NC 1.8 engine "rebuild"

Technical Area Engine, Transmission, Exhaust etc
1
  1. My model of MX-5 is: 1.8 NC
  2. I’m based near: Brighton
  3. I’m looking for technical help or recommendations on: engine partial rebuild

Morning all. We have 2 MX5s in the family. A very decent NB 1.8 in unmolested and largely unwelded condition, and a 1.8 NC that we have recently acquired from our daughter after it developed the dreaded BE knock.

Yes, it had got low on oil (despite my regular reminders to check weekly) but she was wise enough to stop immediately, call me and get the car recovered to our house. She has now bought a new car, and left us with the NC.

The plan is to do a (partial) engine rebuild. I am no stranger to rebuilding older engines, so it does not scare me. I am expecting to hone bores and re-ring the pistons to address the root cause of the oil use, New valve guide seals etc too.

The crank, well, it may, just may, still be OK and a new set of bearings fix it. I won’t know until it is measured.

My questions are:

  1. Is it possible to drop the sump with the engine in the car? If so some guidance would be appreciated, as it looks near enough impossible from a quick look.

  2. How much compatability is there with the ford version of the engine? I am assuming (probably incorrectly) crank, bearings etc are the same. Is the whole short engine?

Once done, my wife will have the NC as her everyday car, as it is ULEZ compliant where her NB obviosuly isn’t, which is a PITA.

Ta, Clive

2

Can’t find the thread right now - but YES - it is possible to get the sump off with the engine still in the car.

It involves lifting the engine off its mounts just enough for the sump to clear the crank/oil pickup tube.

The guy who did it honed the bores, changed piston rings and big end shells with the block still in the car.

3

Thank you, that is very useful to know. Lifting the engine is no issue as I have a chain hoist in my garage. And I should be able to get the car high enough to work under easily. But getting to the age where I am thinking a 2 0r 4 post lift looks very appealing (I just need another 4foot of ceiling height)

I will start another thread about sump removal in case there are some useful tips.

4

I don’t know about ford compatible but I have had the pistons out on my 1.8 NC and have a few threads on the forum about it. This one may help -

I left the block insitu.
Jack the front end up high, head off, timing chain off, I found that jacking the block about 1 inch off the front mounts and packing with bits of wood helps lowering the sump from underneath.
Haynes manual helps with the head and chain but useless for pistons out as it says it’s not possible.
There are some instructions online but it’s not that hard, just be prepared for oil dripping on your face while working underneath!