308gt4 coils/ballast resistors/condensor

I've earlier asked members what pointless ignition upgrade to make on my 75 308gt4 with twin dizzies. Electromotive was the general answer.

For now have decided to stick with the points and want to freshen up the old parts. Plugs and leads are done, and i've replaced the 2 condensors on the distributors (for some reason the service kit from superperformance for a twin dizzie 308 has 4 condensors..mine only has 2 on the dizzies. Will get get a shop to replace points and reset timing and at same time replace leaking dizzie seals.

the car has 2 old no brand visible coils, with what i understand are ballast resistors mounted underneath. There is also a slightly larger type of condensor (stamped 0.5 on the bottom - the dizzie condensors are stamped 0.25) attached to one of the coils.

I'd like to get new coils that will work well with the points systems and perhaps able to make the jump to a pointless system, preferably without the ballast resistors and readily available at a reasonable price.

Does anyone know:

- what does that 0.5 marked condensor off the coil do?

- will any condensor with 0.5 stamped on the bottom work as a replacement?

- what good quality coil would people recommend for plain old stock street performance?

- or what minimum specs should you look for?

- Bosch red i've seen recommended (whereas bosch blue on the weak side?)

- MSD have blaster 2 which is considered higher performance - can one have too much power on a points system?

- how do i know if i need ballast resistors with different coils?

- can i reuse the original ballast resistors or is there a non OEM resistor one can buy? specs?

The coils are now mounted horizontally while i understand the oil filled coils should ideally be mounted vertically, although ferrari happily mounted them horizontally so assume life not performance is affected. a simply aluminium mount could solve that. alternatively there are the vibration models (epoxy?) which mount horizontally - any experience with those?

Not looking for rocket science here, just replacing old parts probably beyond their use by dates

any tips appreciated. thank you!

 

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.

 

- could the condensor off the coil be a noise filter for an aftermarket radio??

- i am guessing that a new coil will come with resistors included if they are needed on that coil (eg Bosch reds seem to come with fitting strap and resistors).

 

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.

 

thanks Crowndog,

yep i reckon that extra is for the radio noise suppression - took a bit of googling to find that! i am no electrical engineer..

i am leaning towards the msd vibration coils which can be mounted any which way and are a reasonable price compared to bosch reds (1/2 price?). Their instructions say resistors MUST be used with points ignition so that question is answered so i am going to order a set plus a pair of their resistors.

 

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.

 

thanks for all the replies - its been said before but amazing knowledge here.

before we lost power 5 days ago i ordered up the MSD hi vibration coils with the resistors - good value and the horizontal mounting is no issue. Will see how they go.

I have considered going to a pointless system but thought i'd just let the car now run on the points system and get more experience with the old girl. It does flutter a bit at low revs and i think thats most likely the throttle shaft bearings in the webers, so a rebuild at Pierce is probably higher on the agenda (i know its possible to DIY but I'd rather get them done right first time!)

 

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

 

right now i have the MSD hi vibration coils installed and i left the original resistors on. The MSD resistors would not have fitted side by side piggybacked on the coils like the originals. I bought these epoxy filled coils so that lying sideways is not an issue.

I had some other issues with plug fouling really down to lack of use (separate post there), but once that cleared the car is running well.

Right now i am planning to stay with the distributor setup and rely on my local shop, who is comfortable working on them, to keep them in shape. I have fresh points to go in and o-rings ready to curb their oil leaks too.

I am not a stickler for originality, this is not a concourse car, but right now this seems the sensible course. If i ever drop the motor our for a rebuild or something then probably a conversion of the points system can be done.

 

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.

 

Crowndog,

for whatever reason my dizzys only have one condensor each - the superperformance service kit for early gt4's comes with 4 total. this did and does puzzle me and i am going to go back again with the inspection mirror and make sure i havent missed them underneath the dizzys...

 

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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hi robert,

clean engine bay.. mine is no competition to that sadly.

are you using aftermarket air filters and if so what?

 

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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