1978 308 GT4 Single Distributor point query

Nick,

I though the 78 model had electronic ignition with the single distributor?

If your cam is one tooth out depending on your ignition timing may be impacting performance(more than one - hitting valves and pistons!)

You might also be burning a series of valves depending on your ignition timing and depending on which cam is out (inlet or exhaust?)

 

My 308GT4 (1979) has a dual dizzy setup...I believe they were all that way.

 

Nick
Hi
I can't help with your query, but I'd be keen to hear how you get on with th Black Stallion kit. My GT4's a '74 twin dizzy, but I'm debating going electronic...
Keep us posted.

 

Not to hijack too badly, but can anyone say WHY Ferrari went with the duplicate ignition setup in the first place? It seems overly complicated to me for no useful reason other than complexity for its own sake. We see today many people retrofitting a single system and they all seem pretty happy about it when it's completed.

Surely Ferrari thought there was a tagible benifit to it....?

Ken

 

The "tangible benefit" was being able to pass US emission requirements

The US point set-up (that retards the ignition at idle) requires 4 point sets -- it just doesn't all fit into the single distributor housing.

 

Ah, I see, Thanks! My distributer has a vacuum retard that does the same thing. Disabled now, of course! LOL So they couldn't do the same thing with an 8 cylinder distributor...too bad.

Ken

 

With the 308 carb layout lacking a large common intake plenum, there really isn't a reliable "average" vacuum signal available at low RPM for a vacuum-based scheme (so I guess we have to forgive them for not doing something similar ).

 

Are you asking about dual distributors or dual points in one distributor? I think the reason Ferrari used dual distributors was because a single twelve cylinder distributor using single breaker points has a very short dwell time (time the points are closed and building the field in the coil) and the use of two six cylinder distributors doubled the dwell time for a much stronger spark. Though not as critical as a twelve cylinder, an eight cylinder is pretty short on dwell time also, thus Ferrari resorted to their time honored use of twin distributors. Remember, Ferrari twelves are two six cylinder engines running on a common crankshaft, and the eights are two four cylinder engines also running on a common crankshaft thus the use of a distributor for each bank is a pretty natural design (plus it looks cool IMHO). The distributor pictured above allows use of one distributor by using a four lobe point cam as in a four cylinder distributor but adding a second set of points positioned ninety degrees from the first. One set of points and one coil for each bank but retaining the longer dwell time of a four cylinder distributor. I think the best set up for cool looks and functionality would be twin distributors converted to electronic ignition pick ups and controls. Best set up considering functionality only would be a crank trigger setup (eliminating the distributors altogether) with either a four duplex coil, wasted spark design, or an individual coil on plug design, the latter probably being the ultimate.

 

Nickt. I am curious too. Does anybody know another supplier for these points? i.e. a good cross reference?

I didn't know that the GT4 put two sets of points in one dist. I have a 78 308 with two dist. and four sets of points. The ol' R1 & R2. One set for the emissions at idle and the other for driving.

Rjay

 

Yes it does... the 365 GTC/4 has 4 points inside 1 distributor body.

 

Was it an improvement?

Seriously, I don't deny that it can't be done (or wasn't done), but on a single-dist 12, the cap is already an enormous diameter (for another reason), and the hex-shaped cam somehow seems better suited to be enlarged. Just noting that with the added benefit of making the 308 wire sets more similar, IMO what they did on the 308 was a reasonable design choice.

 

The cam on a 365 GTC/4 dizzy has only 3 lobes. It's got good dwell and works well if set up properly!. Phasing is extremely important of course.

I get your point, (pun intended) just making a Point of my own! (groan)

 

I know many of you really loath points, and maybe its simply because you didnt grow up with them. Either way, I did, and I find thier simplicity overcomes any of thier shortcomings. In truth, all cars, F1 cars, LeMans cars, all had points ignition into the late 60's at the least. Ferrari won World Championships all over the world running silly old stone age points in their V-12 cars. In fact, the most expensive vintage V-12 cars run just fine with points. So do early Lambo Countachs. All the very TOP makers of cars were the very LAST ones to convert to electronic, with Ferrari probably being the last, even though it had become probably cheaper to go electronic. The reason they stayed with points is pure reliability. The reason they reluctantly changed was because the EPA eventually required a car to run 50K miles without failing emissions, and their went your 10K tuneup, which Ferrari were one of the last to hang onto. A good set of properly adjusted points is virtually bulletproof reliable for a good 10K miles. Many will run twice that far or more, giving poorer and poorer performance, until they finally do quit. But usually a screw driver and a match book may be all thats needed to make them work again and get you back home. Not very presice perhaps, but your not flatbedding the car home either. No electronic ignition can, or ever will, offer that kind of reliability.

Do electronic ignitions make the engine perform better than a points type ignition? Yes, is some cases, and they are generally exact for thier lifetime, no muss, no fuss. But how much better performance? I recently seen a dyno graph from an engine that had a dual point Mallory distributor, making 390HP. They swapped in a electronic distributor and pulled just over 400 HP. But, none of us really know if the advance curves were perfectly exact, or if it was timed perfectly the same, and, we cant know the exact fluctuations of a dyno from one test to another. But 390 to 400 HP is barely over a 3% increase. Just to keep the car running and not die by the side of a road, ill stick with the silly stone age points. I can file them and adjust them either in the car, or simply pull the distributor out and play with it. Heck, in a pinch you could static time it and drive it away, its not a big deal. Not if its the difference between driving it home, or having it towed home because I cant find an electrical control unit on a sunday afternoon 100 miles from home. BTDT. Kinda wrecks a fun day. In the time I would wait for a truck, I could be driving again and having fun. The thing I wanted to do in the first place.

 

even more exotic question does anyone have an early gt4 with dog drive instead of spline drive distributors I have 2 NOS distributors with the dog drive I was going to cannibalize the pins and weights an try to find someone who need the shafts?

sorry for the hijack

rob

 

I always thought the dual distributors on 308s were to meet emissions, given that the Euro cars has a single distributor. So if they could fit 4 sets of points in a dizzy, is that really the reason they did it?? Did they put 4 sets of points in the 365 GTC4 only because it was a huge distributor?

 

Lots of cars meet emissions today with all kinds of emissions equipment deleted. My car is an example of that. I used to have crossover pipes to warm the mixture and rob HP, and an advance of 5 degrees instead of the preferred 12 degrees, and a vacuum RETARD instead of advance which robs low end torque but cleans the emissions. Yet I passed the IL test in 2002 on a 1972 car. My car would have passed the 1972 test as well I would think, without all the BS emissions crap, as today the I think the limits are stricter. And I have an extra 9% HP gain (Euro vs. US spec) as a bonus.

Emission tests confuse me.

Ken

 

I have 79 US 308 with dual distributors and dual points in each distributor. one set of points has been removed, so now
just running on R1 points in each distributor. With the points just about to open the rotor was just passed the point in the distributor
cap so i modified the points base so now with the points just about to open the rotor is exactly opposite the point in the distributor cap.
My question is, is this correct because now one set of points is burning out, even with a new condenser.
Should the points be just opening as the rotor arm is just passed the point in the distributor cap. as it was before.?
Regards

 

The way it is supposed to work is ...

a) the point gap is just starting to open when the "arm" is approaching the peak of the shaft.
b) the point gap is maximum when the "arm" is at the top of the peak of the shaft.

I think you made it so that there is very little gap and therefore the point is burning out.