Ignition conversion

[stevebfl]

Every so often there is a post about the early point triggered transistor ignition systems. MB made an optically triggered replacement that hasn't been available for years. It was made by TRW for MBNA.

For just as many years we have been installing a optically triggered conversion made first by Allison who then sold out to Crane.

The reason I bring this up this morning is that while wandering through some old images I came up with the filter device my brother designed to allow the tachs to work (on cars with tachs).

Since the conversion is especially a good idea on -75 450SEL and 450SL cars due to it ability to allow worn distributors a second life (the ignition point tention can cause trigger point problems due to the uneven loading on a wobbling dist shaft), the need for a tach conversion becomes necessary.

[stevebfl]

Here is a picture of the kit:

[ctaylor738]

You're certainly welcome to hang out here if you get tired of CIS, o2 sensors and other high-tech (to us) stuff.

Am I correct in saying that if you have a 3.5L motor with the D-jettronic injection then you can't do an ignition convertion?

[stevebfl]

The conversion works fine on 108/109 cars and as stated will extend the life of those trigger point distributors.

They are easy as their is no tach so the wiring diagram modification isn't necessary, just the optical trigger kit w/module.

[psfred]

Steve:

Do you have any experience with the Pertronix system? I've been tempted to do that one too, as it is easier.

Peter

[stevebfl]

No experience. The last one of these we did was a 76 Jag v12. We see very few MBs that old where customers care about improving their car. Ten years ago and back it was a different story.

[68greezr]

hey fred,pertronixs are a snap,they work great for me i have done several cars with them.install is about 15 minutes.just carry a set of old style point rotor etc with you in the glove box,just in case you have any trouble you can switch back and be on your way.around here i have to order them from the local speed shop,however you can call pertronix direct and order.they will need the number off your dist.and the number off your credit card!

How about M110 (74 280)?

Of either electonic system being discussed...

a) make any sense/improvement over stock?
b) ease of install?

thanks,
Will

[psfred]

If you have breaker points, I'd change it over next time the points go bad. If you have a breakerless ignition (Hall effect), don't bother. Don't know off the top of my head when MB when breakerless.

Peter

[stevebfl]

They went inductive pick-up in 1976.

[mzsmbs]

lately, I have heard of people with 108s having problems with the Pertonix units, but dunno if that's isolated to those models. I have a crane that's going to be installed in the near future.

[wbain5280]

Originally posted by stevebfl
Every so often there is a post about the early point triggered transistor ignition systems. MB made an optically triggered replacement that hasn't been available for years. It was made by TRW for MBNA.

For just as many years we have been installing a optically triggered conversion made first by Allison who then sold out to Crane.

The reason I bring this up this morning is that while wandering through some old images I came up with the filter device my brother designed to allow the tachs to work (on cars with tachs).

Since the conversion is especially a good idea on -75 450SEL and 450SL cars due to it ability to allow worn distributors a second life (the ignition point tention can cause trigger point problems due to the uneven loading on a wobbling dist shaft), the need for a tach conversion becomes necessary.

Wow, it's basically a frequency to voltage converter.