diff is on the O K edge of acceptable if you are not spending all your time at 9000+.

i would look elsewhere and i would also consider it important to find the fix..


Old 08-05-22, 09:54 AM
  #10  
10000 RPM Lane

iTrader: (2)
 
TeamRX8's Avatar
 
Join Date: Oct 2006
Location: on the rev limiter
Posts: 2,468
Received 844 Likes on 577 Posts
let’s not forget that 3 is a sacred number in the rotor orbiting universe 😇
.
Old 08-11-22, 12:29 PM
  #11  
Junior Member
Thread Starter
iTrader: (2)
 
Mikesfd's Avatar
 
Join Date: Jul 2018
Location: Wi
Posts: 36
Likes: 0
Received 2 Likes on 1 Post
Originally Posted by Howard Coleman
"Mcleod RST clutch" awesome

if you are really having a balance issue it is probably something other than your rotor weights or the CW.

imbalance says hello on an exponential basis w RPM. if you are running near 9000 and above a lot i suggest a dynamic balance.


as to rotor weight... i don't look at rotor coding... i have found rotors 50+ grams apart with the adjoining letters. 50 grams is too much.

of course ideally it would be great if they matched. when the motor gets running the rotors take on lots of oil and probably differing amounts resulting in differing weights. your 30 grams diff is on the O K edge of acceptable if you are not spending all your time at 9000+.

i would look elsewhere and i would also consider it important to find the fix..

howard , this is a motor you built and was fine until the cd009 conversion using the auto counterweight you gave me and the flywheel and clutch from McLoed and the careless conversion kit , just doesn’t make sense with clutch push in and reved up that it vibrates more then normal now

Last edited by Mikesfd; 08-11-22 at 12:39 PM.
Old 08-12-22, 05:32 PM
  #12  
Racing Rotary Since 1983

iTrader: (6)
 
Howard Coleman's Avatar
 
Join Date: Oct 2001
Location: Hiawassee, Georgia
Posts: 6,097
Received 519 Likes on 289 Posts
pm
Old 08-15-22, 08:30 PM
  #13  
Eye In The Sky

iTrader: (2)
 
cewrx7r1's Avatar
 
Join Date: Feb 2001
Location: In A Disfunctional World
Posts: 7,893
Likes: 0
Received 114 Likes on 66 Posts
Best to have the complete rotating assembly dynamically balance! End Of Line.
Old 08-16-22, 03:51 AM
  #14  
Arrogant Wankeler

 
Slides's Avatar
 
Join Date: Nov 2006
Location: Newcastle NSW Australia
Posts: 704
Received 113 Likes on 92 Posts
Can someone move this to another section? Nothing to do with single turbo.
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
kborro01
2nd Generation Specific (1986-1992)
3
01-14-15 04:00 PM
SLKV12TT
Rotary Car Performance
3
04-17-08 11:59 AM
pistonsuk
Rotary Car Performance
10
03-31-06 08:38 AM



Quick Reply: Rotor weight , Picking correct counter weight



All times are GMT -5. The time now is 12:33 PM.