Mopar Action On-line – Tech Questions
Kevin Yardley, salem, IL, 83 Dodge Mirada 318
I’ve got an 83 Mirada 318 w/904. I race this car on a dirttrack. I’m using a mid 70’s Carter 2 bbl. and an electronic ign. w/vacuumadvance. The engine is otherwise all stock including manifolds. my problemis that it missfires at high speed, around 3000 rpm. it revs steady up toabout 3000. I have tried points distributor, different coil, adjust carb,and adjust timing. Could the valve springs be weak, letting the valvesfloat, or the timing chain loose, giving me incorrect cam timing? Any helpwould be appreciated.
Either of those are possible, as are fuel delivery and/or carb problems -the Carter BBD was a good carburetor but nobody ever said it was race-ready.But first, do this:
Manually rotate the engine to the same number of degrees BTDC that you haveat full-mechanical, no-vacuum advance – probably about 35 degrees. Removethe distributor cap, hold the rotor at the full advance position. Make amark on the distributor housing in line with the rotor.
Now reinstall the cap and see if the #1 tower is directly above your mark.If so, the problem is elsewhere. But if it’s off by more than about 4-5degrees, the reluctor in the distributor must be re-indexed. You can do thisby carefully filing (rat-tail file) a new locating slot as needed.