79 308 GTB Stock Ignition Issue

Tvine,

Can you explain what you mean here with the tach? If the guage is jumping, you may be missing or have a bad wire up to your unit. Since you feel the power drain at the same time, your ignition may be missing. I would recheck your gap and dwell on the points along with a complete check on each plug wire. High voltage is sneaky stuff and if it finds ground before the plug, it won't fire. Also, Mike Florio mentioned once to me that the rotor on a dizzy can be in backwards. Check them against the GT4 manual (nice illustration) and convince yourself everything is timed right with respect to #1 TDC.

One other area is that the little plungers in the dizzys that control the rpm for timing, may be in wrong. You'll have to check the threads to see if you can sort it out or, at least, check one dizzy against the other.


-Rjay

 

Since the tach is integrating pulses, multiple pulses can cause the tach to read higher than actual RPM. If the condenser (just a capacitor) is not doing it's job, you can get arcing at the wrong time. This may generate extra pulses to the tach, hence the gauge moves high. Check em' out or just replace. First, make sure the condensers are grounded nicely to the case. Also, check the feed throughs that go through the dizzy housing and make sure the leads are mounted correctly. High voltage wants to seek ground. If you want your ignition system to work properly, you must make sure that no exposed lead is close to ground. The system wants to deliver the voltage and subsequent arcing to the plug, and nothing else. Since I don't actually know the creepage and clearance (fancy names for the spacing across a surface and a spacing in the air respectively) Take a look at these feed throughs on the dizzy and you can see what Ferrari thought these spacings should be since the leads are quite exposed in that area. Then follow all wires in the dizzy and make sure there are no insulation breaks or that the exposed areas are far enough away from ground. In my dizzys the points had long wires with a knot in them to take up the slack - I don't know if that is original but it is not a good design, in that the wire should be short and only long enough to go to the feed through. The longer wire works as long as the insulation is good but it gets in the way for a rotating assembly.

-Rjay

 

Lube the distributors???


Are you getting full advance?

 

Good deal!

Maybe that's what's ailing my yellow #22127, as well......

There are two designs, I'm not sure of the difference.....I notice TRutlands sells the whole wire set with extenders and well seals for about $400

What were the values on the good vs. bad ones???

 

Ricambi also has the correct ones I'm sure, if he'll sell less than all 8......

 

It could be high-voltage, but after sitting for a long period I would suspect condensers or advance hanging up. I recently bought a distributor machine just to keep my 79 running right, and after checking the distributors on the machine, it is amazing to see what goes on with respect to these two aspects of ignition in a dynamic state. The advance is really tricky if everything is not perfect; and the capacitance of the condensers can go away if they are not charged and discharged for a period of time. (You filter-cap Fender amp guys want to comment???)

 

True, I replaced both my coils but a friend said I should have done both condensors as well.........cheap enough!

 

Unless you're going to a concours event (and I know you are not) there is no need to buy OEM wires. Accell 4040R can be cut to fit and work well as replacement wires ($40 at Autozone) and the correct extenders can be found for $8.00 each at GT Car Parts.

 

Rock on, thanks...

 

Cameron, what do you mean by a Distributor Machine? Any Pics? How does it work?