engine swap

[ratiffany]

I have a 1991 Festiva with a 1993 engine. I just purchased a rebuilt 1991 engine and found it did not have the lower timing pulley assembly and the one on the 1993 engine has a larger bore, and the bolt threads appear to have a different pitch. I also have a 1992 for parts and found that the timing pulley on it is the same as the one on the 1993 engine. Did Mazda make a change or does it have anything to do with fuel injection vs carborated intakes?

[oxbrain]

Big nose vs Small nose crankshaft. It's well known in miatas. The earlier B series had a problem with the keyway on the lower timing belt pulley. They key could be installed wrong, causing early failure and wobble. It isn't a problem at all, as long as you pay attention when you install the timing belt pulley. They fixed it in 90-91 and the later engines all have the big nose crank. The keyway is made so the key only fits the proper way, and sticks out if it's in upsidedown or backwards.

You'll need to find an old style pulley assembly, they should be on all 90 and earlier b series.

[Festy46]

I can trade you a small nose assembly for one of your big nose pulleys. We each pay our own shipping and parts are even trade. PM me if you want to do it.