no spark?

[Kevin]

this may be a silly question but does the end of it wear so much that it is to far away in the cap to make a spark phil

Not a silly question at all as a couple of years ago there were some new rotor arms from a deffective batch that caused problems and you could not even see anything wrong with them although most of them should not be in circulation any longer, have you also tried removing a plug and with the lead connected hold it to the engine ( make sure you are using insulated pliers or similar) to see if the spark is getting that far, or have you already done that.

[rayofleamington]

The rotor arm failure is not always visible - on some of them it can spark through the plastic under the brass making a circuit to the distributor shaft.
Due to bad quality parts the rotor arm failure (which was practically non existant for 30 years) is now very prolific.

A multimeter will not find the faulty rotor arm as you need very high voltage before you get a circuit, so the safest way to rule it out is to borrow one from a working car.

As for the spark - did you check it in daylight? You will get a stronger spark from the coil lead than from a spark lead (I think). This is because there is extra resistance as it has to make 2 sparks (it also has to jump the gap between the rotor arm and the distributor cap). If in doubt - test it in the dark (after 5pm)

[Matt]

test it in the dark (after 5pm)

whats wrong with before 5pm... does something nasty happen? can you test it in a garage with the lights off before then?

[Kevin]

whats wrong with before 5pm... does something nasty happen?

Its the normal time that student brains start to function after the day/night before isnt it

[Matt]

not this students! he's at 9am lectures (althouh I don't get hammered very often at all...)

[d_harris]

Not this student either. This student doesn't drink anymore.

[rayofleamington]

whats wrong with before 5pm... does something nasty happen?

that remark was for the students - in case they couldn't work out roughly what time it gets dark

[d_harris]

It gets dark here at about 4.30ish at the moment - its beginning to get a bit 'dimpsy' already (about 2.45)

[Cam]

and some fell on stoney ground!

[d_harris]

nah, just the pavement.

[mixerman]

Colin,
ihave a spark out of the coil but not when i put it back in the distibuter the cap i bought is a side entry the leads are copper with copper ends i am getting a very good spark when i put the coil lead to the engine the trouble has happened all of a sudden when i turned it over it fired on a couple of plugs but then it just turned over with nothing that when i found out no spark on inspection of the old cap it was worn out on the contacts inside so i bought a new one thinking problem solved
minor 1960
998 cc

[Willie]

Try another rotor arm.......there have been many failures lately.
Also check that the carbon brush in the centre of the cap is
free to move and spring back so that it touches the rotor arm.

[ColinP]

Well, I can't remember what type of distributor cap should be fitted - on the East Sussex Parts list there's two top entry & two side entry (Mine's a top entry 1098cc)...

It seems as if the spark's disappearing into the distributor, so it's got to be the cap or rotor arm (and a non-visible tracking fault is really difficult to trace!)

I guess it's worth pulling the leads out of the cap and making sure that all the contacts are ok (clean bright and dry -sandpaper - don't spray wd40 into the little holes). Also make sure that none of the leads are shorting to earth (e.g. plug leads resting on the dynamo/alternator with poor insulation). It's quite difficult to get the spark at the plugs - it really wants to leak out!

I guess the quickest thing is to replace the plugs, HT leads (all of them - and in the right sequence), rotor arm and cap (possibly spare coil while you're at it). Get then from one of the suppliers, quote your engine number to him (her) and you should get a package that works....
My experience is that the parts aren't that expensive, especially compared with the frustration of trying different bits.

I've had the experience of the engine dying about 5-qo minutes into a run. Replaced darn near everything to no avail, then noticed a slight drip from the top rad hose. Stopped that & the problem is now gone (touch wood quickly!)

Colin

[Pyoor_Kate]

Oooh, oooh, just a thought.

For *ages* I had an intermittent fault; the engine would just *stop* and there would be no spark. Power at the distributor, spark across the points when everything was checked.... but it would just die suddenly with no spark. We changed all sorts of bits over time, and then it was found that a tiny bit of insulation had come off a wire inside the distributor, allowing it to earth against the side; but it'd only occasionally do this, and generally the act of taking apart the distrbutor would move it, and the fault would disappear. But generally not for long....

[Willie]

COLIN P....it doesn't matter which type of cap you fit, side or top
entry are both suitable. The side entry gives a much neater lay
out but it is a matter of personal preference.

[ColinP]

Willie,

Many thanks - I thought that there might be a subtle diference. Apart from the way the leads come out! (like 60 thou extra gap between rotor and contacts!).

I like the idea of "neater" (pause while wife has to be revived - she sees the state of this study) ....

Thanks,
Colin

[mixerman]

colin,
i have gone to the morris garage and bought a new roter arm and it seems deeper than my origanal when i put it on the spingle i cannot get the cap on do they make different sizes or is the new cap wrong ?
getting fed up now phil

[ColinP]

Phil,

As Willie notes there are some odd ones around - the last but one I got was so tight that it almost had to be hammered home - then snapped.

It's a real pain, but at about £1.30 each it cost's more to sned it back etc. etc.

Where are you? - just popping into the shop seems very handy! Wish there was one around here (hence the mail order).

Don't give up now.

Colin

[Willie]

Mixerman.. you obviously have a problem there, if you have the
original cap it might be worth putting it back on together with the
new rotor arm?? Failing that you can buy,from Bull Motif, a complete
service kit including cap,rotor arm,plugs,points, and condenser for
£11.79!!! He is on 01386 831755

[rayofleamington]

a complete
service kit including cap,rotor arm,plugs,points, and condenser for
£11.79!!!

and also includes aifilter and oilfilter - top stuff (I picked one up a week ago for the Elmobile)