Are Mk1 & Mk2 engines interchangeable?
Discussion
Right then, I've acquired a Mk2 1.8 MX5. And it needs an engine. I can't seem to find one for a decent price that will fit. I've found a few VVT engines from the later MK2.5, but i've been told to fit one of these I will need to change my ECU and wiring loom. And there are a few 1.8 engines from a Mk1 knocking about. Will one of those fit? I really want to keep the car as a 1.8 so it's not just about buying the first reasonably priced Mk2 engine I find.
So basically:
1) If I buy a 1.8 engine from a MK1 MX5/Eunos, will it drop straight in to my MK2?
2) Will I really need to change ECU and loom to fit a later MK2.5 VVT engine?
3) Anyone know of a reasonably priced MK2 1.8 (pref with ancillaries but not essential)
Thanks guys and girls!
So basically:
1) If I buy a 1.8 engine from a MK1 MX5/Eunos, will it drop straight in to my MK2?
2) Will I really need to change ECU and loom to fit a later MK2.5 VVT engine?
3) Anyone know of a reasonably priced MK2 1.8 (pref with ancillaries but not essential)
Thanks guys and girls!
TAHodgson said:
Right then, I've acquired a Mk2 1.8 MX5. And it needs an engine. I can't seem to find one for a decent price that will fit. I've found a few VVT engines from the later MK2.5, but i've been told to fit one of these I will need to change my ECU and wiring loom. And there are a few 1.8 engines from a Mk1 knocking about. Will one of those fit? I really want to keep the car as a 1.8 so it's not just about buying the first reasonably priced Mk2 engine I find.
So basically:
1) If I buy a 1.8 engine from a MK1 MX5/Eunos, will it drop straight in to my MK2?
Yes, mechanically it'll drop right in, but you'll need to retrofit a cam sensor to the intake cam on the fron of the cover, and you need to retain all the MK2 ancillaries i.e. alternator. You're also giving up 10-15bhp.So basically:
1) If I buy a 1.8 engine from a MK1 MX5/Eunos, will it drop straight in to my MK2?
TAHodgson said:
2) Will I really need to change ECU and loom to fit a later MK2.5 VVT engine?
No, you can leave the VVT disconnected, everything else is electrically compatable, so is more do-able than a MK1 engine3) Anyone know of a reasonably priced MK2 1.8 (pref with ancillaries but not essential)
MX-5 Lazza said:
Mk2.5 has VICS + VVT so would need a change of ecu & harness.
Mk2 has VICS - not sure if that is controlled by ecu.
Better to keep with a Mk2 engine if you can find one - otherwise, if the Mk2 head is still good then fit that onto a Mk1 block and that will be even better
Not all VVT engines have VICS, infact all JDM and EUDM engines won't have VICS, they have the 'squaretop' manifold which is far superior to the USDM manifolds (which look like the MK2 manifolds).Mk2 has VICS - not sure if that is controlled by ecu.
Better to keep with a Mk2 engine if you can find one - otherwise, if the Mk2 head is still good then fit that onto a Mk1 block and that will be even better
The ECU definately controls VICS, though with a bit of thought you can use an RPM switch to activate it.
sorry to hijack the thread, but what would be needed to drop a km2.5 engine into a mk1?
manifolds, loom, ecu.. does the 5 speed gearbox just bolt straight up or do you need the 6 speed? also are the engine mounts the same?
Thinking this would be an option for when mu engine goes bang in the future.
p.s whats the engine weight difference between a mk1 1.6 an a mk2.5 1.8? wouldn't want to upset the weight distribution to much.
manifolds, loom, ecu.. does the 5 speed gearbox just bolt straight up or do you need the 6 speed? also are the engine mounts the same?
Thinking this would be an option for when mu engine goes bang in the future.
p.s whats the engine weight difference between a mk1 1.6 an a mk2.5 1.8? wouldn't want to upset the weight distribution to much.
managed to find an engine, got it dropped in last weekend. Did the usual belt changes and full service. Had my first drive yesterday and absolutely love it! Just something about it, such hoonability (don't care if it's not a word!) Managed to get through £40's of fuel in 8 hours! New engine had a proven 42k miles on it and only cost £350 after including my old engine in the sale! Couldn't be more pleased! All in all the car now owes me just under £1k! But have a sticking rear caliper to deal with now
towelie said:
sorry to hijack the thread, but what would be needed to drop a km2.5 engine into a mk1?
manifolds, loom, ecu.. does the 5 speed gearbox just bolt straight up or do you need the 6 speed? also are the engine mounts the same?
Thinking this would be an option for when mu engine goes bang in the future.
p.s whats the engine weight difference between a mk1 1.6 an a mk2.5 1.8? wouldn't want to upset the weight distribution to much.
Depends if you want to use the OEM ECU or not and/or if you're worried about actually using the VVT.manifolds, loom, ecu.. does the 5 speed gearbox just bolt straight up or do you need the 6 speed? also are the engine mounts the same?
Thinking this would be an option for when mu engine goes bang in the future.
p.s whats the engine weight difference between a mk1 1.6 an a mk2.5 1.8? wouldn't want to upset the weight distribution to much.
If you want to use the MK1 OEM ECU you need to transplant ALL of the sensors and electronics, you won't be able to use the VVT unless you purchase and install the aftermarket VVT controller.
OR you can purchase the entire MK2.5 engine and loom/ECU and fit the lot, it's quite an involved job however...
Thirdly you can use an aftermarket ECU, this will mean you can use either engines sensors and if you pic the right ECU can control the VVT.
All MK1/2 boxes fit, so you can pick between 5 and 6 speeds
Weight distribution I really wouldn't worry about, it's not a lot, and Mazda seem to get away with it....
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