So having sold my 2003 MX-5 Nevada back in the summer, I bought a 97 1.6 MX-5 which after doing a bit of mechanical work on it to make it a good daily, I soon found myself thinking of ways to make it faster. I was very surprised how quick it felt for a supposed 90hp engine, which originally I thought would be a massive let done coming from 146hp to just 90.
So I did some research and found that by fitting the cylinder head from an earlier MK1 1.6 (115hp) it would take you over 100hp. This followed by a quick search on eBay and £55 later I had a complete cylinder head with cams and valves etc. I could have bolted this straight on but… well… I didn’t.
Working in the industry I have access to the right knowledge and equipment to make it better than original, which I was surprised to find there is not much you can do to make them better without going mad and throwing money at it. Having suspected it had been skimmed before I got it, I CC’d the cambers to get an idea of compression ratio which I am yet to calculate. The CC hovered around 39cc per chamber (+/- 0.5cc).
So over the course of many lunch brakes I have been smoothing out the inlet and exhaust ports without taking too much out seen as it will be a mild daily.
I also plan to have the head skimmed, hence why I need to calculate compression ratio. Any advice on this will be greatly appreciated as I haven’t looked into this a whole lot. I know most people go for a .040 shim but I have a feeling its been skimmed before so I need to be carefully I don’t over do it.
Having bought the head, I then looked at my engine bay a thought ‘everything but the engine looks pretty good’ so back onto eBay and a few days later a cam cover arrived on my door step followed shortly by a can of VHT red crinkle finish paint. I went back to the drawing board… well the engine bay and thought ‘well if i do the cam cover, the inlet manifold will get jealous’ so one of them turned up on my door step too (It has since been port matched to the head for less interrupted flow) . Then I realised (if you’re still reading, thank you!) the bits attached to the manifold will standout if I don’t do them too so I now have a throttle body, Idle Speed Controller and fuel rail too. Someone could have told me how addictive this MX-5 stuff is!
The plan is when I swap the cylinder head over, I will give the whole engine bay a tidy up with all the extra bits I have then sell the bits I take off.
Pictures will follow when I work out how… what ever happened to copy and paste!