Silicon Chip Programmable Ignition Module

[enigmas]

The following info maybe of some assistance to you David.
Here are the current settings programmed into the module.

Timing (Static. Locked Distributor)
10° BTDC.

Load Setting
Min Load 37
Max load 147

Settings Mode Data
Stroke 4
Cylinders 8

Set Min RPM
600 rpm
RPM/Site 400 rpm
Max rpm 4600 rpm

Set Min Load
37

Set Max Load
147

Set Maps
2(11x11)

Set Resolution
.5°

Set Response to Low RPM
800 rpm
(A setting at idle speed is ideal according to John Clarke)

Set Dwell
4.7ms
(Lower settings cause misfire under load)

Set Edge
Low

Set Debounce
2.0ms

Set Knock
Off (knock sensor not added to the module)
Limit 4000 rpm

Set Interpolation
On

Set Oscillator
Off

OTHER
Coil Driver.
I have not mounted this close to the coil (as recommended) but close to the module under the PS parcel tray, interior of the car. Primarily to keep it away from heat and the hostile environment of the engine bay. No issues that I am aware off.

The Oscillator
Used when setting the dwell period for spark strength & intensity.
When in the on mode may cause the car's electronic tacho needle to bounce back and forth on the instrument. This is due to the oscillator pulsing the ignition coil.

Piranha Optical Trigger
The trigger will only function correctly with the module in the 'Low Edge' setting.

[dave1800]

Jul 30, 2021 14:04:19 GMT enigmas said:

I really don't believe you'll have any issues configuring the module to run a viable petrol ignition map with your MGB David.
John Clarke is obviously a wiz at designing electronic devices but the writing leaves a lot to be desired from a communication point of view. Not the technical stuff if you comprehend it, moreso some of the explanations for configuring certain specific settings, such as the 'Response to Low RPM Setting' that you've highlighted.

A lot of the design and project build articles for this module were built on top of previous and simpler electronic ignition kits several of which I've built and still have running in my other classics.

I don't pretend to understand the workings or even the inter-relationship of some of the components but do manage to assemble the kits successfully (touch wood.) The configuring part, with several quite confusing settings is really a trial/error/elimination process until the correct values are realized. Most of that being based on knowing the difference between a smooth running engine and one battling itself. So although all the theory behind the electronics of the module may make perfect sense, if you don't have a feel for how an internal combustion engine behaves under stress, then it's all purely academic. (~ Vince)

I will let you know the outcome of my discussions with John. You may wish to note Silicon Chip still have a few programmed PICs available should you wish to keep a spare. The software is also available as a free download.  

My approach is always cautious not to move away too far from the original ignition specifications at first and then only to make gradual changes.  With mechanical distributors I am always careful to ensure that the maximum advance under load can not be exceeded. So far I have been lucky and had engines I rebuilt from scratch run well and not fail.

     David

[dave1800]

Jul 30, 2021 14:42:50 GMT enigmas said:

The following info maybe of some assistance to you David.
Here are the current settings programmed into the module.

Timing (Static. Locked Distributor)
10° BTDC.

Load Setting
Min Load 37
Max load 147

Settings Mode Data
Stroke 4
Cylinders 8

Set Min RPM
600 rpm
RPM/Site 400 rpm
Max rpm 4600 rpm

Set Min Load
37

Set Max Load
147

Set Maps
2(11x11)

Set Resolution
.5°

Set Response to Low RPM
800 rpm
(A setting at idle speed is ideal according to John Clarke)

Set Dwell
4.7ms
(Lower settings cause misfire under load)

Set Edge
Low

Set Debounce
2.0ms

Set Knock
Off (knock sensor not added to the module)
Limit 4000 rpm

Set Interpolation
On

Set Oscillator
Off

OTHER
Coil Driver.
I have not mounted this close to the coil (as recommended) but close to the module under the PS parcel tray, interior of the car. Primarily to keep it away from heat and the hostile environment of the engine bay. No issues that I am aware off.

The Oscillator
Used when setting the dwell period for spark strength & intensity.
When in the on mode may cause the car's electronic tacho needle to bounce back and forth on the instrument. This is due to the oscillator pulsing the ignition coil.

Piranha Optical Trigger
The trigger will only function correctly with the module in the 'Low Edge' setting.


Vince, thank you this is helpful. I found the need to draw together all of the programming instructions into a more logical (for me) and structured menu format on a single sheet of A4 instead of darting around the text. Unfortunately the limitations of the PIC memory mean that John had to create programming procedures that require instructions to be read! I have issues with one of my cameras that has a weird menu structure that takes me a while to get to grips with it if not regularly used whereas I can pick up an other and it all falls into place immediately.  

I don't think that mounting the coil module inside the car away from the heat should pose any problems other than increasing electrical interference as long as it doesn't run next to the trigger connections which I see you are aware of from your annotation. Heat stress is definitely a major factor in component failures. I assume your ground connections for both modules are through the base plate? I don't think the text stresses the need for both units to have separate grounds to a single point on the body to avoid the supply to the program module being affected by the large current switching from the driver unit.  (I also prefer taking a separate power feed wire to the program unit from the one used to feed the coil to avoid high voltage spikes from being fed back as good practice).

 

David       

[enigmas]

Yeah, I agree with you about the module's programming instructions, because if it's not a regular activity, as it is initially during the setup period, then it's very easy to forget. It definitely moves to the recesses of my brain after a time. I keep a small folder of pertinent notes to aid memory recall rather than having to scour through the mass of information in the construction booklet.

As for power feeds/insulation and grounds I've always been diligent about these connections. Classic cars can be an electrical minefield due to aged looms and high resistances on connectors/switches.

Here's the 'Petrol Ignition Timing Map'.


I'm in the process of building an alternate petrol fueling system for this engine, so the MAP hasn't as yet been modified to deduct the 10° BTDC of initial static advance.

If the distributor was set to O° TDC there'd be no need to modify the petrol ignition MAP as written. I'll tweak it though when I fit the modified fueling system.

[dave1800]

Vince, having looked again at your settings I see that you had to increase the dwell to 4.7 m/s to avoid misfires under load. Was this only at lowish RPM? I am not familiar with your engine's original ignition system and my only experience with Piranha was with a very early unit dating back to the 1970s. I assume your Piranha (and original system) may have used variable dwell that decreased as the RPM increased (sometimes called constant energy) and allowed for longer dwell times when starting and at lower RPM.

If my calculations are correct with a 4.7m/s dwell on an 8 cylinder engine above around 3200 RPM the firing is curtailed by firing before the coil is fully charged. This shouldn't be an issue other than maybe the coil running hot.

David

 

[enigmas]

The ignition system on the P76 V8 harks back to 1973. It's a very basic single points system. I bought my then basket case MK3 Rover P5 coupe in 1990 when I was 38 and rebuilt and re-engined it with the P76 V8 over a 2 year period. One of the first electronic ignition kits I added was a points fired module also in kit form from Silicon Chip. Then the Piranha optical system was fitted which I used for over 20 years as the Rover was then my daily driver. The final ignition system for the car is the SC programmable module that still uses the Piranha optical trigger.

The reason for a move to an electronic trigger was due to a 6° variation in ignition timing cyl to cyl with the original points distributor.

And no, the engine doesn't miss under load or if I decide to get on the pedal a bit more than is required or legal. The early electronic kits had dwell extension built into them but certainly AFAIK didn't either decrease or increase dwell with rpm.

Automatics like a lot of advance just off idle with a properly setup motor and LPG fueled engines also prefer a strong spark moreso than petrol. The P5 is a heavy car and currently it's only running a 3 speed transmission and a tall, custom diff ratio (2.9:1)
The tall ratio would make it falter under load if the spark duration was insufficient. The way to optimise it for the particular car (weight/engine/trans combo) is to simply load the engine against the car's brakes until it falters, and then add more duration until it doesn't. And no, the coil doesn't run hot. Coils tend to run hot when they're fed too high a voltage for too long. A lot of enthusiasts who decide to instal an electronic module tend to cook both the coil and module because little attention is paid to rising voltage being delivered to these units. It's always worthwhile taking the engine up to cruise RPMs and then checking the voltage output.

That's where a lot of still inconclusive science doesn't match real world practical experiences David.

[dave1800]

It would be interesting to see your petrol map if you have a copy handy. I am not thinking about the fuelling at this time mainly because of the siamese ports which really limit the option to single port injection. There are a few kits out there that can keep the installation looking similar to the SUs. Rover managed to modify the last of the classic Minis to run with MPI but details are sparse and many have failed trying to copy them. Way beyond my skills I am afraid.

I too have a history with electronic ignitions. The first I built was a capacitor discharge ignition back around 1972 described in the Wireless World Magazine that used a huge transformer and metal cased power transistors. It was a brute but worked well using the points. After that I had a pre-built Sparkrite CDI and then an early Piranha. My next was a slimmed down version of the first that I made around 1979 and this lasted more than a decade before finally giving up without warning in heavy traffic but it wasn't dark or raining! As it was also points based conversion to the standard ignition only took a minute.

Now I am retired I have rekindled my interest in electronics that was mostly parked due to work pressures and that is helping me to keep my brain and hands active. It gives me the opportunity to mix with my interests in cars.

In think the dwell from your programmable unit is probably greater after around 3000 RPM than it was with the points but conversely less at lower rpm. If the coil is not getting hot and the engine is not misfiring that is your real evidence of what is really happening under the bonnet rather than theoretical calculations! One thing I have learned is that the quickest way to destroy an electronic ignition unit is to have badly maintained plugs and plug leads. Any increase in resistance allows the coil (primary) output to rise and weaken the output transistor whether it is an BJT such as in the SC or a more modern IGBT.  I shudder when I ses videos of garage mechanics pulling off the plug leads to check for a spark knowing this will have weakened the system and the damage is cumulative. 
                    
David

[enigmas]

PM me your email David and I'll forward you the petrol map file. Have you finished building the ignition module?

You might find this link of interest. The designer has developed several components to modify SU or CD Zenith Stromberg carbs (on a range of classic cars) to take a throttle body injector whilst maintaining the look of the original fueling system. There is also software and hardware available for all the systems on offer. The original carb setups become fully functional Efi.

Patton Machine
www.pattonmachine.com/TBI-Main.htm







Customer's Cars fitted with Patton's Efi System 
www.pattonmachine.com/TBI-Customer-Cars.htm

[dave1800]

Thanks, I've sent you a PM (note the odd spelling of my email name). 

I have seen something similar to the EFI system you posted and it looks well designed. Although I have a keen interest in electronics I also believe in the keep it simple philosophy. Undoubtedly there would be improvements in engine smoothness, flexibility, economy and compensation for temperature and barometric pressure etc but there is something I find enjoyable about being able to tune a carb and pull out a choke knob when starting from cold. I also value the thought of being able to revert to the mechanical system at the roadside.  

My other vehicles are computers on wheels and there is a limit to what I can sort out with a code reader without purchasing test equipment costing huge sums of money - although problems often still relate to poor grounds and connectors.

To answer your question, I built a couple of the Jaycar units around five years ago but need to better understand the limitations before finalising modifications to run off crank sensors with no distributor. I will contact John after the weekend.

David     

       

[enigmas]

Update 26/08/2022_Adding a Petrol Ignition Map

For those readers of the forum who haven't seen this thread. My Mk3 P5 Coupe (fitted with a Leyland P76 V8) has a programmable ignition module fitted to it. This module allows for 2 ignition maps to be utilized. One for LPG the other for Petrol. Over the last few days I've been modifying/programming a petrol ignition advance map for the coupe. I've primarily run the car on LPG for over 30 years and never really bothered with petrol. The engine runs high compression (11:1) so designing a suitable ignition advance for the various petrol octanes is required. I'm setting it up to run on 91 which is the lowest octane. If it pings or detonates at any point I can knock off a few degrees of advance at any rpm or load point.

This is the Programmable Ignition Module mounted on the PS with the Programmer currently attached.


This is the Ignition map for Petrol. For the nerds here you may note that the advance has negative numbers initially. This is done as the distributor is set and locked at 10 degrees BTDC of static advance. The module then subtracts the difference to where I want it at a particular rpm & load point to correct the timing. It's not as confusing as it sounds.


This is the LPG Ignition Map. Add 10 degrees to every number for actual advance as the distributor is locked at 10 BTDC initial static timing.
* The reason for this is that I found it is easier for the module to add 10 degrees to each timing number rather than 20 degrees.


To clarify the differences

Initial Timing Advance for:

Petrol is 5 degrees BTDC

LPG is 16 degrees BTDC.

[enigmas]

A Quick Update. After some initial struggles, primarily with a carburettor that hadn't seen liquid fuel literally in years, the coupe's now up and running as a dual fuel vehicle. I put a fresh gasket kit through the carburettor (currently the original P76 V8 Stromberg WW dual throat carb) and reset the float height, which was too low.

Interestingly, the engine sounds quite a bit different running on Petrol than it does on LPG. I start it on LPG, warm the engine and then switch it to petrol. Flick on the toggle switch (on the binnacle) that activates the Facet petrol pump wait 5-10 secs, pump the throttle twice (the twin throat Stromberg has accelerator pump jets, then crank over the engine with the throttle open a tad, and the engine fires into life.

Wben I want it back on LPG,I switch the pump off, the carb fuel bowl drains and the engine dies. I then flick the ignition module switch back to LPG, crank the engine, and it fires into life.

A comparison of both fuels.

LPG is a very smooth running fuel that doesn't require a choke on cold mornings.
Petrol produces slightly more power and over time greater engine wear.

[Phil Nottingham]

LPG is disappearing fast in the UK - we will await your electric conversion ready for when petrol is withdrawn

[enigmas]

I'll never go there Phil. It's a souless form of motivation, and frankly it makes litte sense. There needs to be diversity in energy much like any astute financial manager would advise when dealing with your investment portfolio. Can you imagine the military going fully electric, realizing how vulnerable that would make them. And of course limitless electricity is heaven sent and the batteries aren't toxic are they? Me thinks they're not biodegradable. 😉

It's a brave new woke world and frankly one I'm glad I wasn't born into.
Nothing is set in stone yet Phil, we're just buried under propaganda. Several of the largest car manufacturers in the world still aren't committed to full electric vehicles. There are still alternate clean forms of energy being investigated.

[Ken Nelson]

I agree with you Vince. Electric car batteries need lithium and nickel and both of these minerals are appearing to face a significant shortage in the near future, and producing the energy to charge all these batteries at homes is going to put an even greater demand on our energy grids which are already overstressed. Plus the worry about other countries turning off our electric cars with wireless technology hacking means I'm leaving my old cars running on gas as long as I can, or until some truly good solution comes along.

[Phil Nottingham]

Sept 1, 2022 10:06:41 GMT enigmas said:

I'll never go there Phil. It's a souless form of motivation, and frankly it makes litte sense. There needs to be diversity in energy much like any astute financial manager would advise when dealing with your investment portfolio. Can you imagine the military going fully electric, realizing how vulnerable that would make them. And of course limitless electricity is heaven sent and the batteries aren't toxic are they? Me thinks they're not biodegradable. 😉

It's a brave new woke world and frankly one I'm glad I wasn't born into.
Nothing is set in stone yet Phil, we're just buried under propaganda. Several of the largest car manufacturers in the world still aren't committed to full electric vehicles. There are still alternate clean forms of energy being investigated.

I entirely agree - some electric cars in the IK now cost more than their diesel equivalent in running costs given the hikes in electricity costs now and in the future. This is irrespective of the lack infrastructure to power public and home charging

[charlie]

Next it will be get them out of the battery cars and into hydrogen cars when you have spent thousands, I don't think I'll be around for that to bother me and the government won't get me out of electric because I'll never be in one. I'm trying to find post I saw on Tesla forum to post link where in the real world a fella says it takes 22 hours for a full charge[charging at home] and the percentage it loses overnight [which he is moaning that he has paid for electric and lost it] also said he left car in is garage on full charge went abroad for 3 weeks got back and battery was near flat.
www.carwow.co.uk/blog/hydrogen-vs-electric-cars

[enigmas]

Another interesting fact that's not being advertised with the purchase of Tesla or other brand electric cars has to do with battery life. Apparently Tesla batteries shouldn't be ideally charged to more than 80% of capacity or rundown to less than 20% of capacity as doing so markedly reduces battery life. Preserving battery life means the battery's range is down to 60% of it's full charge capacity.

As an aside, can you imagine the second hand market or purchasing a 6-10 year old Tesla. Replacement batteries cost more than the car.

[charlie]

Someone else mentioned Tesla, www.thesun.co.uk/news/19833153/one-bonus-of-microchip-crisis-teslas-dont-start/

[charlie]

Shortage of lithium for car battery's, manufacture's are switching to hydrogen fuel cell.
www.express.co.uk/life-style/cars/1672206/electric-cars-lithium-charging-concerns-hydrogen-fuel-cell-development/amp#amp_tf=From%20%251%24s&aoh=16639381910673&csi=0&referrer=https%3A%2F%2Fwww.google.com

[charlie]

This took me back to the late seventies when it was VHS v BETAMAX
Click on the two related links, Are electric cars really eco friendly? How long does a electric car battery last? What happens at disposal and recycling? youmatter.world/en/hydrogen-electric-cars-sustainability-28156/

[Jens Munk]

Hasn't this thread run slightly off topic?

[charlie]

Sept 2, 2022 15:08:01 GMT Phil Nottingham said:

Sept 1, 2022 10:06:41 GMT enigmas said:

I'll never go there Phil. It's a souless form of motivation, and frankly it makes litte sense. There needs to be diversity in energy much like any astute financial manager would advise when dealing with your investment portfolio. Can you imagine the military going fully electric, realizing how vulnerable that would make them. And of course limitless electricity is heaven sent and the batteries aren't toxic are they? Me thinks they're not biodegradable. 😉

It's a brave new woke world and frankly one I'm glad I wasn't born into.
Nothing is set in stone yet Phil, we're just buried under propaganda. Several of the largest car manufacturers in the world still aren't committed to full electric vehicles. There are still alternate clean forms of energy being investigated.

I entirely agree - some electric cars in the IK now cost more than their diesel equivalent in running costs given the hikes in electricity costs now and in the future. This is irrespective of the lack infrastructure to power public and home charging

Spot on Phil, www.honestjohn.co.uk/askhj/answer/174351/is-it-cheaper-to-charge-a-phev-or-run-it-on-petrol-