Thursday, December 30, 2010

Ignition system

The Ricciardi has a good old Bosch distributor, points and coil system. When in good order they work well (although arguably the advance curve isn't ideal for modern fuels), but this one shows every sign of having been with the engine since 1970, and could do with some TLC.

It's probably not too bad, since the idle at least is fairly regular, but there is definitely some slop in the bearings, which will likely mean that the advance and dwell are not even across the cylinders, and possibly that the curve is incorrect as well. I pulled the rotor out for a quick look, and in addition to being very dirty it's looking pretty worn as well, as is the cap.

All round it looks like time for either a replacement or a rebuild. A bit of investigation showed that it's possible to get rebuilt distributors, and for a little more Alfaholics in the UK sell a rebuilt one with an ignition curve optimised for modern fuels. It's also possible to get a unit with a breakerless module to replace the points. Sounds good in theory, but Australia has fuel with higher octane than is commonly available in the UK, so I'm not convinced that the Alfaholics advance curve will be ideal.

Further research uncovered a firm in the Netherlands called 123Ignition who specialise in electronic advance systems incorporated into a standard-looking distributor. They have a drop-in replacement for the standard Alfa distributor, and it comes with the factory standard curves for each of the Alfa engine models, plus some of the more common after-market curves for modified engines, all selectable by a switch underneath the distributor body. It also provides spark balancing and a few other useful features. Sounds ideal, and I was leaning towards getting one until I saw that 123Ignition also make a completely "soft" version of the same product that can be programmed via a USB connection with any advance curve you like. This was quite intriguing, since it means you could start with a standard curve, and then optimise to the particular engine and usage pattern, and also easily change the curve to account for modifications. It also offers a rev limiter, and can be programmed with two different curves, switchable from the dashboard. The clincher was that it actually appears to be easier to change between curves on the "soft" version, since you can leave the distributor in the car and just plug a USB cable in. The "hard wired" version has to be removed from the car to access the switch that changes curves. Of course, I wasn't at all influenced by the idea of being able to program ignition curves on my laptop, or watch real time graphs of what the engine is doing. Really...

Despite it being Christmas holidays, and despite me currently being on an island in Bass straight which is only accessible by aircraft three times a week, and boat once a fortnight, I have been able to contact a distributor of the product, confirm which model should fit my car, and place an order. Ah, the magic of the internet. The reseller in question is Leen APK in the Netherlands, who seem to have a good reputation both for service and for understanding the product, and won my business by politely answering all my emailed questions within a few hours of the asking.

In the meantime I've confirmed that I've got copies of all the Alfa advance curves I'm likely to need. The plan will be to start with the standard Bosch curve for the 1750, and then experiment to see what best suits this engine.

Really looking forward to this!

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