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Colin Hough


To respond to your comment re the lack of logic of petroil and impact on a Pilgrim pump:

My understanding is that when running primarily on the Pilgrim then about 15 drops per minute – dpm – each side at tickover is required (possibly with the help of some oil in the petrol at around 100:1). In this case a directly connected Pilgrim pump is operating at the very bottom of its operating range because of the high rotating speed. It is because it is operating so low down that there is a chance of it not functioning as required i.e. not giving enough oil over the engine’s full operating range and hence leading to seizures.

The suggestion is than to ‘play safe’ by switching to a ‘half and half’ approach i.e. turn the Pilgrim DOWN to say 6 dpm (as recommended in an earlier post) at tickover and go to petroil at around 50:1. In this situation, a directly connected Pilgrim is being asked to work below its operating range so the result may be ‘half and nothing. Hence, trying to partially substitute petroil and turning down the Pilgrim is not a good idea. The solution if going down this route is to fit a reduction gear (I have). In this way the Pilgrim may be reliable enough to turn down the rate.

The critical message is that the oil rate must be set at a level that allows the Pilgrim to work reliably (which is also a function of oil viscosity). The question is then: what are the majic settings for the selected oil????

Glyn Chambers now supplies Silkolene Comp 2 Injector to go into the oil tank and Comp 2 for mixing with the petrol. His advice is to use ‘a little’ Comp 2 in the petrol and ‘as low as possible’ that can be RELIABLY delivered by the Pilgrim (i.e. the rate needed by the engine is less than that which the Pilgrim can reliably deliver if not fitted with a reduction gear). When fitted with a reduction gear, the Pilgim can be set to the level needed by the engine for which his advice is ‘1 in 4 or 5’ – thats drips per spits.

This is all theory so far based on various (conflicting) readings of the Technicalities etc. My plan is to start at 50:1 plus about 15 dpm with synthetic oil and ‘suck it and see’. Note: the Book of the Scott suggests 20 dpm for the first 1500 miles “whilst the use of petroil is an additional safeguard” so that it is “liberally” supplied with oil initially. After that, it recommends 10 to 15 dpm, but to use the exhaust smoke to judge if it is correct.