79 308 GTB Stock Ignition Issue

I just completed belt service on my car (and a whole lot of other stuff including all hoses; cooling, fuel & vacuum). Cam covers and distributors were off. I have a completely stock ignition. Cams were found and left on the factory alignment marks. Plugs, Points and condensers were replaced about 1 1/2 years ago (1,500 miles). No problems when I took it off the road in November. Now when I open throttle wide above 5,000 RPM, the engine seems to laydown and the tach bounces high. If I back off a little the tach settles back to correct RPM and engine returns to more normal power; but does not seem to have all the power I remember. It has gotten a little better with some driving but not perfect. Distributors were lubed when points were replaced and were advancing well (not checked on dizzy machine though). Timing is per factory spec. (7 degrees BTDC on R1 points).

I have checked all connections on the ignition wiring and everything seems fine. I have a few ideas but thought I would ask the community for your thoughts.

Other than this issue the car drives and idles great.

 

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

 

By "tach" I was refering to the gauge. I did check the rotors and the plungers. I am going to check the wires and extenders as well as change pulge for good measure. I was thinking that a bad condenser could cause this problem also, any thoughts? These can go bad from sitting unpowered too long.

 

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

 

RJAY, I found one mislanded wire today. Power no longer falls off. Tach is still a little unstable over 5000 RPM, but is much better. I think I will replace condensers. Thanks for your help.

 

Lube the distributors???


Are you getting full advance?

 

I lubed them about a year and a half ago. They should be good but... I will check for full advance.

 

I found the problem. I had one spark plug extender that was heat checked. I was able to read reduced resistance through the bakelite (spelling?). I had a spare and replaced it, problem went away.

I have another question; while checking all of the extenders for resistance, one was of a different design. It did not look to be made of bakelite. It looked more like hard rubber and was smooth, no flutes at the top end. It was a straight conductor, not a resistor at all.

Does anyone know what this type of extender is or where came from?

What would be the down side of running them? It has been on the car for some time and seems to run well.

 

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......

 

I was really just checking to see if they were all the same, but I think I was on the 2000 ohm scale. All the good ones read between 20k and 25k ohms.

The one different one read 1 ohm (not the bad one, it read fine from pole to pole, it was just leaking out the side). If I could get a full set of these different ones I would consider running them instead of the resistor type.

 

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?