bepnewt Posted January 31, 2011 Share Posted January 31, 2011 G'morning, folks.It continues to blow my mind as I read threads how much you guys know about these, and other, cars. Amazing.I'll throw an easy one out there for ya. I thought I knew what it was to "bore" out an engine but learned recently that I'm probably wrong. So, here's my question:What actually gets done when a 425 Nailhead gets bored .030 over? What parts are changed? I'm not looking for a mega-detailed answer, just a quick 1-2-3 listing of high-level steps.Thanks,-BEPNewt Link to comment Share on other sites More sharing options...
Guest REX STALLION Posted January 31, 2011 Share Posted January 31, 2011 Take .030 off the cylinder walls,replace pistons/rings with .030 over parts. You did say you wanted a basic answer so.... Link to comment Share on other sites More sharing options...
Paul K. Posted January 31, 2011 Share Posted January 31, 2011 When an engine gets bored it is usually during the rebuilding process when it is discovered the the cylinders have developed too much wear or gotten too large to re-use the original pistons. If the cylinders are being bored .030" over, this means each cylinder was machined .030" wider. The pistons and rings installed after will have to match and also be .030" oversize. The same goes for the crankshaft. When it wears so it cannot accommodate standard sized bearings it needs to be machined and oversize bearings installed. There is a lot more to mention here but this will give you an idea on the subject. Link to comment Share on other sites More sharing options...
bepnewt Posted January 31, 2011 Author Share Posted January 31, 2011 Take .030 off the cylinder walls,replace pistons/rings with .030 over parts. You did say you wanted a basic answer so....When an engine gets bored it is usually during the rebuilding process when...This technical level is exactly what I was looking for, thanks.Is it required to replace the heads when boring out a Nailhead? Is it different than a non-Nailhead in this regard?-BEPNewt Link to comment Share on other sites More sharing options...
RivNut Posted January 31, 2011 Share Posted January 31, 2011 Boring does not require replacing the heads. If the valves and guides are in good shape just bolt them back on. Link to comment Share on other sites More sharing options...
Bill Stoneberg Posted February 1, 2011 Share Posted February 1, 2011 While you could get away with not replacing the main and rod bearings, it is probably foolish not too. Link to comment Share on other sites More sharing options...
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