timson
Well-known member
500 miles after startup and I want to start focusing on the jetting on my Weber to get it all tuned in, but I have a nagging question: is my valve timing correct?
With a recurved DSII set at 18 degrees initial advance (vacuum tube off and plugged), the motor runs very rough. Giving it more initial advance, like at least 35-40 degrees, makes it much smoother, but the vacuum nipple is bumping against the dipstick.
Additionally, at 18 degrees, manifold vacuum at idle is 13 psi and slightly jerky; more timing brings it closer to 15 psi, but no more. (Here´s a video of the gauge at idle:
.) A check for vacuum leaks around the carb found nothing.
I could restab the dizzy, but the question remains concerning timing, leading me to revisit my valve timing from the rebuild.
So, I am attaching 2 pics: my cam card, with my notes penciled on it from when I degreed the cam; and one of my timing gears at TDC before I buttoned everything up. Timing marks are close, but not dead on. I don´t believe Schneider cams have a 4 degree advance built in.
Am I off a tooth in one direction or the other? Might this be the source of my troubles? Should I just focus more on tuning the Weber with an AFR gauge (my next step)?
Thanks for your comments and ideas!!!
Tim
With a recurved DSII set at 18 degrees initial advance (vacuum tube off and plugged), the motor runs very rough. Giving it more initial advance, like at least 35-40 degrees, makes it much smoother, but the vacuum nipple is bumping against the dipstick.
Additionally, at 18 degrees, manifold vacuum at idle is 13 psi and slightly jerky; more timing brings it closer to 15 psi, but no more. (Here´s a video of the gauge at idle:
I could restab the dizzy, but the question remains concerning timing, leading me to revisit my valve timing from the rebuild.
So, I am attaching 2 pics: my cam card, with my notes penciled on it from when I degreed the cam; and one of my timing gears at TDC before I buttoned everything up. Timing marks are close, but not dead on. I don´t believe Schneider cams have a 4 degree advance built in.
Am I off a tooth in one direction or the other? Might this be the source of my troubles? Should I just focus more on tuning the Weber with an AFR gauge (my next step)?
Thanks for your comments and ideas!!!
Tim
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