2.0 wont run properly

[Lyndon302]

I've just finished my build. Was a 2.0L S with T cams.
It now has dc30 cams and some higher comp Wiseco pistons.
It now pops constantly thru the carbs and to a lesser extent the exhaust.
I cannot get a stable idle and after a rev does not return to idle in a timely manner. Stays up around 2 to 3 k for a few seconds.
Idle mixture does not do much if anything.
Timing is set. Throttle linkage does not stick.
I did not go thru the carbs. They were Working.
Lyndon

[TimT]

Congrats, you now bet to play"re-jet" that carb!
Intake pops...= lean

Exhaust pops.. rich..

You rebuilt an engine, changed operating parameters, and plopped the old carbs on..

Refresh the crabs... and fix the jetting..

[Lyndon302]

Ok I have 52 ildle jets ?
Do I go to 55 or 60. Its really bad.

[stownsen914]

Post your carb jetting specs - idles, mains, air correctors, emulsion tubes, venturis, etc. You'll get some opinions.

A wide band O2 setup will help you a lot.

Consider the possibility of air leaks at the carb/manifold as well.

[Lyndon302]

I have 135 mains. 52 idle.
With out pulling them apart again. I'm guessing they are std sixty eight 911 L sportomatic webers.
They are on the sixty seven S engine.
I have some sixty idle jets coming tomorrow.
Lyndon

[stownsen914]

This is for the motor you've been putting together? High comp pistons, correct? S spec cams and heads? Edit - whoops, saw you answered that above

[roblav]

Try clogged jets or passages or idle screws. What size venturis? Are the 6 intakes balanced via the air adjustment screws?

[Lyndon302]

The carbs were done on the old engine last year. With that it ran ok for a worn engine. But I still didn't have any real control on the idle mixtures.
I have never measured the chokes.
Lyndon

[rgofast]

Idle not returning could be the distributor. Turn the key off and back on again rapidly, when the engine is idling to fast. If the idle speed drops then it’s a weak spring in the distributor. Mine was doing that and Jerry Woods rebuilt the distributor. Runs perfectly now.

[Lyndon302]

Is that to force the engine to slow thus returning the springs. It may have week springs as it gets its max advance well before 6000rpm
Lyndon

[rgofast]

Yes

[roblav]

I had 4 early 911's that the distributor advance mechanism was frozen.

[Lyndon302]

Initial findings. 60 idle jets in. Air screws out 1 turn and all is well in the shop. Should be fine to get it inspected so I can get rego and drive it.
The idle mixtures still do nothing ? The rest balanced well.
Lyndon