VF, I know those hall effect sensors might be more durable than the optical sensor, but Im not sure. It was hard to find one that had high enough frequency. I think a well sealed opti with no HV will live just fine. Im glad you found a chip that will work so easily.
Years ago, when HEI was all the rage, I had epoxied spark plug towers to HEI coils, had a mirror on the rotor and a IR detector/emitter in the cap. Everyone said I was crazy. I had found the 1-to-8 data distributor chip (as it was called) back then, but I didn't have squat for money, and the internet was not up.Originally Posted by Aroberson77
The Opti without the high voltage running through it will be just fine. Just clean it up and seal it. The same sensors seem to run forever in the other cars they are installed in.
Nice project, I think it would be much easier just to use uP for coil switching, we are talking about frequencies of about 25kHz at 8k RPM, that's basically a slow signal for let's say AVR or STM32 running at a few MHz... But I appreciate your effort to make it discrete!
Another point that comes to my mind is that almost all of the optis I had replaced had the optical sensor failing due to high temperature, NOT the HV part. It seems that over time temperature causes the LED and phototransistor to lost alignment somehow.
I think a good solution would be to use vortec style cover with CKP sensor for hi-res signal (180 tooth wheel), and only low-res sensor in the opti. The question remains if the CKP sensor is capable of picking so dense teeth.
Thanks dzidaV8, I figured that if I make it hardware based, anyone with a processor can make use of it.
yup, heat kills the optical pickup by increasing the resistance of the led emitter until it burns out or is too dim to work. Heat kills hall effect sensors, too. Roughly at the same temperatures, too. It's just the fact that the emitter generates heat in operation is why it probably fails slightly sooner.
I don't think the vortec timing cover fits the LT-1 due to the water pump/distributor drives. I think you mean the 1996-up timing cover that has the extra 4x reluctor and crank sensor. The tooth density that you speak of definitely would raise issues with the stock crank sensor. They are magnetorestrictive in nature, and can be quite touchy.
A custom hi-impedence sensor would work better....something that develops a higher voltage per tooth, basically.
Last edited by vilefly; 09-17-2017 at 02:54 AM.
I believe what happens is the phototransistor slew rate slows to the point it basically runs into saturation (on all the time) when it gets hot. Theres an "equivalent" sensor that was used by Chrysler in a traditional distributor application that was used heavily in cheap aftermarket optis that did this. The Chrysler application was designed to work in a thermosplastic distributor body, and wasn't able to handle the heat of operating while attached to an aluminum plate bolted to the front of the engine block.
You need to use the 96-97 cover. The crank damper mount is also shorter to accommodate the trigger wheel.
I took the delteq apart and heres some pictures
20170917_213504.jpg 20170917_213527.jpg
I'll agree with you on this one. The optis I've seen fail died in two different fashions. One was the cheap chinese junk replacement off eBay with the Chrysler optical sensor installed that loses high resolution signal when it gets hot. I have one of these and replaced the optical sensor with one from AIP Electronics that meets the specs of the original Mitsubishi unit. The others died because the optical wheel was destroyed by arcing from the high voltage side.
As lionelhuntz mentioned, AIP Electronics makes a sensor that meets oem temperature specs. They're sometimes out of stock, but I've been running one in my triple-c opti from eBay (previous owner installed it) for going on 3 years now. No problems up to 6800 rpm rev limiter.
Last edited by spfautsch; 09-17-2017 at 01:58 AM.
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