Craig Walker Posted September 7, 2010 Report Share Posted September 7, 2010 I'm trying to set my timing to 10 deg before TDC on a 4mill 421cub. Now correct me if i'm wrong by checking on a degree wheel I rotated it 10deg to find about .20 give or take on the dial indicator. Is this number usual for you guys that are running a PVL on a 4mill. Reason why i'm asking is that it seems that the piston is to low to be firing the sparkplug. That and the last motor that I ran a PVL on it was about .10 on a stock length crank. I know whinning over .10. Quote Link to comment Share on other sites More sharing options...
Craig Walker Posted September 10, 2010 Author Report Share Posted September 10, 2010 ok did some more rotations and found 20deg of timing advance is .80, 15deg is .40 10deg is .20, 5deg is .10. Quote Link to comment Share on other sites More sharing options...
wesw Posted September 10, 2010 Report Share Posted September 10, 2010 think 10 degs is 2mm down from tdc use a dial indicator to find tdc clear it and rotate it down 2mm on the compression stroke should be good to go. 1 Quote Link to comment Share on other sites More sharing options...
J-Madd Posted September 10, 2010 Report Share Posted September 10, 2010 ok did some more rotations and found 20deg of timing advance is .80, 15deg is .40 10deg is .20, 5deg is .10. That sounds about right. There is a formula that uses stroke and rod length that can convert from mm to degrees if you need it. But since you're actually using the degree wheel, you wouldn't need to work the formula. Quote Link to comment Share on other sites More sharing options...
PassionRE Posted September 13, 2010 Report Share Posted September 13, 2010 Heres a degrees BTDC vs equivelent measurement of piston BTDC in mm. The 16.7 degrees represents +5.7 degrees. Just decuct 11 from the numbers on the left and look over to the left for mm BTDC in mm for + whatever over stock timing with stock ign. box. This is based on stock ignition being 11 deg. BTDC@9500rpm with 58mm stroke...its very close and is suitable for PVL set-up...Jim http://i57.photobucket.com/albums/g215/passionre/4millpvlc.png Quote Link to comment Share on other sites More sharing options...
PassionRE Posted September 13, 2010 Report Share Posted September 13, 2010 heres a stock stroke http://i57.photobucket.com/albums/g215/passionre/350pvl.png 7mill http://i57.photobucket.com/albums/g215/passionre/7millpvl.png 10mill http://i57.photobucket.com/albums/g215/passionre/10millpvl.png 14mill http://i57.photobucket.com/albums/g215/passionre/14millpvl.png Quote Link to comment Share on other sites More sharing options...
Craig Walker Posted September 14, 2010 Author Report Share Posted September 14, 2010 that is real helpful thnx Quote Link to comment Share on other sites More sharing options...
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