Normally, the powertrain section of a PH Buying Guide is one of the lengthiest and involved. With the
MX-5 NC
, there really isn't a lot to worry about as both the 1.8 and 2.0-litre engines have proven themselves to be near bulletproof.
1.8 only offered with a five-speed 'box
The two engines share the same 83.1mm stroke, with a bore of 83.0mm for the 1.8 and 87.5mm for the 2.0. They each have an aluminium head and block, with steel liners for the cylinders, while a variable intake system aims to balance torque at lower revs with strong power above 5,000rpm. For UK cars, power remained the same throughout the NC's production life, with the 1.8 producing 126hp at 6,500rpm and 123lb ft of torque at 4,500rpm. The 2.0-litre engine provides 160hp at 6,700rpm in early cars and the same power but at 7,000rpm in NC3 and NC3 models. Torque for the 2.0-litre is unchanged at 139lb ft at 5,000rpm in all versions.
Both engines come with a cam chain, so there are none of the concerns about changing a cambelt you have with previous generation MX-5s. There have been a couple of isolated incidents of tensioner pulleys wearing out, but they are cheap and simple to replace, even if access in the engine bay is tight.
Cam chains means no belt replacement
If you don't have to worry about cambelts, you must make sure the car you are looking at has been treated to the correct Mazda-specific coolant every two years. While changing the coolant in any car every two years is good practice, Mazda is insistent this is carried out with its own blend of coolant to preserve the engine. It seems to work as even high mileage NCs start and run easily when regularly serviced.
Servicing will not cost a fortune, even at Mazda dealers, so you can expect a bill of around £250 every 12,500 miles, though independent garages may charge considerably less. A major service comes at 62,500 miles that requires new spark plugs.
The gearbox is just as reliable as the engine. Or rather gearboxes, as the NC is available with three different transmissions. The 1.8 comes with a five-speed manual only, which is shared with lower spec 2.0-litre models, while the 2.0 Sport gains a six-speed manual. For the 2.0-litre only, there is also the option of a six-speed Powershift automatic 'box that has paddle shifters behind the steering wheel.
Exhaust and ECU tweaks make this more fun
The manual gearboxes can experience a stiff change from first to second when they are cold, particularly in cold weather, but this should ease as soon as the transmission has warmed through to deliver the precise shift the
MX-5
is noted for. Clutches will last up to 60,000 miles even with hard driving.
One common grumble among owners is the engine can be too quiet and refined. To solve this many fit an aftermarket exhaust, which often involves a sports rear silencer from a company such as Milltek, which will cost around £700. You can then add a de-cat pipe or de-cat manifold depending on your preference, though the de-cat manifold requires repositioning the air and fuel sensor in the downpipe. A de-cat manifold costs around £350 and a de-cat pipe from £300.
Other tuning options include a simple engine ECU remap, which cost from around £300. One of the most popular options is from BBR, which has been tuning MX-5 since the early days of the original NA model. It can offer everything from a mild 15hp boost for the 2.0-litre engine to a full turbocharger installation that takes power to 270hp to deliver 0-62mph in 4.9 seconds and 150mph.
PHer's view:
"I loved how adjustable it was on the throttle, and you could carry so much speed through the corners that I never found it lacking power, although I will admit to regularly trying to convince the wife that the BBR supercharger conversion was a necessity."
Chris Turner
