Author Topic: Transistor ignition control unit  (Read 565 times)

CJHenderson

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Transistor ignition control unit
« on: February 24, 2024, 00:04:52 »
Another missing connector from the new wiring harness, this time it's for my Transistor ignition control unit. Do I still need it since I'm switching to a 123 Ignition setup?
1970 280SL/8 W113 101624 miles.
1950 MG-TD
2021 Harley Davidson CVO Trike

WRe

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Re: Transistor ignition control unit
« Reply #1 on: February 24, 2024, 06:56:50 »
Hi,
simply spoken, the 123 replaces the distributor and mechanical breaker. The Transistor Ignition Control Unit was part of the ECS and replaced the mechanical breaker.
In my opinion, the real question would be to what extent the ECS is still in operation or can it be completely deactivated by installing the 123?
...WRe

Pinder

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Re: Transistor ignition control unit
« Reply #2 on: February 24, 2024, 14:59:07 »
I have that unit in my 1970.  you dont need it.   the 123 ignition does not need it.
1970 280 SL Light Ivory DB 670. 4 Speed manual shift no AC Limited Slip Diff.

dirkbalter

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Re: Transistor ignition control unit
« Reply #3 on: February 24, 2024, 15:44:19 »
I have that unit in my 1970.  you dont need it.   the 123 ignition does not need it.

Is your vacuum cut-off valve still working correctly? Or how did you program your 123?
Dirk
66 230 SL
70 280 SEL
53 CHEVY 3100
18 C300 COUPE
05 HD FLSTNI

CJHenderson

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Re: Transistor ignition control unit
« Reply #4 on: February 24, 2024, 16:47:44 »
Not sure of the vacuum, but it's nice to get rid of both the transistor ignition and the ballast.
1970 280SL/8 W113 101624 miles.
1950 MG-TD
2021 Harley Davidson CVO Trike

Pinder

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Re: Transistor ignition control unit
« Reply #5 on: February 24, 2024, 17:10:37 »
From what I have read, the transistorized ignition unit is beneficial if you are to use points; It stops the points from burning up.   the 123 ignition systems does not use points.

My 3 way vacuum control value is controlled by the relays and it does work. however i have modified my throttle control by drilling a hole in the same place that the non emissions controls car have the vacuum hole. I can switch and run the car as a 1970 or 1969 system.   with  the 1969, provides fully vacuum at idle and it goes to no vacuum as you accelerate.  So currently with my 123 ignition I am running it as if it did not have the emission controls. 

I can also run it by changing the vacuum line at the throttle body (which provides constant vacuum, and this vacuum then goes to the three way value which gets turned on and off via the emissions control relays and it adjusts the timing on the distributor. This seems more likely to fail , (extra components such as the 3 way) and its why I wanted to run it without all that stuff.

I hope that helps. but please correct me if I am wrong on the use of the transistorized ignition module.

Regards

Pinder
1970 280 SL Light Ivory DB 670. 4 Speed manual shift no AC Limited Slip Diff.

Pinder

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Re: Transistor ignition control unit
« Reply #6 on: February 24, 2024, 17:14:43 »
1970 280 SL Light Ivory DB 670. 4 Speed manual shift no AC Limited Slip Diff.

dirkbalter

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Re: Transistor ignition control unit
« Reply #7 on: February 24, 2024, 17:49:57 »
@Pinder, thank you for the explanation. I did something very similar. My valve or better, the relay wasn't working any more. But instead of drilling the hole, I swapped throttle bodies. I am using the same curve. I was interested to see if there are new developments.
Dirk
66 230 SL
70 280 SEL
53 CHEVY 3100
18 C300 COUPE
05 HD FLSTNI

Pinder

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Re: Transistor ignition control unit
« Reply #8 on: February 24, 2024, 20:45:22 »
I think the solution you have is a great option.
1970 280 SL Light Ivory DB 670. 4 Speed manual shift no AC Limited Slip Diff.

CJHenderson

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Re: Transistor ignition control unit
« Reply #9 on: February 24, 2024, 22:57:08 »
One question that I have is the static timing set at TDC or 8 degrees BTDC? I had set mine at 8 degrees using the old distributor, but I'm unclear on what to set on the 123/tune.
1970 280SL/8 W113 101624 miles.
1950 MG-TD
2021 Harley Davidson CVO Trike