mx1986 Posted May 30, 2013 Report Share Posted May 30, 2013 Couple question on port timing. Where's zero degree bdc or tdc. And on a ten mil cub setup for 300 ft sand drags what is good port timing and duration. Quote Link to comment Share on other sites More sharing options...
tundish2800 Posted May 30, 2013 Report Share Posted May 30, 2013 A lot of guys won't give up there port specs. Quote Link to comment Share on other sites More sharing options...
J-Madd Posted May 30, 2013 Report Share Posted May 30, 2013 I got 1 at 200* exhaust and one at about 194 -195* and they run about the same as long as you have the right pipe and gearing. Not sure either is optimal, just sharing what I have. 198* is probably a good number. Not sure about transfers. Quote Link to comment Share on other sites More sharing options...
possum Posted May 30, 2013 Report Share Posted May 30, 2013 More importantly the angles and port shapes. Quote Link to comment Share on other sites More sharing options...
J-Madd Posted May 31, 2013 Report Share Posted May 31, 2013 I can't port motors, but I wish I knew more about what to look for in that^^^^. I always measure exhaust port timing, squish clearance, and squish band on motors just to see what the builder has done, but that's about it. Quote Link to comment Share on other sites More sharing options...
RadarRacing Posted May 31, 2013 Report Share Posted May 31, 2013 10 mil cubs normal as cast porting is about 194/128 or 130. Quote Link to comment Share on other sites More sharing options...
J-Madd Posted May 31, 2013 Report Share Posted May 31, 2013 http://www.cpindinc.com/pub/view_product/43?lm=3&name=CPI-6864 CP says 196*/130* with 0.012" base gasket. Quote Link to comment Share on other sites More sharing options...
possum Posted May 31, 2013 Report Share Posted May 31, 2013 JM are you playin around? With those 75 drag bikes you got. haha..I know you know a lil more then that. Ive been shown cylinders from different builders. But one builder in particular turned on a light bulb! Quote Link to comment Share on other sites More sharing options...
locogato11283 Posted May 31, 2013 Report Share Posted May 31, 2013 I wouldn't even attempt to port a motor. I would imagine for some people it's just not worth their time or money to mess with it. Quote Link to comment Share on other sites More sharing options...
trickedcarbine Posted June 1, 2013 Report Share Posted June 1, 2013 Different strokes for different folks. Some just have time and money to burn and really don't care about results. I'm fine with that so long as some one doesnt go boasting that they are a proven engine builder just because they ported a few sets of cylinders and they beat their buddies every weekend. Unless their friends happen to have motors from actual builders with good tune and chassis. Quote Link to comment Share on other sites More sharing options...
Coupelx Posted June 1, 2013 Report Share Posted June 1, 2013 Port timings are only part of the story. Kinda like the preface to a novel. I did a set of stock cylinders over a couple years always trying new things and was very happy with them but i decided to step up to a pv cheetah which Wildcard built for me. Its fast its smooth and no anxiety or headache i figuring it out on my own. Quote Link to comment Share on other sites More sharing options...
camatv Posted June 4, 2013 Report Share Posted June 4, 2013 hell try 198/ 130 if your light and on alky you can go to 200/132. hell of a LOT more than just port timings in getting a motor to run worht a shit. take a bad ass port job and crappy frame set up vs a good frame setup and box stock porting.. guess who would win.. 1 Quote Link to comment Share on other sites More sharing options...
registered user Posted June 6, 2013 Report Share Posted June 6, 2013 you can make a decent runner just using crank rotation but youll probly be better off figuring out specific time areas and working with that method Quote Link to comment Share on other sites More sharing options...
J-Madd Posted June 7, 2013 Report Share Posted June 7, 2013 Assuming the rings won't get hung in a port, and negating the effect on piston life; can a motor have too much exhaust port time area? Quote Link to comment Share on other sites More sharing options...
registered user Posted June 8, 2013 Report Share Posted June 8, 2013 i dont know the answer but i suspect its possible to have to much blowdown which is directly related to the size of the exh port. Quote Link to comment Share on other sites More sharing options...
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