The V8 Owners Forum -

Does anybody know anything about the Aldon Amethyst mappable ignition ?

Website here: http://www.aldonamethyst.co.uk/

I ask because:

- I'm happy with carbs on my Land Rover 110 3.5 V8 (have just replaced k******ed Strombergs with brand new SU HIF44s)

- I've been considering going the MJ route to get better running overall and dual mapping for petrol & LPG

- I already have an Aldon Ignitor module replacing points in my distributor & the Amethyst is designed to work with it

- No need for a trigger wheel, coil packs, EDIS, etc (uses existing distributor & coil) so simpler to set up

- Not hugely fussed about ultimate waterproofing; I don't usually go wading or swimming

Amethyst seems pretty new on the block & I can't find many views of it online. The Ignitor module is good kit and has been 100% reliable for 7 years/50,000 miles now - so I'm tempted ! Downside is that there don't seem to be any V8 base maps yet - but not beyond the wit of man (or even me) to write some ?

Any thoughts ?

Cheers,

Nick

Big snag with that approach is you are triggering off the dizzy - including all the slop in the drive. A crank trigger wheel has non of that. If you lock the dizzy advance and map it electronically, you need to be very careful to phase up the rotor arm - as it no longer tracks with the trigger point. Which can be a pain on an 8 cylinder. And, of course, many ignition problems are caused by the rotor arm and cap.

The price also isn't a million miles off a MegaSquirt 1 V3. Which can be used ignition only, while giving you the option to go injection later.

DaveEFI wrote: , you need to be very careful to phase up the rotor arm - as it no longer tracks with the trigger point. Which can be a pain on an 8 cylinder.

Could you expand on this point ? Thanks

Raggylad wrote:

DaveEFI wrote: , you need to be very careful to phase up the rotor arm - as it no longer tracks with the trigger point. Which can be a pain on an 8 cylinder.

Could you expand on this point ? Thanks

The rotor arm moves relative to the dizzy shaft in sync with the advance mechanism. So is always at the same position relative to the plug lead contact when the spark occurs (apart from the influence of the vacuum unit)

If you lock the advance mechanism, and create the advance electronically, this is no longer the case. So you need to make sure the rotor arm is pointing at the correct plug lead contact when the spark occurs. On a four cylinder, this is quite easy to achieve. On an 8, it's more tricky as the contacts are much closer in degree terms.

It's not impossible to do - just one more reason to throw away that dizzy and do the job properly.

Hi
Having recently set up a trigger wheel and coil pack system using megasquirt I would venture that is is simpler and cheeper than using a locked distributor. The actual set up of the megasquirt is a bit of a hassel unless you enjoy wadeing through menus but once done it just works. Having forked out for 4 MSD twin post coils I have at $42 each and got them working I have since been told the pro-mod boys are using the current Fiesta 4 post coil packs with very good results, these are about £17 each off ebay and you don't have to import them! Quite honestly if you can use these on 10.5+ litre 11k rev methanol burning monsters making a several of thousand bhp then I recon its money well spent. As I have found if you remember to put your trigger wheel back on the engine the right way round then the system is fit and forget.
Total for the bits
trigger wheel £19
two fiesta coil packs £34
crank sensor £20
Total £73
Add to that whatever ECU you want and off you go
Best regards
Mike

Raggylad wrote:

DaveEFI wrote: , you need to be very careful to phase up the rotor arm - as it no longer tracks with the trigger point. Which can be a pain on an 8 cylinder.

Could you expand on this point ? Thanks

Using a modified cap with a big hole in the side helps illustrate the problem:


From my notes when i went over to squirt and spark:
http://www.mez.co.uk/ms9.html

Which was followed shortly later with a full EDIS setup which is a solid performer and gives a massive spark.

Yup - when I played with this I cut a hole in a spare cap and used a strobe timing light to see where it was. Lot of faffing about. But I learned quite a bit.

Of course you could start out with this then change it later when funds permit to wasted spark or even sequential if the Aldon unit allows this? Don't really know it. The beauty with MS is there is so much help and knowledge freely available, since it is so common.

Thanks for all the replies. Considerable food for thought.

Nick

Having scan-read the instructions for this kit it seems like a nice bit of hardware. I think there method of locking out the dizzy is a bit dodgy but apart from that it looks very good.

I run a programmable MSD unit and I spent a long time working out how to reduce rotor arm misalignment, the MSD has a degree sweep of 30 degrees but it is also is a multi spark system which fires sparks over a 20 degree range, this adds up to 50 degrees. This equates to 25 at the dizzy so I made sure that the centre line of the rotor arm was never more than 12.5 degrees away from the centre line of the HT post in the plug cap. This sounds hard to do but its not too bad if you draw it out on paper. Due to the width of the rotor arm and the HT post is ensured that there was always some 'overlap' of the two components.