Morris Minor Owners Club

I thought I would tackle replacing the points. The retaing screw wouldnt budge, eventually I managed to remove it.

All was going well, why is it that once you think you have got them set, rotate the engine. recheck there out again( there must be a knack to it)

Anyway the problem is I must have overtightend the the screw its just spining now and not griping......

What do i do now.....

Also that thumbscrew that goes throu the dis which hold the vacum thingy how tight does that need to be. It seems quite lose.

Sounds like you didn't have the heel of the points on the highest point of the distibutor cam, so when you turn the engine over the next time you check the gap, it's bigger.
With a stripped thread you can only tap it out slightly larger and use an appropriate screw, or get anothe back plate.
The thumbscrew is for adjustment and to keep tension on it, there is a spring clip behind it, or should be.

I would look for another backplate - but a large slf tap screw might keep you going meantime - but don't rely on it. The thumbscrew is part of the anchor for the vacuum advance unit - it should be loose enough to move easily - but not flopping about.

Is the backplate a standard item/easy enough to find?-what distrubitor do I look for??

Lucas 25 D. Used on millions of cars!! Always a good idea to have a complete spare in the car.

Just looking on ebay would this work on moggys

http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... %3AIT&rd=1

Yep.

Though the advance will probably be a little out, but shouldn't matter on a bog standard engine

Alternately, you could make me an offer on my dodgy Ducelier... Postage plus a pint would suit me...

Or I could have a hunt around this week and see if I've got any scrap spare 25d's knocking around that could provide a plate...

Basically, any A series dizzy will fit, and if you're up for swapping drive ends round then any Lucas 25, 45 etc 4 pot one will fit, which means you can look at pretty much any 4 cylinder BMC/ BL car as a source

Are you sure it's the hole that's stripped? Those screws are usually made of softer metal to make sure they strip first.

Basically, any A series dizzy will fit,

Apart from the A+ engine as fitted to the Ital etc.

Kevin wrote:

Basically, any A series dizzy will fit,

Apart from the A+ engine as fitted to the Ital etc.

I don't recall ever having a problem fitting any to any - What's the differences?

Could be I never tried, after all I did just have large boxes of random bits so might have got lucky!

The obvious one is the fork type of clamp that is completely different to the Minor one and some of them are electronic from the metro`s I believe and part of it has to be altered to fit, I came across this on a mini site a while ago, there is bound to be someone on here who can explain exactly what the differences are.

Kevin wrote:The obvious one is the fork type of clamp that is completely different to the Minor one

But to me that's part of the engine side of things - It might hold the dizzy in, but it's not directly a part of the dizzy!

and some of them are electronic from the metro`s I believe and part of it has to be altered to fit

The Metro 1275 had a Hall effect dizzy as standard after some point, and randomly thrown on before that date. It's actually remarkably easy to fit to a non-electronic car, but does really need the right coil. I've never tried fitting one of those to anything otehr than a 1275 A Plus Mini engine though, so there may well be differences. If I could get the flipping drive off it I'd fit it to my Triumph (that also depends on getting it back off someone I lent it to...).

I came across this on a mini site a while ago, there is bound to be someone on here who can explain exactly what the differences are.

I'm intrigued now, but a Google hasn't come up with a great deal I seem to recall having a slight struggle with the dizzy on the pickup, the clamp didn't want to open quite wide enough but after an hour or so of swearing at it I think it went on fine - Was a while ago so could be wrong. The dizzy was a random one out a box, so I suppose it might be A plus, might not - I don't do the O word!

The later A + engine used a different dizzy (49 D) - and a different drive shaft up from the cam too. This dizzy is held in by a fork instead of the old style clamp. They cannot be fitted to earlier A series engines - well, not without extensive modification anyway!

Well didnt want to go down worse case sernario. Removed the screw thread striped on screw( thanks peetee). Found a BA screw(brass that OK?) that fitted perfectly.

While I had my head in the engine, with the dis cap off, I thought I would check the vacum advance mec. pulled the tube off the carb and sucked the end of the pipe nothing happend I could hear air being draw up through the dis.

Shouldn't you see the advance mec move?? or am I doing somthing wrong.

Well done with the screw! And YES - you should not be able to suck air - and the dizzy base plate should move when you suck and fall back when let go. Thes vacuum units only seem to last 10 years max. New ones are expensive - if you only do small mileage don't bother with it.

Isnt it there for a reason.

Are there any disadvantages to it not working??

The unit advances the ignition with the revs, don't run without it if the car was designed for it. Some cars did not have the vacuum unit, the cooper s is one, not sure of other bmc cars.

No - the vacuum unit advances the ignition timing according to the inlet vacuum, not revs. Thus on light throttle - with poor cylinder filling - the timing is advanced, on full throttle - with heavy cylinder filling the timing is retarded to prevent detonation. If it's faulty then the advantage of the light throttle advance is lost (and some air gets into the inlet manifold too through the bust diaphragm)- and fuel economy suffers. The vacuum unit also pulls the timing up at idle (high vac) - and so if it's faulty folks tend to advance the static timing to make up for the loss of the vacuum advance - and then run into pinking in top gear.
The centrifugal weights 'down below' are what advances the timing with the revs.
I thoroughly encourage getting a new vacuum unit - but they are £20/25 new - and so it will take a while to get that back in fuel saving if only doing low mileage. Sometimes see them on ebay for very much less - but are they new, and are they working?
Yes - the S had no vacuum advance - this was later recognised as a mistake, and all later 'performance' models did get vacuum advance.

Yes, I'm wrong, more vacuum at lower revs!
Glad they made a 'mistake' on the S, didn't do it any harm!

I recently replaced my vacuum advance. Only £14 from Bull Motif, I think, and it took about 20 mins.