Let me first start off by saying I have already looked at the FSM and MazdaTrix guide for identifying counterweights. I have my idea on what I believe the counterweights I have are, but would like someone's opinions to verify.

The engine I have is an S5 Turbo.

I have 2 counter weights, one from ACT purchased off a forum member, and a non-stamped counter weight included in a clutch kit/flywheel setup I just purchased.

The ACT counterweight is stamped "PN CW01". The second; all I can offer is pictures...

Any help towards which counterweight is which and if either one would work on my application is greatly appreciated.

Thank You,
Ryan H.

 

The act is a s4 but the second one I'm not sure.

 

Thanks. Yeah it has no definitive marks on it to really tell.

 

scan this:
https://www.rx7club.com/rotary-car-p...umbers-284292/
https://www.mazdatrix.com/faq/Rcounterweights.htm
https://www.rx7club.com/2nd-generati...weight-294118/

 

So I have someone that offered me an S6 auto counterweight, which to my knowledge are interchangeable with the S5, but it has this chunk of extra metal on it I haven't seen on a counterweight before. Can anybody tell me if this is normal or problematic?

Thanks,
Ryan H.

 

They did that to add a little bit of weight to it to custom balance a rotating assembly. It only adds a few grams of weight so probably not enough to worry about. Do you have a digital scale nearby? You could weigh it and see how it compares with other people's findings.

 

I haven't purchased it yet, but I can ask if he can weigh it. He said it came off a stock auto FD. It doesn't seem like something that would be done by Mazda?

 

Something to note..maybe.
I tried an S5 auto counterweight on an FD engine and it didn't work.
It binded up when I tightened the "flywheel nut" down.The engine would not turn.

If that is any indication of swapability then I would stick within series of counterweight.

 

Interesting. Thanks for the heads up!