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Updated coil for 3.9 V8 ?


DC_
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So after discovering today that my coil is a goner. A mate recommended thinking about an uprated coil to give a better spark as I also run on LPG.

Can someone shine a light on where to get an uprated coil and if there may be other issues with replacing the normal one?

:)

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I'd suggest getting a spark mp instead, if you run a dizzy. RPI's do one that boosts your spark, and alters your timing so as to be optimum for both fuels. I've been told by a few different LPG tuners/fitters etc that the uprated coil is trouble in a can, and it's better to stick to a standard coil, with good leads and a spark amp.

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I'm not sure if this is true but I have read this on several sites: "the voltage at the coil will climb until the spark plug electrode 'arcs' at that point the voltage will be the voltage that the coil needs to produce. Therefore a standard coil will be delivering the same voltage as a coil that has the potential to deliver a larger voltage"

Its appears that its only if you increase the plug gap or raise the compression that a higher voltage will be required for the electrode to 'arc'. If the engine is standard, then a higher voltage coil will make no difference?

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Ahh right. :)

got a Bosch one in it now and does seem to be running a but stronger and firing better.

Think I'll get another one as back up just incase.

Cheers for the info :)

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A silly coil will burn your points or ignition amp out - check the GM ignition amp upgrade instead.

A big coil will create a bigger back EMF, the breakdown voltage for the spark to form will be the same as SteveRK points out, but the stored energy will be greater so the spark will be fatter and more reliable.

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In my HUMBLE opinion - run a standard coil for now, but instead of getting a spare* - go Megajolt...

Roger

*Maybe I have been lucky but I have only had one coil fail in 40 years of driving - if I carried spares for things that reliable I'd be towing a whole car behind me for backup!

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Thanks for the info.

I like the way you casually say get megajolt :)

the reason for the "spare" is that the one that's in it just now was taken from a disco 1 in a breakers yard :)

So maybe spare was the wrong word, :)

looks like I've got some Reading to do to get a better understanding of upgrading.

Cheers

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Just some research needed then? How much would the system cost etc?

It's a while since I did mine, but I think that £250 should see it through if you source some bits from the scrappy, and already have a laptop for tuning - you will then have totally waterproof ignition with dual advance maps (one for LPG and one for petrol) which produces HUGE sparks.

Off the top of my head you will need:

Coilpacks (x2 Ford Mondeo - scrappy)

EDIS controller (I got mine from American ebay, but there are now local suppliers - some on this forum)

Trigger wheel (Personally I use the Transit one, but others are available)

Sensor (scrappy)

MegaJolt kit

Wires and connectors

HT Leads - you can get them made-t-measure from Fastlane Auto - excellent quality and service and reasonable prices (no connection)

Various brackets (self build)

There is a load of information on the MJ site.

As was said earlier, you can buy and fit the bits in dribs and drabs until the system is complete while still running on the old coil and dizzy setup, then when you are ready you just swap a couple of wires and the HT leads and Bobs your uncle. Then just carry the old HT leads for a few weeks until you gain confidence.

Go for it - you know you want to :)

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I do really want to but not feeling confident on doing it :)

I'll have a good read through the MJ site to find out in more detail what I would need etc.

Coils from any year of mondeo etc or worth getting new ones for reliability reasons etc.

Sensors??

Types of wire.

I'll try get my head round it :)

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If you're feeling really adventurous you can do the same thing with megasquirt, start with ignition-only as described then when that's up and running swap the fuel injector wires over.

With an LPG system already installed and (presumably) being the main fuel - is it worth it ?

DC_, Reading the MJ site is good, but for LR specific stuff there is plenty of help available right here - several of us on this site have Jolted V8s - I am on my second. IMHO the best thing would be to start a "Jolting my V8" thread and ask the questions as you come to them and they will be answered. It's just that writing a complete essay on the whole task (including bill of materials) is a bit time consuming and would only give one man's view anyway.

Cheers

Roger

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Many many thanks for the input. Fridge you try to make my head spin round and round? :D

I think I'll have a good read through the stuff I need to so I can grasp in my own head what needs to be done. A thread is a great idea and I could see that benefiting others in my position who are considering the same option.

Benefits from jolting then? Reliability ? Waterproofing? Satisfaction?

Am I right in thinking the megasquirt would control the LPG more efficently withless chance of backfires etc?

At least now I know I have some Reading to do while the keek is on the TV at the weekend :)

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Roger, do you know of any pics available to view for the MJ ?

If I see pics I can get my head round these things better.

Locations for wiring, HT leads, EDIS controller, and coil packs?

Would be good to have an idea

:)

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Roger, do you know of any pics available to view for the MJ ?

If I see pics I can get my head round these things better.

Locations for wiring, HT leads, EDIS controller, and coil packs?

Would be good to have an idea

:)

There is a cracking MJ thread here and my not-so-good attempt here (using the transit trigger-wheel).

Locations of coilpacks etc are often the same for MS as MJ so you can look at MS threads here and here too for ideas.

Enjoy!

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I tried to upload a file with useful MJ info, but I don't have permission, so I'll try be another route...

I don't know if this will work, but if it does then it should open up my crib sheet which I printed out for future reference when I installed MJ.. (it works for me)

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