Ian you need new pistons. Rings are .0885" ring gap in ring land for a new piston is .001"-.002" . This being said, I have a 1972 Ford WSM that states for all engines " service or wear limit is .006" " The rings do not wear much at all, the piston ring lands do wear. I would not build an engine with the ring land gap of .004" or larger.Were the compression rings broken? If the bore is ok with mo taper or ovaltiy de glaze the bore with a ball type hone. Hope this helps Len Fanelli Abingdon Performance Ltd.
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From: 'Ian Thomson'
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Subject: [mg-tabc] XPAG piston Query
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I wonder if any of you engine building gurus out there can help me. I am checking over an XPAG engine and am trying to decide whether I need new pistons or can get away with just a set of rings. The gaps on the top two compression rings average 6-10thou. whereas I believe they should be 2-3 thou. They also have a prominent wear step of 6-10 thou. with a total ring thickness of 80-85 thou. I would expect some wear and am wondering how much of it will be on the rings themselves and how much the piston grooves will have widened. After all aluminium is somewhat softer than cast iron! Basically if I chance buying rings am I likely to get ones which brings the whole thing into spec. or is it safer to buy new pistons? Regards Ian Thomson Notts. UK.