Component comparison – IHI RHF4/5 thrust bearings

devil is in the detail - high quality Melett turbochargers and turbo parts

Lower Quality Sample
Melett Sample
OEM Sample


Lower Quality Sample (RHF4)

To the untrained eye, initial impressions are that they look ok, however looking at the parts in more detail:

  • The surface is very pitted – pitting can score the thrust parts and lead to premature failure;
  • Badly de-burred;
  • The edges are not clean and sharp;
  • Often they have an over polished surface (focus is on aesthetics, rather than function);
  • No controlled scratches to create surface tension.

Melett Sample (RHF4)

  • Clean, sharp edges;
  • Machined surface;
  • No de-burring – when manufactured correctly this process is not a requirement;
  • Performance mirrors the precision of the design;
  • Controlled scratches to create surface tension.

When an engine is switched off overnight, if the surface is too smooth the oil will run off. The scratches create a surface to retain the oil and prevent run off, so when starting the engine in the morning there is already some oil present to lubricate the turbo.

OEM Sample (RHF55)

  • Clean, sharp edges, similar to the Melett sample;
  • Controlled scratches on the surface finish to retain oil.