Doing points in situ.

[iain.hamlton]

Tell me anyone: can you change, clean and adjust the points with the distributor in situ, without removing the carbs? Do you need an eye on stalk like a slug? Until now, I have always removed the distributor and done it on the bench.

best regards, iain

[john.p.clegg]

Iain
From memory I think you can get the distributor out without removing the carbs?

John

[reb53]

Before fitting a Luminition system and doing away with the mechanical points I always did them in situ.

I recall that a really long bladed screwdriver was essential to enable loosening screws from above the intake manifold.
However, and this is a big however, I always set them with a dwell meter and never bothered with feeler guages.

The idea of removing the distributor to merely change the points seemed to me then, as it does now, a bit too much extra work and I do my utmost to avoid that!

Ralph.

[Jason1]

Hi

I have Webers on mine and did mine no probs, I then got bored and put in the Lumintion without taking out the dizzy.

I found removing the 2 screws that hold the top plate on and removing it so I could then cut down the peg (which you need to do with the optical system) made life easier.

I have never taken the dizzy out of mine but I have taken them out of Ford engines to replace them. I would avoid taking out the dizzy as it is gear driven so you will then need to re-time it. If it was driven like a Mini you can take it out and re-fit it without any worries. Save yourself the hassle.


Jason

[CBUEB1771]

Hi

I have never taken the dizzy out of mine but I have taken them out of Ford engines to replace them. I would avoid taking out the dizzy as it is gear driven so you will then need to re-time it. If it was driven like a Mini you can take it out and re-fit it without any worries. Save yourself the hassle.


Jason

You really need to check the timing after changing points whether or not you took the distributor out. The point gap influences the distributor shaft angle at which the points open which in turn causes the spark. True this is a secondary effect but I have usually found the timing needs to be corrected a bit with new points.

[Jason1]

You really need to check the timing after changing points whether or not you took the distributor out. The point gap influences the distributor shaft angle at which the points open which in turn causes the spark. True this is a secondary effect but I have usually found the timing needs to be corrected a bit with new points

I agree, but the difference in slightly rotating the dizzy and putting it back in completly in a new position is massive. Checking the timing and slightly rotating the dizzy will take seconds, if you take it out and re-time it you could be there for a while.

Try and change the points in-situ and you will save yourself a lot of hassle.

I also agree with the other post and always use a dwell meter to check the gap, using feeler gauges only checks the gap on one lob of the dizzy cam.

Good luck, it's not that bad if you have ever tried to change mini points at the side of the road with the grill on (most Britsh people have) you should find it a doddle.

Jason

[twincamman]

there is no need to remove the carbs -to remove the distributor ---remove the cap and rotor--lift -- and out it comes ----ed

[gordonlund]

I always take the dizzy out to change the points. I have found it is bad practice to change the points without changing the condenser. A breaking down condenser can shorten the life of points considerably so always do them together. Changing a condenser in situ is ny on impossible!! Any way I always check the points gap at each lobe position to ensure the shaft is running true. It's much easier doing it in the vice with soft jaws with less likely hood of loosing small screws and washers. Putting the dizzy back is easy if you don't disturb anything and mark the position of the rotor with a pencil before you take it out. The shaft goes back in 20-30 degress anticlockwise and ends up in the true position because of the helical teeth. Static timing is done with a 12v bulb in the Lt circuit with the ignition on. This gets it running then a Zenon strobe to set the dynamic timing which enables you to check the advance mechanism.

Once in the wilds of North Yorkshire my condenser and points let me down in my +2 many years ago. I limped into a convenient garage late at night in typical Yorkshire weather (pissing down) and asked the attendant for a set of Mini points and condenser. Much to his surprise I had whipped out the dizzy, changed the points and condenser on the garage forcourt (under cover). Set them up by eye and replaced the dizzy as near as I could to the same position I removed it. The engine fired first time and got us back home in Preston. Next day I checked the gap & timing and found I wasn't a million miles out. I was lucky. So from that day on I always change points and condensers together. I have never had a roadside breakdown in a Lotus since (touch wood - banging head). Modern car owners don't know what their missing!!!! or my Peugeot diesel for that matter!


Gordon

Rhubarb & Custard

[iain.hamlton]

Thanks for all the wisdom...

I took the distributor off; fitted points; adjusted them 9only on one cam lobe, though); put the distributor back and did the timing.

Almost everything is great, but there is a patch in the rev range around 5500 when it misses under load. The tachometer needle flicks upwards. It usually passes through the the rough bit and is smooth again by 6k. It did this when I did the points last year and chased the fault changing plugs, leads, capacitor, coil, ensured it was getting enough petrol, reset the float level, cleaned the jets etc.. The problem deminished so I forgot about it, but I suspect there should be more power at the top end than I get. Tonight I will look at the points again, and check them on all 4 cams as Gordon suggests. Perhaps set the gap a thou wider?

Is what I see compatible with the points?

Electronic ignition may be better, but I am sure these engines should be able to rev smoothly around the clock on points.

Any other ideas?

best regards, iain

P.S. while I can get the distributor off without moving the carbs, there is no way I can inspect or adjust the points in situ, never mind change them!

[twincamman]

missing means the gap is not correct ---ed

[iain.hamlton]

Thanks Ed,

I was guessing that was the case.

I have a 43D4 distributor, and set the gap to 15 thou. Anyone know if if 15 thou is right? i was reading somewhere that it is better to use a bit more for a new contact set.

best regards, iain

[Frank Howard]

I have a 43D4 distributor, and set the gap to 15 thou. Anyone know if if 15 thou is right?

Iain,

First, .014 to .016 is correct. Checking the gap at all four lobes will tell you if the distributor is bad. The most accurate way to check the gap is to use a dwell tachometer. As I recall, the setting should be between 57 and 63 degrees. If you get a reading of 55 degrees, the point gap is too large. If you get a reading of 65 degrees, the point gap is too small. You'll have to take the distributor out each time in order to adjust it, but by the third or fourth time, you should be pretty good at it!

[264889socal]

Just curious, as I am now used to setting the timing on a crank fire ignition, how much scatter should you see when you are setting the timing with the engine running? Haven't pulled the dizzy as of yet, but the timing seems to move around a bit when using the timing light. Guess I am spoiled as all my engines have had crank fire since the early 70's.

Rob Walker

[iain.hamlton]

Rob, you get more scatter with a distributor and points than a modern system but, with a good distributor it's hard to see it or measure it with a strobe light, so i'd say less than +/- 1 degree, but i dont know for sure. Also mechanical systems dont give a terribly accurate advance curve. If you try to plot it, the results are only reproducable to a couple of degrees. The maximum advance, which is the most critical, is the also most dependable (flat above 2500 rpm on a weber engine). So I set up timing on maximum although this gives a static value less than the number in the book.

I found my problem. As Ed diagnosed, it was the points. The contacts did not meet over the whole surface, but at an edge. They were also on the tight side, perhaps 13 -14 thou. The new points are set to 16, checked on all four lobes. The engine now pulls cleanly all the way.

best regards, iain

[264889socal]

Iain,

Thanks for the answer. It has been so long since I have done anything with a distributor, my memory seems to be failing. From what I am seeing, it would appear the bearings or advance mechanism in my distributor are somewhat suspect. I was trying to set the advance at 2000rpm based upon the notes from the PO's engine builder. The timing mark is jumping all over the place. Perhaps a 6-8 degree variation. From all of the posts on distributor problems, I am tempted to fit a spare Electramotive electronic ignition with a crankshaft trigger. That system will nail the spark exactly where you set it every time it fires, from zero to what ever rpm you are willing to turn the engine. In looking through the Moss Motors catalog, I note they offer a 23D distributor for the MGB. I read of using various BMC parts, points, starter, etc with the twic cam. Are all the 23D distributors equal, except for the advance curve?

Rob