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Colin Silver
Experienced User
Username: colsilver

Post Number: 47
Registered: 8-2008
Posted on Saturday, 18 July, 2009 - 11:31 am:   Edit PostDelete PostView Post/Check IP

I've spent 3 hours searching the workshop manual, running many searches of this forum and of course Googled. So no telling me off.

This is the resistance results I got:
COIL 0.4
1 0.4
2 0.3
3 0.3
4 0.4
5 0.2
6 0.4

Is this a good range? With some readings accuracy is +/- 0.1 ohm.
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Colin Silver
Experienced User
Username: colsilver

Post Number: 48
Registered: 8-2008
Posted on Saturday, 18 July, 2009 - 01:12 pm:   Edit PostDelete PostView Post/Check IP

More accurate results are
Coil = 0.6 Copper core to under cap only
Cyl 1 = .03
Cyl 2 = .03
Cyl 3 = .03
Cyl 4 = .03
Cyl 5 = .03
Cyl 6 = .04

I'm testing the Delco Remy Cap and leads and why the original combo performs miserably against a mock up high rise Bosch cap, longer rotor button and Top Gun 8 mm silicone leads.

This problem is say 3 months old. My profession (fiscal year related), laziness and tiredness is my excuse.

I've just found that I will get a reading on the coil lead, only if I touch the copper core. I cannot get a reading if I touch the metal 'lug'(?) that inserts to the coil.

Could a spark jump from the copper inner to the coil when coil ignition lead is in situ, thus bypassing the 'lug' and giving me 4 cyl type running?

Should I replace the lug? I've a few brand new silicone leads with same style lug? Damn waste if I have to break up a set. Or should I remove the seemingly good condition lug and re-spike it?

Sorry for rambling again. Come on Richard, give me a serve, or the electronic ignition will go in.
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Colin Silver
Experienced User
Username: colsilver

Post Number: 49
Registered: 8-2008
Posted on Saturday, 18 July, 2009 - 02:53 pm:   Edit PostDelete PostView Post/Check IP

Lug problem fixed. I've de-concours'd (?) the car. Removed lug, shined it up, exposed 1/2 inch of copper, re-assembled and stuck the copper to lug with a covering of solder. People aren't wrong when they say things are basic.

Note on above thread (I can't edit it now)is incorrectly in 100 though when it should be in tenths like my first post. Reading were done with multimeter set on '200' - the lowest setting.

Now to the ohm readings I have, and a summary of three posts. Do the readings look OK?
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Richard Treacy
Grand Master
Username: richard_treacy

Post Number: 1803
Registered: 4-2003
Posted on Saturday, 18 July, 2009 - 06:16 pm:   Edit PostDelete PostView Post/Check IP

I'm not quite sure what you are looking for, but those measurements are somewhat meaningless. 0,003ohms or 10ohms; - whatever - only a marked, factor of 10, difference between identical leads means anything, and composites may even be 40k or 1Meg.

Wire leads are usually very reliable compared to composite leads. Composites are not a good thing on the 6s, but used to be fitted by frustrated owners with too much radio or CD interference. Usually, an NGK BPRxxx resistor plug (once upon a time they used Champion RN8s) is all that is needed.

The composites burn back inside the insulation unless a 0,5mm copper conductor is poked inside the insulation for 1cm at the terminations. Some aftermarket outfits don't bother and wonder why their leads fail in months. Even with inserts, they may burn back over a few short years. Once burned back, the spark can stop and the insulation burn through anywhere in the lead. That's why composites have such a poor life. Worst are the old carbon leads. With carbons or composites, an ohmeter reading is no good. In fact, the only meaningful test on leads and distributor caps is with a Hipot 25kV tester,

If you have a few cylinders missing, but the points and all are fine, then the cap may be faulty. That is not uncommon, either due to a defect or to a spanner dropped onto it. No amount of electronic ignition will cure that, nor a failed rotor arm which is sometimes impossible to detect without a Hipot.

I had a faulty new cap on my R-Type (same cap as a MkVI or SC/S) years ago. It had a hairline crack arcing inside the cap, and the motor ran on four cylinders soon after fitting. It was hard to see the very fine line at first, but a clean-up with fine sandpaper cured it enough to drive 300km home. Of course, I fitted a new cap ASAP. Naturally, hairline cracks become most active in damp weather. Also, the lid which screws onto the distributor cap to retain the leads can have a hairline crack, usually due to overtightening, so it is always best to replace the cap and lid in pairs. You will also read in Tee-One about rotor arms internally arcing to the shafts, cured temporarily by nail varnish inside the rotor arm.

RT.
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Richard Treacy
Grand Master
Username: richard_treacy

Post Number: 1805
Registered: 4-2003
Posted on Saturday, 18 July, 2009 - 06:50 pm:   Edit PostDelete PostView Post/Check IP

Colin, by all means do fit your electronic ignition, but you know my views on that.

To be clear:

You have done the very basic test on the leads. Unless lightning has struck twice, you may assume that a multiple miss is not suddenly a lead problem anyhow.

Distributor cap: the most common cause of a multiple miss - the spark arcs inside between cylinders. Hard to see, but a new (or borrowed) cap is essential to eliminate that.

Rotor arm: usually the motor dies completely.

Condenser: you have checked that.

Bent rotor shaft: not unheard of on any badly treated distributor.

Centrifugal advance system collapsed, or a broken spring: I assume that you have checked that.

Shot distributor bearings: that doesn't strike quickly.

With the exception, but not alwqays the exception, of the condenser, all the above will be just as bad or worse with electronic ignition. That's why I feel it imperative to have the motor working perfectly before converting if you must, otherwise you will be adding more spurious factors. Kind of like having your hair coloured to cure an earache: wow the crowds with a flash hairdo after your hearing has been restored. Once it runs properly, you will wonder why you ever even considered an electronic ignition in the first place.

RT.
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Richard Treacy
Grand Master
Username: richard_treacy

Post Number: 1806
Registered: 4-2003
Posted on Saturday, 18 July, 2009 - 06:59 pm:   Edit PostDelete PostView Post/Check IP

Oh, and ps:

Spiked spark plug lead terminations and screw-in plug caps are alone useless except on copper wire leads.

For all carbons or composites, the copper wire poked at least 1cm along the inside of the lead end is essential to complement the termination to prevent burn-back.
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Colin Silver
Experienced User
Username: colsilver

Post Number: 50
Registered: 8-2008
Posted on Saturday, 18 July, 2009 - 07:32 pm:   Edit PostDelete PostView Post/Check IP

Richard, I think I understand you. If I don't sink it all in, someone in years to come will come across your views.

I still can't compute that resistance wire is not relevant on my Cloud I sixer. Is it because it's standard ignition?

With my old 91 VN Commodore, resistance was very important with ignition leads (I know, very different ignition system).

If I get the time tomorrow, I'll reassemble the Royce ignition. With what I found with the coil lead today, I believe/plead/bleed my 20 cents should rest on the motor. If not, it's off to the professionals.

Thank you for you input.
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Richard Treacy
Grand Master
Username: richard_treacy

Post Number: 1808
Registered: 4-2003
Posted on Saturday, 18 July, 2009 - 08:15 pm:   Edit PostDelete PostView Post/Check IP

Let's put it this way.

An old Holden like a VN V6 has a completely different box of tricks to run its fuel injection and ignition from a Silver Cloud of 1956 to say the least as you point out. Best forget all other brands and models when looking at any R-R/B.

Many cars have one coil per cylinder, and most have no distributor at all these days. Especially with the newer systems, the leads and all are carefully matched to the whole vehicle for a number of reasons.

Lead impedance has lots to do with coil behaviour, spark duration, HT voltage and voltage drop to the plugs and and. Some ignition systems die if the impedance to the spark gap is too low (wire leads), and some microprocessor ECUs go nervous with RFI.

I think the VN V6 may even have 10mm spark pluigs like the old tractor Holden 202 to Cloud (he he) the issue further.

Although the voltage drop over a resistance lead is not bery great, it does however raise the voltages at the distributor and makes arcing inside the distributor and coil overvoltage failure more common on older cars with conventional coils and caps.

Even if modified to electronic ignition, the SC has leads and plugs all matched to the motor, coil and so on. Deleting the points will not affect that.

In any case, the SC specification was always wire leads and N8 plugs, with a service bulletin to allow RN8s to stop radio inteference.

Resistance leads may work fine, but are less reliable and sub-optimal on older cars. As a side benefit, wire leads cost about 40c a metre and resistance/composite leads can cost $5/metre or more, or the earth made up in sets to suit a particular model and year. Try $450 for a set for a puny BMW 6. Stick to wire: they work best on an SC and are very cheap to say the least.

Better than resistance leads in extreme cases of radio interference if resistor plugs don't work is an in-line suppressor in the coil-distributor HT lead.

Other brands ? Many FJ or even HR addicts have come a gutser with resistance leads.

RT.
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David Hughes
Experienced User
Username: wedcar

Post Number: 24
Registered: 7-2004
Posted on Monday, 20 July, 2009 - 11:09 pm:   Edit PostDelete PostView Post/Check IP

Colin
My 2 bob's worth.
Richard is correct in regards to the wire leads and the system as originally fitted, simple and very reliable.
As to the cable resistance - if you use an electronic multi - meter to test, copper/wire leads that show 0.003 ohms resistance is just about zero, and almost perfect, on the other hand silicon or composite leads should have approximately 1000 ohms per foot (300mm)resistance if they are in good condition, this resistance dampens the spark to prevent the radio interference Richard spoke about. If the leads are in poor condition could read "open line" or "no circuit".
Hope that helps.
Regards
David
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Paul Yorke
Grand Master
Username: paul_yorke

Post Number: 357
Registered: 6-2006
Posted on Monday, 20 July, 2009 - 11:37 pm:   Edit PostDelete PostView Post/Check IP

An extra bob's worth . . .

If the leads are in poor condition could read "open line" or "no circuit". . . . or if starting to fail, you can try lightly stretching or bending them which may show a reading that flicks between open circuit and your expected reading.

Also check plug gaps. Most new plugs come set at a larger gap that the non electronic ignition systems should have.
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Colin Silver
Frequent User
Username: colsilver

Post Number: 51
Registered: 8-2008
Posted on Friday, 24 July, 2009 - 02:24 pm:   Edit PostDelete PostView Post/Check IP

Thanks Richard, David and Paul. I understand my wrong thinking now with your help.

It was only when I moved to my electronic ignition coil over cam Holden VN that I put spark plug lead resistance in my mind. I've mistakenly continued that thinking when I've moved back to copper leads.

Latest problem with the Royce Dist cap is sparking arking. The sound is quite apparent that it has only occured since I started playing with the cap and leads.

I'm certain my copper leads are in good condition.

The girl is now driving with my Bosch cap & rotor, but not well. At least I can get her out to roll her along.

I'll report in when I find the problem. I have a cunning plan in process that should give me an accurate fix. Later on I'll give the original cap and leads to a good Auto Elec I know.
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Paul Yorke
Grand Master
Username: paul_yorke

Post Number: 359
Registered: 6-2006
Posted on Friday, 24 July, 2009 - 06:16 pm:   Edit PostDelete PostView Post/Check IP

Is it arcing on every cylinder? Maybe there is a gap between the centre carbon contact and the rotor arm? If the rotor arm centre point is black and rough instead on being a polished dot, that may be the problem.
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Richard Treacy
Grand Master
Username: richard_treacy

Post Number: 1820
Registered: 4-2003
Posted on Friday, 24 July, 2009 - 08:51 pm:   Edit PostDelete PostView Post/Check IP

To explain Paul's point with a picture:

Many, if not most, distributor caps have a carbon with a spring set into the distributor cap. Ours have a carbon dot inside the cap, and a sprung contact on the top of the rotor arm.

So.

- The arm needs the correct sweep length to suit the contacts in the cap

- The arm must have the spring loaded contact.

For heaven's sakes, just buy a new distributor cap and forget it like everyone else. It's not rocket science here. If it has been arcing, then it has probably had its days, probably even if you can stop the arcing belatedly, as the damage is done. They are not expensive from the UK.

You need a spare or two on the shelf anyhow. Sooner or later someone will drop a spanner on yours or drop it and you will be stuck for weeks due to the rarity. You are fighting a losing battle with a substitute, quite apart from the whacky looks. This is a Rolls-Royce, not a Trabant, and parts are understanably not the cheapest on the Repco shelf.

RT.
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Colin Silver
Frequent User
Username: colsilver

Post Number: 52
Registered: 8-2008
Posted on Saturday, 25 July, 2009 - 04:57 pm:   Edit PostDelete PostView Post/Check IP

I'm telling my Mum on you people.

Wonder if Dad will take the Cloud back? I'm off to buy back my Datsun 240K the family refused to ride in - rustworthy but unbreakable.

Seriously, advice is appreciated. I do have 3 or 4 rotors as shown. And caps and leads are on their way.

I am looking after the Royce. You people have dissuaded me from putting the electronic ignition in.

Richard, it is a new sport of mine to rustle you.
240_K
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Richard Treacy
Grand Master
Username: richard_treacy

Post Number: 1829
Registered: 4-2003
Posted on Saturday, 25 July, 2009 - 09:32 pm:   Edit PostDelete PostView Post/Check IP

Cripes. Not even a Datsun 180B, "The Perfect Put-Together". That takes me back. Drag racing against FC Holdens and all. 100mph was blatant exaggeration, but aftermarket speedos and go-faster windscreen wiper louvres and tint bands on the windscreen gave the thrill. Your Silver Cloud will do well over that miserable limit.
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Colin Silver
Frequent User
Username: colsilver

Post Number: 69
Registered: 8-2008
Posted on Friday, 28 August, 2009 - 11:24 pm:   Edit PostDelete PostView Post/Check IP

Ok, I've bought some 8mm ignition wire. The copper doesn't have as many strands as the non standard wire I am replacing.
8mmCopperIn450pixels

This wire will be connected to modern day stainless/brass terminals on both ends (I am not using a Royce Distributor cap)as shown here.
RoyceCapOriginal

but one from a Allis Chalmers tractor made for the same distributor - works a treat with their supplied spring loaded rotor button (same design as Royce original - the button that is)
AllisChalmersDizzyCap

As I stuffed up when opening this thread on resistance, I want to ask two questions.

1/ Does this copper wire 8mm coated wire appear suitable to carry sufficient voltage to my NGK spark plugs?

2/ At a later stage when I go to use this copper wire on a Royce original cap, is their enough strands of wire there for the original cap's pin to get a good spike to the copper?

As a late addition, I can get this wire in a 30 metre roll for $4 or $5 a metre. I'll buy this if copper ignition wire is hard to come by. Members are welcome to have it at cost plus postage.
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Paul Yorke
Grand Master
Username: paul_yorke

Post Number: 386
Registered: 6-2006
Posted on Saturday, 29 August, 2009 - 08:21 am:   Edit PostDelete PostView Post/Check IP

I'd say

1. Yes
2. Yes

You should shop around, a roll should be much less per meter. Have you got tubes for the cable to run through ? Will 4 x 8mm be too thick. ( I think it Probably will be fine, but worth checking.)

Not the cheapest, but http://www.holden.co.uk/displayproduct.asp?pCode=030.160
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Stephe Boddice
Frequent User
Username: stephe_boddice

Post Number: 75
Registered: 2-2005
Posted on Saturday, 29 August, 2009 - 10:04 am:   Edit PostDelete PostView Post/Check IP

Try this: -
Choices from about Aus$1 / metre plus postage
http://www.autoelectricsupplies.co.uk/product_list/22
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Colin Silver
Frequent User
Username: colsilver

Post Number: 71
Registered: 8-2008
Posted on Saturday, 29 August, 2009 - 02:58 pm:   Edit PostDelete PostView Post/Check IP

Yes Paul, that was the price I got from a bloke who knew where to get a roll - and he's added his profit on it. I don't need a roll anyway. I thought copper core was rare these days, but today's searches and Stephe's link show there isn't a shortage.

I haven't found the boots and terminals I want yet in Australia. Was thinking of some MSI sets but now I am going to buy 4 sets of these. (3 x 2 = six cylinders + 2 spares.
http://www.steinertractor.com/JDS643-spark-plug-wiring-set-w-copper-wire-2-cyl EDITED 10 mins later. I won't be getting these as I first thought the assembled boots were for the dizzy, but they now appear to be for the spark plug end... Damn, on with the search

I won't have to join the cap plugs and can cut my wires to length before attaching spark plug boots.

Paul, by tubes, do you mean the genuine metal near rectangle pipes? If so, yes, but I hadn't intended using them on this aftermarket concoction - but just some spacers. When I assemble the new leads, I will have a look how it looks if I put them through the tubes. I think it might look unsightly as the tractor dizzy cap is higher than the original.

Now that I am buying leads with terminals to suit the cap, I'll have no issues with the width.

Stephe, your link is a good top find. Thanks.


(Message edited by colsilver on 29 August 2009)

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