Why is prepping on aluminum block engines critical?
Working with and rebuilding aluminum block engines is quite an art. In addition, the proper equipment is expensive, but necessary. Specifically, on the later model Mercedes and Porsches with 928 and 944 engines, it’s extremely important to do the honing right – that is finish the cylinder walls according to the factory specifications. In Mercedes’ case, for instance, there’s a manual that’s about four inches thick covering how to rebuild those engines. When customers have problems in that process, it always goes back to the fact that the engine wasn’t properly prepped. Furthermore, if rings are forced into a cylinder that’s not prepared properly or if the wrong size rings are selected and you start the engine, it can be destroyed. You always have to check your end gaps; you always have to check everything to make sure it fits properly. When you’re rebuilding one of these engines, there’s no room for error whatsoever.
