Installed a Jacobs CD ignition today. Power has improved :)

[BigBlockMopar]

I've had this older Jacobs CD ignition mounted in my daily for some time now, but today I decided to hook it up 'correctly'.
I've had this unit working once in my '67 Newport, but never really felt or saw any improvement at the time, other then that the sparkplugs stayed clean longer.

But now with the ignition operational on it's own relay'd powersource, I can definitly feel an improvement. Idling is more stable and in 2nd and 3rd I can feel some increase in low/midrange power.

My daily runs on propane and I've tuned it pretty lean on everything except fullthrottle situations. So the extra sparkpower is well needed it seems.

This Jacobs Ignition in installed 'inline' with the original ignition system.
So if the Jacobs bails out or something, I can easily switch back to the original ignition system by just installing the main coil-to-distributor cable again.

The Jacobs box senses the spark output from the original coil, and uses this as a trigger to send it's own much hotter spark to the distributor.
A low rpm it also gives multiple sparks like a MSD box does.


Just sharing the info!

[Loren]

Jacobs...now that's a name I haven't heard in a while. A certain mag editor w/ the initials D. Freiburger used to work sales there in the early eighties while he was attending community college writing classes at night, alongsides a good friend of mine who seems to be going by the name "Steve X", as of the recent Car Craft street racing feature.

They might tend to call into question the credibilty of the place. Ol' Dr. Jacobs was one of those guys calling out the entire oem auto industry for ignoring the brilliant inventors who were leading us toward the 50mpg car, etc. Such as himself.

It's good to hear there was a product that worked.

[Barry Donovan]

awesome. I donlt find much on CDI and examples.
the history shows it for aiming towards tiny stroke engines that could not get a spark fast enough from coil induction. Cool to see it on a big engine in a normal build.

There is other companies on CDI. Tiger (usa) etc. Bosch and porsche shipped CDI in the 70s on regular engines. if I had a diagram, I'd spend the 40 bucks they seem to sell for (must be millions of them)..
this week gets an accel 300+ instead. Also going ther route of double choice for ignition in event one fails.

[Scott Liggett]

I bet the old ignition system parts were running full power like new. Would explain the increase in power. I didn't get any power increase by installing the MSD, but driveability improved dramatically.

[CDMBill]

I have one of these including a Jacobs Nitrous controller taking up space in my garage. All working when taken off my car.

If anyone wants it I'll send it to the first person who'll pay the shipping.

Bill

[cantvalve16]

PM sent, Bill.

[BigBlockMopar]

Scott... "were" or "weren't"?

The car was running with it's stock Mopar electronic ignition system and a stockish (original?) old coil. I removed the ballast resistor shortly after I bought the car because the resistance was too heavy for the coil and the motor kept stalling everytime I put it in drive.
I checked the operating temp of the coil running on the full 12v and it never went above 60C/140F so I decided to leave it out.

[BigBlockMopar]

After reading up some more on the history of Jacobs ignitions recently I came to the understanding that my ignition box is Not a 'CD'-ignition, but an Inductive Ignition.
It also 'senses' spark-jump-resistance and adjusts the power accordingly, to save on sparkplug wear.

[BigBlockMopar]

Uptil a few days ago I was running with the stock .032" gap on the plugs. Car also already had new wires, but only stock 7mm.

To make better use of the sparkpower the Jacobs provides, I decided I would try opening the gaps up to .050".
According to the manual this should be possible.
After gapping the plugs the engine still ran nice and smooth, also in Drive with the brakes on and giving it some throttle.
So I left for home, only to find out that when the engine comes upto temp, it started to develop a miss occassionally when pulling up from a stop.

So the next time in the garage I decided to close the gaps a bit to 0.045.
Tested the engine again, and again it ran smoothly. But the next day I noticed the engine missing again occassionally.
Got a bit tired of this, so back to the garage again, I regapped all the plugs back to 0.035". But heading home and on the way to work the next day, I still noticed the engine missing one in a while.

Checked the plugwires, eventhough they still appeared good I exchanged them anyway for a set of 8mm wires I still had around. These were stranded steelcore wires though, so I had some doubts if this would be ok for the ignition but after reading up on this I found it's only the modern digital boxes that don't like them.

But the engine was still missing now and then once warmed up. That was until I checked the cap and rotor when I found the cheap lightweight cap was heavily scorced inside. Replaced it with a used, but heavier quality Mopar cap and all's right now.

I'm still a bit luctant to start increasing plug gaps again though....