There has been a lot of discussion over the years in vintage and pet circles of the benefits of adding 2 stroke oil to your petrol. A 1:200 ratio has been traditionally used with mineral 2 stroke oils with reports of improved ticker, smoother running and more power on the road. There are also suggestions that this dilution is not high enough. There is much information in the US on tis topic. Summarising the recommendations: Use 2 stoke synthetic oil to TC W3 specification. This is for marine/outboard use. Ratio used is 1:500. The reason for using this spec. is because it burns without formation of ash and deals with water in the petrol and also from the presence of ethyl alcohol. The observed and widely reported benefits are smoother idle, slightly better fuel consumption and better performance coupled with much cleaner cylinder head and plugs.
Two points to note: 1. Much lower concentration used (1:500 as against 1:200). 2. All the reports I read were for "modern" engines whether fuel injected or with carburettors.
There have also been suggestions of lower under bonnet temperatures. It may be that it is stabilising the combustion process between successive combustions. If there is variation in the combustion process this is like having a variable ignition advance i.e. the optimum firing point is not realised with some earlier than optimum and some later than optimum. The latter would give hotter gases around the exhaust valve and higher egt hence higher under bonnet temperatures.
There may be sound science behind this suggestion. In the latest of Paul Ireland's excellent series of articles in Safety Fast on Manchester University's combustion tests on an XPAG, it was found that adding kerosene to the fuel reduced low temperature volatility, hence reducing some of the adverse effects of modern petrol. However, they used much higher, 10%, mix. Maybe lube oil at very low concentrations could be an effective alternative. Or Redex? Regards, David