replacement dizzy advice

[moray]

Hi all,

In my trav i have the original 1100 engine which has been mildly tuned with a sports cam, updated head, balanced.
it has a maniflow lcb exhaust and a weber dcoe40 carb.

the guys who built the engine are mini guys and when they put it together they fitted a 23d non vacuum dizzy as the weber and manifold do not have vacuum take off points.

recently my car has started losing power and cutting out. from reading here i suspect the condenser.
I have replaced it with an old one, but i'd like to replace the whole dizzy and go electronic just to be sure.

should i go for a 23d or a 43d? and who does the best replacement ones?

thanks in advance
Moray

[bmcecosse]

I have to say - that Weber 40 is a big mistake.... You would be MUCH better with a single 1.5" SU on an aluminium alloy inlet manifold. The best dizzy for your needs is a 45D from Accuspark/Powerspark WITH vacuum advance - it's again a mistake to not have vacuum advance. But a sudden loss of power may be more to do with engine/valve condition.. Set the valve gaps and run a compression test - hot engine/throttle held open, to see if all is well.

[moray]

thanks Roy,

at this stage will stick with the weber as it's all i've got.
based on your advice about the 45 vs 25 i should go for the 43 non vacuum given i'm going to keep the weber.

forgot to say the engine has only done about 600k since it was rebuilt, so is still running in.
it runs fine from cold and for about 15-20 k before it starts playing up.

will check the valve gaps, i don't have a compression tester so can't check that.
what should the valve gaps be set to 13 thou?

cheers
Moray

[bmcecosse]

I advise 15 for exhausts - especially with a fancy cam (although again - not ideal in a 1098!!) and stick with 12 for the inlets. Do you know what head is fitted ? Any idea what chokes are in the Weber? I strongly urge you to make a vacuum connection - and use a 45D dizzy...

[philthehill]

As regards a replacement for the 23D:-

http://www.ebay.co.uk/itm/Mini-Cooper-S ... 27be21db52

I would suggest that the standard Lucas 23D distributer is a good choice and match for the spec of your engine.
I have fitted and run the 23D with tuned engines of various sizes and some fitted with DCOE carb(s) and never had any problems.
If it was good enough for the Cooper 'S' it will be more than adequate for your engine even without the vacuum advance.
You can tune the 23D distributer by altering the strength of the primary and secondary advance springs and also changing the size of the advance weights but that means it is all getting a bit technical so I would stick with a bog standard 23D.

These settings taken from Davids Vizards book 'Tuning BLs 'A' Series are a good starting point for an engine of your spec fitted with a 40 DCOE carb.
Choke.................................34
Main jet.............................145
Air correction jet..................180
Emulsion tube......................F16
Pump jet............................45
Idle...................................50F2
Aux vent.............................4.5

[moray]

Thanks guys,

Am pretty sure the head is a 12g940. I don't know what size chokes and jets are in the weber, the garage just said they set it all up to run with the engine.

I'll order a new dizzy and then I can overhaul the current one and keep it as a spare.

My trav is back in the garage at mums place in disgrace until I get the new new dizzy and time to fit it.

I'll report back with the valve clearances and results of the new dizzy when the work has been done.

Cheers Moray

[bmcecosse]

The 940 head is from a 1275 engine - which I thought were 'very rare' where you are! But it is the BEST head on a 1098. Remember you can not run a 1098 above 6000 rpm without risking the crankshaft - and it really should be fitted with a crankshaft damper....Running without a vacuum connection dizzy is fine for a 'race' engine (which a 1098 is v definitely NOT) - you really DO want a vacuum connection for a road car - it brightens the engine 'pick up' and helps fuel economy... Mind you - with a DCOE the fuel consumption is likely to be terrible anyway.......