307 non computer controlled timing.

[Jimmy]

Unless you are noticing bucking or pinging, it is probably carb related. What is the carb off of? Was it rebuilt?

Have you checked for vacuum leaks? If you're pulling too much fuel, it will choke it out. I don't see how it would die with higher advance; the opposite, really.

I have checked for leaks and didn't find any. I'm going to check again with an ultra sonic probe to see if I missed something though. Thanks for the suggestion.

 

[Jimmy]

Unless you are noticing bucking or pinging, it is probably carb related. What is the carb off of? Was it rebuilt?

Its a Jet carb from Summit so yes its rebuilt. It has made a huge improvement in the performance of the car.

 

[TURNA]

While it is running Just spray the intake and carb with wd40. if you notice any difference in the idle you have a vacuum leak

 

[olds307 and 403]

Are you using ported or manifold for the vacuum advance? The Jet carb is hopefully close to where it needs to be, that is the problem with generic rebuilds, you don't know. Try unhooking and plugging the hose for the vacuum advance, that will pull 10 degrees vacuum advance out where you are having the issues. Stalling is usually not enough timing, like I said bucking is the syptom. I needed 22 base with 16 mechanical and a 30 degree vacuum can to have bucking with an actual 9 to 1 Olds 350 with a 214/214 cam. I went down to the Crane adjustable can which only has 20 degrees. Definitely lost part throttle crispness but no more bucking. Your 307 had very aggressive advance curves factory. I am betting your less than 8.5 to 1 Olds 307 wants more timing, it is an old school chamber that likes a lot of timing.

 

[Jimmy]

Are you using ported or manifold for the vacuum advance? The Jet carb is hopefully close to where it needs to be, that is the problem with generic rebuilds, you don't know. Try unhooking and plugging the hose for the vacuum advance, that will pull 10 degrees vacuum advance out where you are having the issues. Stalling is usually not enough timing, like I said bucking is the syptom. I needed 22 base with 16 mechanical and a 30 degree vacuum can to have bucking with an actual 9 to 1 Olds 350 with a 214/214 cam. I went down to the Crane adjustable can which only has 20 degrees. Definitely lost part throttle crispness but no more bucking. Your 307 had very aggressive advance curves factory. I am betting your less than 8.5 to 1 Olds 307 wants more timing, it is an old school chamber that likes a lot of timing.

Ported. The carburetor is a direct replacement it just has the electric choke.

 

[DoubleV]

Use manifold vacuum. If your carb was a direct replacement it would be a computer controlled carb so it can't be... Just saying 😉

 

[Jimmy]

Use manifold vacuum. If your carb was a direct replacement it would be a computer controlled carb so it can't be... Just saying 😉

When I said direct replacement I was referring to the fact of the linkage and the fuel line input being the same. I know that the original was computer controlled and this one is not....just saying. Don't want to get into ported and nonported vacuum debate.

 

[DoubleV]

When your engine was on the computer, it ran the equivalent to manifold vacuum so wouldn't it be logical to continue to do that? If you wanna change that and change everything else timing related ( base, curve, total ) then you're putting yourself on the long road of trial and error in finding your optimal timing.

 

[Jimmy]

When your engine was on the computer, it ran the equivalent to manifold vacuum so wouldn't it be logical to continue to do that? If you wanna change that and change everything else timing related ( base, curve, total ) then you're putting yourself on the long road of trial and error in finding your optimal timing.

More than likely I will try the vacuum on manifold and ported to see which is better for the car. Since it's not on a computer anymore has a different carb, and distributor I'm not sure it would be logical or not to continue that way.

 

[pontiacgp]