Are main pulleys and hubs from the same generation interchangeable? Can you take any hub and pulley from the same generation and mix and match them and still have the marks accurate? Can yo take a pulley from lets say a 85 12A and put it on a 92 13B hub and the marks be accurate?

I am asking because i have mismatched hubs and pulleys and i want to make sure my timing marks are good. I wouldnt swear to it but i vaugely remember reading that the marks are only good when kept with the original hub and that Mazda adds the marks after they are assembled.

TIA

 

well in theory, all the hubs (74-85 and 86-92) are the same, and all the pullies are the same too. but ive noticed a couple of things.

1. if you have it snugish, theres 1-3 degrees of play in the whole thing

2. 12a's have the marks at 0 and -15

3. i recently did an engine where the previous guys had managed to get the timing marks about 30degrees off. i have no idea how thats even possible, but they did it, and made it look like the pulley was never apart.

minimum i would say is to put the crank on tdc (ALL the keyways are in the same place!) and put the pulley and front cover on and see if it lines up

you could go further, and do it in the engine mock up stage, with tools to find the rotors tdc, etc etc.

the more hp you want to make, the more precise the tuning needs to be, and the more important this is...

 

Thanks for the reply. You make a good point, i think i am just going to bite the bullet and buy a racing beat main pulley just to set the timing.

I have had three phubs side by side and you can actually see the keyway in different positions. I also have a pulley that the marks are at least thirty degrees off but i have no idea what it came off of, it has 5 notches on it IIRC.

 

Similar experience here!

I had thre sets of hubs\pulleys, one from a 91 NA, one from a 88 T2, and one from a 89-91 T2. I threw everyting in a box, without marking them, thinking that they were all the same

Ended up buying a serpertine, but to this date; I still wonder if the marks on my current set are correct