"Ensure that the gasket is in good condition" is a phrase commonly found in the workshop manual. Anyone rebuilding an engine or transmission with the assistance of such wise words will probably recognise the phrase, but while we often spend much hard-earned cash buying new internals, the temptation as far as the gaskets are concerned is to try wherever possible to use the old ones. We know it's wrong, evidence of a cheapskate or even a miser, but nevertheless we still do it -...
This is a follow-up to my earlier articles on cylinder head loading. Earlier, I described what is known as one of the most critical failure modes, Thermo Mechanical Fatigue, or TMF. In those articles the three main load cases were mentioned - assembly loads, (peak) firing pressure load and thermal load. For thermal load, further insight was given into the design of the cylinder head cooling jacket. The conclusion was that the jacket is mainly derived from the rest of the structural design,...
It is surprising how often people get mixed up between the prefixes 'hypo' and 'hyper'. While 'hypo' refers to a situation that is less than normal, 'hyper' relates to exactly the opposite. As an example of such confusion I have a neighbour who speaks with a highly refined tone and continually refers to her 'hyperchondriac' husband, when I am sure she means 'hypochondriac.' So too are the differences between hypoeutectic alloys of aluminium and...
I know it's hard to credit it, but before 1937 the 'O' ring didn't exist. Patented in that year by Danish immigrant to the US, Neils Christensen, an 'O' ring, while eminently simple in concept, is in practice a very powerful sealing mechanism. No wonder they can be found in any number of critical applications inside most purpose-designed race engines. At the base of the cylinder liner, around the body of the fuel injector and at the top deck of the cylinder block...
In my previous Heads-Blocks article I described the advantage of Compacted Graphite Iron (CGI) on one of the most severe cylinder head failure modes, Thermo Mechanical Fatigue (TMF). The main area of interest then concerned differences in material properties. Of course, material is not the only contributor to TMF robustness of cylinder head design, so in this article I will give an insight into another parameter influencing TMF, coolant jacket design. As mentioned previously, a cylinder...