My 1984 GK 75bhp high compression engine is specified to take Bosch W5DTC plugs with three earth electrodes.

These are cold plugs that conduct more heat to the head by having a short insulator nose.

 

I ran Champion N6BYC (I think, maybe N9YC like original Mini cooper), then Beru UX56 when I could not find W5DTC any longer.

Switched to Brisk LR14YS (silver intended for LPG) which were brilliant, but they are now carbon fouled since my rebuild with timing wrong and mixture too rich.

I suppose the carbon will burn off eventually when mixture right, but wanted some new plugs to try from scratch, eg read the ceramic nose after plug cut trial..

 

(I'll fit my AFR gauge soon but the wiring hurts my head).

 

Q1.

Can I clean the fouled plugs of carbon off the car?

 

So I found some bargain Bolk c051150 on Mister Auto for Polo 75hp

http://www.mister-auto.co.uk/en/spark-plugs/bolk-bol-c051150_g686_a999BOL-C051150.html

that turned up today as Flaxcar 43013z.

http://webcatalogue.klaxcar.com/catalogue/en/product/43013z

 

They have 3 electrodes like the W5DTC, nice.

But, pretty sure these are Bosch heat range 7 equivalent for 1985 pre-cat Polo 1.3 by looking at equivalents like Beru Z91.

 

Q2.

Anyone recommend some Bosch heat 5 equivalent plugs? Must be cheaper than G40 scene tax items.

 

 

Edited 3 August, 201610 yr by dvderlm
6 or 9 Champion is cold?

Bolk? Flaxcar?! They sound like sh-ite. If you try to clean em, they may foul again quickly.

 

Use NGK plugs all day long, BPR6ES is the 'normal' single electrode plug, so try a colder one like BPR7ES for your engine, or if you want to spend a bit more go for BPR7EIX (or BPR8EIX even colder) those are platinum fine tip for low fouling if you're getting that happen.

 

Also don't fcuk around with plug cuts, it's the 21st century and we have lambda gauges now :)

 

The 3 electrode thing is for extra long life, there's more earth strap to heat up & det, so not entirely performance orientated

typo: I meant Klaxcar

 

Not fitted em yet. Look alright but for long insulator nose (and 16mm spanner size not 21mm).

They'll likely run too hot. It's the Brisk silvers I want to clean.

 

Think the 43046z is Bosch heat 5.from findpart.org. The klaxcar equivalence chart is very vague

http://www.klaxcar.com/images/pdf/CORRESPONDANCES/bougies allumage.pdf

 

NGK led me to bp6et / 1263 which is much more like W5DTC so thanks for that.

and opieoils sell them

http://www.opieoils.co.uk/pv-78417-ngk-spark-plug-bp6et-ngk-1263-single-plug.aspx

 

and found there are NGK Racing plugs for sustained high load/supercharged/nitrous.

Edited 4 August, 201610 yr by dvderlm
forgot to say thx

4 electrode not for performance?

 

beru ux56 suitable for

 

http://www.bandel-online.de/zuend-_/_gluehanlage/zuendkerzen/1_original_beru_zuendkerze_ux56_0002345600_alfa_romeo_alpine_audi_austin_i117_67212_0.htm

• alfa Romeo gtv
• audi Avant 100
• BMW 02 touring
• Ferrari  512bb
• fiat ritmo/strada 125tc abarth
• lancia thema v6
• lotus esprit
• maserati ghibli
• Porsche 911
• Saab 99 turbo
• Talbot simca 1100 TI (82bhp 1294cc twin Weber engine from Matra simca bagheera)
• Triumph tr6
• VW polo 1.3 75ps

and Renault Fuego! ... the ultimate hairdresser's car.

 

 

Edited 4 August, 201610 yr by dvderlm

You ask about plug cleaning. DO NOT use a wire brush on them - especially on the internal insulator, as it will tend to make the 'spark' track along the marks that it will leave.

You COULD try putting the plugs in a heat-proof container with some petrol and set fire to them.

As you say, the carbon should burn off when the mixture is correct and the engine is hot.

Regards

Think the klaxcar catalogue has been updated.

A 43032z is claimed to be Beru UX56 compatible or WR56 and WR78X Bosch so very wide.

 

http://www.klaxcar.com/images/pdf/CORRESPONDANCES/bougies allumage.pdf

 

The 43043z is WR8 or NGK BP5EIX so hot.

 

The 43013z is allegedly FR78. No problems with a set for 500 miles. Just has a small nut size.

I'm fairly sure the 43032z is not cold enough for high altitude, high engine load in the GK engine which needs Bosch heat range 5.

It's fine around sealevel of East Anglia.. 

 

 

Think I went into zone C of this chart, due to the fuel mixture richening at altitude (less oxygen molecules for the same fuel)  plus high air temp on A66 fairly near Stainmore 

and A74M near Beattock - both 1000feet or more above sea level. 

Mikuni advice http://www.iwt.com.au/mikunicarb.htm is to lean slightly for altitude  and I normally run lean at cruise as at sea level.  I had just cleaned the air filters, but a straw lorry

had put lots of loose straw into the air. I did find straw fragments on the filters over the trumpets.

 

I was definitely over 75% engine load climbing the hills. I had 120 main jet 200 air with .10 tube. Think I was at 12.4AFR when power dropped. I'll try to  see what the AFR gauge recorded, but maybe it was 3 cylinders at 11:1 and 1 not sparking

to read 12.4:1. 

 

 

 

Nothing obvious from the AFR data.

Checked compression (with cold engine, well 30degrees in the sun) and cylinder #1 is at 14.5 bar dry and 15.2 bar wet, while the others are nearly 16bar dry.

Fitted some Champion N64Y (cold mini cooper rally plugs). 

Reduced maximum advance to 30degrees (on the +5 static) for added safety. it was 32+5 from 3500rpm, so near the knock limit for 11:1 bowl in piston engine (I filled with Momentum 99 at Carlisle Tesco. Expect it is same octane as in Cambridge) .

 

It starts and sounds normal, not like a dragster crossed with a tractor as it did between recovery truck relays.

I'll retry compression with warm engine.

 

 

Compression with warm engine (dry) in bar  for cylinder 

1. 14,
2. 15,
3. 15.2,
4. 14 

I'll have to dig out the figures from before the rebuild.

I suppose cylinder 1 is coolest as gets coolant first, but there may be some ring damage or valve damage for the 2 whose plug tips melted and shorted.

 

Wear limit is 11 bar, so I may have got away with it

 

 

I may be a bit old fashioned, but unless you are thinking of flying above about 10,000 feet, I wouldn't even bother about altitude.

Concentrating on mixture and ignition timing would make far more sense.

We could argue all day about the pros and cons of single v multi electrode plugs - each have their followers, but at the end of the day, you pays your money and takes your choice.

Heat range, is of course, very important - the snag is though, that it is an expensive hobby to keep changing plugs in order to find the ideal ones for your engine.

 

I wouldn't worry too much about those compression figures, in any case, there is always the possibility that a small amount of oil entered the cylinders when the plugs were removed, causing a higher reading.

 

Regards

That's a relief about the compression figures. Bloody Draper gauge says a difference of 1 bar is cause for concern and #1 and #4 had the melted plug tips.

 

I was running Brisk LR14YS for about two years (16,000 miles?) before changing to Flaxcar 43032z. Those managed 1,150 miles before hills at 1000 feet killed them.

Anyway I have found some New Old Stock Bosch W5DTC, but the Brisk (silver electrode!) jobbies are good for 30,000km (nearly 19,000 miles) so I might refit them instead of the N64Y.  

 

I also found this W5DTC alternatives list

• Autolite 9062
• Beru 14-5DTU
• Beru UX56
• Beru Z44
• Brisk LR12TC
• Brisk LR12YS
• Brisk LX14TC
• Champion N6BYC
• Champion N7BYC
• Champion OE012
• Champion OE109
• Champion RN7BYC
• Denso 5066
• Denso 5307
• Denso IW22
  Denso VW22
• Denso W22EPB
  Eyquem C82LS3X
• Iskra FE85PTRS
• Lodge 25HL
• NGK 1263
• NGK 3684
• NGK BP6ET
• NGK BP7ET
• NGK BUR6ET
• NGK V-line-1
• Torch F6TJC
• Unipart GSP4347
• Valeo 246859

The old Brisk LR14YS look good at tip, but one of them has a loose central core inside ceramic insulator from top. yep, it came apart in my hand. Not seen that before. That's probably why I felt they were ready for change, spark would have been a bit intermittent.

Brisk themselves say the even colder LR12YS is W5DTC equivalent

http://www.brisk.eu/catalogues/spark-plugs/comparison/w5dtc

Reason the spark plug tip melted going rich at altitude. This chart shows exhaust gas temp rise of  200 degrees from AFR 14 to AFR 12

(though cylinder head loses 15 degrees) , which is around one heat range band.

 

Also look at the max power band percentage of max power and fuel used. Why go any richer than 13:1?

Drove with Champion N64Y plugs today in colder damper weather and it's great. Took a bit longer to be responsive from initial start that needed choke for 15 seconds, then was a total joy. 

Edited 9 August, 20188 yr by dvderlm

Found some Bosch 0242245514.

(also known as N 01781144  or WR5DS Bosch silver) for a bargain £2.11 each.

 

I don't think there can be many Audi Quattro or Ferrari Mondial  owners who change their own plugs.