| Author | Message | ||
| '75 308 GT4 (Peter)
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You'll never want to go back to points again after this! I placed my units above the left wheelwell (a nice wide-open area on a GT4, although, the wires were too short to reach the distributors. No biggie, just soldered on extensions) and labled the wires and units: "Sinistra" and "Destra" to the respective bank of cylinders.   | ||
| stacy o'blenes (Stacy)
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I finally got my misfire problem solved. As suggested by H.G. the problem was with the points/condenser in the forward bank. I decided to go with crane XR700's because they seem to have a good track record in 308's. After looking at the system and considering a previous message about mounting two pertronix units in one distributor, that is what I decided to do. The advantages of this approach are; 1) it is much easier because you only have to remove and dismantle one distributor 2) once you get both optical triggers properly aligned in the one distributor, the front and rear banks will always be perfectly synchronized relative to each other. 3) to adjust the timing in the future you only have to play with the one distributor 4) you rely on only one mechanical advance mechanism therefore the advance will always be in-synch in each bank. You do however need two modules and you do rely on the coil, rotor, and cap from the second distributor to send the spark to the right place. Here is how I did it. Set the engine at 1-4 TDC then removed the rear distributor because it is the easier one to get at. The distributor is taken apart, the small bearing on the spider is pulled and replaced (thank you peter for the SKF part number on your previous post), the advance mechanism is lubed. You then reassemble the distributor by installing the trigger wheel. You then fit the two optical triggers in the distributor so that they are aproximately 45' out of phase (90+45=135 degrees apart from each other). The alignment is not critical at this point because you will fine-tune it when you set the static timing. The nice thing is that there are already two holes in these dual point distributors to pass the wires through. You reassemble the distributor and put it back on the car. You then mount the ignition modules in a convenient place and hook them up, one to the front bank coil and one to the rear bank coil. You then hook up the optical triggers to the modules. The trick here is to keep track of which is which. With the engine at 1-4 TDC you set the optical trigger you are going to use for the rear bank so that it is about to fire as per the crane instruction manual. You then turn the engine to 5-8TDC and do the same thing with the other trigger. The triggers will then be 45' out of synch and will fire each bank at the appropriate time. Reinstall the distributor cap and start the engine. Check the timing for each bank and make sure they are the same. I had to readjust one trigger just slightly to get both banks in perfect synch. Once they are in synch then rotate the distributor to get the timing where you want it(you only have to look at one bank because you know the other will be where it belongs). I had the car out tonight and it is running well. The only thing I am worried about is that I mounted the modules on the rear fire wall not far from the oil cooler (HOT) but it seems to be hot everywhere in the engine bay. If anybody can think of any reasons why this approach to installing breakerless ignition might not be a good idea please let me know because I can always switch it over to the usual two distributor technique. |