Discussion in 'Early CJ5 and CJ6 Tech' started by TonyM, Oct 25, 2019.
Sorry, didn't know.
No problem. It was funny.
Depends on your definitions. Electronic ignition is more reliable if you include the expected failure of points due to wear every 25,000 (?) miles. The MTBF for a Pertronix module is way longer than that. I'd also point out, 'crib death' is a well-known phenomenon for electronics - failure is very much more likely at the beginning of life than any other time.
Points are, no doubt, more accessible. You could carry a spare Pertronix module if you were worried. I'd think a field repair would be really easy, if you had a spare module.
I always carried extra points, condenser, cap and rotor and plug wires anyway. I figured I'd still do that as they'll all still be on the breaker plate that I'm removing, or carry an extra Pertronix. I've been pretty much a "keep it stock" guy for the 25 years I've had jeeps ('51 3A, '52 M38 and now a '56 CJ5) but I've reached the breaking point - pun intended - with the points going bad from lack of use. I don't get to use my jeep as often as I'd like (sometimes she'll sit for 6-8 weeks, though I do try to at least start it up and let it run for a bit every 2 weeks or so). When I do get the time to enjoy it I want to simply turn the key, engage the toe starter button and enjoy the ride. I'm hoping that the Pertronix will allow for this. If not, back to points...
So, I pull a piece of emery paper between them, takes about 20 seconds.
Somehow, this seems familiar....
That's actually not a bad idea. Much easier and faster field repair and not that expensive. Going to give serious consideration to put on my list as a precaution.
Let's throw this thought out there. Normally with a points igniton system the condensor is the only thing that fails, and as we have discussed it used to be rare for that to occur. Nowadays the chance of walking into a parts store and leaving with a good condensor seems kind of iffy. This makes a Pertronix seem desirable for sure. However known failures, defective units sent and not working from the beginning makes me go hmmmmm! I'd bet they had much better quality years ago.
I heard the new corvettes have points...
The treehuggers would never allow that lol computer would lose its mind haha
Eight sets of points for all eight coils?
Dwell is the measurement the time points are closed. So a dual point system can build higher spark by splitting the time in half.. if I have that right. might have to dig out my old college notes. So a old school dual point mallory was used for 60s and 70s muscle cars with the big ol yellow coil. I find plug wires make a big difference on the 74 304 v8 AMC. The heads flow as good as a set of 202s with the dogleg ports
Schavenged by a nice set of long tube headers and a set of long purple hornies pointed out the side not down for dust.
My misty teenage conception of the dual points benefit was that at very high rpm, each set only had to operate half as often - thus reducing bounce, float, etc.
That was my understanding.
Yes....... Exactly what it was for. Remember Mallory ?
Not really. The dual points open and close the same number of times per rotation but are placed about 9 rotational degrees apart. This increases dwell time for sure but best reason for dual points was to decrease maintenance on dist and increase performance.
Come to think of it, I believe that is how the OEM distributor works in my 1934 flathead Ford V8. One set begins the dwell, the other set ends it. (?) It allows each action to be timed independently.
What is old is new(ish)?
Yes that is it.
The purpose of dual points seems to be that you can extend the amount of time that the points are closed as compared to a regular setup, allowing current applied to the primary more time to build up the energy (i.e. "saturate") that will become a spark when the points open.
Note that this really only helps at high rpms as at lower speeds a typical coil has plenty of time to saturate anyhow.
Also the extra spark is really only useful on high compression engines.
This is why Corvettes came with dual point distributors & Massey-Fergussons did not.
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