Banging at approx 10 mph

[tempest66]

Hello all. I am new to this site so hello everyone. I have a 1966 Pontiac Tempest. Original motor and transmission. I replaced a few things (cam lifters carb intake pushrods) nothing major. The issue I am having is when your driving around the car runs fairly well how ever when you come to a stop either red light or stop sign at approx 10 mph there is a nice banging. I replaced the vacuum modulator it didnt cure anything. has anyone experienced this or have any suggestions for me? Any advice is greatly appreciated. Thanks!

[TC]

What's your timing set at??.....

[tempest66]

Hey TC the timing is set at factory setting 6 degress BTDC

[MR P-BODY]

First off... is the noise coming from the engine... but if the cam is bigger
then it will need different timing.... but also did you degree the cam in

[tempest66]

Hey Mr P-Body, i believe the noise is coming from the front. I had jacked up the rear and there was no noise. As far as the cam goes the cam is a close to stock as you can get. Its nothing fancy. I probably didnt cause i'm not sure what degree the cam means?

[MR P-BODY]

Hey Mr P-Body, i believe the noise is coming from the front. I had jacked up the rear and there was no noise. As far as the cam goes the cam is a close to stock as you can get. Its nothing fancy. I probably didnt cause i'm not sure what degree the cam means?

After reading your other post I would tend to think its suspension more
than a engine issue

[skullbucket]

troll.

[anotheridiot]

Hey Mr P-Body, i believe the noise is coming from the front. I had jacked up the rear and there was no noise. As far as the cam goes the cam is a close to stock as you can get. Its nothing fancy. I probably didnt cause i'm not sure what degree the cam means?

Degreeing a cam is putting a 360 degree wheel on it and verifying cam specifications. If its a stock cam its not gonna make much difference.

So its a downshift bang then? what is the original trans a powerglide or a three speed? Has the tranny been gone thru or is there 46 years of gunk in the valve body? You should be able to adjust the band on that old tranny which might help, but it would probably be slipping when you are driving. Just sounds like the fluid is not getting released properly and allowing the trans to downshift when the speed wants it to. Did you look deeper into where the modulator is to see if the piston is free so the modulator is actually allowing the internals to move?

[antmnte]

Did you mess with the vacuum lines? My friend had the line from the modulator hooked up to ported vacuum on his Torino and it would bang like that when coming to a stop. Make sure the modulator has vacuum all the time.