Re: broken top compression ring

Posted by Larry51 On 2013/10/16 5:22:39

Piston rings can often do with more lubrication than they get nowadays, since lead was removed from petrol. Good/new rings tend to not let much oil pass to the upper compression ring and of course the valve seats, guides etc don't get lubricated as well as back in the leaded gas days. I personally think using upper cylinder lubricant is a good idea in older engines, especially in early days when newly fitted rings are tight in the bore. It is pure oil which will not burn off, but remains as a thin film on upper cylinder parts including the compression rings as it is delivered via the petrol. You're lubricating from 'both ends' of the piston so to speak.

Of course this is only a prevention measure, so not much help in your situation of having already broken rings.

You can also add a friction modifier to engine oil to reduce drag and therefore 'leverage' on rings. Costs a bit but it should lengthen the period between engine rebuilds.