Lee_in_KC
Active Member
This is an update to my earlier saga here... Sudden Increase in Blow-by
Finally got the motor fully back together and back in the car. Had to get a new seasoned block as the old one had two cracks in the water jacket inside the lifter valley. Upgraded to forged pistons and better rods, otherwise the motor is exactly the same as before I pulled it out.
So, I started it up for the first time today. I put in about 10 degrees of advance when I stabbed the distributor (MSD Pro-billet with a 6AL ignition box). Cranked the motor with a remote button while tending the carbs and the distro. No fire. Added a little advance and it started hitting a little. Added a little more advance and it started. With the blower, this motor runs very rough on a cold start until some heat is built up. I used the idle screw to hold the throttle open at about 1200 rpm and adjusted the distributor to get it as smooth as I could and let it warm up. I checked the timing and it was at 30 degrees!! I backed it down a little and it started running rough again. So I put it back to where it was smooth again and let it run for about 15 minutes to break in the new ring job. After it was showing about 150 water temp I tried backing down the advance again and it went rough within about 5 degrees of retard.
When I built the motor, I spent a lot of time degreeing the cam and making sure I had TDC set dead nuts when I set the timing indicator. I have BDS's shpanky degree indicator set...
Using a yellow paint pen I marked TDC and the 10, 20, 30 and 35 degree ticks.and the tip of the pointer on the indicator. I have MSD's timing light which accommodates the "multi-spark" feature of the ignition box. I am highly confident that what the timing indicator is telling me is accurate +/- a degree or two. I would bet a paycheck on it!
So why is this thing wanting to "idle" at 30 degrees advance?!?! 1200 rpm is 200-300 higher than normal idle (because of the lumpy cam), but the mechanical advance shouldn't be kicking in that low (no vacuum advance installed).
Finally got the motor fully back together and back in the car. Had to get a new seasoned block as the old one had two cracks in the water jacket inside the lifter valley. Upgraded to forged pistons and better rods, otherwise the motor is exactly the same as before I pulled it out.
So, I started it up for the first time today. I put in about 10 degrees of advance when I stabbed the distributor (MSD Pro-billet with a 6AL ignition box). Cranked the motor with a remote button while tending the carbs and the distro. No fire. Added a little advance and it started hitting a little. Added a little more advance and it started. With the blower, this motor runs very rough on a cold start until some heat is built up. I used the idle screw to hold the throttle open at about 1200 rpm and adjusted the distributor to get it as smooth as I could and let it warm up. I checked the timing and it was at 30 degrees!! I backed it down a little and it started running rough again. So I put it back to where it was smooth again and let it run for about 15 minutes to break in the new ring job. After it was showing about 150 water temp I tried backing down the advance again and it went rough within about 5 degrees of retard.
When I built the motor, I spent a lot of time degreeing the cam and making sure I had TDC set dead nuts when I set the timing indicator. I have BDS's shpanky degree indicator set...
Using a yellow paint pen I marked TDC and the 10, 20, 30 and 35 degree ticks.and the tip of the pointer on the indicator. I have MSD's timing light which accommodates the "multi-spark" feature of the ignition box. I am highly confident that what the timing indicator is telling me is accurate +/- a degree or two. I would bet a paycheck on it!
So why is this thing wanting to "idle" at 30 degrees advance?!?! 1200 rpm is 200-300 higher than normal idle (because of the lumpy cam), but the mechanical advance shouldn't be kicking in that low (no vacuum advance installed).