why did 72 LT-1 not have a TI?
any reason not to have transistor ignition other than cost since engine same as 70-71 except compression, right?
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Michael
70 Mulsanne Blue LT-1
03 Electron Blue Z06 -
Re: why did 72 LT-1 not have a TI?
Michael------
The only significant difference between the 1971 LT-1 and the 1972 LT-1 was the change in the horsepower rating from SAE Gross to SAE Net.
Why no TI for 1972? Very simple, TI was discontinued after the 1971 model year. So, it was not available for use on any 1972 engine, LT-1 or otherwise.
Why was TI discontinued? Well, it's speculation but I expect it was related to reliability problems and a cost/benefit analysis. In other words, it was more trouble and costly than it was worth.In Appreciation of John Hinckley -
Re: why did 72 LT-1 not have a TI?
I'd agree, that reliability and technology at that time was quite marginal. Sorry if a bit OT but it's such a negative reminder of those early systems.
I had to carry TWO spare Transistorized Ignition "ECM's" in my '69 Mustang at all times when I got the car in 1972 for $550.
They "reliably" FAILED every 6 months or so.
I was a young electronics engineer at that time, and I knew first-hand about reliability issues with these designs.
Same goes for the early Jaguar electronic ignitions of the era. They were prone to failure, particularly due to heat related issues where mounted deep in the well of the V12's, right behind the big 'ole GM C6 A/C compressor. Jaguar moved it from there to a new mount location just behind the cooling fans, but required a completely new harness due to critical wire length from the module to the dizzy. I devised a way to raise it up out of the well for better airflow. Got point deducts in JCNA judging but at least we drove the car to events without breaking down.
I always carried a OPUS(Oscillating Pick Up System) Module, and also to this day, for the wife's Jag V12 E-Type we cruise around in. Thankfully there is a replacement upgrade with modern technology much like there is today for the GM TI system if all my spares die out.
The OPUS module buried just behind the A/C compressor manifold.....what were they thinking?
If Ken Anderson and his new upgraded module design for the GM TI system was around back in the 70's, it'd have been a much more reliable product.
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RichComment
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Re: why did 72 LT-1 not have a TI?
The 64-71 TI boxes used the original Germanium transistors and that whole technology was replaced by the Silicon transistor. Perhaps it became difficult to get Germanium components in quantity by 1972.
My experience has been that unless moisture gets in the boxes they are practically immortal. My 70 LT-1 still runs perfectly on the original box. Recently, I tested the box off my long term restoration project 67 L-71, and it still worked fine because it was still clean and dry inside. I rebuilt a number of boxes in the early 80's before the modules were available and found that most common failure was the corrosion of the little legs of the trigger transister in the left bottom photo of Rich's 3 photos. All three legs appear to be rusted off of his, and the board has the typical appearance of moisture exposure.
I would probably use a module to repair a box these days. But unless the box is well sealed, I'll bet the new module will fail even quicker than the old boards in the event of moisture exposure. Ever drop a cell phone in the water?Comment
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Re: why did 72 LT-1 not have a TI?
Funny that this question comes up............
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Re: why did 72 LT-1 not have a TI?
My first vette was a 67 L-71 I bought in 70 had the original TI and served me well for the year I owned it...sold for a whopping $2200 and was glad to get it, was not that many years later prices started soring.Michael
70 Mulsanne Blue LT-1
03 Electron Blue Z06Comment
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