A few months ago, in May I believe, we looked at a variable duration cam made in two pieces. While this was a novel approach to optimising the airflow into an engine over a range of conditions, reader Reine Gustafson of AGAP in Sweden contacted me recently about another cam design idea. This too consists of more than one piece and, as you will see, is simplicity itself. Now there can't be a cam designer or engine builder who hasn't been confronted with this problem at times and who...
In researching a recent article on this subject in Race Engine Technology (issue 47, June/July 2010), I spoke to many companies and discussed all kinds of coatings. DLC has been around for a number of years now and its use is widespread; however, this coating still attracts a lot of R&D spending for process development. The aims of this are generally to produce an improved coating in terms of one or more parameters. It would be considered a worthwhile step forward in coating technology...
In an article published in 2009, I looked at some of the design features of the joint face of a split con rod. One important requirement is that the two parts of the con rod - the 'blade' of the rod and its cap - must be positively and reliably located with respect to each other. It is important that these location features are machined into the rod before the big-end bore is finished to size. This guarantees that when the rod is assembled and the bolts pre-loaded to their design...
In my previous articles on the difference between leaded and lead-free bearing shells materials, the heat transport from oil through the bearing shell to the crankcase was discussed. In this article the current status of the leaded bearing is described. First though I would like to pass on a remark made to me when talking to a well-known bearing shell supplier. When discussing the possible reasons why leaded bearing materials are still favoured over lead-free materials, I was told,...
In the article on crankshafts which will appear in Race Engine Technology (issue 50, November 2010) there is a brief discussion on the use of heavy metals for crankshaft counterweighting purposes. There are a number of reasons why it might be deemed desirable to use a high-density material for a crankshaft but, for a given level of counterweight moment, it will lead to a lower inertia crankshaft assembly. The advantages of adding a high-density material to a crankshaft - or rather,...