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After a few days of rain it was dry today so I took the TR6 for a run.

Towards the end of a very enjoyable 45 minute drive (over the ANZAC, Sydney Harbour and Gladesville Bridges) and quite near my place I pulled up behind a Healey 100/4. We stopped for a chat, not too many Brit cars in our area.

I had the car idling for maybe 5-10 minutes. Of course the plugs had fouled up so I tried an Italian tune. This did clear them but living in a built up area the opportunity wasn't there for a really good blast.

I ended up pulling the plugs and wire brushing them, checked the gaps and a test drive showed all is good. I only use BP 98 octane, regarded here as the best for our cars. Fuel consumption seems normal for a PI living near a major city, about 15-18 mpg around town and 25 mpg on a trip.

Do other PI owners have the same problem?

I'd like to know what plugs PI owners are using and what gap they are setting them too. The book says 25 thou which seems small to me, the TR2 is 32 thou.

 

IMG_3461.JPG

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Yes, I am afraid so. I try to avoid leaving the car at tickover, use choke only to start the car (pushing it almost immediately and try to use the car over distances that get everything, including the plugs, up to temperature. But every now and again the plugs will need drawing and cleaning.

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John I would try a hotter running plug. Sounds like your PI is running ok from the figures you have supplied and I don't know which brand of plugs you are using but I find the NGK BP6ES to be fine for me so just as an exercise try using NGK BP5ES or BPR5ES if you need a resistor plug. These run hotter than the 6ES and might, just might, help with your "city fouling" of your plugs. Its certainly a cheap starting point in your quest.

Alan G

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22 minutes ago, cp25616 said:

John I would try a hotter running plug. Sounds like your PI is running ok from the figures you have supplied and I don't know which brand of plugs you are using but I find the NGK BP6ES to be fine for me so just as an exercise try using NGK BP5ES or BPR5ES if you need a resistor plug. These run hotter than the 6ES and might, just might, help with your "city fouling" of your plugs. Its certainly a cheap starting point in your quest.

Alan G

The car has electronic ignition (Lumenition) and the ballast resistor has been disconnected.

I currently have Champion N12YC plugs. They have performed very well but I'm thinking a slightly hotter plug might be better.

I have a set of RN14YC but as the resistor has been disconnected they wouldn't be suitable.

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6 minutes ago, John McCormack said:

I have a set of RN14YC but as the resistor has been disconnected they wouldn't be suitable.

Why? The plug resistance is only there in the HT side to reduce interference with radios. If you have silicone plug leads they do exactly the same thing. There is no comparability between that and the ballast resistor in the LT side of the coil which prevents a low-voltage coil from overheating. 

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26 minutes ago, RobH said:

Why? The plug resistance is only there in the HT side to reduce interference with radios. If you have silicone plug leads they do exactly the same thing. There is no comparability between that and the ballast resistor in the LT side of the coil which prevents a low-voltage coil from overheating. 

Thanks Rob. I am a numpty on anything electronic. The 14 plugs are hotter so using them should reduce fouling?

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1 hour ago, cp25616 said:

John I would try a hotter running plug. Sounds like your PI is running ok from the figures you have supplied and I don't know which brand of plugs you are using but I find the NGK BP6ES to be fine for me so just as an exercise try using NGK BP5ES or BPR5ES if you need a resistor plug. These run hotter than the 6ES and might, just might, help with your "city fouling" of your plugs. Its certainly a cheap starting point in your quest.

Alan G

I keep away from resistor plugs as they cut down the intensity of the spark. Lessons learnt from my motor cycle days! The plug that i use is NGK BP5ES on all cylinders. Your problem could also be that your M/U is running too rich? R type plugs are not required if using suppressed HT leads as most cars are?

Bruce.

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1 hour ago, John McCormack said:

The 14 plugs are hotter so using them should reduce fouling?

It's certainly worth a try, they can do no harm (except perhaps to introduce running-on if they are too hot). Bruce is right that you don't need both resistive plugs and suppressed leads but it wouldn't hurt for the purpose of an experiment to see whether they cure the fouling.

For the record, resistor plugs do not materially reduce spark intensity any more than do resistive leads. All they do is slow down the very front edge of the discharge to reduce radio-frequency noise.  Using suppressed plugs and leads together might give some effect if the ignition system is very marginal.

 

Edited by RobH
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58 minutes ago, Mike C said:

Used to have this problem with BP5ES and BP6ES plugs. Never had it since I switched to NGK BUR6ET triple electrode plugs.

+1

I've used only multi electrode plugs in my Triumphs for years, TR6 on Lucas PI and a GT6 on carbs.

NGK BUR6ET or Bosch WR78 plugs seem more resistant to fouling plus give smoother idling and crisper pick up.

Nigel

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18 minutes ago, Nigel Triumph said:

+1

I've used only multi electrode plugs in my Triumphs for years, TR6 on Lucas PI and a GT6 on carbs.

NGK BUR6ET or Bosch WR78 plugs seem more resistant to fouling plus give smoother idling and crisper pick up.

Nigel

Hi Nigel,

Which type do you prefer Bosch or NGK?

Bruce.

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Hi Bruce,

I can't discern any difference between Bosch or NGK multi electrode plugs, both are better than single electrode.

Some say that once an NGK plug has been sooted up it will never completely recover even after cleaning, and will forever be prone to misfiring and fouling again. I believe this is thought to apply to single electrode NGKs. Can't say I've experienced this problem; no such concerns have been expressed about Bosch. May be hearsay?

So to summarize, I would recommend Bosch and NGK multi electrode plugs.

Nigel

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On my Pi I use  BP6ES for plugs 1-4 and BP5ES for plugs 5-6 (bulkhead end)

5&6 always were the sootiest, furthest from the air intake I assumed. And since using the hotter plug in 5&6 all plugs are typically evenly brown'ish.

As 1-4 looked ok fitting the hotter plug in those would not have been good. No reason not to mix plug heat rating.

 

Alan

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7 minutes ago, barkerwilliams said:

On my Pi I use  BP6ES for plugs 1-4 and BP5ES for plugs 5-6 (bulkhead end)

5&6 always were the sootiest, furthest from the air intake I assumed. And since using the hotter plug in 5&6 all plugs are typically evenly brown'ish.

As 1-4 looked ok fitting the hotter plug in those would not have been good. No reason not to mix plug heat rating.

 

Alan

I have done the same and I’ve had no plug fouling since.

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Raining again today. I put the RN14YC plugs in and it starts and drove for a few hundred metres without issue. The rain was getting heavier so I didn't want to go further.

After cleaning the old plugs yesterday I took the car for a couple of km drive and today they were brown with three (3, 4 and 6) slightly darker but still brown. Overall the mixture looks pretty well setup.

I like the idea of the BUR6ET but they cost a bit.

Edited by John McCormack
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Multi electrode plugs are a little more expensive but will last 20-40k miles according to modern car service schedules.

That makes them much cheaper on a per mile basis... If you cover enough miles.

Nigel

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Hello
We build Bosch WR 78 into every TR 6 machine.
I drove a service life of over 60,000 km myself.
Insensitive to fatty mixtures.
Hand on it for PI'S the best spark plugs!
But the voltage supply for the spark plug must also be top-notch. I think that explains itself.
Ralf

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Hallo Ralph,

good to hear. If you say voltage supply must be top notch, what HT leads and coil do you use/prefer?

Thanks,

Waldi

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3 hours ago, michaeldavis39 said:

Just ordered the Bosch WR78, £24.78 including 2nd class delivery from Green Spark Plug Company- that is not expensive- is it??? To me it isnt.

Michael

That's a very good price. About half of what  my last  set of BUR6ET's cost in Australia.

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