My 1993 1.6L MX-5 with 103.000 Km was starting to make a faint ticking sound, coming from near the Cam Angle Sensor (CAS).

Since the car was due a timing belt and water pump change, I decided to go a bit deeper and pull all the hydraulic lifters to clean them.

From all the 16 lifters, only one was diferent from the others, and had some sort of burned in residue, even after cleaning it. To my surprise, it was the one closest to the CAS (rear of engine, intake side). Coincidence?

Here are pictures of a clean lifter, and the one with the residue: https://i.sstatic.net/XUkCj.jpg

What could have caused this? Could this be the source of the ticking? Should I replace the lifter?


1 Answer 1


Often the exact cause of residue is difficult to pinpoint.

Common causes can be poor oil flow or cool temperatures ie the engine not getting properly hot for a sufficient period of time.

The use of a good quality oil and a thorough run regularly will help once you have replaced or properly cleaned that lifter.

The v8 engine I rebuilt suffered from this prior to rebuild - once I had it rebuilt and was using it, then it did not suffer - perhaps I was "exercising" it sufficiently :)

  • Thank you for your reply. What could be the consequences if putting this lifter back to work?
    – AmiguelS
    Commented Apr 28, 2019 at 14:30
  • If you cleaned it properly and it still works, then none. OTOH, if you did not then you get to take the engine apart again to sort it.
    – Solar Mike
    Commented Apr 28, 2019 at 15:04

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