308gt4 coils/ballast resistors/condensor

A condensor is a capacitor that is rated usually in microfarads (mfd) or (uf)
So .50 would be a .50 micro farad .25 most likely .25uf (microfarad)
These are very common values for these things. The function is to prevent burning of the points when they come together to send along the electrical charge. Kind of like a shock absorber for the electricity.

 

Just noticed you said one was on the coil. Maybe for radio noise suppression? Not real sure about this one.

"In addition to the high voltage secondary circuit, the low voltage primary circuit can add to the noise problems. The main offender in the primary circuit is the breaker points. Noise generated at the points can be conducted and radiated by the ignition primary lead. As this lead generally goes through the vessel to the key switch on the dashboard, the noise must be eliminated from this wire. The most effective way is
to install a 0.5 microfarad coaxial condenser as close as possible to the ignition coil primary terminal. "

From a book on reducing noise in the radio.

 

In the old days we put these damn condensers on everything to try and reduce noise. Then came resistors, then resistor plugs all to keep the buzz out of the radio.

 

Make sure the shop you choose has the ability to test and calibrate the mechanical advance mechanism located in the bottom of the distributors. If the advance curves aren't precisely matched you could have one bank operating 5º - 10º different advance than the other. I have seen differences as much as 15º at a point in the rev range.

 

The 0.5 uF capacitor next to the coil filter out high voltage peaks, which could interfere with the radio. Newer radios had a filter integrated with the voltage supply so there a coil capacitor is not required anymore.

Yes, as long as it is specified for 200-250 Volts.

Bosch Red coils with a 1.8Ω resistor (Bosch supplies these as a package, part #221 119 031) are a very good choice for replacing coils in a points based setup.

You are looking for an ignition coil made for points/breaker setups, 2.5-3.5Ω including resistor and a winding ratio of around 1:80. CDI coils won't work and coils for transistor ignitions usually have a lower primary resistance, which is too low for a points/breaker setup to handle.

Bosch Red works quite well and the build quality is quite good. Bosch Blue coils have a lower winding ratio so they have a 20%-30% lower output (spark) voltage.

The Blaster 2 coil is a good CDI coil, but not so ideal for an inductive points/breaker setup. It delivers a slightly higher output voltage than the Bosch Red coil but the charge time is slower so would recommend to use a dedicated inductive coil to get the best out of your setup.

For a points based setup you want to keep the primary current between 4-5A, as the setup won't handle currents higher than 5A, and having less than 3A reduces the secondary output. So in Ohms, 3.5A is a primary resistance of 3.4Ω (12V/4A = 3.43&#937, 5A requires 2.4Ω.

Have a look at the primary resistance of the coil in question (as example, 1.8Ω for a Bosch Red coil), then add a resistor to reach 2.4-3.5Ω if required. The Bosch setup uses an external resistor with 1.8Ω so the sum is 3.6Ω (coil 1.8+resistor 1.8), which is fine.

The original Marelli ballast resistors came in 0.8Ω and 1.5Ω, the value is printed on top of the resistor. Both work great with the Bosch Red coil, the 0.8Ω gives slightly more power but the 1.5Ω is quite sufficient already.
There are a range of OEM resistors available, check the comment above for the right value your coil requires. If the coil has a resistance of not less than 2.4-3.0Ω then you don't need to add a resistor.

I haven't had problems with vertically mounted, oil filled Marelli coils yet. A typical defect is rust at the bottom and in severe cases the coil could loose oil if the rust gets through but if you take care of your coils this shouldn't be an issue.

 

Correction, i meant "horizontally mounted coil" in the post above.

 

You are right about the oil filled coils mounted horizontally, a big no no but every 308 does it (and the 512 Boxer too)

I use the regular High Vibration MSD unit (with stock Ferrari OEM resistor) as they are solid potted so it makes the mounting position a mute point.

Fits stock bracket too!

 

What i meant was that i don't see a fundamental problem with horizontally mounted oil filled coils. Many cars had this setup in place, not only Ferraris. If you loose oil due to a defective coil body (rust can do this), you could have winding shorts due to the missing isolation but that will also happen if you mount the coil vertically if you loose enough oil.

Oil is a very good insulator and does excellent heat transfer, making it a very good choice for street and performance cars, especially for inductive coils which can generate a lot of heat if dwell is not managed correctly. Epoxy is not that effective in transferring heat, which can reduce the service life of the coil, but supplies better mechanical support to the iron core for high vibration environments, so its a good choice for Marine applications, rally sports or offroad applications.

 

Have you thought about the Pertronix setup? I have it in my 308 and it was easy to install. Goes right inside the dizzies. You can't tell there is an upgrade.

 

It sounds like you don't do to much work on your car. A points system has a tendency to deteriorate and requires maintenance. Also Ferrari points are prone to problems on these engines. I had my car for about 3 months before I had my 1st problem with the points. Unlike other points based cars I have had this was by far the most difficult to setup. So the first thing I did was replace the points with a Pertronix setup and Bosch Blue coils. I did this back in 2001 and have not touched the dizzy's since. Set it and forget it. Wait until one set of points start to get intermittent and you end up blowing a muffler. Hopefully you won't have that problem. Good luck.

 

I have a GT4 and have only replaced the points once in 17 years, with original coils. I am only running one set of points and drive the car about 1000 miles a year. I assume you are running one set also? Some one hot rodded my advance and even though I have played with it I have never got it to run better than it does. I did notice that by changing the rubber bushing on the distributor shaft from a 2mm thick one to 1mm it also improves the response.
Not sure why this is one of the things the guy that hot rodded it did.

I am a big fan of originality if it works. I have been lucky and think my car is blessed.....

Rob

 

I can't remember any car with a verticle mounted oil filled coil that I owned back in the day. They were all mounted horizontal, Jag XKE, JAG XJ6, FIAT 128, TOYOTA CELICA and I think even my Old's 442. Never had a problem with any of them except the Jag XKE. I had a dual point distributor on that which created more damn problems. Noise, poor running etc. That was the one I cut my teeth on learning to supress noise from the ignition system. And to think I traded my non-functional A/C system for it. Felt so good turning it into a High Power target. Ultimatly replaced it with a single point. Sorry for the digression. I saw on the 308 GT4 WSM that there are two condensers(capacitors) on each dizzy by the way. We did this also, one for each lead + and -.

 

Agreed but, the idea is to filter this as close to the coil as possible. Why? because the lead going back to the system and then the radio act as a big radiating antennae broadcasting the original signal plus all the harmonics. I learned this from practice putting newer radios in older cars like ours.

 

If you look in this manual you will find a diagram and I believe it shows both caps on both dizzys. You can't hurt anything by adding them as long as they are added correctly. Leaving them out won't hurt anything either but your points may not last as long. IMHO

Try this link: http://www.ferraridatabase.com/The_Downloads/The%20Documents/Workshop%20Manual%20308GT4.pdf

 

I think there are two condensors on each dizzy because there were originally two sets of points per dizzy (USA version). One for each.

 

True, but only for emissions...controlled by micro switch on throttle.

Not sure when they were added.

You obviously drive on the "non idle" set 95% of the time....

 

The US 2 Distributor version has two condensers one for each point. If you only use one point you only need one condenser.

Does anyone have the early dog drive distributor. If so I have so rare parts on ebay, unused and unworn weight trays!

I am running original coils, and single point with grew results for almost 18 years.

Rob
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Guy,

I am using a K&N filter and Baldwin B253 oil filter,there has been lots of talk about it here but I feel with the K&N and Tubi I can feel a seat of the pants quicker response. I felt a bit more response after switch to synthetic oil, however I was having oil leaks after switching to Redline 15/50, after switching to Valvoline racing VR1 20/50 they seemed to go away. I am still trying to chase down a small GB leak. I worked two years replacing all my hoses and other stuff and think maybe I have some seals that went bad but can't track them down so dot feel bad the engine won't stay this clean for long! HA

Like everything I think I am over analyzing it and need to get out and drive it. ON a side note I bought the last two S 159 C distributors which were made for japan and have only one condenser, however they have a very weird distributor cam and only three pins in the weights and have not been able to have anyone explain what they would do. I want to try one out but have been chicken up to now!

I know lots of people switch to newer set ups but I have found that the standard set up works great and stays good for years with little maintenance if set up right.

I love GT4's

Rob
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