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[JamesV6CDX]

...The quad-electrode plugs can be retro-fitted to older cars than came originally with the twin-electrode, but the performance gains are very small if at all....

Correction: the quad-electrode spark plugs are meant to increase the service interval from 40k/4y to 80k/8y, so this is not performance related, but personally I would change them every 40k/4y anyway (which is what I did on mine).

I would still change at 20k

I agree with this.

If I have a nice car, I always do mine at 10-15k... probably OTT, but it's not exactly a big job..

[Martin_1962]

Plug changes, well I remember them from years ago

Leaded petrol killed plugs, a 2 storke would need plugs probably every 3 or 4 thousand.

They used to be changed every 10,000 on cars.

Unleaded greatly increased life, 20,000 minimum life span now it seems.

[Taxi_Driver]

Plug changes, well I remember them from years ago

Leaded petrol killed plugs, a 2 storke would need plugs probably every 3 or 4 thousand.

They used to be changed every 10,000 on cars.

Unleaded greatly increased life, 20,000 minimum life span now it seems.

As MJ says quad electrode....vx recommend 80k......twin....40k

I change mine every 10k with twins.....your pushing it a bit Martin....seeing as your on lpg  

[Martin_1962]

Plug changes, well I remember them from years ago

Leaded petrol killed plugs, a 2 storke would need plugs probably every 3 or 4 thousand.

They used to be changed every 10,000 on cars.

Unleaded greatly increased life, 20,000 minimum life span now it seems.

As MJ says quad electrode....vx recommend 80k......twin....40k

I change mine every 10k with twins.....your pushing it a bit Martin....seeing as your on lpg  

With plugs usually of they look OK they are OK

I reckon 20,000 with LPG and NGK

[paul.c]

i had quads on my cav sri for a couple of years took them out and they still looked new

[Markjay]

I actually replaced my original set of quad-electrode at 40k (instead of the 80k quoted by Vx). The old plugs seemed OK and there was no noticeable difference to the engine... so I recon 40k is about right.

These are the 6 Bosch plugs that were factory fitted to my car and came out at 40k:




Yes in the olden days we used to re-gap every 3k and replace every 6k... but spark plug last very long these days. My wife's Toyota is specified as 100,000km (63k miles), and the Toyota garage said to stick by it - they refused to change them at the 30k service even though I specifically asked them to...

[Andy B]

........ My wife's Toyota is specified as 100,000km (63k miles), and the Toyota garage said to stick by it - they refused to change them at the 30k service even though I specifically asked them to...

A friend had a Camry years ago, plugsfor it were around £30 a piece. If they're still as 'cheap' perhaps that's why they leave 'em in fro 100 000kms.  

[Kevin Wood]

My quad electrodes were still fine when changed at 40k. Thinking about it, they're in my wife's MX-5 now after a substitution when chasing a misfire

Quad electrodes gives more surface for the spark to eat away at and therefore longer life but no other significant benefits. In fact the spark is slightly more shrouded by the extra electrodes.

Kevin

[Marks DTM Calib]

The original plugs for the 2.5/3.0L V6 were twin-electrode, later V6 engines came with the quad-electrode plugs. The quad-electrode plugs can be retro-fitted to older cars than came originally with the twin-electrode, but the performance gains are very small if at all.

So your 'Bosch Super-4' will be fine, and as said you need to buy two more. Incidentally, the correct Bosch model for the Omega B V6 is designated '520'.

Its worse than that, the peformance gains are zero and the quads in theory only offer extended plug life.

Given that the twin electrode ones last 40K miles and its not unknown for the quads to work loose before the 80K service life specified and considering that the extra electrodes can actulay hinder the flame front…..

….. I would buy standard twin electrode Vx ones.

[Markjay]

Incidentally, the quad-electrode idea is not a new one... the original plugs in my 1979 Alfa Romeo were Lodge 2HL, which were quad-electrode. Butt somehow the idea did not catch-on until recently. Not to be confused with Alfa's 'Twin Spark', which means two spark plugs per cylinder, and which similarly did not catch-on outside Alfa Romeo...

[Marks DTM Calib]

Incidentally, the quad-electrode idea is not a new one... the original plugs in my 1979 Alfa Romeo were Lodge 2HL, which were quad-electrode. Butt somehow the idea did not catch-on until recently. Not to be confused with Alfa's 'Twin Spark', which means two spark plugs per cylinder, and which similarly did not catch-on outside Alfa Romeo...

Unless on an aero engine or a 1928 Rolls Royce Phantom Two.....yes, its was not Alfa who were first to use it!

[Martin_1962]

Quad electrodes gives more surface for the spark to eat away at and therefore longer life but no other significant benefits. In fact the spark is slightly more shrouded by the extra electrodes.

Kevin

This is why they are not recommended for LPG conversions

[Markjay]

Incidentally, the quad-electrode idea is not a new one... the original plugs in my 1979 Alfa Romeo were Lodge 2HL, which were quad-electrode. Butt somehow the idea did not catch-on until recently. Not to be confused with Alfa's 'Twin Spark', which means two spark plugs per cylinder, and which similarly did not catch-on outside Alfa Romeo...

Unless on an aero engine or a 1928 Rolls Royce Phantom Two.....yes, its was not Alfa who were first to use it!

I see... well I did not have either one of those so I wouldn't know!  

[Marks DTM Calib]

Yep, the Rolls has an impressive setup…..two plugs per cylinder and two distributors (one at the front of the engine and one at the rear) which are linked by a small prop style shaft. This shaft has a centrifugal advance setup in it so as the revs increase the time between the sparks reduces…..a REAL work of art.

But then on a car currently worth best part of 500K!