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Discussion Starter · #1 ·
Hi guys, I know this topic has been covered a lot before becuase ive been reading through all the threads. However theres still some things im unsure of. Ive got 2 days to swap a 1.8 into my 1.6 shell so any advice that will make things work faster is much appreciated!

The 1.8 is a 1995 uk spec 1.8is
The 1.6 is a 1990 uk spec

The 1.8 from what i understand has a slightly tweaked ecu being the 'is' model as well as extra bits like electric windows, drivers air bag etc. Both cars have power steering.

I made the mistake of cutting part of the 1.6 engine loom where it runs past the gearbox to the back underside of the car, making it difficult to reuse the 1.6 wiring. However I would like to use the 1.8 ecu etc anyway as i want it run and perform best as possible. So far I have been unable to find out how much of the 1.8 wiring i will need to transfer over and what if anything needs to be disabled in order for it to work.

Do both engines use the same fuel pump?

I have a brand new 1.6 clutch, can i use this with the 1.8 gearbox and engine?

Im assuming my 1.6 driveshafts and welded diff will be able to handle the minimal power increase ok?

The loom that runs along the PPF towards the diff, where does it go? Guessing fuel pump/battery?

Anything anyone can think of that will help me get this done in record time will be hugely appreciated!!

Matt
 

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the loom along the PPF runs the reverse switch along with another transmission switch. I think there's some smaller cables that pop up through the boot floor but there is also the main battery feed too.

The 1.6 clutch will work with any mx5 gearbox (mk1, mk2 & mk2.5) but you'll need to retain your 1.6 flywheel.

If you've cut your loom you're going to have a load of fun, the engine looms are completely different and it all forms part of the main loom through the dashboard too. Try searching, there are a few 1.8 conversions about.

Dan
 

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Discussion Starter · #4 ·
thanks for the replies, its now (almost) finished and has taken us just over 2 days so far. Ended up swapping over absolutely everything, all the looms, dashboard, steering rack, engine, gearbox, engine mounts.

Few things to bear in mind for anyone doing it is the looms are pretty easy to swap over providing you swap them all, clocks and indicators won't be the same if the cars are a different age (1990 1.6, 1995 1.8) and the steering column needs swapping for the mounts for the indicators. Need the dashboard for the dash loom and need rear loom for fuel pump wiring.

For some reason my full beam doesnt work when you click it forward but does when you pull it back. Theres a spare wiring plug on the engine loom by the passenger side bulkhead so im guessing im missing a relay but cant find it anywhere. Can anyone confirm what the problem might be? Also for some reason steering column bottom bracket doesnt quite reach the bolts on the inside of the bulkhead??
 
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