My son’s 1990 Eunos has 132,000 miles on the clock but still goes great but, it seems to burn a fair bit of oil. I was basically given a mk II 1.8 with an engine/gearbox in excellent condition and less than 80,000 miles on it, which is now in my garage.
I’d like to know what needs to be done to make it work in the Eunos and which other bits will need changing. The plan is to prep this engine on a stand with new belts, clutch, full clean and painted camshaft cover before it goes in. If the other engine does die, then we can put this new one in.
Mk2 1.8 with VICS intake. If you don’t want a functional VICS (less power), the FM kit will work I think. I believe some have used aftermarket ECUs to get the VICS functional. Otherwise, you will need a 1.8 ECU and loom
Mk2.5 1.8 with VVT; probably the hardest tp put in. I think you need aftermarket ECU or full Mk2.5 ECU and loom.
Its probably easier to refresh the engine you have or to find a replacement 1.6.
I’ll start looking at the various options. It’s a 1998 car and I have the ECU but not the whole wiring loom. The engine came out with everything on it and I have the airbox, etc.
The Eunos doesn’t have a catalyst which makes things easier, though I kept the one off the mk II. Ideally, it would be a mechanical swap as much as possible, reusing as much of the electronics and wiring from the Eunos as possible.
I’ve built my own car from scratch so I’m happy doing electrical/electronics, plumbing, etc.
I’d really like to get the engine running on the bench/stand before we physically drop it in. I’ve got a spare radiator, exhaust bits, etc.
I would not consider anything other than a like for like engine, so the 115bhp 1.6 engine from the early MK1 1990-4 and Eunos 1989-97. The original engine in your 1990 would have a short nose crank. To avoid possible issue I would opt for a long nose crank, fitted from around 1991 on.
MK2 engine into MK1 - loom, dash, auxiliaries, etc. Ideally import loom with BP5A ecu but more likely end up with UK loom and either aftermarket megasquirt/ME221 type ecu or stock with factory immobiliser.
MK2 1.8 engine(non VVT) in good order worth good money for the right car; your 1990 Eunos is definitely not the right car.
What is causing the oil burn and how much? Is it getting worse and is there any related peformance loss? Our Eunos has burned oil since purchase in 2008 and no doubt before. Perhaps a litre every 400 miles. Too involved and risky to resolve so we just top the oil up as and when required. Obviously if it were stressed on track or relied on for long journeys there would likely be a problem. I guess the real issue is oil rings but as the car still performs faultlessly and breezes through emissions, will leave alone.
ie. the Mk2 engine can be put in, and made running using the 1.6 ECU and wiring. You will need to fit the 1.6 throttle body, hence the FM adapter plate.
The current 1.6 engine is good. It pulls strongly and revs freely to 7000rpm but it burns oil and runs a bit rich. It’s done 213,580km (132,712 miles) and has new belts, water pump, tensioners, craft shaft seals, etc. so it’s good for a while yet. One day it will die. The rest of the car is rust free and in excellent condition. It has been restored to ‘as new’ condition in all respects apart from the suspension which is next on our list. I have a second set of sub-frames and suspension arms which will be bead blasted and powder coated.
The thing is, I got the 1.8 for free and it is relatively low mileage and has a known history as it came out of a friends car which was scrapped due to rust. It’s got a verified milage and full Mazda main dealer service history to go with it. I’ve got all the anciliaries and needed parts from the ‘donor’ car. It’s already sitting in my garage so it makes sense to prepare it for when the time comes and start getting it ready to go in now.
The whole reason I bought the car was for my son to get hands on experience as a mechanic, so the money spent and invested in the car so far is really an investment in my son really. Money is not an issue in this respect.
It might be simpler to find an exact match 1.6 but it will have no known history and is likely to be much higher mileage. I’m also not in a rush and we can take our time to do the research and preparation, to get the installation right and done to the highest quality. It also gives us a chance to learn new skills and try new things, like painting camshaft cover, ceramic coating headers, etc.
I’m not looking for the easiest solution here, just the one that results in a good outcome and lots of learning, using what we have in our garage right now as much as possible. My son’s Eunos is much more than a car to him now. It was his first car, bought when he was 16 and is one he will never sell. Our plan is to keep it running and in excellent order for another 30 years or more and it will only ever be a fun/weekend car, kept in a garage.
Read the Flyin Miata document and it all looks pretty straight forward. Engine hoist and a stand have been purchased and we are going to do the clutch in the 1.8 engine first, then tackle all the belts and change the water pump. Going to do a red crackle finish on both the cam covers too. The whole of the 1.8 engine is going to be cleaned up and spruced up as a summer project for my son. Glad I took as many bits of the donor as I did before we scrapped it! I have the airbox and pretty much anything else that was under the bonnet
If you had the whole Mk2, hopefully you kept the rear end and drive shafts. The 1.6 viscous LSD will be ok for a while. The 1.6 rear is 4.3, and the 1.8, if a 5-speed, will be 4.1 final gearing… If fitting the Mk2 exhaust manifold, some fabrication needed to hook that to the 1.6 catback. The 1.6 manifold won’t fit, and I’m not sure a Mk1 1.8 manifold will fit to the Mk2 head.
You can actually bolt a 1.6 flywheel on a 1.8, and use a 1.6 clutch. The lower mass of the 1.6 flywheel allows the engine to spin up better. The best factory flywheel to get hold of is a 1.6 flywheel from either a UK spec Mk1 1.6 (and t has to be UK spec) or any Mk2 1.6; these used the same and lightest flywheel.
