Digiplex V Elektronik Saches

[Weg]

I've replaced the Digiplex electronic ignition system on Clarissa with Elektronik Saches, same as fitted to my previous builds.
Wow ---- Transformation.

The Digiplex is triggered by fixed pegs on the flywheel picked up by a fixed position sensor in the crankcase housing. No provision for timing adjustment.
One feature is vacuum advance/retard coming from inlet manifold to ignition unit.
On small throttle openings, the ignition is advanced. Open the throttle, vacuum is lost and ignition is retarded to prevent pinking.
On my engine, this resulted in loss of power when needed for acceleration.
On small throttle openings, cruising up to 50-55 she ran sweet as a nut.
To prove the point, I elongated the vacuum pipe into the cockpit.
Before accelerating, I kinked the pipe in half, thus retaining the vacuum which improved performance a lot.
Not practical in reality.
The E - S system is fitted to the crankshaft on big block Guzzis and is fully timeable, with 9 different advance curve settings.
Short road test to the CoOp yesterday was brilliant. Longer road test today.
Just reporting the facts.

[Throwley]

I found that the ignition timing wandered massively using the standard Guzzi distributor setup, I assume because there's a lot of backlash built in to the system. I changed to the Silent Hektik system (which I think is pretty analagous to the Sachse) as it has a generator-mounted pickup and found it did improve the timing control throughout the range and found both mid-range and high load conditions appeared to be improved. The best thing, though, is no more point heel wear and fiddly left/right points plate timing setting.

Incidentally, a bigger improvement in timing control was achieved by dumping the chain and fitting timing gears (steel, from Gianni Caruso). I didn't expect to feel any improvement from this change, but the engine is hugely different at high rpm, with noticeably more torque and significantly smoother delivery. They do make a dreadful noise, though, like there's something really wrong with the engine!

[Weg]

It's been pointed out to me by Mussellermark, who has first hand experience of under-bonnet fire, the perils of backfire possibly caused by wasted spark ignition.
I may have inadvertently, in the eearly design stage, minimised the risk with out-splayed carbs.

[Spaniard]

Where did you source the weather stripping attached to the firewall? That looks like it makes a good seal.

[Weg]

I sourced this from ebay
https://www.ebay.co.uk/itm/122843171771
It did need warming (hotting) up with the hot air gun to get it to follow curve.
Easiest to do this job with engine removed so you can see what you are doing under bonnet.