mellonman Posted January 25, 2012 Share Posted January 25, 2012 i had a similar problem then it stopped running completely and it turn out to be a wire was braking down at the the points i cant remember completely it was 13 years ago and the car was older then me at the time Quote Link to comment Share on other sites More sharing options...
SupraDan24 Posted January 25, 2012 Author Share Posted January 25, 2012 i had a similar problem then it stopped running completely and it turn out to be a wire was braking down at the the points i cant remember completely it was 13 years ago and the car was older then me at the time I have an electronic ignition system, so no points i'm afraid, just a rotor arm and a cap Quote Link to comment Share on other sites More sharing options...
mellonman Posted January 25, 2012 Share Posted January 25, 2012 i think i best just shut up then:whoosh: Quote Link to comment Share on other sites More sharing options...
Thorin Posted January 25, 2012 Share Posted January 25, 2012 Just sell the bloody thing Quote Link to comment Share on other sites More sharing options...
SupraDan24 Posted January 25, 2012 Author Share Posted January 25, 2012 Just sell the bloody thing Neverrr !! Quote Link to comment Share on other sites More sharing options...
steve spedd Posted January 25, 2012 Share Posted January 25, 2012 what size Needle are you running? have you changed the exhaust or anything like that? On mine when i did the stage one tune i had to change the needle size... Quote Link to comment Share on other sites More sharing options...
steve spedd Posted January 25, 2012 Share Posted January 25, 2012 http://www.niksula.cs.hut.fi/~mdobruck/siililand/mini/diy/3/su-tune/needle.html Quote Link to comment Share on other sites More sharing options...
jagman Posted January 25, 2012 Share Posted January 25, 2012 You appear to have misfire on light loads and lower rpms , not as much on heavy loads or high rpms -right ? normally this is the opposite with ignition defects , but advance retard needs checking - a good old fashioned timing light helps here . worth checking your "new" carb , often air leaks past the shaft that holds the throttle plate at each end (there is a seal here or bush) there should be no play in the shaft -its a common wear point in the SU , cost about 1 groat ,as I remember Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted January 25, 2012 Share Posted January 25, 2012 Yes, as Jagman says, I would see if the timing is wandering, a broken advance / retard spring might cause that. Did you check the baseplate grounding wire I mentioned earlier? poosibly irrelevant with electronic ignition. What make is it? Some of the early kits were less reliable than the points and condenser. Have you done a leakdown and compression test on it? Quote Link to comment Share on other sites More sharing options...
dangerous brain Posted January 25, 2012 Share Posted January 25, 2012 There must be a mini specialist you can drop this motor into to get it sorted rather than buying lots of stuff to try and sort it by internet committee? Quote Link to comment Share on other sites More sharing options...
SupraDan24 Posted January 25, 2012 Author Share Posted January 25, 2012 There must be a mini specialist you can drop this motor into to get it sorted rather than buying lots of stuff to try and sort it by internet committee? Lol i've been researching this today as i dont think i'm going to crack it myself. i've been trying to sort it myself because i enjoy tinkering on the car and the parts i've been buying are in rediculously cheap bar the Carb, but that needed replacing anyway as the one that came off was cracked. Quote Link to comment Share on other sites More sharing options...
SupraDan24 Posted January 25, 2012 Author Share Posted January 25, 2012 Yes, as Jagman says, I would see if the timing is wandering, a broken advance / retard spring might cause that. Did you check the baseplate grounding wire I mentioned earlier? poosibly irrelevant with electronic ignition. What make is it? Some of the early kits were less reliable than the points and condenser. Have you done a leakdown and compression test on it? I had the timing checked when it was in the garage having the carb set up and the guy said it was fine. I'll have a look for the baseplate grounding wire, i'm not sure if mine has one. Going by the H manual, i believe i have the Lucas 65DM4 dizzy. I haven't done a leakdown test on it yet, i thought changing the cap and Rotor Arm would solve it tbh as they're prone to causing running issues. I may bite the bullet and take it to a professional as i dont have a timing gun to doube check it myself or the ability to do the leak down test. Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted January 25, 2012 Share Posted January 25, 2012 Get a hold of the rotor arm and try and turn it clockwise and anti clockwise. It should have no, or virtually no free play, but should rotate with a firm twist a few degrees in one direction. If it will rattle to and fro, rotationally, a spring is probably off or broken in the advance and retard mechanism. I can fix that and put it on an original distributor testing machine to check it out. Engine's don't come any simpler except in lawnmowers, so I am sure we can sort it out Does it not miss at idle at all? What if you pull each plug lead off in turn, does it drop revs a similar amount? Just for the hell of it swap over the number 2 and number 3 leads at the plugs and tell me what it runs like then. There is oil in the carburettor dashpot, isn't there? Do you know what make / type of elctronic ignition conversion it's got? is it Lumenition? It will have a plastic chopper disc inside the disi that passes between an LED and a photocell. if it is that type try cleaning the diode and the photo cely with a bit of clean soft cloth or whatever gentle cleaning medium you can get in there. make sire the plate holding the two optical devices isn't loose. Does the engine rattle a lot from inside the timing cover (fanbelt end of engine)? If so the timing chain could be totally shot, a timing light would show that up straight away. Jeez, it would be quicker to rebuild the little blighter than to carry on like this.... Quote Link to comment Share on other sites More sharing options...
SupraDan24 Posted January 25, 2012 Author Share Posted January 25, 2012 Get a hold of the rotor arm and try and turn it clockwise and anti clockwise. It should have no, or virtually no free play, but should rotate with a firm twist a few degrees in one direction. If it will rattle to and fro, rotationally, a spring is probably off or broken in the advance and retard mechanism. I can fix that and put it on an original distributor testing machine to check it out. Engine's don't come any simpler except in lawnmowers, so I am sure we can sort it out Does it not miss at idle at all? What if you pull each plug lead off in turn, does it drop revs a similar amount? Just for the hell of it swap over the number 2 and number 3 leads at the plugs and tell me what it runs like then. There is oil in the carburettor dashpot, isn't there? Do you know what make / type of elctronic ignition conversion it's got? is it Lumenition? It will have a plastic chopper disc inside the disi that passes between an LED and a photocell. if it is that type try cleaning the diode and the photo cely with a bit of clean soft cloth or whatever gentle cleaning medium you can get in there. make sire the plate holding the two optical devices isn't loose. Does the engine rattle a lot from inside the timing cover (fanbelt end of engine)? If so the timing chain could be totally shot, a timing light would show that up straight away. Jeez, it would be quicker to rebuild the little blighter than to carry on like this.... Thanks for the info Chris, i'll give these ago tomorrow. The ones i can answer now are: It doesnt miss at idle, it runs okay. It only misses when driving at a constant speed at a low rpm. Yes there is 50w oil in the dashpot atm. I havent noticed any rattling noises from the timing cover. Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted January 25, 2012 Share Posted January 25, 2012 50W is a bit thick, but that won't be your problem. Certainly sounds electrical to me. Quote Link to comment Share on other sites More sharing options...
SupraDan24 Posted January 26, 2012 Author Share Posted January 26, 2012 50W is a bit thick, but that won't be your problem. Certainly sounds electrical to me. I used the 50W because thats all i had to hand when installing the new Carb lol. I'll change it over to 3in1 tomorrow. I'll test the HT leads like you said tomorrow when i put the new ones on Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted January 26, 2012 Share Posted January 26, 2012 It definitely won't be the oil, if there was NO oil in the pot then it MIGHT give a stuttering as the mixture would be changing rapidly due to an undamped piston. Changing the leads over is a flyer, a lot of people used to get the centre tow cylinder's firing order wrong, but it would idle badly if that was the case. I suspect internal disi issues or the electronic conversion is up the spout. Does it say anything on the coil itself? make, resistance, part number, mention of a ballast resistor? Is it silver or blue? I could sort it easily if were here Quote Link to comment Share on other sites More sharing options...
Swampy442 Posted January 26, 2012 Share Posted January 26, 2012 Save all the ignition based dicking about and get one of these. Im putting one on my '71 Saab once Ive researched which is the best choice. http://www.mgbreakers.com/Distributors.htm http://www.simonbbc.com/distributors/4cyl-standard-electronic/25d-electronic-distributor-powermax-early-mini Quote Link to comment Share on other sites More sharing options...
jagman Posted January 26, 2012 Share Posted January 26, 2012 There must be a mini specialist you can drop this motor into to get it sorted rather than buying lots of stuff to try and sort it by internet committee? You have to laugh , a bazillion minis were kept on the road with a screwdriver ,matchbox strike for points and plug spanner , now 50 years on ,you need a specialist -progress !! Quote Link to comment Share on other sites More sharing options...
dandan Posted January 26, 2012 Share Posted January 26, 2012 Take the dizzy cap off, remove the rotor arm and then post up a picture so we can see what electronic ign kit it is. Quote Link to comment Share on other sites More sharing options...
dude Posted January 26, 2012 Share Posted January 26, 2012 I am one of the few forum participants old enough to be truly familiar with SU carbs, Lucas disis, and suchlike, If i can help, let me know. I must be the other, after 13 Dolomite sprints !!!!! Numerous series 2 jags and god knows what else. Quote Link to comment Share on other sites More sharing options...
GazB Posted January 26, 2012 Share Posted January 26, 2012 I'm another old timer then! With my list of previusly owned cars there's a few old timers in there with points and condensers and damp in the dizzy caps to contend with Couldn't believe somebody didn't know how to check the gap on a set of points, but then again i can't remember the last time i did a set Isn't there any back street garages with 'mechanics' in Great Yarmouth? Quote Link to comment Share on other sites More sharing options...
SupraDan24 Posted January 26, 2012 Author Share Posted January 26, 2012 I fitted the new HT leads, didn't make a blind bit of difference. I tried switching over leads 2 and 3 like you asked Chris and the car wouldn't even start so i've switched them back. I've taken a couple of pictures of the Distributor and Coil as requested and also a short video of the rotor arm movement. I did notice today that if i drive with the choke fully out then the misfiring goes away, even at 1500rpm. Quote Link to comment Share on other sites More sharing options...
SupraDan24 Posted January 26, 2012 Author Share Posted January 26, 2012 Click the picture to watch the video. If you watch carefully at the second video, you can see the rotor arm's spin isnt completely circular, it's kind of oscilating as it spins. Is this normal? All the points at the cap seem to be firing no problem. Quote Link to comment Share on other sites More sharing options...
SupraDan24 Posted March 27, 2012 Author Share Posted March 27, 2012 I decided to let a specialist have a go at it in the end, as i was having no luck with. After 3 weeks he handed the keys back to me and it was running good as new. There was various issues with it which i wont bore you with, the main one being it needing a new vaccum advance unit and the carb getting no vaccum. I got him to stick a new coil on it at the same time for good measures as the old one was looking very tatty. Annnnyway, i digress, so there i am standing next to my pride and joy beaming and the guy says to me "Start her up and see how she runs :d", so i hop in the drivers seat and switch on the ignition. Thats where it all went horribly wrong He'd left the car in gear and the handbrake off with some big metal paint tins right infront of the car up against the wall of the barn. The car stalled forward and without the handbrake to stop it the car almost went through the front of the barn. The tins did the rest of the work The bumper bar squashed the can easily, but unfortunately the tins had their lids on, so the tops were substantially stronger than the middle. The end result was the front wing was caved right in, my nice shiny grill is now scrap, the headlight was pushed out, the indicator was smashed and is now not working and there's a fair bit of paint damage. I was gutted to say the least, so was the guy as he thought i'd damaged his barn wall....never fear, it was okay. The guys on the other side of the wall (it's the typical woodern wall btw) were a bit shook up as the whole wall suddenly leapt out at them trying to get hold of their tea and biscuits. After a small rant from me, i walked away and calmed down and we talked the whole thing out. The blame was split as, even though he parked it 6inches away from his wall, left the car in gear with the handbrake off, it was me who actually turned the key so we were both at fault. The car will going back to him on Thursday and he will carry out the work of knocking the dent out, applying the filler then respraying the whole front end including the black bonnet i had just bought from him lol. I told him i was happy to pay for any materials ie paint, filler etc that he was going to use, but i didnt want to pay for the labour involved in sorting the dent which he has conceded too. He's only going to charge me £150 for spraying the whole front end which is a good price so i was happy to accept that offer. Overall i'm a bit gutted it has happened, but i'm happy that i'm dealing with a decent guy who is willing to help me sort the problem rather than wiping his hands clean of it. Quote Link to comment Share on other sites More sharing options...
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