Points vs Pertronix Article by Rob Siegel

[Jimmy]

23 minutes ago, avoirdupois said:

 

Any pics of the Jacob's installation? 

IIRC, Jacobs recommends a huge spark plug electrode gap, and am curious whether you followed that advice and whether there were any noticeable operational benefits.  Vaguely recall someone touting extremely large gaps using Bosch silber plugs, WR9LS (?), but wondered then (and now) if the extended electrode might not incur some "resistance" with valves or pistons.  And, NO, I am not advocating using this plug in the stock M10 platform,  but I remain curious about the Jacobs CDI and these plugs.

 

 

 

 

   

 

I have many pics. It wasn't done in the most aesthetically pleasing manner, but it was connected according to the manufacturers recommendation. This consists of using a couple flimsy junction blocks hanging off the coil so that the Jacobs unit intercepts your points and fires the coil itself instead. The idea being that if it's configured that way, you can easily disconnect the jacobs unit and return the car to stock. It was a peace of mind gimmick for selling them. What are you hoping to glean from a picture of it?

 

As far as plug gap, going from 35 to 45 should never result in piston contact, but casually monkeying around with plug heat range can result in electrode depth and thread reach changes that may cause problems. When running non-stock plugs it's good to be mindful of installed dimensions.

 

As for more spark/bigger gap, that's a gimmick as well. If you want to wear out your cap and rotor and retard your timing, go for it.

[avoirdupois]

1 hour ago, Jimmy said:

 

I have many pics. It wasn't done in the most aesthetically pleasing manner, but it was connected according to the manufacturers recommendation. This consists of using a couple flimsy junction blocks hanging off the coil so that the Jacobs unit intercepts your points and fires the coil itself instead. The idea being that if it's configured that way, you can easily disconnect the jacobs unit and return the car to stock. It was a peace of mind gimmick for selling them. What are you hoping to glean from a picture of it?

 

As far as plug gap, going from 35 to 45 should never result in piston contact, but casually monkeying around with plug heat range can result in electrode depth and thread reach changes that may cause problems. When running non-stock plugs it's good to be mindful of installed dimensions.

 

As for more spark/bigger gap, that's a gimmick as well. If you want to wear out your cap and rotor and retard your timing, go for it.

 

An acquaintance pulled a Jacobs unit from his V-8 powered ski boat and asked about retrofitting it to a low compression 4 cylinder engine (MG).  My first reaction was to question whether there is enough engine bay room, so he suggested using one of my cars for testing.  Hence the reason for photographs.  (I also considered it for an M30 engine with a bigger engine bay, but haven't found the need or the time to play with the project.) 

 

Perhaps you could elaborate concerning your use of the term "gimmick" when describing larger plug gaps?   It was my limited understanding that that was the Jacobs' forte and I have heard unconfirmed reports of "measurable" performance increases with various aftermarket ignition systems.  Confirmed reports have eluded me.  From memory, the example I referenced involved .065" or possibly much larger gaps that allegedly ignited extremely lean mixtures.  This also has the alleged benefit of eliminating flat spots or common progression problems that often plague questionably jetted carburetors set to comply with heightened emissions requirements.  IIRC, many manufacturers favored larger gaps that fired leaner mixtures at lower compression for reduced combustion temperatures and reduced emissions (and possibly increased fuel economy).

[Simeon]

Wow! Jacobs make some interesting claims about their products. It’s like drinking with your crazy Uncle ‘who tells the stories’. ?

 

[Jimmy]

11 minutes ago, avoirdupois said:

 

An acquaintance pulled a Jacobs unit from his V-8 powered ski boat and asked about retrofitting it to a low compression 4 cylinder engine (MG).  My first reaction was to question whether there is enough engine bay room, so he suggested using one of my cars for testing.  Hence the reason for photographs.  (I also considered it for an M30 engine with a bigger engine bay, but haven't found the need or the time to play with the project.) 

 

Have you not seen the module? It's just a little box maybe 3 inches by 6 inches by an inch or so. Mine was mounted on the core support. You could mount one anywhere.

 

11 minutes ago, avoirdupois said:

Perhaps you could elaborate concerning your use of the term "gimmick" when describing larger plug gaps?   It was my limited understanding that that was the Jacobs' forte and I have heard unconfirmed reports of "measurable" performance increases with various aftermarket ignition systems.  Confirmed reports have eluded me. 

 

Exactly. ?

 

11 minutes ago, avoirdupois said:

 

From memory, the example I referenced involved .065" or possibly much larger gaps that allegedly ignited extremely lean mixtures.  This also has the alleged benefit of eliminating flat spots or common progression problems that often plague questionably jetted carburetors set to comply with heightened emissions requirements.  IIRC, many manufacturers favored larger gaps that fired leaner mixtures at lower compression for reduced combustion temperatures and reduced emissions (and possibly increased fuel economy).

 

Running larger gaps has a predictable effect as does running smaller gaps. The factory setting is arrived at as a compromise of all normal engine operating conditions with some cushion included for wear so that it doesn't start to run like crap too soon after you put the tools away.

 

Larger gaps can increase misfire at high rpm, especially in high compression and forced induction applications. A higher energy coil can compensate at the expense of component longevity. Simply claiming you can run larger plug gaps with a Jacobs is puffery. You can run larger plug gaps without a Jacobs.

 

The question you need to ask is what are you are you trying to accomplish. Ridiculously large gaps can burn ridiculously lean mixtures, to the point that the engine isn't making enough to power to warrant the effort.

 

Carburetors are not the most precise or dynamic contrivances, running a wide range of mixtures well is quite a challenge. Heck, running a narrow range of mixtures well is difficult for many of them.

 

Some people look to things like ignition modification to solve a problem that really needs to be solved in the carburetor. Some people look to carburetor modifications when they really need to fix their ignition. Some people like to diddle around with things because the results of countless persons entire careers in the automotive industry aren't sufficient for them. Peas porridge in the pot, nine days old.

 

I viewed the Jacobs as adding longevity/durability/reliability to the breaker points. They remained looking brand new the entire time I used it, so from that perspective it was undoubtedly a successful modification.

[avoirdupois]

Thanks for the responses.  I vaguely recall the Jacobs CDI, in situ, and careful attention was not paid to it, especially since everything was color coordinated in metallic turquoise,  Supposedly, the removed unit and its peripherals is in a bag weighing approximately 15 lbs.  This may be an over-approximation since this measurement is second handed. 

 

I suppose the other CDI installations will have to suffice, as they have also resulted in significant breaker point longevity.  Instead, we will direct our attention to other "proven" modifications.

 

Any experience with the Pogue Carburetor and a perpetual motion machine and will they fit a 1600 model? ?

 

Sssshhh.

 

 

[Jimmy]

1 hour ago, avoirdupois said:

Thanks for the responses.  I vaguely recall the Jacobs CDI, in situ, and careful attention was not paid to it, especially since everything was color coordinated in metallic turquoise,  Supposedly, the removed unit and its peripherals is in a bag weighing approximately 15 lbs.  This may be an over-approximation since this measurement is second handed. 

 

We're not talking about the same thing. A Jacobs ignition module is a small single unit like I described. If someone went full retard installing all of the components Jacobs sold, trigger, coil, etc I could see it maybe weighing 15lbs all in. Coils are relatively heavy.

 

1 hour ago, avoirdupois said:

 

I suppose the other CDI installations will have to suffice, as they have also resulted in significant breaker point longevity.  Instead, we will direct our attention to other "proven" modifications.

 

Or you can dig up a Jacobs. Mines like this one (NM/NA) https://www.ebay.com/itm/Jacobs-Electronic-Ignition/163514073804?hash=item261232c2cc:g:hFAAAOSwTxJcQjQ2

 

1 hour ago, avoirdupois said:

Any experience with the Pogue Carburetor and a perpetual motion machine and will they fit a 1600 model? ?

 

Sssshhh.

 

 

 

There are so many problems with this before you even get into what the carburetor actually does or does not do.

[avoirdupois]

4 hours ago, Jimmy said:

We're not talking about the same thing. A Jacobs ignition module is a small single unit like I described. If someone went full retard installing all of the components Jacobs sold, trigger, coil, etc I could see it maybe weighing 15lbs all in. Coils are relatively heavy.

 

Glad you clarified.  From memory, the kit has more than two components and includes plenty of wiring and junction boxes.  I'm guessing that it resembles something more like the bottom exemplar.  The top most example would be a relatively simple installation, presumably not much different than installations for comparable MSD, Allison or even Permatune ignition components.  The system I had in mind was installed on a big block V8, and it probably includes even the 8 x 8mm high tension leads.  Per my initial inquiry, there may be an upside to installing the whole kit, but any upside shall,  .  .  .  for the moment, remain shrouded in mystery.    

 

 

 

 

 

 

 

 

 

 

 

Edited February 4, 2019 by avoirdupois

[Jimmy]

The ignition coil pictured isn't critical to the installation, any coil meeting your systems requirements could be used. that coil does show the little junction blocks and the plug that my car had installed.