Hi all, I have a turbo mx5 1.6 running Megasquirt (DIYPNP) Supra 312cc injectors. But is more or less stock other than these.
Since ownership I had a series of problems with it:
- The water pump was leaking a bit so this was replaced in addition to doing the cam-belt whilst the water pump was off.
- The cam belt was about a tooth out on the inlet and outlet and this was rectified when fitting the new belt.
- However we were ignorant with Megasquirt and didn't know you then had to sync the timing with Megasquirt.
- We did a trackday in it the following day (Another mistake...)
- Noticed some slight rattling/possible pinging at high revs and should have probably stopped but hey-ho, you learn ay!
- On the trackday the car was overheating a bit (Getting about 3/4 on the temp gauge and bubbling back into the expansion bottle).
During the trackday it began smoking quite badly which we though was the turbo going. I've chucked a new turbo back in the car which has significantly reduced the smoke. However it is still letting out a small puff of smoke occasionally; although quite often this is under load. I also think the car was loosing a tiny bit of coolant and needed topping up occasionally.
We took the head off and were presented with the following:
Basically, pistons #1 and #4 have melted on the Intake side.
We just can't figure out why those two and not the others? Any suggestions?
So far we think it may have been a combination of the timing being a bit out, overheating and possibly causing detonation.
Is this what you'd expect from detonation, or is it more likely due to running too lean? If so what would cause this problem on just those pistons?
PS the piston crowns are shiny from the wet compression check thats just wet carbon
Cheers for any help/ideas
Edited to attach the map