Ok so I have an 87 formula with a 305 4brl. It currently has an Edelbrock performer intake mani and edelbrock performer 600cfm manual secondary carb. Also has an HEI coil in cap type distributor with vacuum advance.

Im trying to time the car correctly but im having a hard time. I can get it timed to the point where it seems to run ok at idle or free revving but when driving it seems to be a little laggy and possibly knocking under lower rpm load. Also when it comes right off of idle with very light throttle i shakes for just a second. Its hard to explain but lets say it idles ar 500rpm. Its fine at 500rpm but between 600-700rpm it has a little shake then it goes away very quickly.

Is it possible that my timing light is shot? It seems to work as it flashes and I see the timing mark but it is very old.

How should I go about timing this correctly?

Thanks for any help!

 

First off are you unhooking the vacuum hose from the distributer when timing it? Untill you get the timing set it will act different. What are you trying to set the timing to at idle? I set most of mine to 12 degree's to start off. I had a problem with my '86 bogging very bad untill I found that the balancer had slipped and the timing marks were way off.

 

If the distributor is computer controlled, you still need to disconnect the brown EST wire before you can set the timing.

There's also a possibility that the distributor is worn out. The weights could be worn out or seized. The shaft bushings could be worn out.

 

when I attempting to adjust the timing i have the vacuum advance connected. Should it not be? I didnt think it would advance at all during idle vacuum? I figured since it would never be in the condition where the advance is not connected then why set base timing in that condition?

It is an HEI that to me seems stand alone. I removed the stock EST style dist and coil as there are so many sensor disconnected from the manifold and carb being changed to standard non electronic types the computer was most likely in limp mode or something similar. The CEL is on of course.

Is there a way to check visually the conditions of the advance weights? I haven't had the cap off for a while and cant remember how much I can see below the rotor.

Should I replace it with one from a different car? Should I just get a new one? How much can they really be?

Thanks for the help!

 

Take the cap and rotor off. The shaft should have very little side to side movement. The weights and springs should move freely. You would have to remove them to find out if the weights or pins are worn out.

Years ago I was pulling caps to get different weights and cams to recurve a distributor. I found one that was so worn out that I can just imagine the last owner constantly complained about the performance and finally scrapped the car.