SLORYDER Posted November 17, 2009 Report Share Posted November 17, 2009 Can someone please tell me real quick how far my exhaust port roof needs to be from my deck for 195 duration. I believe everything is stock but I think I read somewhere that the top of the piston is not supposed to protrude from your deck at tdc but the crown of mine does. Don't know if that means anything but i thought I'd note it. Thanks, Marcus Quote Link to comment Share on other sites More sharing options...
mopar1rules Posted November 17, 2009 Report Share Posted November 17, 2009 the very top of the piston crown, will protrude above the cylinder deck. the very edge of the piston crown won't. also 195* exhaust is 27.2mm, using cometic and OEM base gaskets and head gaskets. Quote Link to comment Share on other sites More sharing options...
SLORYDER Posted November 17, 2009 Author Report Share Posted November 17, 2009 the very top of the piston crown, will protrude above the cylinder deck. the very edge of the piston crown won't. also 195* exhaust is 27.2mm, using cometic and OEM base gaskets and head gaskets. Sweet thanks. Quote Link to comment Share on other sites More sharing options...
SLORYDER Posted November 18, 2009 Author Report Share Posted November 18, 2009 the very top of the piston crown, will protrude above the cylinder deck. the very edge of the piston crown won't. also 195* exhaust is 27.2mm, using cometic and OEM base gaskets and head gaskets. Wait I'm confused. It is 27.2 mm from deck regardless of gaskets or what not right... Quote Link to comment Share on other sites More sharing options...
blowit Posted November 18, 2009 Report Share Posted November 18, 2009 Wait I'm confused. It is 27.2 mm from deck regardless of gaskets or what not right... What gaskets?? Base gaskets make a difference, head gaskets do not. Well, timing wise anyway. Quote Link to comment Share on other sites More sharing options...
mopar1rules Posted November 18, 2009 Report Share Posted November 18, 2009 Wait I'm confused. It is 27.2 mm from deck regardless of gaskets or what not right... i said that's w/OEM base gaskets and cometic gaskets. don't remember the OEM and cometic thicknesses, but whatever gaskets are the same thickness as cometic and OEM, will give you the same 195* duration w/27.2mm from cylinder deck. Quote Link to comment Share on other sites More sharing options...
SLORYDER Posted November 18, 2009 Author Report Share Posted November 18, 2009 (edited) Oh ok But you do mean 27.2mm from deck to top of exh port right? And it should be a uniform taper from exhaust window to exhaust flange outlet, right? How much would you take out of the id of the flange outlet? I am at about 69% bore on my exhaust right now Edited November 18, 2009 by SLORYDER Quote Link to comment Share on other sites More sharing options...
SLORYDER Posted November 18, 2009 Author Report Share Posted November 18, 2009 I went too far, eh Quote Link to comment Share on other sites More sharing options...
mopar1rules Posted November 19, 2009 Report Share Posted November 19, 2009 Oh ok But you do mean 27.2mm from deck to top of exh port right? And it should be a uniform taper from exhaust window to exhaust flange outlet, right? READ MY LAST SENTENCE IN MY PREVIOUS POST ABOUT 27.2MM. YES, IT SHOULD TAPER NICELY FROM PORT WINDOW TO EXHAUST FLANGE. what measurements from cylinder deck, to exhaust port roof do you measure at now? Quote Link to comment Share on other sites More sharing options...
misterww225 Posted April 7, 2010 Report Share Posted April 7, 2010 Many ways to "skin a cat", however, forget using a distance measurement to get degrees. As you have just discovered, several other dimensions will alter the port height. Instead, find a degree wheel and attach it to your crankshaft and use a dial indicator to find TDC. With chinese tools everywhere, this should not a problem. If you can't find a degree wheel, print one out and glue it to some posterboard. Calculate the degrees for the desired timing and after bluing the cylinder, move the crank to this position. Mark along the top edge of the piston with a 90 degree dental tool. This is a reference line. Always double/triple check the degree positions and dial indicator references before cutting. Use the same brand of base gasket for marking and assembly. Final markup can be made using arbituary symetric guidelines and/or a shape developed using 2-stroke software and/or graphics software and printing/cutting with a razor. This pattern for the port(s) can then be transfered to the blued cylinder. Quote Link to comment Share on other sites More sharing options...
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