Running on only two cylinders
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- Minor Friendly
- Posts: 15
- Joined: Sun Oct 23, 2005 2:19 pm
- Location: Northern Ireland
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Running on only two cylinders
Hi everyone, i really need your help. I have just bought another minor (non runner), and i have just fitted the following:new points, plugs, leads, condenser, dizzy cap , rotar arm and coil, i eventually got her started, but alas shes only running on number one and number three cylinders , with no spark at all going to cylinders numbers two and four. Has anyone any suggestions as to what is going on? All suggestions will be very gratefully received. Thank you in anticipation. Sam.
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- Minor Friendly
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- Location: Northern Ireland
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Hi Onne, yes i have, three actually, with no results i'm afraid, sorry forget to mention, when i take the dizzy caps off, there are metal filling inside them, and ther are big tracks cut into the four metal inserts inside the cap, could the dizzy drive shaft be bent?, would this cause her to run on two cylinders?Many thanks. Sam.
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- Minor Legend
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- Joined: Tue Feb 12, 2002 12:00 am
- Location: S E London
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two cylinders
Well, logic says that if two of the cylinders are receiving a spark that rules
out the points, condensor, and rotor arm. You are left with a faulty dizzy cap,
faulty spark plugs, and faulty HT leads to numbers 2 and 4. A remote poss-
ibility is that chronic wear on the dizzy cam lobes means that the points are
not opening on 2 and 4 but that is easy to observe. You could also look at
the electrodes in the dizzy cap which pick up the voltage from the rotor arm.
These can build up a very thick greyish layer which chips off very easily if you scrape it with a knife or similar. I assume that you have swopped over
the working plugs with the non firing ones to eliminate faulty plugs? If no joy
then swop over one of the working plug leads with a non working one. If still
no joy are you sure that it is faulty ignition and not lack of compression etc??
out the points, condensor, and rotor arm. You are left with a faulty dizzy cap,
faulty spark plugs, and faulty HT leads to numbers 2 and 4. A remote poss-
ibility is that chronic wear on the dizzy cam lobes means that the points are
not opening on 2 and 4 but that is easy to observe. You could also look at
the electrodes in the dizzy cap which pick up the voltage from the rotor arm.
These can build up a very thick greyish layer which chips off very easily if you scrape it with a knife or similar. I assume that you have swopped over
the working plugs with the non firing ones to eliminate faulty plugs? If no joy
then swop over one of the working plug leads with a non working one. If still
no joy are you sure that it is faulty ignition and not lack of compression etc??
Willie
[img]http://i39.photobucket.com/albums/e197/wuzerk/mo9.jpg[/img]
[img]http://i39.photobucket.com/albums/e197/wuzerk/mo9.jpg[/img]
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- Minor Legend
- Posts: 3204
- Joined: Tue Feb 12, 2002 12:00 am
- Location: S E London
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non firing
Oh, just seen your additional post! If the dizzy spindle is running true (turn
the engine on the starter and observe) then you had better compare the new
rotor arm with the old one as it looks as though it is physically too big!! I have
only once seen metal filings like yours and that was because only one of the
spring clips which hold the dizzy cap on was fixed which allowed the cap to
tilt when the engine was running.
the engine on the starter and observe) then you had better compare the new
rotor arm with the old one as it looks as though it is physically too big!! I have
only once seen metal filings like yours and that was because only one of the
spring clips which hold the dizzy cap on was fixed which allowed the cap to
tilt when the engine was running.
Willie
[img]http://i39.photobucket.com/albums/e197/wuzerk/mo9.jpg[/img]
[img]http://i39.photobucket.com/albums/e197/wuzerk/mo9.jpg[/img]
Are you sure the spark leads are in the correct order - 1342 - with the rotor arm running anti-clockwise. It would be easy to have 4 and 2 swapped round in the wrong order! You say 'no spark' - but have you actually tested for a spark on these leads ? It could be a very badly worn (or bent) dizzy - can only suggest waggling the spindle to check for wear - and measure the points gap on each lobe in turn to check for bent shaft. The rotor arm could be too long I suppose - you would need to measure it and compare with the diameter across the cap between the contacts.



Hang on - you said 2 and 4 before, now it's 2 and 3 ! I ask again - is there really no spark - or are these two cylinders (2 and 3) just not firing ? If so - it's almost certainly blown head gasket between the two. Turn the engine over with the handle - and feel if there is even compression on all 4 cylinders.



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- Minor Legend
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- Joined: Tue Feb 12, 2002 12:00 am
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no spark
Well, if you are sure that the rotor arm is the correct one there can only
be a bent spindle if you are getting metal filings!!
be a bent spindle if you are getting metal filings!!
Willie
[img]http://i39.photobucket.com/albums/e197/wuzerk/mo9.jpg[/img]
[img]http://i39.photobucket.com/albums/e197/wuzerk/mo9.jpg[/img]
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- Minor Legend
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- Minor Friendly
- Posts: 15
- Joined: Sun Oct 23, 2005 2:19 pm
- Location: Northern Ireland
- MMOC Member: No
Hi all, well i'm just back from my shed (its 20miles away) and its.........GOOD news, she's now running on all four cylinders. it turns out the dizzy spindle was bent , as soon as i put another dizzy in, she started up on all four straight away. I would like to thank you one and all who offered advice as to what the problem might be. Sam.