I'm currently in the process of reringing/honing my 88' 4.0L renix motor and have hit a problem. All my pistons were stamped '50' on the crown which led me to believe that this motor was once bored over to .020" (.50mm) So I purchased the .020" oversize rings and it turns out they are too large (can't make them fit in the cylinders w/out some serious gap filing). The cylinder ridges have all been reamed flush to the uppermost compression ring contact area.
My question to you all: Based on the '50' stamping, are these pistons standard size or are they .020 over? I don't have any means of checking the actual diameter of the bores or the pistons. I suppose I could gap each new ring to within the spec. range, but something tells me these pistons are actually std. size and therefore I should have purchased the std. size rings. any info would be appreciated.
Eric
My question to you all: Based on the '50' stamping, are these pistons standard size or are they .020 over? I don't have any means of checking the actual diameter of the bores or the pistons. I suppose I could gap each new ring to within the spec. range, but something tells me these pistons are actually std. size and therefore I should have purchased the std. size rings. any info would be appreciated.
Eric