Megajolt - the start of a saga?

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TwoSheds
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Joined: Thu Jan 18, 2007 8:01 pm
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Full Name: Roger Watkinson

Megajolt - the start of a saga?

Postby TwoSheds » Wed Nov 14, 2007 5:50 am

Introduction

I feel quite daunted starting this - after all I am standing on the shoulders of some pretty large giants in this forum, so what can little old (too old!) me bring to the party? Well I guess I can bring my noviciate status in many of the technologies and techniques that will be required for (hopefully) a successful assembly and installation of the Megajolt kit. I have spent may happy hours trawling through the incredibly detailed and helpful accounts of both Megajolt: http://www.autosportlabs.net/Main_Page and Megasquirt: http://www.bgsoflex.com/megasquirt.html installations on forums, and a load of web sites that I have found useful as well, and now I think I know enough to make start... Well, at least: I know what I know, and I know some of what I don't know, it's what I don't know I don't know that worries me, but that's why this is a bit of an adventure isn't it :)

Now some caveats:
    I do have a tendency to do things my own way so please don't be offended if you offer advice (which I hope you will) during the course of this ramble and I ignore it - it's just that sometimes I have to make my mistakes in my own way :(
    I am not in a hurry to get this done and this first part of The Plan (see below) I fully expect to take me until Christmas. So don't get your hopes up...
    I make no appology for the fact that this post is also in 'another place' - it's called code re-use and anyway I thought that some people on here who don't trawl other forums (fora?) might like to look at it...

So why I am doing it? After all I am on a very limited budget and the RRC's engine is not really up to much (a bit rattly and leaky) and there are 101 more sensible things that I could have spent the money and time on (if I was sensible..). Well I guess that the answer depends on who I am talking to:

a] SWMBO: "The original system was shot and replacement components are expensive" (This statement is technically correct, but the original system could have been re-instated for probably 1/3 of the cost of Megajolt)

b] Car-nut: a] and: "It enables running on LPG with a more correct advance curve, thus improving efficiency and saving the planet"

c] LR-nut: a] and b] and "It has well known multiple benefits, but it's mainly for it's improved wet-conditions running"

d] Hobbyist: a] and b] and c] and "It gives me a chance to experiment with new technologies and techniques"

e] The truth: a] and b] and c] and d] and "yes... ok... it's bling and I want one" :D

Stage One - The VR Sensor and Pulley Assembly

Remove crank-bolt
This was set to 280 ft-lbs at the factory 17 years ago and was expected to be a struggle... So it was first gear low box with the hand brake hard on and then:
First try was with the rattle-gun and impact socket.. Nothing :x
Next a breaker-bar on it with a copper mallet.. Nothing :x :x
Next a two foot extension on the breaker-bar - happily inched the rover along the drive... but move the bolt? Nah. :x :x :x
Having read about people who place the breaker bar on the OS chassis and then let rip with the starter so that the bar has a good swing before it hits the NS chassis, I sat and pondered this option for an hour or so... Didn't fancy having a breaker bar and socket flying off into the scenery, so finally discounted it. :(
Despairing now - back to the impact driver (apparently has a break-away torque of 500 ft-lbs IIRC) and this time I just ran it until the compressor cut in, gave it a rest and then when the compressor stopped again I repeated the cycle. After about eight or ten such cycles it came away! :D :D :D Lesson? Give the rattler a chance to work! ;)

Remove the plugs and set engine to TDC No 1
Not strictly necessary at this point but I thought that I might as well.

Remove the crank pulley
After checking that the keyway was near the top (I once dropped a woodruf key into the sump on my Series 1 years ago) I gave the pulley assembly a little tug and away it came :)

Remove timing pointer and trim back
The timing pointer needs to come off since it rides quite close to the harmonic balancer ('HB' from now on) so it will need trimming back a bit to clear the trigger wheel, and since it is plated with something and trimming will remove the plating, it will need painting too.

Lever off thrower
With the pulley assy on the bench I now levered off the inside thrower. This is very flimsy and is easily bent, but came off ok, although care was necessary not to bent the 'catcher' that it sits inside while levering away.

Remove 6 pulley assy bolts and remove the catcher
In my scheme, the Transit trigger wheel (Ford part number 1 078 767) is going to sit between the catcher and the hub of the HB with the tangs pointing forwards over the outer part of the HB

Drive out roll-pin (trigger wheel wont go on with it in place)
Actually it's only necessary to drive the pin flush with the HB hub and even then only because the trigger wheel won't go on with it there. Later (after timing the wheel) the internal dia of the trigger wheel (TW) will need filing to clear the roll pin.

Assemble the TW into the pulley assy
Lightly clamp the TW between balancer hub and catcher, true it up (I used my venerable old dial calipers) to the HB outer (which I assume is pretty centred) and position it back on the crank and check clearances. In my case I had a bolt head that was a bit close but nothing fouled. Checking around with the VR sensor showed that the only place it can really go is at 3 o'clock looking from the front. Conveniently there are two decent bolts available for mounting it's mounting bracket on at this position :)


Design/construct sensor bracket
Like most people I made the bracket out of a bit of right-angle bent metal which I fixed onto the front of the engine using the bolts previously mentioned. I positioned the bracket so that the part which will mount the VR sensor is vertical, then I found where to put the hole for the sensor by lining up a ruler with two of the cross-head screws that hold the crank oil-seal cover in place. In this manner I ensure (as far as possible) that the VRS would be radial to the axis of the crank. I marked and drilled for the snesor (two holes - one for the working part and one for the 6mm bolt that will hold it. Again - in common with most people I will use washers to position the sensor radially to get the correct clearence to the TW.


'Time' the trigger-wheel
Note: In the next bit I am always viewing from the front of the engine, the engine turns clockwise and No 1 is the nearest cylinder on the right hand bank (when viewed from the front remember!)
With the sensor and the crank pully assembly in place I checked again that No 1 was on TDC compression. Then I slackend the six pulley bolts a little and moved the TW around until the VR sensor was central to the fith tang after the gap in the TW (that is - the gap has already passed the sensor 50 degrees ago with the engine going clockwise) In summary, with No 1 on TDC (compression), the VR sensor is at 3pm and the gap is at just before 5pm (viewed from the front of the engine. Once checked again I then nipped up the six crank bolts to hold the TW still (it's not necessary to true up the wheel at this point)

File a clearance slot for the roll-pin
With the pulley asssy back on the bench I filed a small nick in the TW at the position of the TDC mark, then stripped the six bolts and catcher off, and marked where the roll-pin goes. The TW needs a small area filing in it's inner diameter at the roll-pin position to clear said pin. I didn't even try to make the notch a fit on the pin, but left a little clearence so that the TW would be able to move a little for fine tuning later.

And THAT is where I am at the moment. Still to come is:

Paint the bracket, TW and the timing pointer
Assemble bracket and timing pointer to engine
Assemble pulley assy to mark, true up and nip up tight. Insert the roll-pin.
Check run-out of TW and clearence to VRS. (less than .020" run-out and .040" clearance will be aimed for)
Remove the crank assy and pot the TW with Sikaflex.
Reassemble pulley assy to engine and do up crank-bolt (280ft-lbs!)
Mount and adjust sensor to just clear worst of run out ( by .020"?)
Temporarily wire up the EDIS system, turn the engine and watch the sparks light the night sky![/b] :D :D :D
Stage Two: Assembly of the Megajolt Kit (including extra circuit to drive the original ECU for the injection)
Stage Three: Mounting/Wiring/Assembly/Testing of the rest of the system
Easy Peasy!

TwoSheds

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davew
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Postby davew » Sat Nov 17, 2007 10:36 am

The one thing that constantly surprises me about Megasquirt is just how easy it is if you take a methodical approach. I'm about to do my 6th Megasquirt conversion, the biggest problem with Megasquirt is deciding which of the 1001 different options to use !

I have a 3.9 engine complete with toothed wheel and sensor, coil packs and the rest if anyone fancies giving it a go btw.

Are you running EFi ? If so, how are you going to simulate a single coil output for the EFi ECU ?

Personally I prefer Megaquirt over Megajolt with EDIS purely because it saves having to get hold of EDIS units and saves on the number of spare parts you need to carry. My original setup used EDIS but I wouldn't go that route again now Megasquirt has on-board wheel decoding and coil drivers.

I do have a couple of spare EDIS-8 units too.... though now I come to think of it, 1 of them might be Paul's....

TwoSheds
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Joined: Thu Jan 18, 2007 8:01 pm
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Full Name: Roger Watkinson

Postby TwoSheds » Sat Nov 17, 2007 11:43 am

davew wrote:The one thing that constantly surprises me about Megasquirt is just how easy it is if you take a methodical approach. I'm about to do my 6th Megasquirt conversion, the biggest problem with Megasquirt is deciding which of the 1001 different options to use !

I have a 3.9 engine complete with toothed wheel and sensor, coil packs and the rest if anyone fancies giving it a go btw.

Are you running EFi ? If so, how are you going to simulate a single coil output for the EFi ECU ?

Personally I prefer Megaquirt over Megajolt with EDIS purely because it saves having to get hold of EDIS units and saves on the number of spare parts you need to carry. My original setup used EDIS but I wouldn't go that route again now Megasquirt has on-board wheel decoding and coil drivers.

I do have a couple of spare EDIS-8 units too.... though now I come to think of it, 1 of them might be Paul's....

How much for the 3.9? (Got one anyway, but... Y'know :) )

How much for the spare EDIS-8? (Got one anyway, but... Y'know :) )

Got any spare coil packs? (Got two anyway, but... Y'know :) )

EDIS-8's are still plentiful and cheap in the US (£30 delivered)
Coil-packs are still plentiful (90's Mondeo) but getting expensive since scrappies are realising what they are being used for ;) (£25 for 2 with leads)
Trigger-wheel is still plentiful - new from Ford for £15 :D

I am mainly going to be running LPG which is why I thought it not worth going down the MS route. The original EFI ECU will still handle the injection when on petrol by virtue of a little circuit that picks up the fly-back voltage from all four coils through diodes and a zenner. It's an adaptation of the circuit on the MJ site that Fridge Freezer on LR4x4 said was suitable for the 3.9 ECU, and should give me the rev counter too I think.

TwoSheds

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davew
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Postby davew » Sat Nov 17, 2007 5:02 pm

No idea on the engine/spares etc... no reasonable offer refused.

I used Land Rover packs because I know exactly what vehicles they are fitted to and the HT leads don't use odd ball connectors. Originally I bought a set of Britpart HT leads that I used to get it up and running then changed to Magnecore leads and the Britpart leads went in the spares box.

I have 3 coil packs, 2 on the engine and 1 in the spares box.

I've has some problems getting some makes of rev counter to work at all regardless of the circuits I tried - never managed to get my TIM rev counter working since fitting MS. Tried every single circuit suggestion and a few of my own too. That may have been a quirk of the TIM rev counter though as the TD5 one I have now works fine.

repton
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Full Name: Paul Everett

Postby repton » Sat Nov 17, 2007 6:56 pm

davew wrote:I do have a couple of spare EDIS-8 units too.... though now I come to think of it, 1 of them might be Paul's....


I think you're right, I'll have the spare one back if it's no longer of any use to you, although as I'm not going to be at Greenhow tomorrow I'm not sure when we'll next be in the same place at the same time.

Paul


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