318 +.030 Dieseling

[swies]

Vac at idle is a little bouncy between 10 and 12".

 

[RustyRatRod]

Vac at idle is a little bouncy between 10 and 12".

Classic symptom of low initial timing is low manifold vacuum. 10-12 in your situation is low.

 

[swies]

Classic symptom of low initial timing is low manifold vacuum. 10-12 in your situation is low.

Thanks!
So today after work, I will stop by the parts joint and see if they have a vac can.

When I get home, I will bump initial up to 18*.
Then I will try to confirm then mechanical is 22*.
I did not get a chance to check last night if it had been adjusted / limited down or is malfunctioning. Accel says it should have 22* mechanical but the math says it is only giving me 13ish.
May scrap the whole distributor and order a new complete unit.

On the vac issue, with this motor / cam / intake / carb, where should my vac be at idle?
If I go with the new distributor, which do you recommend? Bearing in mind that I am budget minded, (gotta be, two kids in college) and want the car mostly for the occasional cruise and trip to the track.

 

[AJ/FormS]

OK, firstly; they dont seem to make an exact fit dizzy. Almost every combo needs tweaking. Without spending a ton of money, you wont find a drop-in, ready-to-go, dizzy. So, give the new one that you already have, a chance.I dont know what the guts in yours look like, but there are basically, just two,or three kinds. If you can get a pic of the guts,with the rotor off,that would be most helpful in explaining how to modify it.
Secondly; as to engine vacuum.
There is no written-in-stone magic number for manifold vacuum at idle. It varies with the tune, and the combo,and the ring-seal,the Static cr, and even elevation.The single biggest decision maker is the intake closing angle. the later the closing point, the lower will be the vacuum.The next guys to fool with the vacuum number,are the Scr, and the initial timing.
-Going back to post #4, It seems you have the XE268H cam. It has a ICA(closing point of about 60*ABDC.)I had a similar cam. With the timing dialed in, it idled at about 13/14*or a bit better,IIRC, at around 700rpm@ 750 ft elevation.I wouldnt be overly concerned with the number at this time.Just so long as the engine is not getting air from anyplace other than where its supposed to; namely,the primaries, and the PCV.

 

[crackedback]

Buying new parts won't fix it. You have a modified engine that will likely not run right with ANY off the shelf distributor from a parts store.

Got a protractor? You can figure out the distributor mechanical advance with one.

See post 4 again and again and again until it sinks in...