H.T.Leads.

mike-b · Post by **mike-b** » Sun May 26, 2013 3:57 pm

Hi Reader,
Found the engine running a little rough - spitting & back firing.
Done the usual checks, timing - fuel getting to cylinders - plugs.
Eventually found all silicon leads had some weird readings.
This is what I found.
No 1 = 9.52K Ohm.
3 = 3.6K ( ??? )
5 = 10.9K
7 = 12.2K
2 = 13.8K
4 = 11.7K
6 = 13.2K
8 = No throughput whatsoever.
The leads were measured disconnected both ends ( not through dizzy ).
I would say new leads required, this being (say) the case can anyone recommend a particular make. I`m using the 35 DML 8 dizzy - NGK BP6ES ( no "R" ) and the famous 15210 electronic unit. Off the king lead I can get a spark 25mm from the bodywork.
The lead resistances can`t be right .... Can they?
A longer lead a greater resistance - fine understandable until you look at No. 1 & 3.
Comment please .... Many thanks Mike-B

stevieturbo · Post by **stevieturbo** » Sun May 26, 2013 4:33 pm

Resistance will vary with length, although Ive never actually measured any myself.

Just replace with a decent quality set of leads. Spending a fortune will yield no benefit over good quality cheaper ones unless you need a set specifically intended for a CD system or something

DaveEFI · Post by **DaveEFI** » Sun May 26, 2013 5:47 pm

Bosch leads are usually pretty good if you can get a decent price on them.

It looks a bit like you weren't getting a decent contact or whatever, as they should be directly proportional to length. Normally about 5k per foot. Were they all the same make?

mike-b · Post by **mike-b** » Sun May 26, 2013 10:26 pm

Hi Stevie / Dave,
Many thanks for your replies.
I fully understand resistance should and will be higher in a longer lead of say two leads with the same cross sectional area, however that theory seems wrong when looking at the resistance of leads numbers 1 & 3. A mistake taking the reading did not occur as I checked it three times. It could be the make - they are 7mm silicon leads with "Commercial Ignition" written on them. Where from would be a guess.
It seems new leads wouldn`t be a bad idea as stated by your good selves.
What are your thoughts of copper leads ( I couldn`t hear the CD anyway with the whine from the gearbox - straight cut gears ).
Copper leads SHOULD produce very little resistance at the length they need to be but the interference may well be great though not a problem to any electronic ECU as its an aged Granada Mk2.
Regards & thanks .... Mike.

DaveEFI · Post by **DaveEFI** » Sun May 26, 2013 10:33 pm

Decent quality modern resistive leads will have a good life. The suppression is not only for your car, but for others watching TV or listening to the radio, etc.

stevieturbo · Post by **stevieturbo** » Sun May 26, 2013 10:49 pm

I'd just buy a set of decent leads. You dont need to go nuts on the most expensive set you can find.

At least then you have peace of mind that they should be ok.

A little bit of googling sees places selling leads ranging from £20-40 per set. Rimmer being at the more expensive end at £42

Or some place Ive never heard of on ebay etc, Powerspark at £18 a set.

mike-b · Post by **mike-b** » Mon May 27, 2013 11:12 am

Stevie / Dave,
Many thanks guys.
Dave - I know I need the suppression - should I care - well yes of course I should and will - I wouldn`t like it done to me.
Stevie - Yes a decent set of SILICON leads will do the job. The Bosch type should be Ok as I have used them before on my Granny. It seems then there is no real purpose built set unless I am prepared to spend about £80 plus and that is not going to happen - not on my setup.
Nuff said .... Thanks lads.

DaveEFI · Post by **DaveEFI** » Mon May 27, 2013 11:35 am

You can buy cable on its own and re-use your existing connectors, with care.
Vehicle Wiring Products sell it. That would be the cheapest fix.

mgbv8 · Post by **mgbv8** » Mon May 27, 2013 6:25 pm

Powerspark leads are really good value I think. Simonbbc is the name of the supplier.

Well worth a punt.

mike-b · Post by **mike-b** » Mon May 27, 2013 7:31 pm

Hi Dave / Perry,
Thank you both for your last.
Dave - I know about Veh. wiring products I have dealt with them for years - get all my wiring products from them except the cable crimps - they are a lot cheaper at screwfix.
Good point about the HT leads ....... of course !!!!!!

Perry - Thanks for that - its another supplier to explore.

The car was running great, put him to bed and two days later the car seemed to loose power after a difficult start-up. Got it going and though it ran reasonably smooth it was lacking somewhere - it was then I found No.8 was doing bugger all. Checked all the other leads and found other faults. No good messing about - new leads a must.
All replies have been helpful - so thank you all. ................. Mike

mgbv8 · Post by **mgbv8** » Mon May 27, 2013 8:45 pm

mike-b wrote:Hi Dave / Perry,
Thank you both for your last.
Dave - I know about Veh. wiring products I have dealt with them for years - get all my wiring products from them except the cable crimps - they are a lot cheaper at screwfix.
Good point about the HT leads ....... of course !!!!!!

Perry - Thanks for that - its another supplier to explore.

The car was running great, put him to bed and two days later the car seemed to loose power after a difficult start-up. Got it going and though it ran reasonably smooth it was lacking somewhere - it was then I found No.8 was doing bugger all. Checked all the other leads and found other faults. No good messing about - new leads a must.
All replies have been helpful - so thank you all. ................. Mike

I run Simons silicon leads in the MGB and the Escort. They have been in for over a year now with no problems. MGB runs boost + a bit of nitrous. Escort runs a 200 shot of nitrous. Both cars run fat MSD ignition with no lead problems

stevieturbo · Post by **stevieturbo** » Mon May 27, 2013 9:19 pm

mike-b wrote:Stevie / Dave,
Many thanks guys.
Dave - I know I need the suppression - should I care - well yes of course I should and will - I wouldn`t like it done to me.
Stevie - Yes a decent set of SILICON leads will do the job. The Bosch type should be Ok as I have used them before on my Granny. It seems then there is no real purpose built set unless I am prepared to spend about £80 plus and that is not going to happen - not on my setup.
Nuff said .... Thanks lads.

Dont get why you would need to spend £80 when there are cheaper leads ?

Or is yours a non standard fitment for the engine ?

DaveEFI · Post by **DaveEFI** » Mon May 27, 2013 10:39 pm

Just as some added info, you can also buy spiral wound HT cable by the metre if you don't like the more common stuff. Still cheaper than buying ready made.

mike-b · Post by **mike-b** » Tue May 28, 2013 6:52 pm

Stevie,
Oops, that should have read "I am NOT prepared to spend £80 plus......."
I may be a bit daft but i`m not completely stupid ......... well not yet anyway.
You read it right .... I wrote it wrong. For the last two days anything that could go wrong did.
I contacted Paul at "V8tuner" ... parts are on the way.
Thank you all for your input gentlemen - where would I be without this forum, probably in the s..t.
Regards Mike.

sidecar · Post by **sidecar** » Tue May 28, 2013 8:36 pm

I found this interesting....

http://www.magnecor.com/magnecor1/truth.htm

Yes I know it was written by someone at Magnecor so you have to take it with a large pinch of salt.

(I run Magnecor leads with my MSD system)