Engine 850: B5254S/2.4/20v: Iridium Spark PLugs?

[riffbiker]

I guess this may have been covered before, but I cannot find a thread on it.

I recently changed the spark plugs on my Yamaha Motorcycle to NGK Iridium of the correct compatibility - I must say there is a definite improvement: better cold starting and cold running (air cooled engine), a touch more power and improved fuel economy. There is also a difference in engine tone - it sounds more 'aggressive'.

I am therefore considering fitting NGK Iridium plugs to my 1996 (late issue) 850 CD, 2.5 litre petrol, 20v. The current plugs are Volvo branded and have been in for a few years and due for a replacement, not that they are causing any problems. I believe the NGK Iridium are single electrode and the Volvo OEM as currently fitted are multi-electrode.

Has anyone tried the NGK Iridium BKR6EIX (product code 6418) in their Volvo?

Your experience would be appreciated.

Best Regards.

[iamawookie]

Two schools of thought here... They're fine or don't do it!

You'll possibly find rough and lumpy running with them (I know have on 2 Volvos), switch back to gen volvo ones and issues are resolved.

[cookie]

They are like genuine volvo plugs, in as far as they fit, beyond that they are an expensive experiment, that many (if you search) have done b4, I did it years and years ago, and reverted back to genuine, they work, but don't last as long, and aren't as good, just order some genuine from Rufe (FRF volvo) or wherever, nearly all the highly modified T5's still run on stock plugs as there isn't anything better out there

[riffbiker]

Many Thanks to Iamawookie and Cookie,

That is just the sort of valuable experience I was looking for. Guess I'll stick with Volvo OEM then.

Much Appreciated!

[sdg1970]

An old thread but I'll add something. I've had iridium plugs in my 1997 V70R now for around 38,000 miles with no problems. Reckon I'll leave them in up to around 45000. I was just perusing various old threads here, as I was looking at the plug leads interval as I'm about to change them after 60000 miles/12 years.

[PSJVTHEBEST]

Just replaced genuine Volvo with genuine Volvo after scouring opinions across this forum. No issues with them at all under high load. That's not to say Iridium won't perform the same, of course. Perhaps the other thing to mention is that I had already replaced many of the items that could (mis)lead you down the path of thinking the plugs were to blame for a problem.

[riffbiker]

Wow - my old thread (flagged me by e-mail).

Thanks to the replies all those years ago, I never went down the Iridium route in my 850. Currently running genuine Volvo OEM which I changed again 18 months ago. Best value and sweet running!

sdg1970: Be very careful with your plug leads!!! The VERY BEST are the genuine original Volvo OEM ones, made by Bougicord (French), marked on the leads themselves Bougicord 403 Class C-1. These leads are Reactive / Wire Wound - a carbon-coated fibreglass core wrapped in stainless steel wire. They have an extremely long life - I am still running the ones fitted at manufacture in 1995 and they are perfect!

The outside of these Bougicord leads can be wiped clean with a damp slightly soapy cloth, wiped dry, and wiped over when clean with silicone lubricant spray (available from your UK major chain car and bicycle accessory supermarket). The integrity of the Bougicord leads can be tested with a digital multimeter set to resistance: ...

The spec for Bougicord as above is, nominally, resistance in Ohms Ω :
cyl. #1: 4,97 kΩ,
cyl. #2: 4,47 kΩ,
cyl. #3: 3,58 kΩ,
cyl. #4: 3,13 kΩ,
cyl. #5: 2,58 kΩ,
to ignition coil: 2,72 kΩ.
If measured resistance close to spec, then ignition leads need NOT be replaced.

The GENUINE sets for the 20-valve engine (Grey plug caps) are no longer available from Volvo, or from Bougicord (in France). The 10-valve (Blue plug caps) sets are available but INCORRECT for 20-valve engines!.

If you decide to change them, beware - the plug caps are DIFFERENT for 10-valve and 20-valve sets. 20-valve sets have GREY plug caps, 10-valve sets have BLUE. Some after-market suppliers list the cap colours incorrectly. The difference is the DEPTH of the plug cap, because of the different cylinder heads.

The GREY plug cap (20-valve) is 5mm shorter than the Blue (10-valve) plug cap.
Grey (20v) = O/A = 129.6 mm (5mm shorter than blue cap)
Blue (10v) = O/A = 134.6 mm (5mm longer than grey cap)

As I understand it, the difference in the type of cable used in the leads is its resistance which affects the way it interacts with the ECU programming, other cable types (there are several categories) will work but might lead to rough running.

If you have original Bougicord, check them carefully - they are probably fine.

Best Regards.

[PSJVTHEBEST]

Originally Posted by riffbiker

Wow - my old thread (flagged me by e-mail).

Thanks to the replies all those years ago, I never went down the Iridium route in my 850. Currently running genuine Volvo OEM which I changed again 18 months ago. Best value and sweet running!

sdg1970: Be very careful with your plug leads!!! The VERY BEST are the genuine original Volvo OEM ones, made by Bougicord (French), marked on the leads themselves Bougicord 403 Class C-1. These leads are Reactive / Wire Wound - a carbon-coated fibreglass core wrapped in stainless steel wire. They have an extremely long life - I am still running the ones fitted at manufacture in 1995 and they are perfect!

The outside of these Bougicord leads can be wiped clean with a damp slightly soapy cloth, wiped dry, and wiped over when clean with silicone lubricant spray (available from your UK major chain car and bicycle accessory supermarket). The integrity of the Bougicord leads can be tested with a digital multimeter set to resistance: ...

The spec for Bougicord as above is, nominally, resistance in Ohms Ω :
cyl. #1: 4,97 kΩ,
cyl. #2: 4,47 kΩ,
cyl. #3: 3,58 kΩ,
cyl. #4: 3,13 kΩ,
cyl. #5: 2,58 kΩ,
to ignition coil: 2,72 kΩ.
If measured resistance close to spec, then ignition leads need NOT be replaced.

The GENUINE sets for the 20-valve engine (Grey plug caps) are no longer available from Volvo, or from Bougicord (in France). The 10-valve (Blue plug caps) sets are available but INCORRECT for 20-valve engines!.

If you decide to change them, beware - the plug caps are DIFFERENT for 10-valve and 20-valve sets. 20-valve sets have GREY plug caps, 10-valve sets have BLUE. Some after-market suppliers list the cap colours incorrectly. The difference is the DEPTH of the plug cap, because of the different cylinder heads.

The GREY plug cap (20-valve) is 5mm shorter than the Blue (10-valve) plug cap.
Grey (20v) = O/A = 129.6 mm (5mm shorter than blue cap)
Blue (10v) = O/A = 134.6 mm (5mm longer than grey cap)

As I understand it, the difference in the type of cable used in the leads is its resistance which affects the way it interacts with the ECU programming, other cable types (there are several categories) will work but might lead to rough running.

If you have original Bougicord, check them carefully - they are probably fine.

Best Regards.

Excellent post, Riffbiker. Full of information and extremely useful to me having spent hours researching leads recently. I changed mine for 'VOLVO 850, 20v. 2.0, 2.5cc Formula Power ORIGINAL 10mm RACE Performance HTleads (180969774215)' from a company who make them up (Formula Power Ignition Leads) after a recommendation from I can't remember where as part of a scattergun, fault-finding exercise. But I kept the originals and will be checking them against your spec. Thanks again.

[Clan]

Originally Posted by riffbiker

I guess this may have been covered before, but I cannot find a thread on it.

I recently changed the spark plugs on my Yamaha Motorcycle to NGK Iridium of the correct compatibility - I must say there is a definite improvement: better cold starting and cold running (air cooled engine), a touch more power and improved fuel economy. There is also a difference in engine tone - it sounds more 'aggressive'.

I am therefore considering fitting NGK Iridium plugs to my 1996 (late issue) 850 CD, 2.5 litre petrol, 20v. The current plugs are Volvo branded and have been in for a few years and due for a replacement, not that they are causing any problems. I believe the NGK Iridium are single electrode and the Volvo OEM as currently fitted are multi-electrode.

Has anyone tried the NGK Iridium BKR6EIX (product code 6418) in their Volvo?

Your experience would be appreciated.

Best Regards.

Always use genuine volvo spark plugs they are the best you will get and designed to work with your engine.
If those NGK made that much difference to your motorcycle the old ones must have been well past it :-)

[sdg1970]

Originally Posted by PSJVTHEBEST

Excellent post, Riffbiker. Full of information and extremely useful to me having spent hours researching leads recently. I changed mine for 'VOLVO 850, 20v. 2.0, 2.5cc Formula Power ORIGINAL 10mm RACE Performance HTleads (180969774215)' from a company who make them up (Formula Power Ignition Leads) after a recommendation from I can't remember where as part of a scattergun, fault-finding exercise. But I kept the originals and will be checking them against your spec. Thanks again.

See my other thread, I asked precisely that question in terms of the Formula Power leads. I'll be getting them and I'd wager they're as good as Bougicord..