289 Timing?

[renaissance man]

Is there a "standard" for 289 Timing? I am trying to dial in my car and it was set at near, BTC, causing a lot of backfiring (Pic). I found a 289 forum online and it suggest just setting for 8 degrees Before TDC, and it's "that simple". I'm running an MSD 6A Ignition and MSD Blaster 2 coil, and MSD distributor. Brand new plugs gapped at .044

Cannnot get pics to upload...I will try later.

Still backfiring a bit when letting off the throttle.

1. How normal is the backfiring?

2. Suggestions on setting the timing differently?

[Tommy]

Originally Posted by renaissance man

I am trying to dial in my car and it was set at near, BDC, causing a lot of backfiring (Pic).

Is BDC a typo?

[renaissance man]

@Tommy

Yes, Typo

[Tommy]

Has this engine run right for you in the past? If so, what changes have you made?

If it ran good in the past AND you know the timing mark on the balancer is in the correct place, then this should come down to putting the distributor in at the right place. That's usually done by turning the engine over until the #1 piston is at TDC and confirming that with the timing mark. Then drop the distributor into the hole so the button on the rotor is pointed at the #1 spark plug wire on the cap after it is fully seated into the cam gear. With that done, install the plugs and wires, and tighten the distributor hold down so you can just move it by hand. If you have vacuum advance, disconnect it and plug the hose for no vacuum leak. Start the engine and slowly turn the distributor to get the smoothest, highest idle. Check the timing with a light and compare it with the goal of about 8* before TDC. When the engine is warmed up, adjust the carb and timing for the best idle again. Then check the timing when you increase throttle to to raise the RPM to see your "all in" advance. When all looks right, tighten the hold down and reconnect the vacuum advance. There's more, but this should get you close.

[jhv48]

Backfiring on deceleration is usually caused by an exhaust manifold leak where the headers meet the heads. Check that your header bolts are tight. All it takes is a small leak to blow the gasket apart.

[twobjshelbys]

Originally Posted by jhv48

Backfiring on deceleration is usually caused by an exhaust manifold leak where the headers meet the heads. Check that your header bolts are tight. All it takes is a small leak to blow the gasket apart.

It can also be caused by a rich condition.

[eschaider]

I sort of like the idea of the backfiring, especially at night. On those long lonely drives home in the dark, the back firing is sort of like a wake up call preventing you from dosing off ...

[twobjshelbys]

Originally Posted by eschaider

I sort of like the idea of the backfiring, especially at night. On those long lonely drives home in the dark, the back firing is sort of like a wake up call preventing you from dosing off ...

And also provides a little motivation for the tailgaters to back off.

[Seagull81]

Dave, you have a PM.