DIR Return Create A Forum - Home
---------------------------------------------------------
Old Leafsprung Land Rovers
HTML https://ollr.createaforum.com
---------------------------------------------------------
*****************************************************
DIR Return to: Technical Archive
*****************************************************
#Post#: 3622--------------------------------------------------
KWD's Megajolt Ignition
By: Goose Date: January 12, 2012, 2:17 am
---------------------------------------------------------
So, after being inspired by OTLY, ex of this parish, this is a
conversion I have been meaning to do for some time, but i'm only
just getting round to it. I aim to keep a record of the
instalation, and the results here. This will be going onto my
2.5 petrol engine, which is running a 2.25 timing cover etc.
What is it? Well, as some of you will know, there is a another
type of fuel available, other than diesel. It's called Petrol,
because it's made from refined pets. This type of fuel
requires electricty to make sparks, in order for it to explode
at the right time and produce power. Making this spark happen at
the correct time, is really rather difficult, and in the old
days they used a device called a dizzytributer. This device is
full of points, condensors, rotor arms and centrifugal weights
and advances. In the olden days they were accepted as being
adequate. Alas, these days they seem to be made from cheese,
and wear out and break often. Yes, a good one is fine for a land
rover engine, but I suspect there should be a bit more power and
economy to be had from having a stronger, more precise and
accuratly timed spark.
As my dizzy is a useless peice of badly made shite, I have
decided to retrofit the ignition system off of an old 1990's
ford. This ford system is called an EDIS system, which stands
for a string of pretty dull words. It does away with the
distributor entirely, and instead it has a magnetic pickup
mounted to the crank pulley. This sensor reads the position of
the crank using a toothed wheel, which is designed with one
tooth missing. As the teeth pass by the sensor, something
called the Hall effect (After it's discover, the Emeritus
Professor of Engineering DaveH). What this means is, that as the
teeth pass the sensor, a electrical pulse happens. This pulse
is fed into some electronics, and then lots of magic happens,
which I won't bore you with, and sparks happen in the correct
places. This also means that you no longer have any mechanical
slop and wear between the crank, camshaft and dizzy drive to
worry about.
The Megajolt itself, is a tiny programable box, that interfaces
with the EDIS system, and allows you to create and customise
your own igniton maps, so you can very finely tune your petrol
engine, and get the most power and efficency out of it. It will
also allow you to select between 2 maps, so you can have one for
petrol and one for LPG. It does a multitute of other things too.
All of this means, that I will no longer need a distributor, and
I will no longer have to muck about with points and timing. But
"Hah!" I hear you say, "You've now got a load of complicated
electronics to go wrong instead, you fool!" Well, yes, I
suppose. But the actual system itself is pretty simple, and
there are no moving parts to go wrong. If the megajolt goes
wrong, then the EDIS system simply switches into "limp home"
mode and sets the timing to a static amount. And you can leave
the distributor in place, so you can always just swap the HT
leads over if you must, But I would hope the megajolt and EDIS
system should be far more reliable than the pants £19
distributors you can buy are.
I appreciate this system isn't for everyone, but electronics is
what I do, and I fancied the challenge, and I am keen to see if
there is any improvement, or if I'm about to waste a few weeks
of work. So if you're interested, read on....
The bits!
This is the basic EDIS system, as it is when ripped out of some
old Ford:
HTML http://i654.photobucket.com/albums/uu264/Goose76UK/Megajolt/IMG_2613.jpg
On the left, is the connector for the EDIS module, along with a
section of the required wiring loom. In the middle, the big
plastic brick thing is the EDIS module. On the right, is the
coil pack. This has 4 HT lead sockets, for each cylinder. At
the bottom is the "VR sensor" which is what reads the position
of the crank shaft.
HTML http://i654.photobucket.com/albums/uu264/Goose76UK/Megajolt/IMG_2615.jpg
A closer look at the VR sensor, it's just a plastic lump with a
magnet and a coil inside.
HTML http://i654.photobucket.com/albums/uu264/Goose76UK/Megajolt/IMG_2616.jpg
The EDIS connector. Starting at the left, we have 3 wires for
the coil pack and the tacho. The brown wire is ground, and the
black is +12v (Ford wiring colours are retarded) The next 2
blueish wires are for the VR sensor, and the rest go to the
megajolt.
Speaking of which,
HTML http://i654.photobucket.com/albums/uu264/Goose76UK/Megajolt/IMG_2619.jpg
Here is the wee beasty, all assembled. The thing that looks
like a phone socket is where you plug your laptop, and the other
thing is the vacuum advance from the manifold.
HTML http://i654.photobucket.com/albums/uu264/Goose76UK/Megajolt/IMG_2622.jpg
On the back is a complicated looking connector, that allows you
to interface with pretty much everything, and also connects to
the EDIS system (Although, you only acually need 2 wires
connected between the EDIS and megajolt)
Next, you need to mount the trigger wheel:
HTML http://i654.photobucket.com/albums/uu264/Goose76UK/Megajolt/IMG_2626.jpg
.... to the crank pulley:
HTML http://i654.photobucket.com/albums/uu264/Goose76UK/Megajolt/IMG_2625.jpg
I took my crank pulley to a chap called Bob, who is a very
clever man who is an automotive engineer. (Cheers FenTiger for
putting me in touch with him). Whilst we drank tea, and bob
regailed me with stories of making wooden pistons to get out of
the desert in Africa, he trued the pulley up on the lathe, and
spun a resess into it, to allow the toothed trigger wheel to fit
centrally, with mimimum run out. He did this all the old
fashioned way, and needless to say it fits perfectly. Top bloke.
HTML http://i654.photobucket.com/albums/uu264/Goose76UK/Megajolt/IMG_2629.jpg
HTML http://i654.photobucket.com/albums/uu264/Goose76UK/Megajolt/IMG_2632.jpg
Once I have worked out the correct position, this will be welded
on.
Next, I made up a rudimentary precision engineered bracket for
the VR sensor. This was made from a rusty old bit of steel
found in a skip, and bent into a right angle.
Trial fit on spare timing cover, shows it should work ok,
hopefully:
HTML http://i654.photobucket.com/albums/uu264/Goose76UK/Megajolt/IMG_2637.jpg
Conveniantly, there are 2 threaded holes on the timing cover,
which are pefect for mounting the sensor onto.
Thats all so far, I hope to get more done in the week!
So now you're all really enthused (or appalled) you'd maybe not
want to know where you can buy all these bits!
Well, eBay is where I bought the second hand EDIS system. You
want one thats still complete with the nice waterproof ford
connectors if possible, rather than one someones butchered with
side cutters.
The megajolt box is available from
HTML http://www.autosportlabs.net/Main_Page
HTML http://www.autosportlabs.net/Main_Page
Which is in America. You
can buy it as a kit form, or readily assembled for a bit more.
The trigger wheel is from
HTML http://trigger-wheels.com
HTML http://trigger-wheels.com
Who sell a wide range of wheels and
parts (including ready made megajolt boxes) I have used the
5.75" ring wheel.
I have yet to actually touch my land rover with this
instalation, as the timing cover was a spare, and the pulley was
a new one (my old one is wankered and leaking oil) from
craddocks. So the next job is to get that bastard crank bolt
undone, and get the existing timing cover (which is also fecked)
off my engine.
I'll keep you posted on my progress, and I hope at least some of
you were not bored to sleep...
:D
#Post#: 3623--------------------------------------------------
Re: KWD's Megajolt Ignition
By: Goose Date: January 12, 2012, 2:21 am
---------------------------------------------------------
No photos tonight, as I forgot the camera. But I got a few bits
done. The crank puley nut is off, using the wedge a bar on the
chassis and blip the starter motor trick.
I also made up a vacuum take off from the manifold, as the
megajolt requires direct manifold pressure, rather than ported
manifold pressure, which is what you get from the standard
vacuum advance when taken from the carb. As described on the
megajolt website:
[quote]Most vacuum advance takeoff ports are designed in such a
way that vacuum is measured through a hole, which is actually
covered by the edge of the throttle plate at idle. That is
called Ported Vacuum. That is done to cut off all vacuum advance
at idle, which in turn slows the engine and makes it easier to
achieve stable idle with the tiny throttle plate opening used at
idle. Vacuum measured on such a port, therefore, has no vacuum
at idle, moves to maximum vacuum just off idle, and then
decreasing vacuum as the throttle is opened further. The
discontinuity just off idle makes such a port awkward to deal
with on the load map.
You can test whether you have ported vacuum or not: pull the vac
hose off the vacuum advance unit. With your finger over the end
of the hose, you should feel vacuum with the engine revved above
idle. Assuming yes, let the engine speed drop back to idle. Is
there still vacuum? If not (most likely), that means you have
ported vacuum, and should find another source of vacuum,
somewhere on the manfold. [/quote]
So I have used the take off that would be used for a brake
servo. This should work perfectly.
Other stuff I have done is to paint the timing cover (yes... I
know..) and also start to work out where to locate the parts in
the engine bay. I also managed to brand myself with an M5 bolt
while cutting some down.
The plan is to get everything ready to fit, and then swap over
the pulley and timing cover in one go, without having to leave
the engine open and exposed to dust/rain/chickens/etc on the
farm.
I'll head down after work tomorrow and get a bit more done
hopefully.
#Post#: 3624--------------------------------------------------
Re: KWD's Megajolt Ignition
By: Goose Date: January 12, 2012, 2:21 am
---------------------------------------------------------
Tonight I mounted up the coil pack and EDIS module to the
bulkhead. I've mounted them up nice and high, in the hope they
stay dry. Having said that, all the connectors are supposedly
waterproof, so I am hopeful they should be better than your
normal dizzy in the wet.
HTML http://i654.photobucket.com/albums/uu264/Goose76UK/Megajolt/IMG_2639.jpg
No, i've not stuck it on with blue snot, that was just so I
could line up the holes to drill for the screws that hold it to
the bulkhead.
I also made a start at the wiring. The plan is to run all of
the wires into a plastic housing, where any connections will be.
The idea behind this is to keep water off the connections, and
to also neaten things up a bit. This is the box i'll be using:
HTML http://i654.photobucket.com/albums/uu264/Goose76UK/Megajolt/IMG_2641.jpg
I plan to mount the megajolt box inside the cab, in the dash
tray, to keep it safer from mud and shite. There are only a
couple of wires, and the vacuum advance to pass through the
bulkhead to the megajolt.
Vaccum advance, bodged out of bits of pipe. Works well enough:
HTML http://i654.photobucket.com/albums/uu264/Goose76UK/Megajolt/IMG_2640.jpg
I'll carry on with wring things up tommorow, and then come the
weekend I'll get on with swapping the timing cover over for the
new one.
Cheers!
#Post#: 3625--------------------------------------------------
Re: KWD's Megajolt Ignition
By: Goose Date: January 12, 2012, 2:23 am
---------------------------------------------------------
[quote]For the parts, what Ford's are we talking about - model /
year? [/quote]
These ones! And possibly others too.
So, EDIS-4 is for 4cyl engines, EDIS-6 is for 6 cyl (V or
straight), and EDIS-8 is for the V8 folks.
EDIS-4
gopher.createaforum.com:70 /forums/ollr/p/483:230: port field too long