Thread: 1993 Disco

Hi, bought a 93 Disco in February 2009. Since then it has been a steep learning curve in how badly people treat their cars. It had buckled rims, a very bad misfire and a major high speed vibration. Well the buckled rims was an easy fix, I replaced the rims, with this most of the vibration went, then it was the misfire. I replaced the leads, spark plugs, distributor cap and rotor. Still no help. I did find that the plugs were carbonning up very badly. The plug out of cylinder 8 was solid with carbon (no gap). I did a lot of research on the net and found that by putting a spark plug with a higher heat rating could help with the burn off effect of the spark plug. I did this and the old girl has been great. The plugs come out cleaner and there is no sign of any heat damage to the plugs. So with all the stuff that I have fixed there is one that I am looking for some help with. The 3.5l V8 that is under the hood is suffering from a brown residue on the rocker covers, rockers, valve springs, and probably throughout the engine. Does anyone know of a way to try and reduce the build up? Any help will be appreciated.

The Rover V8 needs oil changes every 5000km using good quality oil. A bad buildup indicates the servicing might have been less than brilliant.