383 timing issues

[jays69bird]

Greetings,this is my first tech topic on the site.Had trouble with my carb on my bird after 40 yrs. the AVS was shot plus cracked.I found a place in Texas that had reman AVS carb's.Got it running had a heck of a time getting it tuned in.Good idle,carb was ok until I crack open throttle,the it would backfire through carb usually with a fireball.Thought it was carb at first,then I started checking other things,timing was ok however I got the advance dial light out at 2200 rpm Iam only getting about 23deg.advance.with the car running,I loosened the dist. and cranked the advance up manually,I cracked the throttle didn't get the backfire.the point plate seems free,my vac.pump is MIA so I couldn't check diaphram.The car sat for a while didn't know if maybe the mechanical weights might be the problem.Any ideas?

 

[Big John]

More likely the timing mark is off.

The outer ring on the harmonic balancer moves around as the rubber holding the ring gets old and dries up.

 

[Basketcase]

welcome to the site :cheers: and I agree with what Big said. gotta be timing.

 

[69hemibeep]

Me to and welcome :cheers:

 

[1BADBIRD]

Welcome! :cheers:

 

[Hoosier Bird]

Welcome........ :cheers:

 

[Roadcuda]

Welcome to the birds nest!

 

[george68hemirr]

welcome....let us know how you made out

 

[SomeCarGuy]

If it isn't advancing, I don't think you would get a fire ball. I think it would just be real lazy.

Are you saying you are showing 23 degrees at idle? That would get you a fireball I'm pretty sure.

 

[Big John]

Just for laughs, check the firing order on the plug wiring too. Especially 5 and 7

FYI, firing order is 1-8-4-3-6-5-7-2 with the distributor gong CCW.

 

[jays69bird]

Big John,I did change the plugs not to long ago so I will check that.Checked the vac.advance it moved with the pump as did the point plate seemed to hold vacuum.I was going to TDC it on # 1 and see were the timing mark comes up,I didn't realize the balancers had that issue moving around.In response to the one post I had 23 deg. advance at 2200 rpm.Also as I said in my original post I advanced the dist. by ear and didn't get the backfire.

 

[SomeCarGuy]

What is the advance at idle?

what is the total advance?

You need 34-36 or so not long after 2200 RPM. It needs to advance all the way out to the total w/o vac

 

[John69RR]

Welcome to the site. :cheers:

 

[jays69bird]

Ok guys got an update,finally got time to play around.On thing I did last year when I started having trouble was change the vac. advance with one from NAPA.As we all know a 3/32 allen will adjust these I started playing around with it,I hooked up my mighty vac pump and adjusted it Ive got about 32deg advance total between the mechanical and vac.Now with the timing mark on the tab I would still get a pop.I set the dist. so the mark is just off the tab,I know Big John said not to trust the mark on the balancer.No pops when I cracked open the throttle,I pulled out of the garage and took a short test drive (my NYSI is from 2007 so it was very short) seemed to run good I did have a slight hesitation in 2nd gear when I slammed open the throttle but that maybe a air valve adjustment on the carb. It didn't spark knock or start hard so I think Iam ok even though I don't like the balancer mark off the timing tab.Thanks to all of you that gave me advice.

 

[John69RR]

Glad to hear you're back on the road.