Operation: Busted Knuckles

[brentsydlik]

ive tried all the small vacuum ports on the carb... never had  any prob before with the stock dist.

[GRONK]

Small port from carb could be manifold vac, could be ported vac.  Your HEI will also have a 10-19deg swing.  Might neeed to adjust the advance curve.  My guess is impropper vac source to dist and possible incorrect timing.

[brentsydlik]

timed at 8degrees, when i hook up the vac that only applies as throttle is applied it goes to about 15 dgrees at 1500 rpms or so and then skips time and dies.

[brentsydlik]

totally disregarding the timing advance issue... what would cause it to run great in park and miss under load...

[mudkicker715]

What's the plug gap at.

[brentsydlik]

45 thousanths but i think i may have figured it out... the 4 screws that hold the coil in the cap were over tightened and cracked through the bottom exposing them to the rotor... all 4 have burn markings on them so i will have to prucure another cap tomorrow.

[brentsydlik]

bought a new cap and installed it. Smoothed out alot. i can actually drive it now. But #3 and #4 both have an intermittant miss. i have no idea why. Just using the timing light on the each of the wires and pointing it at the ground i can watch the 3rd and 4th cylinders just lose fire and miss. all the rest of them fire nice and steady.

[68AMXGOPAC]

Good trick with the timeing light, I have used that before.

[AMCKen]

Partially remove the wire from the bad plug and hold it a short distance away from the plug so the spark has to jump a gap to reach the plug. I had 2 plugs on my J20 that were bad and the extra resistance of jumping the gap helped them fire. Fresh plugs fixed them.

[brentsydlik]

tried that... no use