360 Issue

[Vick68]

OK my engine is 1971 javelin 360 V-8. I have the new plugs, new wires and new distributor. I've checked the firing order and placement of distributor and it seems correct, but it still seems to have a problem with idling rough and some back firing. Any suggestions?

 

[jasonmark1993]

Could be a mixture problem.

When is it backfiring?

Have you played with the enrichment screws yet?

 

[Vick68]

no I haven't still working with carb, probably going to have to rebuild it. The guy helping me seems to think that it is an issue with the valves. idk

 

[jasonmark1993]

Thats possible.

Backfiring can either be some sort of ignition event (timing or too much fuel left over) happening when the exhaust valve is open or an actual mechanical problem with the valves or valve timing (timing chain).

Usually it'll be the former with some left over fuel due to incomplete ignition or too much fuel. I'm breaking my engine in and I started noticing a little popping in the exhaust at cruise; had to lean it out.

Pop a spark plug or two out and see what they look like. Optimum color is a light yellow.

 

[derf]

Timing is the easiest to check assuming you have a timing light. And my experience says it's the more likely culprit.

 

[jasonmark1993]

Affirm on that one. Or just a misfire or some sort.

 

[Torxhead]

Another possibility could be a skipped tooth on the timing gear caused from a worn out timing chain. Cancel that thought if you are familiar with that engine prior to installing it.