To Balance or Not to Balance...
#1
To Balance or Not to Balance...
Just assembled my 1993 13b block and now I am at a fork in the road. I have matching rotors and front counterweight, but rear counter weight is off a 1994 auto. Traded flywheel for counter weight at 90k miles. Ran car 15k miles until oil control ring broke. Noticed slight main bearing wear(mostly at the bottom where babbitt coating was gone) and eshaft journal wear during rebuild. New rx8 eccentric shaft and proper main bearings installed.
Should I disassemble the block and get the rotating assembly balanced, get a new Mazda flywheel, or run it like it is? This will be a babied street car that I want to last another 100k.
Thanks in advance.
Should I disassemble the block and get the rotating assembly balanced, get a new Mazda flywheel, or run it like it is? This will be a babied street car that I want to last another 100k.
Thanks in advance.
#7
Polishing Fiend
iTrader: (139)
Balancing a rotating assembly is only for those that regularly want to/need to rev the engine way out past 8k rpms. For example NA rotaries for racing, properly ported, make decent power all the way out to 10k rpms. In this case balencing is a good idea As Rich mentioned below 8k, don't worry about it.
Regards,
crispy
Regards,
crispy
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#9
Rotary Freak
iTrader: (5)
What about for an auto-x application . where I would like to raise the rev limit to 9k . even if it doesnt make power , but jsut so I dont have to shift right before a turn rather hten bounce off the rev limiter?
I plan on using an RX8 shaft , new bearings .
Would I need it rebalanced?
I plan on using an RX8 shaft , new bearings .
Would I need it rebalanced?
#12
Rotor Head Extreme
iTrader: (8)
Having matched rotors means nothing if they are not matched to both counterweights. There are 5 weight divisions on pre Renesis rotors A-F. What if you had all "A" weights and installed a rear counter matched to all "F"s or vise versa? You would have a rotating assembly WAY out of balance. Having all "C" weights is middle ground for all the counter weights. Also the lighter Rx8 e-shaft effect the overall balance as well. Your mix matching too many rotating parts. I recommend a balance.
#16
Wastegate John
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Having matched rotors means nothing if they are not matched to both counterweights. There are 5 weight divisions on pre Renesis rotors A-F. What if you had all "A" weights and installed a rear counter matched to all "F"s or vise versa? You would have a rotating assembly WAY out of balance. Having all "C" weights is middle ground for all the counter weights. Also the lighter Rx8 e-shaft effect the overall balance as well. Your mix matching too many rotating parts. I recommend a balance.
#21
Rotor Head Extreme
iTrader: (8)
Example: You have all C rotors and damage 1. You can replace that rotor with a B or D rotor and not need balancing. Your staying within the 1 weight limit. Now if you damage both C rotors, you need to find both rotors near the C weights B or D.
The weight division thing can be confusing. I personally made a mistake on my own 91 vert rebuild back in 2005. Both my A-B rotors were damaged when the engine blew. I replaced both rotors with a matching C set thinking I was ok and within Mazda's weight guidlines. I thought that as long as both rotors were close in weight to each other was all that mattered. I was wrong as my engine vibrates. It took me years to figure out what I had done wrong. During research, I found out that "A" rotors are the heaviest and E's are the lightest. So overall my C rotors were lighter than the A-B"s that I originally had. That's why my engine vibrates.