Pertronix ignition - suggestions

[Atchisvw]

Which Pertronix ignition did you install on your 280S?

[Tomguy]

Atchisvw,
Since you replied to a ~13 year old thread, where the OP hasn't been active in over 11.5 years, I moved this to be a new thread of its own.

Hopefully someone who has done a Pertronix conversion can provide you suggestions / input on the best unit to use for your car

[Mike D]

I've used the standard Pertronix for 5 years or so on M110's and M115's with no problems.

The "Ignitor" II and III sets are not recommended for use with the solid core wires used by Benz.

From the Pertronix web site:

"You cannot use solid core (typically copper) spark plug wires with this product. Solid core wires do not suppress electro magnetic interference (EMT) which will interfere with electronics in your vehicle. A suppression style or spiral wound spark plug wires must be used. "

Best way to get the proper set up is by distributor number.

[97 SL320]

If the distributor is a used forever Bosch, I'd be real tempted to blend 1980's factory electronic ignition from a Volvo / Saab / VW. In theory, one could use the ignition pickup parts in the old housing.

[Atchisvw]

My ignition on my 1970 280S is a transistorized unit. Will this affect the operation of the Pertronix ignition?

[Atchisvw]

Currently using distributor #0231142003

[Tomguy]

If one is going to use later factory electronic ignition from Bosch, may as well use one from an m116/m117 such as a later 4.5, or a 380, 420, 500 or 560. I'd imagine the distributor itself would be plug-and-play (at least from a later 3.5/4.5, if not the aluminum-blocked engines). You're more likely to find one of those in a junkyard too, I'd imagine.

And as for the Pertronix "Interfering" with transistorized ignition... the point of the Pertonix is to replace said ignition.

[97 SL320]

Originally Posted by Atchisvw

My ignition on my 1970 280S is a transistorized unit. Will this affect the operation of the Pertronix ignition?

I'd use the existing distributor if the internal pickup coil is in good condition to trigger a modern ignition module. A 4 pin GM module is inexpensive. I'd use a GM external coil to finish off the setup.

The Pertronix system is to replace a standard ignition that uses contact points ( breaker points )

What country are you in? This makes a difference as to what parts are easily available.

[Graham]

Originally Posted by Tomguy

And as for the Pertronix "Interfering" with transistorized ignition... the point of the Pertonix is to replace said ignition.

A Pertronix can replace the transitorized ignition. MB call it the "Switchgear". To do that, the switchdear is bypassed and a new coil is usually required (e.g. Petronix Flamethrower).

However, a Pertronix unit can also be used to just replace the points. This overcomes problems with worn distributors (shaft wobble) and eliminates need to adjust or replace points.

Depends on the reasons owner has to consider using a Pertronix. There is a thread here with wiring diagrams for both options. Here is the one from BW (Should be very similar for 6s)
https://www.benzworld.org/forums/r-c107-sl-slc-class/1714668-pertronix-install-without-switchgear.html

By the way, the Pertronix site now says to not use even the original Ignitor 1 with copper core wires. But this is likely an error. Many of have used those Ignitors on our Benzes for many years. I have had one on my 4.5L V-8 350SL since 2008.

Search for that distributor on Pertronix site came up empty, but this site suggests model 1867A :

Bosch 6 Cylinder - Pertronix Ignitor

I know nothing about this one, but Kent is quite reliable

A complete new distributor from 123Ignition might be another option (under $500 in USA)

[Graham]

Originally Posted by Tomguy

If one is going to use later factory electronic ignition from Bosch, may as well use one from an m116/m117 such as a later 4.5, or a 380, 420, 500 or 560. I'd imagine the distributor itself would be plug-and-play (at least from a later 3.5/4.5, if not the aluminum-blocked engines). .

Is the 280S a 6 or an 8 cylinder? (I get confused with the 280 series!). If a 6, the M116/117 distributors wouldn't be correct. Might not fit anyway on a different block.

[Atchisvw]

Thanks for the info! The 280S is a 6 cylinder M130 engine. I ordered the Pertronix 1867A but was hoping to use my recently replaced coil. I was having difficulty locating some ignition parts in Canada, so decided to go with the Pertronix 1.

[Graham]

Originally Posted by Atchisvw

Thanks for the info! The 280S is a 6 cylinder M130 engine. I ordered the Pertronix 1867A but was hoping to use my recently replaced coil. I was having difficulty locating some ignition parts in Canada, so decided to go with the Pertronix 1.

Another Canadian eh Happy Thanksgiving!

If you retain the MB switchgear, then there is no problem using coil if it is same as original.

If you bypass the switchgear, then you may need to look at coil. I am not totally sure, but the OE MB coils used external resistors and had fifferent winding ratios that conventional coils. The Pertronix coild are more conventional. This is what they say on subject:

What type of coil can I use with the Ignitor™? How do I check my coils resistance? (12V negative ground only)
To determine if your systems coil is compatible with the Ignitor, some measurements should be taken prior to installation of the Ignitor. Caution… While performing this test, never leave the ignition switch on for more than 30 seconds at a time.

Set your voltmeter to a 15 or 20-volt scale. Attach an 18 or 20 AWG jumper wire from the negative coil terminal to an engine ground. Attach positive (red) lead of your voltmeter to the positive side of the coil, and the negative (black) lead to an engine ground. Turn the ignition switch to the run position. Now read the voltage at the positive coil terminal. Turn the ignition switch off. If the voltage measured is approximately 12 volts, no resistance wire is present. A typical resistance wire will provide 9 - 6 volts.

The next step is to determine the resistance in the primary ignition. Label the wires attached to the coil terminals and note their appropriate location. Make sure that the ignition switch is off and disconnect all wires from the coil. Adjust your meter to the lowest ohm scale. If you are using an analog style meter make sure to zero the needle.

Measure from the negative terminal to the positive terminal. Write your measurement down.

Now the maximum system amperage can be determined, divide your voltage measurement by your coil resistance measurement. This will give you the system current or amperage.

Four and six cylinder engines should not exceed 4 amps. Eight cylinder engines should not exceed 8 amps. If the total amperage in your system is higher than the amount recommended for your application, you should install a ballast resistor.

Example
Voltage 12
Resistance 1.5
12 / 1.5 = 8
Total amperage 8

You can buy a Flamethrower coil on Amazon.ca or elsewhere for about C$50. I bought one but have never installed it - still using the 46 yr old switchgear. It's pretty rugged!