Coils: Bosch vs. Pertronix

[Jub]

Hi all,

Recently converted to Pertronix electric ignition....so decided to also get pertronix 40,000 flamethrower coils (3 ohms).

Long story short...got them...seem smaller than my original Bosch...and the instructions recommend I bypass my ballast resistor (see attached pic; red wire).

Is this right, are they better than Bosch?

Jub

[Marrs]

Some (maybe all) Pertronix coils have the resistor contained within, if you check the paperwork that comes with the Pert system you will see it also has an option to use your ballast resistor if you use another coil, such as Bosch. I am not saying this is better or worse, but I chose to use the ballast resistor, got a new Bosch coil (with no internal resistor) and used them with the Pertronix ignition. Long story short, if your coil has internal ballast resistor then you bypass the one on the fender wall, if it does not you need to keep it in the loop.

[sjefke]

I have two Petronix Flamethrower coils in two different cars and both are set up to bypass the resistor. Best is to get the positive voltage for the Flamethrower from before the ballast resistor. Mine is very reliable and I might rate it a bit better than my old blue Bosch coil. But then again, that had a whole switch gear set up behind it too, all of which could cause a problem.

It is a simple setup. And simple is good, imho.

Bert

[Marrs]

I will clarify that the only reason I went with the Bosch red coil and ballast resistor rather than the Flamethrower was that I liked how it kept the original appearance under the hood. My car is not even a show car, I just like it, but as stated by the other member simpler is better if you're just going for reliability on a driver.

[dirtyharry]

if you really wanted to, you could keep the points, and run with an aftermarket or OEM Bosch Volkswagen coil. something from the early seventies with a resistor built into it. cuts the voltage from 12 to about 9v which is just enough so the points don't arc. then eliminate the switchgear and resistors in the stock wiring as they all fail from time to time. and I dont really think a $40 BERU ballast resistor is exactly justified, when you can buy the coil for that much.

[Jub]

Update:

So I switched to pertronix coils last week but really hadn't diven much (grocery store, etc). Had a meeting 1 hr away (plus DC traffic) and started to notice a funny smell.

Checked temp gauge and engine was running really hot. Missing meeting was not an option so I cranked on the heater full blast (to draw heat away from engine; 70 degree weather; in a suite). After hell ride and meeting I tore out the pertronix coils and put back my Bosch coils.

Not sure if it was a coincidence or a faulty thermostat but for now I think I will just keep in the Bosch (ordered new thermostat). Those god forsaken flame throwers!

[pedrocamp]

I installed a Pertronix system with Flamethrower coil in my 68 W110 230 a year ago and have had great success, not one issue. I removed the resistor per their instructions. I do keep the points setup with Bosch coil and resistor in the trunk, just in case though. Did you check your timing?

[sjefke]

You do need to check timing after you install Ignitor in distributor, because timing will be different. Bad timing can cause overheating. I have had Flamethrower for more than a year and never had a problem. But I did reset the ignition timing.

Bert

[Jub]

Timing... hugh, makes sense.

I think Pertronix, of coarse, makes amazing electronic ignition conversions (I love mine). In fact when I converted the instruction did mention to check timing (which I did). But there was no mention in the instructions about checking timing when swapping out coils.

Maybe this is a no brainer for seasoned mechanics (I have owned two MBZ 72 280, now a 71 250)... but I didn't really hear anything about this until after my hellish experience with the flamethrowers.

Luckily, I was able to dial back my initial reaction (to throw the coils into a nearby river) until I heard from you all. I will give them another shot. I think I will hold off probably till after the new year; still a little bitter .

Thanks everyone (stay tuned).

[sjefke]

Just swapping out coils should not affect timing. Only when you mess with the distributor can you get a change in timing. In general, with a "better" coil you should experience better starting and better burn because of better spark.

Make sure you wired things correctly. It can be tricky with the ballast/no-ballast wiring. And I think there are a couple of different Flamethrower coils - some of which do or do not go well with either Ignitor I, II or III. On my second (non-MB) system, I called up a guy and asked him what I needed because I could not make heads or tails out of what Petronix had put on their website.

Bert

[WANT '71 280SEL]

Jub,

In what model car did you install the Pertronix?

Best Regards,

David

[Jub]

Final update:

Turns out it was a bad WATER PUMP (see attached; note the green fluid below pump). Seal may have broken (may just replace the whole thing).

Jub