1700 Supersprint ignition timing and smoke/steam

[AnkerB-S]

I can't figure out whether the idle ignition advance on the 1700 Xflow should be 10 or 14 degrees. The Weale book is a bit confusing, it says 10 degrees Bosh 14 degrees Caterham. Does this refer to the distributor? If it does, how do I identify it?  Mine has an orange cap. Does that help? It is really hard to examine it as it sits undet the carburetors.

The other thing is a bit of a puzzle. When the engine is up to temperature I see a bit of smoke/steam come out from under the transmission tunnel. Initially I thought it came from the crankcase breather, but it definitely isn't coming from the engine block. It could, of course be exhaust that makes it under the car, but any ideas?

[harrebe]

just unscrew the dizzy and turn it to the left or right until the engine idles nicely.

The smoke under the tunnel is more than likely from the breather. In the old model the breather hose runs under the gearbox. Better lead this hose to a catchtank.

[Roger King]

If you have an orange dizzy cap you probably have a Bosch dizzy, although be aware that I have seen a few aftermarket Lucas caps in orange.

If you have the Bosch dizzy you are a lucky boy because the Lucas based "Caterham" distributor has a truly horrible advance curve that will lose you around 10bhp at full advance. It was introduced for unleaded fuel, was completely unnecessary, and seriously took the edge off performance.

I think I read somewhere that your car is 1987? If so, the Bosch dizzy would have been standard, assuming the engine came from Caterham.

Timing for the Bosch dizzy is 10 degrees BTDC at idle. Timing for the Lucas dizzy is 14 degrees BTDC at idle. You should then check max advance at around 4500rpm where the Bosch should show around 34 degrees BTDC. The Lucas will normally only get to around 24 degrees BTDC at the same revs, but it is EXTREMELY variable and could be anywhere between 19 degrees BTDC and 30 degrees BTDC.

Even if you have the Bosch dizzy, you may well have the truly appalling Lucas electronic ignition system fitted. This can be easily identified by a rotor arm that has a slotted steel skirt attached to it (four slots). This skirt triggers the ignition, but often works loose on the rotor arm meaning that your ignition timing can go all over the place. If you have this, replace it at all costs with...................anything................ even contact breakers are an improvement. This system was introduced by Lucas as a cheap aftermarket electronic ignition system and was never intended for use in a high performance application - and even then it was marginal to say the least.

Incidentally, don't confuse this system with the Lucas competition system which has a normal rotor arm. That system is reliable and very powerful.

[AnkerB-S]

Thanks Harrebe and Roger,

I saw in a note about needing a catch tank in one of the service invoices from the previous owner. I guess they run it that far back to prevent oil fumes from wafting into the cockpit. I'll definitely do one.

Good info on checking the distributor. The bad news is that there is a Lucal electronic ignition amplifier mounted on the firewall, so looks like I have the apalling device.  I'll do an advance test at 4500 RPM and see where it sits and then consider my options. Sounds like I definitely should plan to ditch the electronic ignition from the prince of darkness.

Getting advice from here is invaluable. With so many different configurations I can understand why there isn't a regular shop manual available.

Anker

[elie boone]

Aldon is the way foreward https://www.aldonauto.co.uk/ignition

[AnkerB-S]

Thanks for the pointer. I asked them for a recommendation for my car.

[Richard K]

I have the Aldon Ignitor 1 fitted to my car for over 10 years now.

Easy to install but looking at their website there was not the 'range' of choice they now offer.

Might be worth contacting them direct if you are thinking of using one.

Richard 

 

[7 wonders of the world]

Or if you can run to it DIS with TB's and an Emerald ECU - night and day compared with Carbs and a dizzy

[AnkerB-S]

I contacted Aldon yesterday and received a response from them this morning. They need more information before they can make a specific recommendation.