[Pete04222]

Went out this morning to go fill up the car because Marni and I were going to take it to some friends of my Parent's house about an hour away. Well I started it up and when I left the driveway I noticed a couple of backfires. That was odd because it had never done it before but I figured it might just be cold. Well after I got fuel I took a little drive to warm it up and it got worse. No power at low engine speeds but it will kind of snap out of it and run properly at high engine speeds. It was running rough and backfiring quite a bit. I noted the backfires seemed to be coming from the driver's side pipes. The temp gauge was reading a little lower than normal (although when I picked up the lid the engine seemed as hot as usual).

Two days ago I put about 100 miles on the car and it performed flawlessly; yesterday I moved it around the yard a bit and noted no abnormalities. The only thing I have done to the engine recently is check the oil. I believe it may be ignition? I tried to pull a couple of spark plugs to look at them and now have a new problem - how do I get the plugs out? The sockets that fit down the hole are too small for the plug. The regular spark plug socket is too big to fit down the hole. Anyone have any ideas as to what may be causing this poor performance? I have now lost my confidence in the car's reliability and will not drive it until it is 100% again. I have not had time to look at anything else on the car (distributor caps, wires, etc.) due to the fact that this happened 1/2 hour before we were due to leave (had to take the pickup truck )

I also noticed that the 3 rubber mounts for the coolant reservoir had failed and the coolant reservoir was hanging from the hoses. I won't drive the car until I can replace those. I am sure I will be having more problems with the rubber goods on a 23 year old car.

 

['75 308 GT4 (Peter)]

I have been having a similar problem to yours, except mine is worse, it'll pop and bang at idle. I haven't had time to look at it, but will now as I'm off work for a couple of weeks.

I too believe ignition is the culprit, as everything else has checked out okay. On my car, its something I must be overlooking, something simple.

After its cooled down, stick your nose to the tail pipes (I'm serious). I noted on mine strong gas odors out of one set. Something's not getting proper spark.

As for your car, give us some details about ignition set-up (points/electronic) and any other details (other mods, recent service history).

For the expansion tank, on GTB/S, they are vertical and hang off the rear firewall? They may use the "cotton-reel" bushes that I've found on my GT4, hanging the oil-cooler. I think Minis used them to hang the exhaust pipes (but those could be too big). For the time being, you may get away with using just bolts to hang the tank, making sure nuts are tightened so the tank can't fall off.

 

[Edward Gault]

The plug wire extenders are one of the most frequent failure items. The condensers for the points can be troublesome also. I highly recommend you changing the ignition system to an electronic one. Some of the factory ignition parts on the older points type ignition are discontinued and horribly expensive if you can find them.

 

[Pete04222]

Peter,
Thanks for the reply! I didn't have time to look at the car yesterday and may not have any time to until Tuesday. On Wednesday I leave for work for 3 weeks (I work offshore) so it is either find the problem on Tuesday or worry about it until August. I have internet access offshore so I will still be able to visit the board.

Dennis McCann has the coolant reservoir mounts for $8.00 ea. so I will order up a set of those.

For the running problem, I was thinking about it during the day and it has to be ignition. What I believe to be happening: Several cylinders, or a complete bank, are shutting down at low engine speeds causing the loss of power and allowing the fuel/air mixture to accumulate in the exhaust system. When the cylinders kick back in the fuel/air mixture ignites in the exhaust and causes the backfire. Obviously I want to cure this as I don't want to damage the muffler. I am hoping it is just fouled spark plugs. I would just go ahead and get another set but I want to wait until I can pull some of the plugs to see if I want to go up on heat range or not. Right now I can't get the plugs out. (When I find the correct socket I will post details for Barry and Dane's benefit).

My next target (guess) would be the ignition points in one distributor are faulty, a condenser is bad or there is a poor connection on the low-speed ignition system. I have been doing some reading and there are 2 sets of points in the distributor; at high speeds only one set of points operates, at low speeds the current passes through both and provides retarded timing for the lower speeds. If I determine that it is one whole bank shutting down at low speeds, the problem could be something as simple as a break in the wire from this second set of points to the microswitch on the accelerator.

 

['75 308 GT4 (Peter)]

If you want to continue running points, delete the R2 set (the ones signalled by the microswitch) and just run R1's. Set them at 7* BTDC (which they should be already) and leave it.

One of the benefits of using only one set of points, you don't need the two wire condensor. The original one-wire Marelli condensors are inexpensive, but if you can't wait, GM condensors work perfectly (same size and microfarad rating - 0.18 MFD). Go down to NAPA and ask for a Echlin MA3 condensor.

If you need points, get them from Superformance in the UK. Absolute least expensive in the world - no exaggeration (around 17 UK Pounds each)

The best is like Ed said, switch to electronic ignition. Even if its just the type to replace points (Pertronix or Crane).

 

[Pete04222]

Got to work on it a little today. Finally was able to get some of the spark plugs out. I will make a separate post on how I got the plugs out for the benefit of others.
Still need to go through it, but initial assesment looks like Ed was right (THANKS!!!) I found one plug wire with the end burnt out right at the extender. I have yet to disassemble that to see if I can salvage it or if I need to replace it. The low-speed ignition wire I was talking about looks suspect also. I like the idea of converting it to electronic ignition. Anybody got a supplier? part Number? I priced out some of the points stuff and I bet I could convert to electronic for the same money or less.

Thanks again Guys! I keep you posted on my progress.

 

[Dane]

Pete,

I'm sorry to hear about your car but it sounds like you're getting some great help here that's showing results. Please keep posting on your progress. I'm sure things will work out for you.

Forza,

Dane

 

[Pete04222]

Dane,
Yes, very depressing but not unexpected on a 23 year old car. I will get it sorted out and will keep everyone posted on my findings.

Getting the spark plugs out was intimidating at first but I have it down now so it is not that bad. I will make a seperate post on plug replacement for when you need to pull the plugs on yours.

 

[Magoo]

Pete, Find yourself a thin walled 13/16ths deep plug socket for your plugs. Be sure it has the rubber piece inside to hold the plug as you remove it from the head. Craftsman at Sears, Snap-On or possibly Napa carries them.

 

[Pete04222]

OK, I am back from work now and took a look at the car yesterday. Put the new mounts for the coolant reservoir in, finished cleaning the spark plugs (they are Bosch W6DC), and repaired the spark plug wire with the burnt end. I took a test drive and it still had the same problem of running rough and backfiring at low speeds. I removed the wires for the R2 points set and wrapped them up with electrical tape. Problem solved. Runs smooth now.

The new problem is that without the retarded timing the R2 points provide, the idle speed is too high. I have the idle adjustment screw backed out all the way and the idle is still too high. I think that rather than messing with the timing and carbs to get the idle speed back down, I will live with the high idle for now and plan on replacing the all the points and condensers to put it back to the stock set up utilizing both points sets. I will probably wait until I put the car up for the winter to do this.

Having never changed the points in a Ferrari, It looks like it would be easier to remove the distributors to change the points than try to do it with the distributors in the car. Anyone? I am also planning on putting to use some of the tips I have gotten from you guys by getting some hotter coils and going up a heat range on the plugs and increasing the gap. (my plugs were a bit black from soot.)

At any rate, my car is back on the road and I had a big smile on my face all day as I was riding around! Gonna wash 'er today and ride around some more. Right now it is sunny and 70° outside, perfect Ferrari weather.

 

['75 308 GT4 (Peter)]

The new problem is that without the retarded timing the R2 points provide, the idle speed is too high. I have the idle adjustment screw backed out all the way and the idle is still too high.

It may be the fast-idle device that's still keeping the throttle open. It's the little cam-shaped thing, mounted on the coolant cross-over tube joining the two cylinder heads. The cam acts on an arm, which has a setscrew on the end acting on the throttle bell-crank. Its supposed to back off from the heat circulating through that cross-over pipe (and thus lowering idle speed), but they can get stuck. Take the screw out if its the case

Having never changed the points in a Ferrari, It looks like it would be easier to remove the distributors to change the points than try to do it with the distributors in the car.

Yes, it makes life so much easier. Line up the middle of the rotor face to the red notch on the edge of the distributor body. This is #1 (or #5 for the front bank dist.) timing mark and from that point you can set dwell (which is very important for proper running) and the actual timing. Before pulling the dist.'s off the motor, bring it up to TDC #1. This will make it easier to put the dist.'s back in the correct place. A multimeter is a must in order to establish the EXACT moment the points break (set to ohms, one lead to the body, the other to the points lead. But you probably knew this already...).

The goal is to get the timing set so right in the distributor, that the base of the dist. body should be flush with the cover plate.

 

[Pete04222]

Peter,
Thanks for the info! I knew you would come through for me. I will check the fast idle device and I am hoping that's the answer. If that is it then I will leave the points alone since the car runs fine except for the high idle.

Thanks for including the pics, if I do end up changing the points those pics will help me out a lot.

 

[Pete04222]

[quote='75 308 GT4 (Peter)]

(set to ohms, one lead to the body, the other to the points lead. But you probably knew this already...).

[/quote]

Yes. This actually gave me a little chuckle for you to say it. How did you know that I even knew what a multimeter was? It is not that I am unwilling or unable to change the points in the car, it is just that I am lazy and will not do it unless I absolutely have to. Truth is, I used to be a diesel mechanic and my home garage/shop is well equipped (compressor, torches, press, every tool Craftsman sells, etc.). I stopped being a diesel mechanic after a revelation I had one day when I decided that I liked wearing a white shirt and driving big ships more than I liked laying in the bilge of a fishing boat trying to get the oil drain plug out of a Caterpillar 3208.

 

['75 308 GT4 (Peter)]

I stopped being a diesel mechanic after a revelation I had one day when I decided that I liked wearing a white shirt and driving big ships more than I liked laying in the bilge of a fishing boat trying to get the oil drain plug out of a Caterpillar 3208.

I'm still at that point, where I crawl underneath tanker-trucks and get severe burns from over-head aluminum welding. But not to the point where I want to give it up and wear a shirt-and-tie. Been there, done that and never again. No, I need to find a nice clean TIG-welding shop where I make little widgets and gadgets. Easy money... :lol:

 

[Pete04222]

[quote='75 308 GT4 (Peter)] No, I need to find a nice clean TIG-welding shop where I make little widgets and gadgets. Easy money... :lol:[/quote]

That would be sweet!! Thought about starting your own metal fab shop? Yeah, I couldn't do the suit and tie office thing either. I worked in an office for 6 months for Western Australian Petroleum and hated every day. I had a little cubicle on the 22nd floor. The upside was that I had no direct boss and no one really knew what I was supposed to be doing (including me). I generated paperwork for 6 months and everyone told me what a great job I did.

Now my "office" is on the bridge of a 56,000 HP drillship. That rig is the unlimited tonnage version of a Ferrari. Not very fast but it sure does handle. Fuel effeciency is about 250 gals/mile.