I was curious if there is a place to get a used crank that would be similar to what I have in my 99 1.8? From what Ive read its forged and the earlier models are cast? I bought the motor from a friend who thought it had rod knock but after I tore the motor apart it looks like he was hearing the crank pulley wobble. the crank Woodruff is buggered up, I talked with the machine shop I use for doing the machining on my blocks and they said it would be a minimum of $150. would you guys suggest them just welding and re-machine or trying to source a used junkyard crank? Either way Im going to have them turn it to get all the imperfections and wear out of the lobes.

 

94-05 cranks are all the same. Id try and source a used one before spending any money on your current one.

 

^This. All Miata cranks are forged, even the 1.6 ones.

And the OP started this thread in the wrong section.

 

Are the Miata’s the only car that uses this 1.8 that has the forged crank? This would be the bp4w correct?

What section should this be posted in?

 

All Miata crankshafts are forged. There were some Mazda 1.8 in other cars that had non forged crankshafts. Get a crankshaft from a Miata to go in your Miata and it will be fine.

 

All BP cranks are forged. I would suggest you get a BP crank for your BP.

 

01-05 cranks have a wider thrust surface, definitely different from the 94-00 part.

 

Interesting. I knew there was a difference with the MBSP in the NB2, but didn't know the crank was different as well!

 

Is this true? I knew the blocks/thrust bearings were taller but I had always thought the cranks were machined at the same height and haven't visually noticed a difference.

Maybe Ill measure some tonight for curiosity

 

I recall some of the 99's had thrust bearings that would remove themselves without notice.