timing issues?

[SirDan]

long story short, car was running good but now its not.

73 318 engine, headers, 340 cam, ld4b intake, edelbrock 600 cfm, orange box.

timing is at 10BTDC and when i rev it it knocks at about 2500 rpm. the timing also goes down to the 0 mark at 2500 rpm.

are the distributer weights screwed up? or could it be a bad plug wire or ecu??

 

[67Dart273]

You can easily check the plug wires. Only way something like a broken cap or bad wire would "SEEM" to cause that is because of a crossfire situation.

I can't think of anyway that a dist. would RETARD the spark. You DO have the vacuum disconnected?

If you are using one of those "dialup" timing lights, try borrow / get a "standard" light.

 

[Prine]

Fingers Crossed : timing chain?

 

[SirDan]

timing chain has probably 2k miles on it tops.

I did plug the vacuum advance hose and I am using a standard timing light.

 

[pishta]

How the heck does it retard the spark? Are you sure your reading your timing tab right? If it goes "back to zero from 10" that sounds like you are 10 ATDC and then advancing to 0. YOu should never fire after TDC, thats wasted power. Try to time to about 8 BTDC just by turning your distributor and getting a spark, or point opening at 8 BTDC. It should start right up and run with that initial setting. Mopars like up to 38 BTDC at 3000.

 

[67Dart273]

How the heck does it retard the spark? Are you sure your reading your timing tab right? If it goes "back to zero from 10" that sounds like you are 10 ATDC and then advancing to 0. YOu should never fire after TDC, thats wasted power. Try to time to about 8 BTDC just by turning your distributor and getting a spark, or point opening at 8 BTDC. It should start right up and run with that initial setting. Mopars like up to 38 BTDC at 3000.

Kinda my thoughts, too, Pisha