autolite 1100

[myblue67]

When I decelerate in gear I get a popping noise from the exhaust. I do have an exhaust leak at my header to pipes that makes a ticking noise. I need to to fix that, but I was told the popping could be from a rich setting on the carb? I tuned my autolite 1100 with a vacuum gauge so I thought it was at the right setting. What do you guys suggest?

Thanks
SG

 

[FalconSedanDelivery]

Fix the exhaust leak first

 

[chad]

2X what he (FSD) said -
if it is a repeated pop (pop pop pop) it's just the valves as the motor breaks for the vehicle slowing down ("lugging")....

 

[myblue67]

I fixed the exhaust leak and I still hear the popping noise coming from the mufflers on deceleration. Is it a carburetor problem?

 

[Invectivus]

My car did that when my 66 SCV dizzy vac can was shot, so i was running on base timing at all rpms. Swapping for a mech advance dizzy off a 69 and porting to manifold vac fixed it. Doesnt mean thats your issue, but its something to think about.

 

[Frankenstang]

Some 1100's have a single dashpot (the accelerator pump) on the driver's side of the carb (typically for manual transmission setups) which delivers a shot of fuel to bridge the vacuum lag when you rapidly open the throttle plate, and others have a second dashpot on the passenger side of the carb (anti-stall dashpot for auto trannies) that delivers an extra shot of fuel on deceleration to prevent engine stall or excessive rpm drop due to auto tranny drag on the engine. Which one do you have?

If it's the dual dash pot you could probably dial back or dial out completely the anti-stall dashpot screw. Invectivus thoughts on poor responding advance unit are worth looking at, and you can check the action on the distributor breaker plate with the cap off by rotating it a few times and making sure it snaps back into place smoothly and correctly. Good luck

 

[myblue67]

Some 1100's have a single dashpot (the accelerator pump) on the driver's side of the carb (typically for manual transmission setups) which delivers a shot of fuel to bridge the vacuum lag when you rapidly open the throttle plate, and others have a second dashpot on the passenger side of the carb (anti-stall dashpot for auto trannies) that delivers an extra shot of fuel on deceleration to prevent engine stall or excessive rpm drop due to auto tranny drag on the engine. Which one do you have?

If it's the dual dash pot you could probably dial back or dial out completely the anti-stall dashpot screw. Invectivus thoughts on poor responding advance unit are worth looking at, and you can check the action on the distributor breaker plate with the cap off by rotating it a few times and making sure it snaps back into place smoothly and correctly. Good luck

I have the single dashpot because its a standard trans. I got two new flowmasters that im going to get put on and hope this fixes the popping.

 

[chad]

Does any 1 suspect unburned fuel igniting aft the combustion chambers? I thought of that when he said "new mufflers"?

/OR/
still:
"...the vehicle slowing down ("lugging")...."

as in going down a hill w/ 'foot off it' & baffles missing in muffler or other less restrictive exhaust (pin holes)

 

[myblue67]

Does any 1 suspect unburned fuel igniting aft the combustion chambers? I thought of that when he said "new mufflers"?

/OR/
still:
"...the vehicle slowing down ("lugging")...."

as in going down a hill w/ 'foot off it' & baffles missing in muffler or other less restrictive exhaust (pin holes)

What would I do to fix either of those problems?

 

[chad]

the 1st is still the timing thing folks above mentioned
or valves

the 2nd is a muffler/noise suppression thing
(Lugging is what I call it when U allow the engine do ur breaking)

I like the latter due to having an affinity for that sorta sound when I hear it. I have a pin hole (small rusted thru place, don't know if it's pin sized) in my muffler now (in the rig in my sig. below) & it has a nice quiet 'rap' as it goes along. Loud enuff to please but not a major att3ention drawer. Hey, what can I say - I'm 60 yrs old...
8^ )

 

[myblue67]

Thanks for the input guys. I'll clarify the noise. When I come to a stoplight ill down shift and that obviously slows the car down and raises RPM. Along with that comes loud pops from the mufflers. How exactly do I check if ky vacuum is working? I actually think iv accidentally driven the car with the vacuum line disconected after checking timing and I didnt notice change. What do i do if its a valve problem? What do i do if its a fuel problem, iv only got the two adjustments on my 1v carb and I adjusted it with a vacuum gauge reading 20 hg.

Thanks
SG

 

[hutchstang]

best thing you can do in my opinion is just mess around with it, change it drive it, change it drive it, just fiddle with things make one change at a time though. I was runing my car so rich and really bad timing. make sure the fuel screw is all the way in then I thinks its 2.5 turns out... dont quote me on that though.

- ryan