I had this rattle on mine - and I know of at least 3 other 3.7 owners who had the same at around 3k rpm... I emailed the factory several times (no reply) and the engine importer said 'no comment'. I also took it to Revolve Engineering who prepared the ECU and had them turn off the variable valve system via software - it still made the noise - so I turned it back on. A company who prepares these engines for racing in Nobles said part of their preparation involved dispensing with the variable valve timing completely.....
I wrote to Aero Racing twice (who take the timing chain out I believe and replace it with another), but never had the courtesy of a reply.
I don't think it's ECU related - but I could be wrong. I think it's the plastic guides on the timing chain hitting the sides of the front of the engine block. Something you wouldn't hear in a Mustang due to sound deadening. Again, I could be wrong, it's really hard to diagnose, particularly with zero support or interest from the factory.
I bought a Plus 8 in the end as I couldn't live with it. I lost £25k on the Roadster which was virtually brand new.
Neil, I appreciate that you investigated the rattle issue to some extent, but did you not take the car back to the dealer and ask them to get it resolved under the warranty, I presume it was still under the 2 years warranty at the time and this would have covered any engine issues?
