Mustang MonthlyHow To Tech Qa
1971 Mustang Mach 1 & 1966 Ford Mustang Fastback - Beyond The Basics
Vintage Mustang Tech Advice From Bob Aliberto
Perplexing PedalI have a question you've probably answered many times, as I know many people have had cars with the same problem. I have a '71 Mach 1 429 CJ with a four-speed. I just installed a Centerforce III clutch. Now the clutch pedal does not return all the way. It comes up only to the same height as the brake pedal, and it should come up about 2 inches higher. I have all the original springs installed in all the correct places. Could the adjustment rod be too short? I would appreciate any technical assistance.Wayne ReynoldsVia the Internet
I'll assume the clutch pedal did return properly with the original clutch, and this problem occurred after the installation of the Centerforce unit.
If the new clutch functions properly without slippage or chatter, you should be able to get the pedal to return with either a rod adjustment or spring tension. Try lengthening the adjustment rod until there is approximately 1 to 111/42 inches of free-play or travel in the clutch pedal before you feel the clutch pressure. Free-play is necessary to ensure the throw-out bearing pulls away from the pressure plate when the clutch is engaged so the bearing does not spin continually. This adjustment will also affect the clutch engagement point or the distance the pedal travels from the floor to engage the clutch. If the correct adjustment does not eliminate the problem, then you can change the return spring to one with more tension. Sometimes an aftermarket clutch simply requires more spring tension to return the pedal than the stock Ford unit. A spring attached to the bellhousing fork that pulls the fork forward will allow the pedal to return and also guarantees that the throw-out bearing is indeed disengaged.
Help With PertronixI have a '66 fastback with a 289 Hi-Po, four-speed, dual-point distributor, and factory Rally-Pac. I decided to switch to a PerTronix electronic ignition unit to see if there was any difference in performance. Upon starting the engine with the PerTronix installed, the engine ran for one or two seconds and quit. It would not restart until I pulled the PerTronix and reinstalled the points. It's run fine ever since. Are the PerTronix units incompatible with the Rally-Pac? Have you had any experience with this, or do I have a defective PerTronix unit?Steve KepleyVero Beach, FL
I find the PerTronix units work better when full battery voltage is applied to the positive side of the ignition coil. Vehicles equipped with points require a resistor between the ignition switch and coil in order to drop the voltage that's fed to the coil. The reduced voltage greatly increases points life without affecting engine performance. Modern electronic ignitions, including the PerTronix, do not need a resistor, as there are no points to protect.
The resistor on your Mustang is a wire that's an integral part of the underdash wiring harness. It's a pink wire that the Rally-Pac wire plugs into and is sometimes marked, "Do Not Cut Or Splice." If the resistor is eliminated by running a new wire from the Rally-Pac to the coil, then full battery voltage will be fed to the coil.
A quick check can be performed by reinstalling the PerTronix unit and running a jumper wire from the positive side of the battery to the positive side of the ignition coil (marked "Batt" on the coil). The engine should start and run properly if the PerTronix is good. The ignition switch and resistor wire are eliminated during the test and the jumper wire must be removed in order to shut off the engine.