coil tracking

[bodger]

i have fitted a new coil becuse i was getting the sound of tracking from the old one
i have also put a new coil to dissy lead and it's still doing it and i got a right good jolt off it today too

it fact when i ran it with rubber boot on the coil lead lifted up it was jumping sparks across to the LT leads ...
it's a good quality bosch 12v unballasted coil too ..
and you can hear it tracking almost constantly when it's running ...

any idea's please ?

[ramon alban]

it fact when i ran it with rubber boot on the coil lead lifted up it was jumping sparks across to the LT leads ...
it's a good quality bosch 12v unballasted coil too ..
and you can hear it tracking almost constantly when it's running ...

any idea's please ?

Hello Bodge, Some bright ideas right out of left field, maybe crap but ya never know.

# Could it possibly be a 9 volt coil in a 12 volt overcoat.

# Could it be producing higher HT voltage than the leads are specced for.

# Some Shorted primary LT coils causing too high HT voltage.

# Damp - fix with WD40

# Suppression condenser missing/faulty/not working

# Bad coil earth so its jumping wherever it can.

# Do you get sparks at plugs? if not is the dissy cap/rotor arm combo faulty - so the sparks are trying to get elsewhere. They gorra get to earth somehow.

# are the plug gaps too large and the sparks wont jump the gap under compression.

# Are some of the plug leads broken/faulty so some sparks are jumping elsewhere.

# Ditto plugs.

[bodger]

i have just been out side to try something and it does' it more on LPG ??

[ramon alban]

i have just been out side to try something and it does' it more on LPG ??

Which narrows the problem down to plugs and/or plug gaps as they are the only part of the system affected by the environment change inside the combustion chambers responding to the change in fuel.

[sidecar]

i have just been out side to try something and it does' it more on LPG ??

I don't know why but I've been told that running an engine on LPG causes the HT leads to fail after a few years, they just fall to pieces! Quite how a fuel inside an engine can do this I don't know!

My dizzy had some issues that could cause the issue that your having. Basically for some reason the rotor arm on my dizzy was not very near a dizzy cap HT post when the pickup was telling the coil to fire. The engine would run OK for a while but after about 50 miles the rotor arm would start to conduct. When I put another arm in the same thing would happen again. The cheap rotor arms are worse for this than the lucas ones.

This could be the issue that your having, the arm is not near a post so the HT is finding somewhere else to ground itself. (Mind you I'd expect the motor to be running very rough as one or more plugs would not be firing)

You can check this by turning the crank to 10 degrees BTDC or whatever you fire number 1 plug at. Then remove the dizzy cap and check to see whether the rotor arm is right under the dizzy HT post for number one plug. If the post is 180 degrees away then turn the crank one revolution.

If the rotor is still a way off the post then this could be the issue. I fixed mine by grinding out the lug in the rotor arm, I then fitted a pin in the correct location. My mates who run the same dizzy as me do not seem to have had the same problems as me!


Regards,

Pete

[bodger]

thankyou Ramon & Pete , the leads / cap / arm are well les then a year old
the coil is only a few days old and the plugs are less than 2000 miles old

[ramon alban]

thankyou Ramon & Pete , the leads / cap / arm are well les then a year old
the coil is only a few days old and the plugs are less than 2000 miles old

Bodge, With respect, that does not address the possibility of the gaps being too large or (new idea - just maybe) the spark plugs being the wrong type.

The fact that the leads, cap and arm are new does not address the possibility that they may be an incorrect combo, as Pete points out, if the physical location of the arm in relation to the cap is wrong, the sparks may be seeking an easier route to ground.

And dont forget DAMP/grime and some of the other wild things mentioned.

Keep Rucking.

[ramon alban]

I don't know why but I've been told that running an engine on LPG causes the HT leads to fail after a few years, they just fall to pieces! Quite how a fuel inside an engine can do this I don't know!

Hello Pete, Yup its almost beyond comprehension, except I've been studying ignition systems for the past 3-4 weeks and came across a paper that showed that incorrect temperature plugs and or plug gaps and changes in the combustion environment inside the chamber will affect how well the spark will propogate across the gap.

So one must assume that the difference is cause by the change in fuel.

[ChrisJC]

In my experience, if your ignition system is a bit marginal (e.g. poor insulation etc), then running on LPG will show the fault, but running on petrol will be 100% fine!

I closed my plug gaps up a shade as I run on LPG all the time. I think 30thou instead of 40.

Chris.

[bodger]

had any dealings with ACCEL HT leads ?

there's a set on ebay for a £15.00 ..worth it ?