As I have to attend to a detached liner in my petrol tank I thought I had better check and clean my oiling system while I am at it. My late Shipley model has been converted to run gravity drippers but there is no visual indication of flow which has always worried me slightly. However, there is nothing much wrong as its always smoked well when opened up leaving town and the crankcase wells have always been nicely full of oil when I have checked.
The system I have is a simple gravity system with vents in the line below the adjusters. I rigged up a temporary tank and measured a flow of 22 ml on one side and 24 ml on the other side over the course of an hour. I appreciate that the flow will vary with temperature, the header height of oil above the drippers and the viscosity of oil but a rate of 46 ml per hour will do for some back of the envelope calculations. If I assume an average speed of 30 mph and a fuel economy of 50 mpg (I have never measured this) then in an hour it will use 0.6 gallons. That equates to 2.7 L and a calculated petrol:oil ratio of 58:1. That seems a bit lean to me so feedback would be appreciated on what I should aim for.
I don’t think that you are factoring in the increase in flow rates as the revs increase ? To be discussed tomorrow if you can make it to the meeting in Bingham….
Yep, I am expecting to make the meeting so will bring the unsophisticated device with me. However, I have a purely gravity fed system that is vented to air so is independent of engine rpm. My ccrankcase doors are devoid of anything mechanical to do with oiling 😛
Dredging up my O level chemistry, I think there are about 20 drops in a ml. You are aiming for one drop every six seconds or so in each dripper, i.e. ten drops a minute making 30ml per hour to each side. Add in 50:1 mix in the petrol and it seems reasonable to me. I would be inclined to look for sight glasses though.
Keith, even if you have a fully functioning Pilgrim pump, the sight wells are vented to atmosphere via small diameter holes beneath the lipped edge of the ‘window frame’. The suction generated by the engine is partly proportional to engine revs, as every time that the piston rises it generates a partial vacuum, which is connected to the oil inlet pipes. More revs equals more suck…. A couple of days ago I sent an article about alternative oiling systems to Kev Bayliss. 🙂
My vents are fairly large diameter (~6 mm) holes with a crude mesh screen. Thus, there would little if any meaningful vacuum being produced in my system. In fact, I have long wondered if my bikes fondness for choke on warm starting is partly due to the quantity of air being sucked into the crankcase via the vents 😯
The airt vents on the dripers on a 27 500 flyer are 1/16 they work ok . Regards DF.