Ignition Amplifier

[dooley1414]

Hi everyone.... is there anyone out there that has had the same problem I am with their Ignition Amplifier?

Sometimes when I start my 'e'.... she wont even try to spark and start up? but if I give the Amp. a little tap on the top and then turn her over.... she will fire into life?

Is there anyone that knows if you can buy just a NEW amp. on it's own.... I have been looking but can only find the whole system (dizzy.... coil.... amp. and ballast resistor).

Any help or recommendations would be most helpful.

Des.

[AussieEtype]

Sounds like you have a dry joint on the circuit board and when you tap it contact is then made.

These have always been problematic and I am sure you can get replacements by themselves (not sure where) but maybe time to upgrade to more modern replacements that are now available.

Garry

[lowact]

These (Lucas AB3) amplifiers are a cinch to repair. But 1st check for cracked, broken or loose wires. Even though it is (for now) fixed by tapping the amp, also check the wire connections to both sides of the resistor. Give them a firm tug, if they break, there’s the problem?
If u do decide to upgrade yr ignition, be aware that only by changing to vacuum advance system will there be noticeable improvement in performance/efficiency.

[dooley1414]

Ok Thanks all.... If they are a Cinch to repair.... what do I need to do.... Many Thanks In Advance.... Des.

[42south]

Hi Des
If it is the original amplifier OPUS, probably still in the valley, or maybe shifted to the front rail, then don't waste your time fixing it, replace it with the later HEI amp and dizzy as fitted to the later V12's These can be sourced from wreckers. The OPUS is notoriously unreliable, and prone to failures.
That package you refer to is probably the one available from SNG? If so it may look expensive but don't forget that you get money back for your old amp and distributor from SNG when you buy the package.
A new amp,coil, distributor, and ballast will get rid of a whole lot of reliability issues for you. Also will give a much better spark with better cold and hot starting.
regards
Mark

[dooley1414]

Hi Mark.... yes I think I'll be going that way.... changing everything and getting one from SNG.... Saving a lot of hassle it seems.... Des.

[lowact]

My understanding, the SNGB offering, you DON’T get the later HE (CEI) distributor. The CEI distributor uses vacuum advance. The SNGB offering gives you the same distributor that you currently have ???
Imo it is a lot of money to pay if the problem is only a cracked wire? Yes it would address hot start issues, but that is not yr problem? Hot start issues were due to the amp being mounted in the valley. You have Texas import, the amp will be mounted on the front cross-rail, this should not have hot start issues?
To fix the Opus; 1st ascertain that the problem is not the wiring that is external to the amp. 99% of the time it is. The amp is easily disassembled, inside is a simple circuit board with standard, colour-coded, components. Easy to check each and continuity with a multimeter. With mine I couldn’t find anything wrong. Didn’t trust myself so I took it down to the local electronics shop, asked them to give it the once over. They said everything checked out ok; but qualified this by saying that results could be temperature dependent. This would not be your problem, seeing as how yr problem is when the car is cold and because it behaves for a bit after you’ve hit it ☹ So if the problem is internal to the amp, it is likely as Garry said, a dry joint, quick touch with a soldering iron should fix this. In my case the problem was cracked wires at the terminals connecting to the ignition switch side of the ballast resistor. Won’t be yr immediate problem but these are wires from the ignition and starter motor solenoids (the latter redundant with CEI ignition) that will need to be renewed regardless of what ignition you end up using. With the Opus system, the arrangement of the wiring connecting the amp, distributor and ballast resistor is important. This wiring is long, folded back on itself and firmly clamped. Shortening reportedly causes issues. If it is not clamped to prevent flexing, over time the wiring can fatigue and crack, just needs to be renewed with the same size/length.
If after checking the wiring the problem is not resolved, I would do as Mark says, getting a full CEI ignition system from wreckers, including distributor. I’d then send the distributor together with my left hand rear carburetor off to British Vacuum Unit (https://www.britishvacuumunit.com/) for them to refurb the distributor, fit the appropriate vacuum unit for a V12E, drill/fit a throttle-edge tapping for vacuum advance onto yr carb (a service they perform for GBP 25).

[Woolfi]

In my car is the modern AB14 ignition amp plus a distributor from a HE-motor plus a drilling at one carb for the CORRECT vaccuum from a "tappered edge" piont to a advance capsule.
Result: no problems since 12 years with the ignition and a lower gas consumption at part throttle.
Regards Wolfgang Gatza

[42south]

Hi guys
The amp from SNG does use the HEI chip the same as in the later cars, and the distributor is rebuilt to HEI spec, but with a vacuum module as per the original system.
It’s easy to change to a vacuum advance module at a later stage. British vacuum can supply suitable ones.
I can vouch for British vacuum, they drilled a carb for me, and supplied the advance module.
If you buy a second hand distributor, get it rebuilt as most have a frozen mechanical advance.
Cheers
Mark

[lowact]

Mark, so you did change your SNGB distributor from vacuum retard to vacuum advance? Exactly what was involved? The retard unit sucks the pick-up anti-clockwise against springs. The advance unit needs to suck it in the opposite direction, clockwise (against opposite springs)? I'm imagining there would be a fair bit involved I'm making this happen, that it would be easier to get a proper CEI distributor?

[42south]

Hi Colin
I’m not sure what’s involved, mine was fitted by British vacuum when they drilled my carb as well.
British vacuum are very user friendly and will answer any queries.
Their website is a mine of useful info on vacuum advance modules, and distributor numbers etc.
Cheers
Mark

[baganz.sven@web.de]

My SNG replacement system has the vacuum the vacuum port on the same side like the original one.
So I think it will fit and have the correct functionality.
Sven

[42south]

Whilst your in the ignition mode.
I fitted the sng kit and ran it quite a while with no issues. Then I started getting moisture or vapour buildup in the distributor cap, leading to missing.
Jaguar had issues with distributor caps exploding due vapour leaking into the cap, through the distributor.
So I fitted the vented distributor cap as fitted to later v12 s and the xjs, since then the cap has remained dry internally, no more missing.
It’s available through the usuals.
Cheers
Mark

[Curt]

Colin L. You stated the Ab3 amplifier is easy to rebuild could you share how it is done in detail.
Thank you in advance.
Curt
1971 XKE V 12

[lowact]

Hello Curt, just noticed yr question, i think it is answered by my #7 above? Otherwise, I have perfectly funtioning ab3 for cost of the postage, pm if u want it ...