I am currently running a Lucas 29D dizzy in my Mini K. I have a standard 1089 engine with an unleaded head, twin 1 1/4 SUs and LCB.

I have tuned it to 15 BTDC at 1000 rpm (with the vacuum advance unplugged) using a timing light and whilst it runs well most of the time it runs rough over 3000 rpm when on the road (in all gears).

I replaced the points and regapped them at 0.35mm and put in new RN12YC plugs gapped at 0.6m but the problem still occurs. On inspection of the dizzy I noticed that the Vacuum advance is slightly lose but can not be tightened any more could this be the cause of the problem If my vacuum advance is faulty what are the signs to look for Do I really need a vacuum advance or can I remove it completely

Thanks Martin

not sure, I don't have a vacuum advance, but to me it sounds too advanced. Did you set the timing with the light at idle or with a few revs. My mechanic mate showed me what to do and we held it at about 1500rpm and set it to the first mark on the flywheel, runs great. Doc will give the proper answer though

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Thanks for the info Simon,

I initial set it with the car idling at 1000rpm, I then checked the timing at various levels increasing gradually upto 3000. Everything seemed okay and it was not until I was not until I got the car up to a decend speed that I noticed the rough running.

I still don't know if the vacuum advance is working or is the cause of the problem, in a way I am hoping it is so that I can just fix it or ditch it

My guess, and it is only a guess, that the dissy has an issue, do you have a spare, if not, i may have one you can borrow to test with. It is possible that the advance surve of the dissy has gone askew somewhere along the way, the a spring may have dropped off or lost tension. Only way to tell i guess is to try another. Noticed your in crows nest, im am over in pymble PM me if you need a dissy to check with. I am sure there will be other solutions thrown your way soon also.

Cheers

Aaron

Most 29Ds I've seen are worn all loose in the advance mechanism. You could replace it with a later one- 45D is much more common.
Unless it's a concourse car though, I'd suggest go get a Nissan Pulsar dizzy and fit that. It really transforms a 1098... ask Gafmo or Mini Mad or Bobtel or.....me!
I'm running 1 in each car.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Yep get a Pulsar Dizzy...or I have a my old 45D if you wish to check your's

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