Lucas ignition amplifier replacement by Bosch 024

Here's the history! Just built a new 4.2 engine for the 1978 two door,thats another post some time,and all was well.
Doing about 80k around some back roads on a break in engine run,no warning,total engine fail,radio,all dash lights,electrics and steering..whoo!! pulled onto verge luckily no one behind me.
If that was on the motorway might not have been quite as relaxed..
3 year old rugrat pipes up from the back seat "Oh dear,Wange Wover is dead,,you fix it?"

Ok,'don't panic ,don't panic'.. as corporal jones used to say

Turned key off,then back on,all lights returned and it started with some thought..
30 km later about 1/2 a click from house,shutdown again.

OK,hot engine,new build..fuel/ air /spark?

Kinda knew the history on rover ignition modules,so had a chinese lucas one spare,swapped it over,and carried on.
Next long run,it did the same after about 50km ,no warning just engine failure and forced landing practice,pick a paddock..

Had the fuel air mix on the 14cux dialled in,so gotta be lectricity,and by luck found Bee Utey's magic post,,would still be floundering in lucas evil darklands,if it wasn't for his sharing the knowledge,big ups :):)
Great gems from other contributors too helped fine tune ,cheers.

Set up was Britpart distributor,(don't start;0) with attached britpart ignition amp on side.
Standard Lucas sport db coil.
Newly installed Kingsborne 8mm Lead set
(check them out,really very high quality,beat magnecor in my book,and way cheaper.great email comms from the company,and even negotiated cheaper snail freight from the usa.they have fully made up rover v8 sets and they click fit great,no leakage at all with the lights out,superb)

The ignition amp overheating coincided with the change over to these excellent leads,is there any thoughts why better leads might cause the thing to melt? or maybe i was doing longer runs,hotter around the module for longer?

Followed instructions,slowly as lectriks not my forte'
Ruined the nasty cheap connectors in the blue rubber side sleeve so re crimped better ones attached to the jaycar 2.8mm spades with a small solder dab over both to stop them potentially losing contact as was suggested.
The thought being,i can still get them off if i change the distributor.

Used a standard bosch coil i had lying around,likely oem for disco 1/late classic.
Slightly blown away ,1) I hadn't fried anything,it started 2) how well this made the car go,mid range torque improved and as someone earlier mentioned hillclimbs with ease,wow.

May contemplate installing a MEC717/723 improve that lean mix burn,even better torque,thoughts?

Slight erratic tach (off the coil )at low rpm,so had two goes at closing the air gap on the **** blitpart dist,down to .002inch approx with solid steady ish idle,barely a blip.

Many long runs since,not a hint of shutdown,and placed on the wing,that coil and module stay cool to touch,nice.This is a must do..

It's important to realise that the original ignition module is designed to be used with high resistance carbon cored leads of the day, not these fancy new and "better" inductive cored leads. Resistive leads work by dissipating the peak current flow as heat which is lost from the leads never to be of any further use. Inductive core leads work partly by storing some of the peak energy in the lead's internal magnetic field, within the spiral wound core of the lead. This energy is returned to the system after the peak has passed. Back EMF from the coil primary is then fed back to the switching module's transistor, creating added heat where it was never designed to come. The Bosch module is simply better suited to handling increased currents due to it being used with much higher powered coils than those used on stock Land Rovers. As for a LRV8, the later Bosch OEM coil seems to be entirely adequate for the job, so replacing it wouldn't be my highest priority.

Here endeth the lesson. [biggrin]

The bosch ignition setup runs great,i had a slight idle miss that i was chasing.
It's not the bosch setup wiring as i reinstated the original config and the occassional blip/miss at idle was still there,so the cause is elsewhere.Will chase that later.
I had a few old ignition amps laying around from years gone by,so thought to build a 'dummy module' that would let me use the standard lead that comes with later model disco 1 /late range rover classic with the remote ignition amp,and hook it into the bosch setup.

The remote kits are available,but very expensive for what you get..

Had been to a local wrecker for the remote plate,and found a lead that had the right connector to fit on top of the dummy amp.

First ignition amp was an ancient original,and i sort of butchered it trying to get the white plastic plate off,wrong side to attack..
Second one was a britpart special,dremell cut an edge under the 'metal plate side' and the plate lifts up with a broad flathead screwdriver.

Observations: The original is chocka full of nice circuits and wires and a gloopy clear liquid.
The britpart one had barely anything in it,and only a ''thin coating'' of the circuit board with a white heatpaste silicon ,no wonder they cook..

Warning:I did recall a warning not to touch the liquid that seeps from leaking ignition amps ages ago.
An early manual states the originals have beryllium in them,this is highly toxic,so gloves a must,long sleeves to avoid skin contact,maybe the full ghostbusters kit to remove the slime.
I presume the beryllium is in the gloopy heat transfer gel, so dispose of it responsibly.

I used the nearly empty britpart shell,took the same precautons,but very little of anything in these ones.

Used a wire to the cars battery pos+ and tested which pins fed which tab with the voltmeter.
Then looked at the wire colours on the lead that plugs into the top of the ignition module that runs to the BIM024 .
I wanted to have it so red went to #3 and black to #7.
Drew a quick sketch on paper which pin led to which tab,as too hard for braincell to remember.
Quick messy micro solder job,only cos i'm crap;)

Silicone the edge of the now open plate side dummy module to waterproof it ,reattach it to the distributor.
Module is screwed solid back on the heatplate so now you have standard wire connection via the blue rubber sleeve,,with removable lead plug.Just another option.

on the distributor are two pins to the magnetic pickup; is the left or the righthand pin negative/ earth?

Quote:

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Originally Posted by onno wielinga

on the distributor are two pins to the magnetic pickup; is the left or the righthand pin negative/ earth?

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Neither terminal is negative or earth. The output of the pickup is alternating current and what matters is the polarity of the current at the triggering point. I haven't run an oscilloscope to determine which way the current goes at this point as this knowledge isn't needed to get it to work. There are only two ways to connect the pickup after all.

So I completed this conversion about 12 months ago on my Rover SD1... works great when cold, but once the car has warmed up (approx 10 mins) it starts dropping spark randomly at idle. Maybe a blip every 1-3 seconds which doesn't happen when cold.

Any ideas?

Cheers,

Tom

Quote:

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Originally Posted by psoma

So I completed this conversion about 12 months ago on my Rover SD1... works great when cold, but once the car has warmed up (approx 10 mins) it starts dropping spark randomly at idle. Maybe a blip every 1-3 seconds which doesn't happen when cold.

Any ideas?

Cheers,

Tom

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I'd be checking the clearance of the pickup to the rotor and tightening it up by a bee's dick. Cold idle is often faster than hot idle. Then go around and check that every connection is completely clean and tight.

Thanks bee utey.

I’m actually running an aftermarket ECU without idle control so my idle speed is actually lower (700rpm) than when warm (1000rpm). I will recheck my connections but is there a chance this thing is overheating even in under 10 mins?

Cheers,

Tom

Quote:

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Originally Posted by psoma

Thanks bee utey.

I’m actually running an aftermarket ECU without idle control so my idle speed is actually lower (700rpm) than when warm (1000rpm). I will recheck my connections but is there a chance this thing is overheating even in under 10 mins?

Cheers,

Tom

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Possibly. Your heat sink must be big enough, and the white paste applied thickly enough to take the heat out of the module. I've seen plenty of dodgy versions of this conversion done by other people who use things like tiny scraps of stainless steel, no paste or low quality crimp connectors. However, my guess is still on slightly loose or dirty power connections.

Quote:

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Originally Posted by BigJon

Couple of photos of the conversion I did today. This is 96 Disco ignition, although it is fitted to my 87 RRC.

I reused the original wiring where possible. You can see where the distributor blue and red wires have to connect to the new module.

Ignition timing was still OK, test drive to come.

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8 years later and still working perfectly.