Hey guy's, I have a 77 308 GTB carbureted. The other day it all of a sudden dropped the front bank. When it happened, the tach goes to zero or dies when the throttle is pressed and returns as soon as the throttle is released and of course it has lost power. I verified it is the front bank by removing the coil wire. it will start with the front bank coil wire removed but will not with the rear bank coil wire removed. Any ideas? Could it just be a bad coil? If so, what is a good replacement? Thanks, Greg
Hi I lost my rear bank with similar loss of rev counter etc Changed, the coil and condenser and tested leads, only to find it was a loose connection of the white wire that runs into the side of the distributor. Take the distributor cap off and make sure the white wire is secured near the points - Took me a week to find but fixed it in 3 minutes
Update: I swapped the original coils (front to back and vise versa) and still have the same issue, front bank not firing. So it is not the coil. Any suggestions?
Well, after a lot of troubleshooting, here is what I found out. The points have been replaced with Mallory Unilite modules. Looks like the timing advance module in the front bank has died. That also explains why the tach was going to zero when the throttle was pressed as the tach wire comes off the - terminal of the front bank coil and when the advance is called for there is just a constant 10 volts on the terminal. So I have to remove the front bank distributor and replace the module. Any hints or special things I should know before unbolting the distributor and pulling it off? Does anyone know of a written procedure? Thanks
Can you change the module in place without disturbing the cam drive/gear orientation?? Just trying to keep it simple......
Timing advance is in the weights/springs...OEM. Not sure how the Mallory system works...good luck tho!
So what is controlling the advance? As I understand them, the Mallory modules just replace the points
You might try going to the Pertronix MR-183 set up for dual distributors. I've had good luck with mine, fairly easy to install and makes the second distributor a slave, so less shenanigans with timing etc. If you search the forum here you'll find good info. On the other hand, the Mallory system may be great and parts readily available, I just don't know anything about it. Good luck! Jeff
I went with Electromotive's Forza Modified eXtreme Direct Ignition System I don't think you candy better
There are 2 modules in each distributor. One for idle timing, one for advance/ The idle micro switch on the throttle controls a relay for each distributor which activates what module is active.
I installed the Mallory setup in my Jag. It's the only thing that has ever quit on me, well other than Pertronix units, and it's a bear to get to. I would suggest going back with the points. They are durable, easy to fix, and relatively cheap to replace. I know that they are not the best ignition system but they work.
A little update: Replaced both Unilite modules in the front distributor and everything is good. I just need to fine tune the timing now as it has changed. I rough adjusted it by driving then tweaking, but it really needs fine tuned with a timing light. Anyone have a good timing procedure besides the one in the manual? Thanks,
Hardest part about timing is seeing the damn marks. I used yellow parts paint to make a big yellow line on all the flywheel marks. Once you do that then time it where you want it at 5k rpm. Then test it a lower rpm against the curve in the manual. If it's off too much for your liking you need to recurve (spring) your distributor which means you need to find a shop with and old school machine and the know how. Good luck. Let us know what you do.
Yeah, there are no marks at all that I can see!! Does anyone know what a tooth on the flywheel equals in degrees? I can find 1-4 and 5-8 TDC easy enough by pulling the plugs. If I knew how many degrees a tooth was, it would be easy enough to make my own timing marks. Thanks
I know this isn't helpful to your specific situation, but I cannot tell you how much better an Electromotive ignition is than dual distributors and points or points replacements. Just having one advance curve for the whole engine makes a big difference. Hotter spark, no fouled plugs, starts right up, adjustable advance...
