22-01-2025, 11:12 PM
The phenomenon is known in the trade as "pumping oil". On the downstroke, oil floods into the oversize ring gap from below, on the changeover, the oil passes behind the ring and on the upstroke, the oil is transferred to a space directly connected to the combustion chamber.
Was it present/more pronounced on the top compression ring/gap? If so, I would suspect an over-rich mixture. Excess petrol will wash the lubricant out of the top ring area. What sort of carburettor are you using? What make of piston are you using? Are the gaps in the pistons worn or is it just the rings?
Short runs with a lot of use of the choke will also show this problem.
I've seen this symptom on Seven pistons before, the rings sometimes worn to half thickness and the edges like razor blades. Sometimes, just the ring is worn, sometimes the ring and the gap in the piston are equally worn. May indicate some materials failure in the rings....
It's very unlikely E10 is responsible; we've been using 5% ethanol fuel for some years and remember Cleveland Discol? Ethanol = Ethyl Alcohol, i.e. the stuff we consumed in vast quantities on a Saturday evening in the past.
The same stuff Distillers Co. sold to Cleveland Petroleum Products Co. to make their blended fuel.
Nothing new in E10, except possibly, the quantity.
427px-Im196204Aus-Cleveland.jpg (Size: 141.83 KB / Downloads: 348)
File: https://www.gracesguide.co.uk/File:Im196...veland.jpg , downloaded 22/01/2025 22:00
Was it present/more pronounced on the top compression ring/gap? If so, I would suspect an over-rich mixture. Excess petrol will wash the lubricant out of the top ring area. What sort of carburettor are you using? What make of piston are you using? Are the gaps in the pistons worn or is it just the rings?
Short runs with a lot of use of the choke will also show this problem.
I've seen this symptom on Seven pistons before, the rings sometimes worn to half thickness and the edges like razor blades. Sometimes, just the ring is worn, sometimes the ring and the gap in the piston are equally worn. May indicate some materials failure in the rings....
It's very unlikely E10 is responsible; we've been using 5% ethanol fuel for some years and remember Cleveland Discol? Ethanol = Ethyl Alcohol, i.e. the stuff we consumed in vast quantities on a Saturday evening in the past.
The same stuff Distillers Co. sold to Cleveland Petroleum Products Co. to make their blended fuel.Nothing new in E10, except possibly, the quantity.
427px-Im196204Aus-Cleveland.jpg (Size: 141.83 KB / Downloads: 348)
File: https://www.gracesguide.co.uk/File:Im196...veland.jpg , downloaded 22/01/2025 22:00