J-Madd Posted October 15, 2013 Report Share Posted October 15, 2013 I think I know the answer to this, but a friend of mine has a Blaster that had a forged wiseco 67.00 mm piston that had a ring snag, and is re chamfering the ports and bought a Namura 66.92 cast piston. Can he just hone and drop this in? Quote Link to comment Share on other sites More sharing options...
Coupelx Posted October 15, 2013 Report Share Posted October 15, 2013 Most likely not especially seeing the size difference.. You need a fairly tight clearance for a cast piston. Quote Link to comment Share on other sites More sharing options...
BANSHEE HP Posted October 15, 2013 Report Share Posted October 15, 2013 They the same size pistons but measuring the bore and finding the clearance is the right way. .003-.004 for a cast blaster piston Quote Link to comment Share on other sites More sharing options...
J-Madd Posted October 15, 2013 Author Report Share Posted October 15, 2013 I always thought the cast pistons swell more? I told him to measure the piston to bore clearance. Quote Link to comment Share on other sites More sharing options...
Coupelx Posted October 15, 2013 Report Share Posted October 15, 2013 Forged grow more. Quote Link to comment Share on other sites More sharing options...
lms1977 Posted October 15, 2013 Report Share Posted October 15, 2013 Cast is is usually .001 less clearance. Quote Link to comment Share on other sites More sharing options...
J-Madd Posted October 15, 2013 Author Report Share Posted October 15, 2013 Good to know. I could've googled that shit and not seemed like a dumbass, lol. I knew they had different clearances. Quote Link to comment Share on other sites More sharing options...
J-Madd Posted October 15, 2013 Author Report Share Posted October 15, 2013 Guess that makes sense. The molecules are closer on the forged. I was thinking the cast had more room to move because of the space between the molecules, but they could expand into that space, and the forged cannot. I didn't google that shit, was just thinkin backwards. Quote Link to comment Share on other sites More sharing options...
Zillaguy Posted October 15, 2013 Report Share Posted October 15, 2013 I always run forged pistons a little loose... That way when they are at operating temp they are within spec.. Other wise they will be too tight at op. temp. and can lead to heat seizure. Quote Link to comment Share on other sites More sharing options...
Coupelx Posted October 15, 2013 Report Share Posted October 15, 2013 I run shit as per manufacturer specs. Quote Link to comment Share on other sites More sharing options...
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