Hello,
I need a hand identifying the correct counter weight. I am putting an S4 NA engine into my first gen. I need a counter weight to put a light flywheel in. I bought an auto tranny counter weight and it looked just like one from a 12A. (The one on my 85 SE engine looked very different). So, I took it to a Mazda shop and they told me that it was off a 12A. The guy I bought it from said it is off a 88T2.

Here are my questions:
Does the S4 NA and T2 use the same counter weight?
Does anyone have a photo of a S4 NA counter weight, or a casting number, or the actual weight of one of these counterweights?
How do you tell, which counter weight is which?

Hey, thanks for your time ~ JEB

 

All engines within the same series, that are automatic, use the same counterweight. For example...s4 engines, though there are 2 different compression ratios, have rotors that weigh the same. Therefore, the ctwts are the same. Same for s5 and later (they all weigh the same)...s3 13B and earlier, and 12a's. So, if you have an s4 NA engine, and an auto ctwt for it, the ctwt also fits the s4 t2 engine. But not the s5 or s3.

Now, as far as identifying ctwt's once theyre off the engine? I have no clue. In all my taking apart of cores (hundreds), and years of experience, I have yet to find a way to identify/compare the various ctwt's. They are shaped basicaly the exact same way, with exception of front counterweights (the s3 and s6 ctwt's are different from the s4/s5 in shape). Still, if you have an s4 and s5 ctwt side by side, you will no longer know which one was which unless it was marked.

Perhaps with a super-accurate scale (drug dealers anyone?) you could find a very small weight difference between them.

 

S4 TII counter weight should have 1855 grams if i am correct

And since S4 NA and TII front counterweights are same, i believe NA and TII rear counterweights should be same as well....

Weight yours and tell us.

 

I will weight the ones I have and letyou know!
Thanks a lot!

 

The 3 counterweight i had, all were supposed to be S4 ones was

1850
1855
and 1860 grams

(on digitall drug dealer scale ;p)

Question is, how much S5 one is supposed to be?