10-11-2021, 10:38 PM
Assuming there is no backing expander, Davids photo looks like Cord rings with a filler spacer to moderate the number and the friction. Use as oil rings, more benign.
When I first got my Seven into use away from home, close neighbours were Lester Reader who owned the Rubber Duck and his colleagues, all of whom had recently grown out of Sevens and Seven specials. They reckoned steel expanded rings robbed Sevens of power, and considered Sevens went best when worn out! Unfortunately I did not know enough at the time to quiz them extensively.
i am amazed that Cord rings were suggested for diesel engines, which rely very much on the operating priciple of conventional comp rings. I am surprised Cords rings still made. Might be more helpful if they made ring spacers as these now seem unavailable , making it difficult to renovate old pistons.
When I first got my Seven into use away from home, close neighbours were Lester Reader who owned the Rubber Duck and his colleagues, all of whom had recently grown out of Sevens and Seven specials. They reckoned steel expanded rings robbed Sevens of power, and considered Sevens went best when worn out! Unfortunately I did not know enough at the time to quiz them extensively.
i am amazed that Cord rings were suggested for diesel engines, which rely very much on the operating priciple of conventional comp rings. I am surprised Cords rings still made. Might be more helpful if they made ring spacers as these now seem unavailable , making it difficult to renovate old pistons.