MSD streetfire ignition box opinions

Dr.Jeff said:
I wasn't very clear, sorry. I was referring to a stock electronic ignition (e.g. the later Bosch system on X1/9's) as compared to a aftermarket system (e.g. MSD). I fully agree that points should be eliminated. But that can be done easily and inexpensively with a "trigger" retrofit device, without the need for a full aftermarket system like is being discussed.
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I agree, triggering with something other than points is best. I also agree that it's a good idea to convert the original dist to replace the points with something solid state. What systems are available to replace points in the Marelli dist? I made a cursory attempt to find a Pertronix system that would fit the 128/X1/9 Marelli dist but nothing came up.
 
Honestly Mike I don't know what's available for a Marelli. I've only had Bosch dizzy's and never a Marelli. Hopefully someone else knows. But there are several makers of electronic trigger systems to replace points, beyond Pertronix. So it might be a matter of searching more, I'm sure there must be something available.
 
I fitted one of these point replacement units to the S135 dizzy on my ‘78 1300

https://www.ignitioncarparts.co.uk/PartDetails.aspx?s_pc=ICP-EK048&s_vid=

Works well and seems to produce more consistent timing.

Unfortunately if you have an S178 dizzy the item listed by ignition car parts doesn’t fit (but they can modify your dizzy if you send it to them). On my other car, a ‘88 1500 with an S178, I decided to retained the points. TBH the S178 cartridge style points system is quite reliable and the dwell can be adjusted precisely via an Allen key without having to take the cap and rotor off each time.
 
this is interesting: my dizzy is the S135; is this contactless device used to drive an electronic box, correct? wich kind of box (inductive\capacity discarge) you use?
 
Ghostdancing, they are a replacement for the points. Replacing the point (mechanical contact) trigger with an electronic (non-contact) one. That makes them life-long in terms of not wearing down as points continually do. It also means they never need re-adjusting as points do. Electronic trigger units are more precise, faster responding (although that really won't matter much), and have circuitry to take care of the dwell more efficiently than points will. So you will get a more consistent signal at all times (which you won't with points as they continually wear). Basically an improved method for the points. Therefore you could use them to trigger some "electronic boxes" (CD, inductive, etc), provided the particular box is compatible with the trigger's signal. That is something you will have to determine for each specific box by researching it (try contacting the maker of any boxes you are interested in to be sure). The maker of each electronic trigger (points replacement) can provide the specs of the signal produced by it.
 
Not a fan of the majority of aftermarket electronic distributors when a know proven quality Bosch electronic distributor is easily available. This distributor can be recurved as needed. Do know most of the distributor mechanical advance is in by 3500 rpm, above 4,000 rpm is is mostly a non-issue.

Keep in mind the large diameter of the magnetic trigger unit's arms in the stock Bosch distributor when compared to the majority of aftermarket offerings. The larger diameter has less trigger angle error due to the larger diameter. When the trigger diameter is reduced, much greater precision is required to equal what is so easy to achieve with a larger diameter triggering device. Add to this the high quality and durable mechanical parts used in the stock Bosch distributor, where the vast majority of aftermarket offerings are usually very questionable for quality of materials, durability and reliability.

This Bosch distributor with the MSD 6 ignition unit and stock Bosch coil has been the staple of every exxe owned for decades. All have been totally reliable with zero problems over the decades. The problem waiting to happen is the stock Bosch rotor with resistor built in. The MSD 6 will fast roast that resistor in short time causing an ignition failure. Either a non resistor Bosch rotor can be used or bypass the resistor with copper tape and solder.

As for failing MSD boxes, we used them in the Mazda rotary powered LeMons racer, both Triumph cars, the 74' exxe and where possible. None have had any problems what so ever. All previous points based ignition cars run and start MUCH better with the MSD and proper coil and spiral wound ignition wires.


Bernice
 
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