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Jacobs Mileage Master Ignition

9926 Views 25 Replies 11 Participants Last post by  jaamzg
Most people think that going to a CD (capacitive discharge) ignition is overkill on a truck since low RPM grunt is what you are after. Well, that is only part of the picture.
What I was after was easier starting, better throttle response and better gas milage.
The Jacobs system did all 3 plus more.
My RC starts much eaiser hot or cold than it did, that is a big plus. In the mornings when I was climbing the steep hill out to the street the truck would tend to bog a bit because of the steep angle and a cold engine. Not anymore. The throttle response improvement was the biggest difference. It is very crisp now and my gas mileage improve 2 MPG on the hwy.
There is a "off road" version of the system now that has some features for off roading but it is very similar to the Mileage Master. You are looking around $320 if you buy it new. I lucked out and found mine on Ebay for $130. (lucky me)
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What are the specs on your truck?
Specs are:

'85 Ramcharger 4x4
360 8:1 comp with Edelbrock performer #1406 carb and Performer intake.
MP RV performance cam. Close to stock, .450 lift
14* inital timing with of vacuum advance.
Jacobs Mileage Master ignition with 8mm Accel wires. Colder than stock heat range plugs with .45" gap
3.21:1 gears, 31" AT tires. Auto tranny
Just an FYI.
I was told by Jacobs that the Mileage Master is an inductive ignition, not CD. The Pro Street, Pro Ten and Marine are all CD.
Well all ignition systems are inductive. They use a step-up transformer to produce the high voltage. But the method of producing the multi-spark is capactive. So if it is a multi spark ignition it is a CD which the Mileage Master is.
ramchargertodd said:
Well all ignition systems are inductive. They use a step-up transformer to produce the high voltage. But the method of producing the multi-spark is capactive. So if it is a multi spark ignition it is a CD which the Mileage Master is.
Here is an exact quote from Chris Byrd at Jacobs:
"Our product line includes both capacative discharge and inductive type ignitions.
Our Omni series is a single spark inductive ignition, our Mileage Master series is an inductive Multi spark, our Pro series, ie. Pro Street, Pro ten, Marine Master, and iCE PAK ignitions are Capacative Discharge Multi spark".

I know it seems odd to have a multi spark inductive ignition because of the longer rise time inherent in inductive ignitions, but this is what he told me. I assume he knows what he is talking about. I think I will try to find out for sure by testing mine.
Yeah, the milage master and the off road kit look nice, I'm going to save up for the offroad kit even though jacobs ignitions run for more money, from what I've heard their worth it,
And yes, according to their site it is multiple spark inductive (but the offroad kit is capacitive).
my only question on the jacobs stuff is, does the place you are getting it from keep parts in stock? I was told it can take a while to get parts in, it would suck if the truck is down waiting for parts.
I dont want to start a flaME war, BUT I need to give my .02.
I installed a Jacobs Ultra team on my 1990 dodge W150, with a 360TBI. The truck immediatle woke up, it idled better and got a little better mileage. Here is down side.
After 6 months the truck spuutered and died. The Ultra coil went bad, I changed the coil to have the Jacobs iginition module die a month later. At that point I switched to an Accel setup, but left the jacobs plug wires. 2 months later The Jacobs plug wires fell apart, I mean literally the insulation was just cracked and peeling everywhere! This engine does not get warm. I have never had something last this poorley.
Damn! :eek: Never had a problem with my coil or computer. I did have a wire get brittle at the boot, but this was after some overheating problems.
I guess shit happens, I bought 2 wheel cylinders from Autozone, and both leaked!!!
I have heard numerous times that Jacobs stuff works well...when it works. I've never heard a thread about Jacob's stuff without two or three people chiming in about how everything fell apart in a month or two. Also heard getting the warranty honored can be ineteresting. Just a little info I'm passing on.

Travis
Interesting. I have warranteed wires several times, the only time it was a pain is during a transition when they were bought by another company back east, and they were in the process of moving.
KThaxton said:
Interesting. I have warranteed wires several times, the only time it was a pain is during a transition when they were bought by another company back east, and they were in the process of moving.
Back east? I was told that one of the biggesy problems with getting parts/replacements was that they are in California now!?!? Hell, this was the salesman that I was asking about them that told me this. Also said the same thing as DusterRT, When it works, it works great. Just takes some hassle to get it to work. (hmm, same thing I keep hearing about holleys)
Yup, I believe it was one of the Carolina's they told me they were moving to. But now that I think about it, there was some place in Denver too, that handled warranty stuff. Nobody mentioned CA though.
Ignition modules and coils failing usually BAD GROUNDS.
I usually run redundant grounds. Ground things in 2 or 3 different ways.
MP ignition modules are bad for failing because of bad grounding.
ramchargertodd said:
Ignition modules and coils failing usually BAD GROUNDS.
I usually run redundant grounds. Ground things in 2 or 3 different ways.
MP ignition modules are bad for failing because of bad grounding.
AMEN, BROTHER! I learned this the hard way.
My Jacobs system went bad in my 79. I endind up putting a HE Ford coil in place of the standard coil and it has run just fine.
This truck is left at the farm most of the time. This past summer a rodent of some kind took the sheathing off of all the wires leading to/from the coil except for that going to the distributor. Darn truck still runs.
What is up with rodents eating wire insulation? I mean, it can't taste good, and it can't be good for them, yet they eat up the PVC like it's candy.
LOL!, They've eaten my coolant lines on my motorhome!
KThaxton said:
LOL!, They've eaten my coolant lines on my motorhome!
I hope they liked the liquid center. ;D
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