20b counter weight problem

Old Feb 5, 2007 | 08:52 PM
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From: new york queens
20b counter weight problem

i have a 93 rew motor and used a 20B automatic counter weight with a os giken twin disc clutch and now i have a major vibration in the motor do you thinks its the counter weight or is it in the motor itself. does any one know if the 13b weight is the same as the 20B one

Last edited by fc3sturboTT; Feb 5, 2007 at 09:01 PM.
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Old Feb 5, 2007 | 09:03 PM
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From: https://www2.mazda.com/en/100th/
20b is different
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Old Feb 5, 2007 | 09:05 PM
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would this give such a bad vibration and why is it so many guys use 13b flywheel with out any problems
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Old Feb 5, 2007 | 09:10 PM
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flywheel bolts up to the 20b counter weight same as all the other counter weights
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Old Feb 5, 2007 | 09:19 PM
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From: new york queens
i seen people use a 13b flywheel on a 20b and the factory one dose not use a counter weight to bolt up
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Old Feb 5, 2007 | 09:27 PM
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20B Rear CW is TOTALLY DIFFERENT..
You need a standard 13B Na or turbo CW 89-2002
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Old Feb 5, 2007 | 09:37 PM
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thanks alot japan2la i was going crazy trying to find out what the problem was but would it damage anything in the motor since i used the wrong counter weight , and is a bad vibration caused by useing the wrong counter weight
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Old Feb 5, 2007 | 10:01 PM
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My understanding of counterweights is that they're similar to balance shafts in a piston engine. That is, if they're not there or balanced incorrectly, the main effect is that the engine vibrates a lot.

But I would think that would leave the potential for some damage in a rotary.
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Old Feb 5, 2007 | 10:54 PM
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I will swap you a 13b REW counter weight for your 20b one if you want.
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Old Feb 6, 2007 | 05:05 AM
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Who was the dumbshit that told you it was okay to do that?


-Ted
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Old Feb 6, 2007 | 10:53 AM
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Yeah man ..there kind of different , you shouldn`t change them use the 20B one swapping it for a 13B unit is not a good idea
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Old Feb 6, 2007 | 11:56 AM
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there is no aftermarket "13B" flywheel. The way you adapt it to your motor is you use the counterweight which is designed for your engine wether it be 13B or 20B.
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Old Feb 6, 2007 | 12:27 PM
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YEs, switch it before it is too late.. Using that 20B CW on your 13b engine will destroy yor internals.. The your rotating assembly is completely out of balance... The 20B CW is only for 20B.. Also, the 20B CW is NLA so it is somewhat of a rare item... Guru is now selling their own CNC 20B CW since Mazda discontinued production...and its not cheap! I have the correct part you need and will sell it to you for $75.00 delivered if you want to buy from me..

Anyway do something before its too late..if its not too late already....
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Old Feb 6, 2007 | 12:42 PM
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Originally Posted by RETed
Who was the dumbshit that told you it was okay to do that?


-Ted
Niiiiiiice and gentle.
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Old Feb 6, 2007 | 01:18 PM
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From: new york queens
can any automatic counter weight 13b one work
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Old Feb 6, 2007 | 05:42 PM
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Originally Posted by fc3sturboTT
can any automatic counter weight 13b one work
if its an series 5 or higher (89+).
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Old Feb 6, 2007 | 08:30 PM
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u need the counterweight designed for your engine. S4 & S5 CW's are different. what engine do you have?
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Old Feb 7, 2007 | 12:26 PM
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if you are using s5 turbo, Fd, or 13B-RE rotors, you need an automatic S5 turbo CW (japan only), an auto FD CW, or an auto 13B-RE CW.
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Old Feb 7, 2007 | 09:36 PM
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Originally Posted by fc3sturboTT
i have a 93 rew motor and used a 20B automatic counter weight with a os giken twin disc clutch and now i have a major vibration in the motor do you thinks its the counter weight or is it in the motor itself. does any one know if the 13b weight is the same as the 20B one


Just because the 13b rotors are the same weight as the 20b rotors, doesn't mean you can use the 20b counter weight to properly balance the rotating assembly. The e-shaft phasing is totally different. 13b is 180 degrees while 20b is 120. That's your major difference and why you have this vibration. As others have already told you, locate the proper front and rear counter weight for your engines rotors. Peace!
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Old Feb 8, 2007 | 07:08 PM
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From: new york queens
i chaged the CW weight today and took the back gear out of the motor. it looked fine no damage on the rear bearing but should i pull the front bearing out as well i did not get a chance to start the car today hopefully tomorrow i will get it running
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