Ferrari 308 gtb keeps burning points???

Sounds like a bad condensor.

 

Swap in an electronic ignition system.

 

Another thing to check is the voltage on the "+" terminal of the coils (relative to ground) when the engine is running. I believe your early euro set-up has a relay that puts the full +12V on those terminals when the key is in Pos III (starter motor cranking), but then when the key is released to Pos II (engine running), the voltage should drop to something like +8~9V due to the ballast resistors (so if this always stayed +12V that would be a sign that there's something wrong with the special relay arrangement). Also, your alternator could be bad, and putting out a very high voltage at high RPM and greatly increasing the current flowing in the point path (on a more modern car, this would cause other problems, but on yours, the only other symptom you might notice is the headlights getting brighter at high RPM). In either case, if your mechanic measures the voltage on the "+" terminal of the coil primary during engine running at low and high RPM, he/she can quickly rule this in, or out, as a problem.

 

I would check running voltage at the + side of the coils. There is a resistor below the coil that drops voltage while running, and is bypassed during starting to provide full 12V power. It is possible someone wired the coil wrong by bypassing the resistor. I am not sure this would effect the points in this way, but I do know it would overheat the coil. IIRC, I read about 9 volts on mine while it was running. If you see 12 volts, you need to look at the wiring below the coils. I believe the yellow wire's in the harness run to the input sides of the resistors, and the red wire's go to the output side.

Provided the system is mechanically sound and wired correctly, you can tell the ability of the condensor by noting which side of the points are transfering metal. The points system is much more sensitive to changes and alterations. If your not running stock wires, extenders or correct plugs, or have different coils, and your frying points, you will need to select a condensor based on observing metal transfer at the points. If your losing metal on the ground side of the points, you will need a stronger (higher mfd) condensor. And vice versa.

One other thing about points, dont leave the ignition on when the engine isnt running. That will burn them up too.

 

Sorry to hear about what had happened with such a smart car. I feel electronic system is the best option. It will give you a more efficient mixture burn to reduce exhaust emissions, significantly increase the life of your points and reduce the effects of points bounce, which helps to reduce misfire at high revolutions.

 

Electonic ignitions don't have points.

Here is a 308 MSD ignition install.

https://www.msdignition.com/forum/showthread.php?t=7061

 

Somehow this post was ignored. Burned points is a CLASSIC indicator of a failing condensor.

 

First the resistors or lack of will cook points,but rpm drop off is usually a poor coil. It will flatten out the best engine. Get some new ones and try again,cheap fix if it is the problem . Ive had it happen many times, also a poor coil will eat points,GOOD LUCK. If you have room try MSD coils, at least try some cheaper ones and watch polarity.

 

DITTO on the condensors

 

First is this a single distributor car or a dual distributor car? In either case, if the points are burning up, yes the condensor is at fault. However, what's cuasing the condensors to burn up? The most likely cause is the coil, you can ohm out the coil til the cows come home and come up with factory specs. When the coil is charged however, the secondary is probably shorted to the primary causing the condensor to fail and then the points. Do yourself a favor, change the coil or coils, replace the points and condensors and install an MSD ignition. Make sure you use noise suppressed ignition wires for the MSD, it won't operate otherwise. Leave the points as a triggering device and with the MSD you won't use the condensors.

 

+3, start simple. put a load tester on the battery and measure the alternator output at idle and at 5500 rpm to see if it has bad diodes, but i would think if the car was recently running fine, that the condensers are showing their age, or may be mis matched for the application if they were recently swapped in. after that, check the coils and the resistors at the coils as others have stated.

 

Didn't ignore it, but maybe I misunderstood what the OP was trying to say -- my translations of the sequence of events was: 1) both points "melted", 2) his mechanic replaced both points, both condensors, and spark plugs, and 3) both points "melted" again.

Simon -- Can you reclarify the sequence of events that you and your mechanic have already been thru please.

 

Say you own a old house that came w/ a primitive outhouse and no sewage connection. Years later, modern technology developed plumbing and running water and now you can connect to the sewage plant but you keep using the outhouse because it ain't broke. Finally, outhouse fills up and roof cave in. Do you rebuild it or enjoy the advantages of better technology?

Same goes for old distributors w/ points. They came that way because when the car was built, that was the only way the engineers know how. Soon after the 308, all cars came w/ electronic ignition systems because of the advantages (more power, less moving and fragile parts to break, cleaner emissions, ....) of the better technology and reasons posted above.

I can understand some die-hard collectors all-original purist not wanting to upgrade their cars worried it will subtract concours points, but when your sh!tter is broke and full of crap anyhow, now is the time to enjoy the advantages of taking a dump in the warmth of your home.

 

Ignition condensors have a "shelf life". It has been decades since manufacturers switched to electronic ignition and the parts available (New Old Stock) may be defective. This is not to suggest that all condensors should be discarded, only that some will fail even when "new".

Certainly there is an argument for converting to a modern (MSD, Pertronix, Crane, etc) ignition. It is however just fine to stick with the old "tried and true" points and condensor with all of its limitations.

 

And points ignition will (almost) never leave you sitting by the side of the road 300 miles from home on a Sunday afternoon. BTDT. And in the very rare occurence it does act up, it is the ONLY ignition system that can be coaxed back to life with a screwdriver and a pair of pliers. BTDT too.

It is more like a difference between a claw hammer and a pneumatic hammer. They will both put a nail into a 2X4, and there is no arguing the pneumatic nailer is a bit more efficient. But when the compressor is out, or when the diaphram blows on the nailer, the claw hammer will still operate if you know how to work it. So will an outhouse. Flush toilets are great as long as you have a water supply. Knock turn off the water and see how well they work.

Simple may not always work better, but its still working when everything else fails.

I also have to address some of your other comments. Electronic ignition was being used in racing since the mid 60's, and had been around quite longer. But in road cars, Ferrari, Rolls Royce and Mercedes Benz were the very last automobile manufactures to move from standard ignition to electronic, and it was for NONE of the reasons you claim. By 1980 Chrysler, GM and Ford had been electronic for over 8 years.

The reality was, and still is, that a mechanically sound points system is almost 100% failure proof for a good 10K miles or so. But after that point it demands maintainance. By 1980 the United States EPA required automakers to meet stricter emission standards, and to warrantee that the cars they sold would meet those standards without maintainance for 5 years or 50K miles. So everyone got electronic ignition whether it worked or not, because the manufactures did not want to pay to service anything. And that was also about the time it became common to see dozens of cars stalled on the roadside each morning when you drove to work.

 

Every collector car group goes back and forth about electronic vs. points ignition. I owned a Triumph TR3 that had been converted to electronic ignition, but I switched it back, due to the fact that ignition bugs will affect both points and electronic...the difference is that points are easily replaced, and the same problem can often fry the electronic box.

Either way, you'll have to check the same problems:
-Alternator
-Coil and ballast resistor (if your 1.5-1.8 ohm resistor is shot, it will fry the points, condensor and coil!)
-"switch" -- meaning the thing that gives you one set of points at start up and another when running.
-Condensor, but as 2NA pointed out, condensors are all NOS now, so you're not going to be able to get "new" ones.

 

Folks, we're missing a key word here - or at least I missed it: "melted"

A failing condenser usually causes the points to burn, not melt. The condenser provides the ground circuit for the coil as the field collapses. If the condenser is failing, the points spark intensely causing the damage. If you are using the word "melted" literally, then you probably have a shorted coil, perhaps only at high temperatures. Others have suggested that you test the alternator for regulation issues. That's always a good idea. Is the supply voltage stable at all engine speeds?

Check the resistance of the coil with all wires disconnected. Check it over-night cold and after-a-run hot. Post the resistance values you read here so we can ponder the numbers.

rick

 

The OP can comment, but people often use incorrect terms to describe simple things. Fried, burned, toasted, roached, nuked, smoked, melted and many other terms are often used in place of a more proper word.

For some reason, higher energy is passing into the points and destroying them at an accelerated rate. I doubt they physically melted, more likely they were arcing more than usual and eroding the points surfaces and appear badly burned away. Most people "back in the day" would refer to this as "melted".


The issue that is confusing in this case are that BOTH sets of points are showing excessive wear. Both coils or both condensors can not BOTH go bad at the same time. Okay, anythings possible, especially if the wrong parts were installed to begin with.

Check you actually have 12V non resistor coils, that the external resistors and wiring is correct, and that you have the correct capacity condensors (.025mfd), spark plugs (NGK-BP6ES), extenders (black, not tan) and non resistor (solid core or equivelent) spark plug wire. IIRC, the OEM plug wire should be about 400 ohms per foot?

 

For it not to work at high RPMs sounds like the gap is not within spec (eg small gap or almost closed). The other problem I had with mine was the gap "shifting" when I went to snug the adjustment nut. I had to set, tighten and double-check it. I was also advised to lubricate lightly at the cam with machine oil.

When I got done it ran pretty good. But, still I had an occasional miss and cylinder not wanting to fire at idle. For me, I decided I needed to *carefully* go through checking condition, resistance, specs for this: plugs, extenders, plug wires, advance mechanism, timing, points, brush, cap, rotor, coils, Christmas tree of wires around coils including wires from MSD 6As.

I had already been through most of the above about 1.5 years ago with the exception of the advance mechanism and all the Rube Goldberg wiring for the MSDs.

At this point I went Electromotive. Given the quality of the spark and the rock solid consistency of it I find it hard to call this the dark side . But, I admit I regretted leaving behind the old mechanicals - can't say why exactly. Good luck.

 

Cam timing is completely unrelated. If it ever ran well (assuming the belt didn't jump a tooth, unlikely) it should again with a proper distributor setup. I have found the replacement point sets that are sold today to be of variable quality. I've had contacts fall off and rivets come loose right out of the package. It's possible you just have crappy parts.

My bet is still a faulty condensor or perhaps the coil is hooked up wrong.

 

Agreed. The other possibility is the key was left on without the engine running. If both sets of points are closed with the key left on, which I believe is very possible, it would burn them up.