Back to points/condensor, no more Pertronix

[old-tank]

Back to points/condensor, no more Pertronix for now.

On the way to Batavia the rotor in the distributor of my 55 burned the tip off...the thing was actually on fire at one pont. replaced the rotor and drove to Batavia and home ~3,000 miles and pulled the distributor to clean it properly and found the new rotor was starting to destruct: evidence of lots of arcing and chips of plastic missing at the tip. The car runs well. I have the lobe sensor unit and their "Flame Thrower" coil. (I thought that "Flame Thrower" was a marketing designation, not a literal description...)

I have had the Pertronix installed for 20,000 mile sith no trouble. Pertronix has no technical support so unless I get a definite diagnosis it is gone.

Willie

[Guest imported_bjr]

It's either a cheaply made rotor or the coil is to powerful for the stock rotor. I have the same Pertronics unit and coil on my 54 Special and also on a 51 Willys jeep with no problems. If you cannot find a better made rotor, to solve your problem just change the coil back to the stock one and use the pertronics unit in place of the points and condenser. It is the high output coil that is burning your rotor up. Brian

[old-tank]

Brian

Thanks for taking the time to offer some suggestions. I am using Standard brand components which at least used to be good products. The Pertronix unit never did work using the stock coil or the "Flame Thrower" with the resistor in place...tended to die when idling, so I had been using the FT coil with with the resistor bypassed. The plugs were gapped at 0.036 instead of the stock 0.032 per their suggestion. The plugs looked good today but were in service for a long time (multiple clean and regap)...my guess is the coil or old plugs. Today it is all stock with newer plugs and (still) runs good, gonna try that for a while until new info.

Willie

[Guest imported_MrEarl]

I see this auction on ebay for a dual point set up. what is the advantage of dual points?

Dual points

[Charles2]

Each set of points only handles half of the coil switching. If you have a dual point/dual coil setup then each coil has more time to recover from the previous cycle than a single setup (better coil saturation) and thus a hotter spark. Also, the points will open faster than they would with twice the lobes on the cam; this also can "hot-up" the spark. Other advantages: better high rpm performance since point "bounce" is less likely and the points will last longer (usually) since they are opening and closing (and arcing) half as much as with the single setup. The disadvantage is that dual point setups are a bit harder to set accurately and you can have different spark timing with each set of points if the point mounting plate is not made accurately.

[NTX5467]

Dual points were a "high performance" addition in the earlier days, which resulted in 40 degree dwell periods rather than the 30 degree dwell periods for a normal "single-point" ignition. The longer dwell time resulted in greater coil "satration" for a more reliable spark in the higher rpm ranges (which at that time would extend to about 6000rpm or so, just depends on the engine). They worked on the same distributor cam lobes and the single point sets did, so NO advantage to decreasing "point bounce" unless they had a stronger tension spring in them (which some "higher performance" single points could also have. It was mainly about getting the coil more fully charged before the "trigger" fired the spark plugs.

Some GM divisions went "dual points" on their high performance engines, while others did not. Some dyno tests reported higher power with them than others, but it probably had more to do with a stronger tension spring than not, OR it was compensating for a coil that should have been a little stronger to start with (especially for 7000rpm engine speeds back then). Ford and Chrysler typically had more dual point distributor models than the GM divisions did, as I recall.

A properly maintained ignition point system can work very well, provided the lobes on the distributor cam are not worn such that the dwell spec AND the point gap spec can both be achieved at the same time. We used to get reliable use for over 12K miles out of them back then too! How many "collector" cars are now driven that much now? Of course, we all know that electronic systems are much more "maintenance free" with no points to adjust or degrade. Add in a spark plug upgrade and ignition maintenance can pretty much vanish from what we used to know of it.

The little vial of "point grease" (which USED to be in the package with each new set of points!) is highly important too. GM still catalogs it in their Standard Parts Catalog, plus Mallory used to sell it too.

I suspect the extra .004" of gap had no real bearing on the situation as that's still close to the (generally) normal gap of .035" that most GM and other vehicles used back then. Regarding a coil's "power rating", it's only going to produce what it has to to get the spark to jump the gap at the spark plug. IF it's "rated" at 50KV, it's not going to produce that unless it absolutely has to in order to fire the spark plug. Therefore, unless there is an "extraordinary" need for higher spark energy, such coils are not really needed. Many manufactuers will recommend them as the "suspected/intended use" of their product might include racing or other activities that would place greater demands on their product, hence the "bigger might be advisable" orientation.

By observation, many coil/cap combinations are not quite as "substantial" as they were in prior times. I suspect most of them come from a common supplier, yet sold in various packaging for particular end-sellers. Unless you upgrade to Accel or similar, they'll probably be all the same. Of course, these upgrades to Accel and such could also result in a change of cap color (something that would not reallly matter for the rotor, though) from black to tan.

One thing that's seemed to surface in recent years is more efficient spark plug designs and materials, even for resistor plugs. If the spark plugs don't "absorb" quite as many KVs to fire, more of that electrical energy can reach the plug gap. Similar with using magnetic suppression wire than normal resistance plug wires too. Of course, it would take an ignition scope to really see these things (how many shops still have these things now???).

By observation, different people can have different "luck" with the same or similar products. What ever works best in the individual "environment" can vary. Finding the comfortable "sweet spot" for each vehicle can be somewhat elusive, sometimes, though.

Just some thoughts and observations.

Glad you made it back ok, Willie!

Enjoy!

NTX5467

[Guest imported_MrEarl]

Man you guys know your stuff!!! thanks

[old-tank]

Lamar

As stated above dual points offer no real advantage except for"braggin' rights". Those setups that use the stock distributor usually have the condensor(s) mounted externally, the setups with an after market distributor usually don't have a vacuum advance making them less suitable for routine driving, and the points are not stock/generic items , making replacement difficult or impossible today.

Willie

[Guest imported_PackardV8]

Yes. Dual points are strictly a gimmick.

On the Pertronix: If u want a high energy ignition why not install a GENERAL MOTORS PRE-computer HEI????? How can u get any better than that at any price????? Look at the Packard DF and u will see where one person there has mofified a GM HEI to fit Packard.

[NTX5467]

From what I've seen in earlier articles on the GM HEI system, the spark output drops somewhat over 5000rpm, which could be of concern to some -- BUT it seems that all it takes to cure that is an MSD replacement module/circuit board (which requires a little internal rewiring) and a "better" coil. Remember that the HEI was originally designed in the pre-computer emissions era so it was designed to fire a spark plug gap over .080" reliably, although (again, from what I read years ago) spark plug wire condition became an issue with those larger gaps.

Davis Unified Ignition (DUI) has a set-up to externally mount and wire an HEI module (outside of the distributor housing, usually on the back side) on non-GM distributors. I've seen some on A-block Chryslers, in magazine articles. Depending upon energy loss issues, you could probably do a remote mount pretty much anywhere and then finesse and hide the wiring in a number of ways (i.e., rewinding the taped "conduit" with the additional wires inside, inside convoluted tubing when appropriate). Just depends on what you what to do and how you want to do it.

Most of the aftermarket HEI modules will be for the pre-knock-sensor (approx 1981?) HEI setups (which have fewer pins). If you want to go to the trouble, it's pretty easy to add the knock sensor module to an existing HEI. Find a Chevy or GMC C/K pickup with the "ESC" nameplate on the rear tail gate, for example or look down on the right hand side of the V-8 engine block (first debuted on the higher compression 305 V-8s and was also on similar 350s) where the block drain plug normally would be located. The "box" is located up behind the glove box inside the cab. Then you'll need the appropriate HEI module to run the situation.

This would be a reasonably easy thing to do (for some reason, 305s and 350s take a different sensor and control box), if you can extend or rebuild the wiring harness for the system and the distributor. This way, a somewhat incognito upgrade that would allow a more normal base ignition timing yet would retard the timing when detonation rattle is sensed. If an engine has a main bearing knock, after it starts, it'll usually retard the spark enough to kill the motor--by observation.

I suspect the rh block drain plug hole was a convenience location as later knock sensors are mounted in the lifter valley area, so location in an "add-on" situation could be variable. Most current V-8s have two sensors mounted in the valley, for example.

Enjoy!

NTX5467

[Barry Wolk]

After three frustrating years of tinkering around with my engine I installed the Pertronix II on the 1956 Continental 368. It has an uneven idle and seems to have to run rich to run halfway decent.

I installed the HE coil without the resistor and put a new cap and HE wires on it. It ran pretty good for a 5,300 lb car. Lugnut, on the michiganlcoc.org forum suggested that I open the gap to .043 and now it purrs like a kitten and the exhaust smells much healthier.

On the first leg of a recent 600 mile trip the new ignition worked flawlessly. We got almost 15 mpg on the way there.

I figure that the double-platinum spark plugs coupled with the Pertronix ignition, with all new components, and factoring in 2,000 miles use a year; I believe I've done my last tune up on this car.

Continental Collection