Jacobs Ignition System?

I didn't know Jacobs ignition units sent multiple sparks to the plug.

 

I went to there sight and read up on some of there stuff, it looks like there fire control ignition boxes are a multi spark like the MSD unit.

 

Sparky there is a section of "download instructions" that gives a basic discription of what the components in the system do.

 

Sparky, I used an Omni-Magnum and Jacobs plug wires with my stock points distributor and didn't like it much. I had a problem with the spark arcing to the other terminals inside the cap. Didn't happen all the time, when it was working good, it did add some power over the stock coil, but when it wasn't working good, the engine ran poorly. I got frustrated with it and switched back to the factory ignition. I've been thinking about switching to a HEI setup lately, but don't have the money right now.

 

I installed one on a Nissan Pathfinder once. I can't remember the exact package I got, but it was pretty much "the works"! I think, all together, it cost me about $400.

I wasn't very impressed with it, to be honest. I didn't notice a big different (~150K mile V6) and I remember having a fair amount of trouble getting it to work just right.

Personally - I wouldn't buy one again unless it was REALLY cheap.

 

I agree. They gotta do something good, or they wouldn't still be in business. I might have just had an engine that couldn't be helped! (or maybe I didn't install it right - that was waaaaaay back in the day).

Sure can't hurt anything!

 

If memory serves me correctly, the big selling points was the HP and mileage increase, along with "virtually curing" all ignition system problems. Used to be you could call their tech support number and they could give you the numbers for the vehicle in question. When I crunched the numbers and figured the cost, it didn't make much sense to me to use on the CJ... 18 mpg was/ is my mileage using the stock Prestolite. Who the heck knows (cares) what my HP is. Just my .02.

 

Sparky: Never used their ignitions, but have used their wires and dial back timing lights. All were quality items. If you can get it cheap, go for it.

 

Sparky, I put one in a '90 ford p/u w/ 302. Just the coil helped a bunch - better starting and more power/mileage. The ignition unit was good quality and worked well also. And, I used their plug wires. "Dr. jacobs" wrote a very good book on ignition systems. It's worth reading if you get a chance.

Lynn, you said you've had a Jacobs coil for years. Is that for your HEI? I'd be very interesting in replacing the (very old) coil in my HEI with a Jacobs coil.

 

I put a mileage master unit and wires on my newly built 454 back in 1996. It went on new with the motor so didn't get to compare it without.
I also run an MSD on my jeep.
Personally, I don't think I would spend the money on either again. Not that they didn't work, but I am not sure how much they really help. Of course in both cases I was running an HEI already, maybe a different stock ignition would see more benefit?
My blazer (454) has been sitting at my friends house on the mainland for the last 5 years, he had a problem with the Jacobs box (groudn wire I think) so he just disconnected it. Maybe I'll get home on leave this year and get the monster running(needs a battery) and drive it without the jacobs.

I will say I believe in using quality plug wires. Both the Jacobs(blazer) and MSD (Cj5) are good items. I would go with either, whichever is cheaper or easily available (or matches your color scheme??!!)

I also ran a jacobs omni pak on a toyota 20r. It worked fine for about a year, and then had a problem. There was a spark plug wire that went on the stock coil that had a pigtail that just went to ground. I don't know what it did exactly, but after a year, where the spark plug wire mated to the grounding pigtail developed a open circuit and big sparks would arc out to ground. When I called Jacobs they wanted some absurd amount for the part and were rude to boot. I rate their consumer support a 0 on a scale of 1 to 10.

The milage master unit did have a neat anti theft feature. You could set it and then if someone started the vehicle without pushing the secret button within so many seconds, the vehicle would run for about a minute and then shut off and not start back up. Supposedly this would put the carjacker out of the driveway parking lot and into traffic, now with a stalled vehicle making a spectacle. Also it makes the charge grand theft rather than vandalism if he couldn't get it started at all, because the car moved (according to the ad copy). I believe at one time it was available separately as "stop theft" or something.