The HEI Ignition system is not a traditional Ford ignition system, but there are good drop in replacements for the standard Ford distributor that make this an easy upgrade for the Mustang. If you believe all the claims, it's a hotter spark, longer dwell and simpler design. Initially we had gone with the original distributor, a Pertronix ignition module, and a Pertronix Ignition coil. After the issues we had with the ignition while doing the T5, we did a bit of research and found that it would not be much more expensive to replace the whole distributor, electronic ignition, and coil with an HEI. This would also correct the strange issue we were having with cracked distributor buttons. We are on our 4th button in the 3 or so years the car has been running, and there are not that many miles on it in that time.
The Pertronix Module
Old Ignition Coil (that went bad)
The old distributor, wires, and ignition coil
Adjustment of the Pertronix
Replacing the vacuum advance
So this fall when it got cold, we had a number of issues. We ended up adjusting the distance of the Pertronix module, changing the vacuum advance, and a few other debugging steps. Looking back on this, I think part of our problem was that the ignition coil was starting to fail.
Here is the new HEI replacement that includes the distributor, the ignition control module, and the coil.
HEI Distributor with Vacuum Advance
While upgrading the transmission we found that we were getting voltage sag at the ignition coil, which is a common issue, and easily remedied with an ignition relay. These are common since probably the 1970's but this car did not have as part of the original design. This was already on the to-do list, so we went ahead and added that to get things running again.
The new kit included new wires, and recommended a spark gap of 0.045 to 0.050" which is larger than the standard gap so we decided it was a good excuse to do the plugs too.
Before pulling the old distributor, with the spark plugs off, we turned the engine to the TDC mark on the crankshaft pulley. We know from our previous experiments, that the TDC mark is for cylinder 6 and NOT cylinder 1. With this in mind, we started with wire 6, and went around the firing order listed on the engine 1-5-3-6-2-4. So we wired 6-2-4-1-5-3 starting with the wire where the distributor button was pointing at, and going clockwise around the distributor.
Fired right up! A quick twist, and then we readjusted the wires for the new TDC position we needed. Second start was nice and smooth. We also now see the timing gun fire on every pass. Previously it was skipping a strobe once in a while, and looking back that's probably a misfire, or a cylinder that would diesel and run rough.
Connor has dreamed of upgrading the 3 speed in his Mustang to the Tremec 5 Speed since learning this is a relatively easy drop in upgrade. Since the clutch was getting really bad and we would have to pull everything apart to do the clutch, we talked about finding one in a junkyard. The Bog Warner T5 transmission has been used in everything Ford, Chevy, GMC, AMC, Pontiac. It's been in use since the early 1980's and was still featured in the 2010 Mustang. It's popularity means you should be able to find one somewhere in a salvage yard.....
The price tag for a new transmission is well outside the budget for this daily driver. He scoured the local salvage yard and happened upon a 2002 Mustang GT with a 5 speed manual. The T5 he was looking for. He unbolted it and dragged it out to the register and had the envy of everyone in line. He even had a few offers to sell it on the spot, but Connor had different plans for this find.
So we ordered up the parts we needed. A clutch, an adapter plate, a crossmember and a slip yoke. Once we got the parts in hand we were ready for a long weekend project!
We had a few snags along the way, the first one we hit and moved right on past without noticing. When we bolted the transmission to the bellhousing, we had a slight gap between the two. The bolts spanned the gap, and so we just cranked each bolt a little bit at a time and "drew in" the transmission to the bellhousing. More on this later. The second issue we had was that the new mounting bracket did not fit, we had to bore out larger bolt holes on each side so that it would fit the bolt pattern on the car that had shifted slightly over the 50 years the car has been on the road. The bracket was also needed a few slight modifications to make it fit our version of the transmission. Lucky for us, we had some steel plate laying around, and were able to weld up what we needed. The real fun however, was yet to come.
So we found out just a little too late, that the input shaft of the newer T5 used in Mustangs is a bit longer, and too long for our bracket. We wandered our way to a solution, first by cutting the throw-out bearing guide shaft down, then by adding more "adapter plate" by creating our own adapter plate shim from aluminum plate stock. If we knew the throw out shaft modification was only a partial solution, we probably would have skipped that and created a thicker adapter plate. We could have gotten away with 3/8" thick easily. So with all these issues behind us we were ready to road test.
And so we pushed it back into the garage, and removed the transmission once again. It went into reverse for our test, but we could not get it into 1st or really any other gear. This was quite odd since we had it running so smoothly before we put it in. When Connor brought it home, it did have some shifting issues, but when we disassembled it we thought we had it all worked out. Apparently we had more work to do.
So we removed the transmission yet again, and pulled it apart. Once opened up we found that the synchro key for Reverse had slipped out and was preventing a smooth shift between gears. This was the issue the transmission had when Connor brought it home from the salvage yard. When we did the original rework of the transmission, we did not realize that the springs that held the keys were out of place, and just re-inserted the key and slid the synchro into place. Since we did not fix the keyspring issue, it popped out once we were spinning at speed, shifting out of reverse. This time after a lot of detailed research, and watching a full disassembly video, we knew how to correct the issue. We fixed up the synchro keys and reassembled the transmission, then placed it back in the car and went for a test drive. This time we had success!
This project took from February 3rd through February 16th, 2017. We spilled some transmission fluid, lost some skin, and made some great memories along the way.
