HT Leads....what flavour?

[gmw9666]

Too much choice but fancy a pair of Red Magnecor ones just to brighten up the engine bay :-)

Cheapest I've found is = http://www.dcperformance.co.uk/cheap/620406/tvr/ma...

What does everyone else run?

[carob]

Bosch originals. Range Rover Classics from Halfrauds. After market been discussed lots of times. I went after market years ago and found myself ripping them out after a few running problems and sticking the originals back in and no problems whatsoever.

Rob

[mrzigazaga]

Save your money mate..Magnecor are shyte...Peoples opinion will of course differ but i have heard a few people say that they have changed them back to the cheaper variety, Which are also available in Red, Blue, Black...I have a standard set as recommended by Rover and they are as good as gold..And were under £30 so i don't mind replacing them each year to ensure a good healthy spark...As a surety though make sure you replace the king lead as often the one included is far too short...Unless you fit the coil to the plenum...Ziga

[celcius]

As above

[Transmitter Man]

I ordered these Taylor ignition 10.4mm wires: http://www.summitracing.com/int/parts/tay-79203/ov...

Phil
420 SEAC

[adam quantrill]

Range ROver £12 from the flea or 4x4 specialists but the king lead you have to make - as it's too short - you can use the ends off the new one.

[gmw9666]

Cheers all, sounds like a unanimous "save your £££ and get a standard set"

Can I get red standard ones? ......me being lazy........will look lol

[V8 Fettler]

Bosch from ebay. I used accuspark to supply the king lead, about £5 delivered (for the king lead only)

[Number 7]

Magnecore - don't get me started! A couple of mine broke at different times, and despite the so called lifetime guarantee, I still had to pay for new ones - I should add that I am always careful, so no user damage.

Slung the lot and bought a set of Moroso leads from Real Steel. You cut them to length and crimp on the connectors at one end. Use the proper tool though (if you go this route I can lend you one).

[gmw9666]

thanks for all the advice

using this chap up in Telford who is making me a set up :-)

£30 + £4 P&P didn't sound bad

http://stores.ebay.co.uk/mrretroleadsplugs/

[matt-man]

By pure coincidence I have just ordered a set for the wedge. I got mine from powerspark and will be intrigued to see what they are like. They are making a kinglead to my desired length too as the normal sets never have a long lead for this.

28 quid delivered... Seems very cheap to me.

[KKson]

Be keen to see how they are as also looking for new shiny red set.

[simonwedge]

carob said:

Bosch originals. Range Rover Classics from Halfrauds. After market been discussed lots of times. I went after market years ago and found myself ripping them out after a few running problems and sticking the originals back in and no problems whatsoever.

Rob

Ditto!

[JVaughan]

gmw9666 said:

thanks for all the advice

using this chap up in Telford who is making me a set up :-)

£30 + £4 P&P didn't sound bad

http://stores.ebay.co.uk/mrretroleadsplugs/

Did you give him the measurements or was it an off the shelf item ?

Jason

[gmw9666]

JVaughan said:

gmw9666 said:

thanks for all the advice

using this chap up in Telford who is making me a set up :-)

£30 + £4 P&P didn't sound bad

http://stores.ebay.co.uk/mrretroleadsplugs/

Did you give him the measurements or was it an off the shelf item ?

Jason

its a tweak to a standard order.....I had the SD1 / Rover V8 leads but had him make a longer king lead with 90 degree connector on one end and straight at the other (I just emailed him to agree / arrange)

[Andy JB]

For balance my Magnecor reds lasted 10 years without issue until one of the copper grips snapped off last year thought it was time to replace.

Changed to 10mm from Formula Power 02088 969172 with 10 yr Gtee - not cheap but work well with useable g'tee & great reputation.

Only downside is when you cut plug leads open the wires inside are tiny, so the thickness appears only to relate to the rubber shield externally which i can see has some merit but not against price differential the wider wires command.

[honestjohntoo]

Sadly, these two quotes seem to represent much that can go wrong with selection of High Tension Spark Plug Leads for the RV8 Efi Engine

gmw9666 said:

Too much choice but fancy a pair of Red Magnecor ones just to brighten up the engine bay :-)

Cheapest I've found is = http://www.dcperformance.co.uk/cheap/620406/tvr/ma...

Andy JB said:

Changed to 10mm from Formula Power 02088 969172 with 10 yr Gtee - not cheap but work well with useable g'tee & great reputation.

Only downside is when you cut plug leads open the wires inside are tiny, so the thickness appears only to relate to the rubber shield externally which i can see has some merit but not against price differential the wider wires command.

The former selects according to colour and lowest cost as opposed to finding leads to meet the original specification.

The latter selected leads with a thin wire and inevitable low resistance as opposed to the necessary carbon composition conductors giving the correct resistance per foot for optimum RV8 Efi performance and interference suppression.

Also squeezing 10mm leads into smaller separators will inevitable cut the expensive insulation unless unsuitable larger separator are found.

Oh dear!

• Spark Plug Leads are the main highways of the ignition system, the path allowing the high voltage pulse of current to move safely and efficiently from the distributor cap to the spark plugs where it readily jumps to earth across the inviting gap.

• Living in a harsh environment, the importance of good quality leads cannot be over-stated having to cope with extremes of temperature, abrasion, contamination and vibration induced flexing.

• They must also safely insulate the HT so the voltage cannot jump to earth outside of the combustion chamber.

• An added complication is that when such high voltage energy passes through a conductor it sets up a magnetic field resulting in something called electromagnetic interference (EMI) which is embarrassingly the cause of a buzzing noise heard typically through a radio or television receiver. This interference can also wreak havoc on other electronics systems such as the ECU of a fuel injection equipped car.

• Original equipment plug leads generally combat EMI by using a carbon core material that has a high resistance to the flow of the spark energy.

• High street or internet boy racer outlets offer a variety of pretty leads with lower resistance to maximize spark energy but if tempted, also investigate the specification for good EMI suppression.

• It’s important to ensure that the terminal to wire crimp is in good order otherwise a poor connection thereabouts will cause intermittent performance, or maybe even a lifeless cylinder.

• Lastly, bear in mind that good quality plug lead boots are needed to resist the extreme heat of exhaust manifolds.

• So as we see, High Tension Leads can be public enemy number one, and like coils, habitually blamed for ignition failure elsewhere followed by premature replacement, often with high cost, snake oil, after-market versions, too thick to fit existing separators.

• All quite unjustified because, from the get-go, their very nature demands outstanding insulating properties for safety and fire hazard reasons so, really, even lower cost original specification items should last a very long time.

• Unfortunately this presumes no abuse, such as pulling directly on the lead instead of the rubber boot when disconnecting from coil, plug or distributor, unwanted contact with hot exhaust pipes, neglecting to ensure they are fixed securely in their separators and failure to keep them clean.

Fortunately, Wise Owls hereabouts advocate, as follows:

carob said:

Bosch originals. Range Rover Classics from Halfrauds. After market been discussed lots of times. I went after market years ago and found myself ripping them out after a few running problems and sticking the originals back in and no problems whatsoever.

Rob

mrzigazaga said:

Save your money mate..Magnecor are shyte...Peoples opinion will of course differ but i have heard a few people say that they have changed them back to the cheaper variety, Which are also available in Red, Blue, Black...I have a standard set as recommended by Rover and they are as good as gold.

celcius said:

As above

Number 7 said:

Magnecore - don't get me started! A couple of mine broke at different times, and despite the so called lifetime guarantee,.....Slung the lot

I urge doubters to follow their advice.

One final point. Often it is an outcome that low resistance leads allow for a Larger Spark Plug Gap and a Hotter Spark. Whoopee!

To enable the hotter spark, the only common adjustment is that mentioned gap size. Opening the gap makes it more difficult for the spark to jump across, causing high tension components to try and build up a larger voltage before the spark will propagate. This added strain on the secondary components of the ignition system will inevitably shorten their life.

To avoid a predictable system breakdown, now all the Ignition Components have to be uprated, Coil, Insulators, Distributor Cap and Rotor Arm.

All so unnecessary in my honest opinion. Lots more stuff on ignition here:

http://www.vintagemodelairplane.com/pages/Download...

http://www.vintagemodelairplane.com/pages/Download...
.
.

[adam quantrill]

Hi HJ2, one thing I've wondered about is how the lead length is reconciled with the design, when using RISTS resistance leads? Some of the plug leads are twice as long as the others and therefore have twice the resistance (I have measured them, they range from 3k to 6k ohms).

Either this resistance is negligible compared to the gap resistance, and has no effect, so we may as well use copper leads, or there's a significant imbalance in spark strength (so... ditto).

[honestjohntoo]

adam quantrill said:

Either this resistance is negligible compared to the gap resistance, and has no effect, so we may as well use copper leads, or there's a significant imbalance in spark strength

At the simplest level, AT THE POINT WHEN THE SPARK JUMPS and the gap resistance becomes zero, effective suppression depends largely upon two constant components.

Lead Resistance and Lead Capacitance. The classic C x R circuit?

I have no idea what the capacitance value is or how it is measured, but it probably increases with lead length, ie somewhat proportional to Resistance.

However, if the lead Resistance is very low or zero, the Capacitance is still present, but the effective noise suppression is also very low or zero.

The resistance figure of 3000 up to 6000 ohms would be irrelevant regarding the minimum required spark energy, methinks.

The important thing being - Lead Resistance is not zero.

Of course there may be other factors at play - ie. Resistive spark plugs, primary side suppression condenser, Resistive boots, custom built resistance leads in numbered sets.

At the tender age of 76, my electronic fundamentals recall can range from - 'utter crap' to 'well thought out' - you decide?

[celcius]

I would like to thank you
HJ for the help you have posted many times on this forum .
I myself have been a bit stuck in the past and your info is priceless.
Cheers
Greg

Edited by celcius on Saturday 13th December 08:54