well rings would do that but if theyve gone its normally constant smoking! well if its def not overfilled and u got the rite oil in it and it only does it from cold sounds to me like valve stems! were they good valve stems? Good stem oil seals come with a washer that sits under the valve spring and stops them from lifting! cheap ones dont and consequently lift up the valve shaft and leak! normally when ur turbo goes it smokes all the time, on boost or on over run off the throttle!