Hello everyone I will start this off with what I am doing and why. My dad has a 94 miata with 165k on it. It was overheated about 2 years ago and started to smoke on start up and has just got progressively worse with time. It is now to the point where he wants to fix it. After much talk we want to rebuild the motor.


Two days ago I bought a 99 1.8L that seems to be ok was told it had similar issues as my dads hard to start and smokes on start up. This engine was over heated as well. I want to rebuild this one then just swap it in to his car so he has minimal downtime on his car.


So first thing I cant seem to find out. Other than the pistons (Compression Ratio) what are the differences between the na 1.8l and the nb 1.8l I know about the heads I am focusing on the block. I have a full set of stock bearings and rings I did not use in the past new in the box for a NA 1.8L can I use these on the NB 1.8L? Are the main and rod bearings the same size and are the piston rings the same thickness. Also can you use a NA oil pump on an NB motor considering it is going in an NA. From what I can gather online I beleive they are the same but not good information is out there on it. The last thing would be the timing belt kit. Is the timing belt water pump the same on all non-vvt 1.8L if so then I have a water pump as well. Any information you have would be great. I choose to rebuild the 99 because it will make a little more power than the 94 motor in his car with less down time on the car and I got it for $75. Complete

So here are some bullet points for those that don't want to read the whole things I need to know the following.

1. Are all 1.8L NA & NB non-vvt rod/main bearings, and piston rings the same
2. Can I use a NA 1.8L oil pump on my NB 1.8L block the engine is for a NA
3. Are all 1.8L NA & NB non-vvt timing belt water pumps the same

 

1 yes
2 Not sure
3 yep

 

2 - Yes