350skabarat Posted August 26, 2012 Author Report Share Posted August 26, 2012 I have done some home made porting, because I live in Finland and just like you, far away from Professional builders. I need to ask you, how you can measure " .2 " degree? I have had some serious problems even read my exhaust durations, like is it 198 or 199 or even 200. ..just asking, and I want to learn more. I had the exact same problem when I first measured my ports with a degree wheel. The problem is we judge by eye when we think a port opens or closes. How big must the gap be when the port is officially open? Who knows? The first few times I measured with a degree wheel I kept getting different answers. What helps a lot is using a feeler gauge like 0.1mm thick. What you do is you basically put the tip of it into the port and then push the piston up against it. This will at least give you consistent measurements. You must also find true tdc with a dial gauge. The other method which I think is way more accurate is to measure the distance from port roof height to the top of your cylinder. You must then put your piston at tdc and find the differents between the piston top and the cylinder top. This is your deck height. Myn measured 0.8mm. After you determine deck height you must subtract it from the cylinder top to port roof measurement. the answer you get is a distance you use to calculate port timing via trigonometric triangular calculations. You must also take your crank stroke and conrod length into consideration. If any one of those change so does your timing. I didn't explain everything step by step but you get the point right? Now my vernier measures too two decimal places. All I do is take the exact measurment I get acurate to two decimal places and put it in an equation program I wrote, the program doesn't round numbers off so what it gives me is an answer to lots of decimal places and I just decided to round it off to 1 decimal place. I know 0.2 degrees won't make a differents but I just decided to work accurately. Quote Link to comment Share on other sites More sharing options...
trickedcarbine Posted December 2, 2017 Report Share Posted December 2, 2017 Another corpse dug up. Quote Link to comment Share on other sites More sharing options...
gusto Posted December 2, 2017 Report Share Posted December 2, 2017 I was looking at the cc specialty tool kit. Damn it’s expensive. Quote Link to comment Share on other sites More sharing options...
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