History Repeats Itself.... Ignition Question, Coil Overheats, Have Mallory, What's best solution |
|
Porsche, and the Porsche crest are registered trademarks of Dr. Ing. h.c. F. Porsche AG.
This site is not affiliated with Porsche in any way. Its only purpose is to provide an online forum for car enthusiasts. All other trademarks are property of their respective owners. |
|
History Repeats Itself.... Ignition Question, Coil Overheats, Have Mallory, What's best solution |
DrinkMan |
Jul 11 2019, 04:04 PM
Post
#1
|
Newbie Group: Members Posts: 45 Joined: 25-February 17 From: Hoschton, GA Member No.: 20,872 Region Association: South East States |
A couple of nights ago, we were taking the 914 out for an evening drive to dinner. It didn't feel quite right and there were more backfires than normal (we are used to a few burbles under decel) and all of a sudden, it just died about 8 miles from home. We were unable to restart the car and were getting no spark.
We decided to sleep on it. I researched the history of the car from the previous owner here (he did a great job documenting his activities) and found this was not the first time with these symptoms. Overheat Coil No Spark So, the next morning, before troubleshooting, we tried to start the car and it started fine. After just about 2 minutes of running (pulling it out of the garage and turning it around to put it into a more service friendly position), I shut it down. The coil felt pretty warm to the touch. Looks like we had an overheating coil (yellow Accel 8140 with external ballast resistor giving a total resistance of about 3 ohms). I replaced the coil with another 3 ohm coil I had laying around without the ballast resistor. While we were at it, we cleaned the contacts in the distributor cap and rotor (Mallory 45xxxxx, same as mentioned in the thread above). Now, with the new coil, we restarted the yellow beast. Wow, not only did it fire up faster than ever, but on our test drive, all the backfires were gone and the performance was the best we have ever experienced in our 2 years of ownership. All this background is leading up to my question - I noted that our car's Previous Owner (not Dreaded Previous Owner, but Great Previous Owner) had to replace his Mallory at one point. Mallory is no longer available and my question is - what is the right solution if I want to replace the ignition system? (2056 with dual Weber 40's) I have a Compu-Fire DIS ignition system on our Opel and love it. It was originally designed for VW and the Opel used the same Bosch distributor and works well on it. However, my research here on 914World does not show it as a very popular option (advance curves on Bosch 009 not great for 2056?). And on the same track, if the 009 advance curves for Compu-Fire aren't great, wouldn't that mean the Pertronix is also not the desired solution? I hope this question is not as bad as asking what is the right oil type (I'll never ask that on a forum, I know better) as I assume there may be some difference of opinion on best ignition solution for a 914. The 123 system is tempting but my search did not see it as a preferred system. Thoughts? (btw, I'm a little reluctant to drive the 914 great distances for a while. My wife suggested I buy a pair of epoxy filled 3 ohm coils and carry with us as spares) |
tejon007 |
Jul 11 2019, 07:42 PM
Post
#2
|
Newbie Group: Members Posts: 45 Joined: 10-February 10 From: Northern California Member No.: 11,344 Region Association: None |
"I replaced the coil with another 3 ohm coil I had laying around without the ballast resistor. "
Generally, the Mallory Unilite uses a ballast resistor (or loom resistance). If you run without one, you're eventually going to destroy the ignition module. The ballast resistor is to reduce the current flowing through the coil. You'll also need to measure the resistance of your coil. The Unilite is a great distributor and have used them for a long time. But, you should download instructions from Mallory and make sure you set up the ignition system correctly, including the correct coil and ballast resistor (there's also one from Mallory) is the correct one and everything is wired correctly (i.e. you can destroy the ignition module if you get it backwards)... Only problem is that parts are getting hard to come by...I've stockpiled things like ignition modules and caps. IMHO, keep the Unilite, it's a good fit for your 2056... |
DrinkMan |
Jul 12 2019, 04:33 PM
Post
#3
|
Newbie Group: Members Posts: 45 Joined: 25-February 17 From: Hoschton, GA Member No.: 20,872 Region Association: South East States |
"I replaced the coil with another 3 ohm coil I had laying around without the ballast resistor. " Generally, the Mallory Unilite uses a ballast resistor (or loom resistance). If you run without one, you're eventually going to destroy the ignition module. The ballast resistor is to reduce the current flowing through the coil. You'll also need to measure the resistance of your coil. The Unilite is a great distributor and have used them for a long time. But, you should download instructions from Mallory and make sure you set up the ignition system correctly, including the correct coil and ballast resistor (there's also one from Mallory) is the correct one and everything is wired correctly (i.e. you can destroy the ignition module if you get it backwards)... Only problem is that parts are getting hard to come by...I've stockpiled things like ignition modules and caps. IMHO, keep the Unilite, it's a good fit for your 2056... Thanks for the input. I'll go download the instructions and study them. The Unilite has been in there for years. The Previous Owner did a thread on his adventures with it and I've not touched it until the coil overheated (perhaps too much load due to cap and rotor wear/scorch). But one question I have - what is the difference between a Coil + Resistor with 3 ohms total vs a 3 ohm coil? Same current. I'll be glad to get a epoxy coil and resistor combo with total load that is the same. |
Lo-Fi Version | Time is now: 18th April 2024 - 01:36 PM |
All rights reserved 914World.com © since 2002 |
914World.com is the fastest growing online 914 community! We have it all, classifieds, events, forums, vendors, parts, autocross, racing, technical articles, events calendar, newsletter, restoration, gallery, archives, history and more for your Porsche 914 ... |