Contact breaker point help desperately needed:-(

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adamskibx
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Contact breaker point help desperately needed:-(

Post by adamskibx »

Hello- Im hoping someone will have a knowledge of old distributors with points. Basically, I have today and tomorrow off work and am 100 miles away from Loughborough where I live- Im trying to fix the GS in order to start it before the end of Wednesday as I need to deliver it to Newcastle. Im not driving it but towing it but in order to do that I need to get the suspension up!! Ahhh, blimmin Citroens!! lol When last used it was fine but when I tried to start it the other day, the electrical sytem died and me and the new owner wasted 1000 miles driving in the BX. Im back to sort it out. Basically, what has happened is this. It was dark and I needed to reconect one of the low tension leads that I disconected for security reasons- I think I may have connected it to the wrong terminal on the coil which is why it wouldnt start. This has caused the wires within the distributor to melt and short out. Ive soldered new ones in and retentioned the points spring. The system now works again but I cant work out how to adjust it. I connected a bulb up and it flashed 4 times per revolution as it should but spends more time off than on. With previous points like the 2cv ones, id just stick a feeler guage in and set the gap like that but this is a "cassette" type points that slides down into the distributor and so you cant measure the gap with a feeler guage as its inside when the cam is in contact in the correct way. Instead, the Haynes tells me to measure the dwell angle. Was just wondering what this means and how I measure this- can it be done without the distributor in the engine? Also, although I marked the position of the distributor to the engine fixing point, I forgot which way the rotor arm was pointing-it looks like there are only two ways it can point so at the moment I have a 50/50 chance of success even if I get everything else right:-( Was just wondering if there is any way of determining the orientation of the arm. The firing order etc is known but apart from that im a bit lost. Any pointers would be very apreciated. Regards, Adam
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j_roc
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Post by j_roc »

To measure the Dwell angle you will need a decent multimeter with this function, or a dwell meter - as these are a single function tool you can pick them up for a couple of quid for a cheepish one. If you want to trek down to Swansea (I dident think so :-s ) you can borrow my Multimeter as it's got this function. P.S Dwell is the angle (degrees) that the points open and close within. Hope this helps - Alex
maddave

Post by maddave »

Just to add. Yes, dwell is the angle/gap of the points. You connect one end of the dwell meter to the negative side of the coil and the other to a good earth if I can remember correctly. You then start the engine (if you can!) and note what dwell is recorded. Then off with the engine and adjust the points gap then try again! Its best if you can set the gap with feeler gauges to get a prelimenary reading first!
adamskibx
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Post by adamskibx »

Oh OK thanks for that ill pop round to Halfords tomorrow and try and get one of those. Thanks for the dwell angle explaination- I take it thats the number of degrees the engine turns rather than the rotor arm. Actually I suppose they must be the same coming to think of it. At the moment the points are closed for a very short space of time- ive connected a bulb up to test it and it literally flashes on and off as I turn the rotor arm by hand and spends most of its degrees in the open (off) status. The Haynes states that the points gap value for this cassette type distributor is the same as the gap for the ordinary points found in the other make of distributor that was fitted to some GS engines. I had an idea of how I might set it and this would cut out the need to use a dwell meter if it worked but I dont know how accurate it would be- Basically, as the gap has to be measured when the highest point of the cam is in contact with the lifter, the fact that the cam thing is flush in the round housing means that the highest point is in perfect contact with the outside edge of that round bush in the cassette- I thought maybe if i got somthing perfectly straight and rounded I could push it up against the points pusher thing and measure the gap with a feeler guage. I think ill try and lay my hands on one of those meters now that youve explained about those though! But this is what I will do if I cant get hold of one. Many thanks for the reply, Adam
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Mandrake
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Post by Mandrake »

Hmm,

In all the time I had my GS, I never needed to use a dwell meter, I'm sure that you can use a feeler guage on the points, with the aid of a small mirror to see what you're doing, in fact I'm certain I've done this before.

Are you sure you can't ?

Regards,
Simon
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citronut
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Post by citronut »

are you have magnetic marely distributor,best to set them with dwell meter,if i remember it needs to be set at about 52 degree's dwell,first thing i would do is try to clean the contact points with a very fine piece of wet and dry,the rotor arm will only locate properly in one place,as on the spindle it fits onto there is a flat section that you need to line up with the flat inside the arm,to work out where number one lead should be with distributor of the car,you will find a scrib marke on the edge of the dist body where the cap sits,now on the rotor arm blade there is a line in the centre on top of the blade,line up the two marks then the rotor is pointing to number one lead when you relate it to the cap
regards malcolm


ps. i think i used to manualy check the gap on those with just the points in the dist,without there plastic holder,then you can just about see what you need to
Linegeist
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Post by Linegeist »

Just to clarify here - the dwell angle is the amount of distributor cam rotation during which the points are closed (and the ignition ccil 'charging up'). When the points open, the magnetic field in the coil collapses inducing the high tension current that creates the spark at the plug.

I played joyously with these casette type points some years ago when I was in 'the trade' and I can remember regularly removing the distributor (after marking its position for timing purposes) in order to both fit the new contact breaker casette and to get a feeler gauge into position to set the initial gap. Remember also, to put a blob of grease under the heel of the plastic or fibre lifter that contacts the cam lobes. If you don't, rapid wear can occur which will quickly close your carefully adjusted points back up again!!! Frabjous joy!!! :roll:

Also, from memory, I seem to recall a number of casette equipped cars (Renault 5's and some Simca's certainly) had a small hole in the distributor body that allowed the dwell to be adjusted while the engine was running using a long allen key. Look for a small rubber blanking grommet on the distributor body. S'easy when you've got the right kit.

Hope that helps...............
Regards
Bob
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Post by bxbodger »

Not much tio add, except that the engine doesn't actually have to be running to use a dwell meter- you can get a reading just by cranking it over, which should be enough to actually then get it running!! The old analogue needle types are much easier to read than digital under these circumstances as well.

I always use them with mechanical c.b. set ups- they are a hell of a lot quicker, and more accurate than a feeler gauge too as they can compensate for wear in the point tips, which a feeler can't do.
adamskibx
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Post by adamskibx »

Cheers guys I managed it:-) I wasnt after a fine adjustment but just enough to get it started as the points will need replacing anyway now. This is because the spring actually carries the current and had heated up and lost its elastic memory- I bent the sides of the cassette outwards to remove the spring and bent it so it works again, soldered in new wires and even had to bypass the plug assembly as this was so melted and enlarged that the distributo cap wouldnt sit flat. The rotor arm itself only fitted the one way, but it looked like the side that joins the end of the camshaft would fit 2 ways-luckily it didnt quite so that was one problem out of the way. Went to Halfords etc but couldnt afford the £45 for a multimeter with dwell facility so I removed the cassette, put a screwdriver into the hole where the cam would normally go to lift the points up and measured the gap to 0.35 mm approx, and using some card and a protractor checked the dwell angle that way (about 55 deg.). The haynes told me which way to adjust with allen key which was the opposite to what I thought originally- Like you say, its the angle between points closing then opening and had the idea originally that it was the other way round- the fact the the gap looked massive made me realise. And as for the timing, well that was a blimmin challenge too! The manual said there was a mark on the flywheel on late engines, and timing advance settings written on the bell housing- This was missing so I had to look up how to set valve clearances and work out the crank position from where the valves were- The point two flywheel teeth before both valves shut was what I had to set the static timing to and my god was I releived when the thing started! Thanks a lot for your help again I would have been a bit lost if it wasnt for the first few posts and probably wouldnt have managed this on time!
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