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Hi all.

Anyone running NGK Iridium plugs in their TR6? My plugs need replacing & thinking of getting some Iridium NGK BPRE IX but the suppliers “look up” table only lists them compatible with post 72, CR engine, (125 BHP) & not the earlier, CP engine (150 BHP); my 6 is also stage 2 tuned & possibly nearer 180 BHP, although I've never had it on a rolling road!

 

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22 minutes ago, Richard Crawley said:

Hi all.

Anyone running NGK Iridium plugs in their TR6? My plugs need replacing & thinking of getting some Iridium NGK BPRE IX but the suppliers “look up” table only lists them compatible with post 72, CR engine, (125 BHP) & not the earlier, CP engine (150 BHP); my 6 is also stage 2 tuned & possibly nearer 180 BHP, although I've never had it on a rolling road!

 

Welcome back Richard. They would be fine for your car.

Stuart.

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Hi there,

Iridium spark plugs do not bring any particular advantages in the TR6.
The situation is different with Bosch Super 4 spark plugs.
Designation WR78.
These are real multi-range spark plugs with 4 electrodes.
However, you should not use ignition cables with resistance.
Add a red Bosch ignition coil and it gets really bright in the cylinder.


Many greetings
Ralph

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I run Iridium plugs on my TR6 race engine (240 bhp) following enthusiastic recommendations from my engine builder. 

The rolling road operator that it goes to says they're a waste of money.

So who's got it right?

I've run them for 4 or 5 years without any problems but can't say that I've detected any major advantages either.

Dave McD

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I tried them in the MX5 Turbo on the rollers as a way of combating spark blow out and there was no advantage over std plugs in bhp and the spark was still being blow out as as nearing max boost. The solution was std plug with a better stronger spark from COP's which allowed a bigger plug gaps which cured the problem.

Iridium plugs are supposed to regress slower and last longer but over all IMO a waste of money. May as well change your plugs a bit more often.

Andy

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16 hours ago, Richard Crawley said:

Hi all.

Anyone running NGK Iridium plugs in their TR6? My plugs need replacing & thinking of getting some Iridium NGK BPRE IX but the suppliers “look up” table only lists them compatible with post 72, CR engine, (125 BHP) & not the earlier, CP engine (150 BHP); my 6 is also stage 2 tuned & possibly nearer 180 BHP, although I've never had it on a rolling road!

 

I used NGK Iridium plugs and was not impressed in a 1973 CR TR6. The spec. of the engine is also up graded.

Bruce

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I run Iridium plugs in a GM V8 because of their long life- the back plugs against the firewall are horrible to change. For my TR6 CP I use NGK BUR 6ET's- tried most plugs over the years but never found any as good , especially for anti fouling & reliable starting. The chaps that built my engine in the early 1990's said it would be good for 180 Hp at the back wheel.

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I have a tuned TR6 engine in mine, (head, cam, steel rods, TLE manifold, 2.5" exhaust), & used to run Lucas PI. This performed faultlessly on NGK 6BPES for tens of thousands of miles.

It is now converted EFI, & use NGK BKR 7EIX, due to the stronger spark (coil pack, etc).

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Oh, that's all very interesting! So is the general consensus, its all “hype” & not worth 3x the price? My 6 has only done limited mileage since completing it’s marathon nut & bolt rebuild in 2004 & this is mostly local with very few high speed, longish runs. I’ve been running NGK BP6ES but they seem to have a tendency to foul up fairly regularly &, as the plugs need replacing anyway, the “blurb” seemed to indicate they would improve things but maybe not!

I note the comment re Bosch 4 electrode plugs; I used to run these in my old BSA motor bike many years ago with good effect & initially considered these but thought Iridium might be better. Any more thoughts & suggestions greatly appreciated.

 

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I've been using NGK BUR6ET or Bosch WR78 in several Triumph sixes, standard and tuned, including my near standard CP series TR6. In my experience over more than 10 years, these multielectrode plugs give better starting, smoother idling and crisper pick up than single electrode NGK or Champion.

Nigel

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Hello All 

             I use Bosch WR78 in Spitty with ITB EFI and engine mods

But be aware there are 2 types and one has bigger gaps (I forget the numbers

Roger

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6 hours ago, Richard Crawley said:

Oh, that's all very interesting! So is the general consensus, its all “hype” & not worth 3x the price? My 6 has only done limited mileage since completing it’s marathon nut & bolt rebuild in 2004 & this is mostly local with very few high speed, longish runs. I’ve been running NGK BP6ES but they seem to have a tendency to foul up fairly regularly &, as the plugs need replacing anyway, the “blurb” seemed to indicate they would improve things but maybe not!

I note the comment re Bosch 4 electrode plugs; I used to run these in my old BSA motor bike many years ago with good effect & initially considered these but thought Iridium might be better. Any more thoughts & suggestions greatly appreciated.

 

Hi Richard,

Don't get me wrong. If you're in and out of the garage on choke, or going up the Alps and you foul a plug, that is pretty much it. Fit a new one.  I am not sure if there are better plugs that would survive better in this regard.

 

That said, if you are only using the car in the UK, and not going in and out of the garage on choke, or doing very small journeys, you should not foul a plug. If you are fouling plugs, frequently & easily, your MU is probably set too rich ?

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3 hours ago, TRTOM2498PI said:

Hi Richard,

Don't get me wrong. If you're in and out of the garage on choke, or going up the Alps and you foul a plug, that is pretty much it. Fit a new one.  I am not sure if there are better plugs that would survive better in this regard.

 

That said, if you are only using the car in the UK, and not going in and out of the garage on choke, or doing very small journeys, you should not foul a plug. If you are fouling plugs, frequently & easily, your MU is probably set too rich ?

I've had my TR since 1975 so know all about "choke" control but the PI doesn't have a choke on the air supply, as in the old conventional style, it has an excess fuel lever on the MU which isn't quiet the same; that said, I appreciate over-fueling can foul the plugs & I appreciate firing up the car between infrequent runs is not ideal. My TR does have an uprated MU, supplied by the PI "Godfather" himself, which was regulated in line with my state of engine tune & the + fuel setting at higher revs probably isn't helping but exhaust pipe & plugs don't show signs of excessive richness &, having spent all that money, I'd be reluctant to downtune the fuel supply & loose the extra power the engine tune has given. It's always been mainly cylinder 5 that gets the problem which may indicate some other underlying problem with the MU, distributor or induction but I'm not about to rip things apart to investigate what is really just a minor annoyance. My particular circumstances are not ideal I admit but everything else is fin & I'm just looking for a plug that might cope better, what ever configuration or heat range.

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On 2/25/2022 at 9:19 AM, Dave McDonald said:

I run Iridium plugs on my TR6 race engine (240 bhp) following enthusiastic recommendations from my engine builder. 

The rolling road operator that it goes to says they're a waste of money.

So who's got it right?

I've run them for 4 or 5 years without any problems but can't say that I've detected any major advantages either.

Dave McD

Your rolling road operator!  My business used to sell motorcycles and when Iridiums first became available here we were told by the supplier that they would eliminate plug fouling in high performance two-strokes.  We found out pretty quickly that they fouled just as easily as the standard plug but at many times the price.  We ended up advising customers to run the standard plugs for that reason.  They're not designed to avoid fouling on an engine which is prone to this happening such as the TR6, their purpose is long life for those engines that have plugs in places with difficult access and are capable of functioning for in excess of 100,000 km.  I run the BUR6ET as do many others.

Gavin

Edited by KiwiTR6
grammar
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17 hours ago, rogerguzzi said:

Hello All 

             I use Bosch WR78 in Spitty with ITB EFI and engine mods

But be aware there are 2 types and one has bigger gaps (I forget the numbers

Roger

The difference is the length of the thead.

WR78G has the short thread for the TR 4 cylinders, this is the one I use on my 4A,

WR78X has the long thread for the TR 6 cylinders.

Ciao, Marco

Edited by Z320
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11 hours ago, Richard Crawley said:

I've had my TR since 1975 so know all about "choke" control but the PI doesn't have a choke on the air supply, as in the old conventional style, it has an excess fuel lever on the MU which isn't quiet the same; that said, I appreciate over-fueling can foul the plugs & I appreciate firing up the car between infrequent runs is not ideal. My TR does have an uprated MU, supplied by the PI "Godfather" himself, which was regulated in line with my state of engine tune & the + fuel setting at higher revs probably isn't helping but exhaust pipe & plugs don't show signs of excessive richness &, having spent all that money, I'd be reluctant to downtune the fuel supply & loose the extra power the engine tune has given. It's always been mainly cylinder 5 that gets the problem which may indicate some other underlying problem with the MU, distributor or induction but I'm not about to rip things apart to investigate what is really just a minor annoyance. My particular circumstances are not ideal I admit but everything else is fin & I'm just looking for a plug that might cope better, what ever configuration or heat range.

Hi Richard

I had a fouling problem with cyls 5 & 6 so I copied a few on here and replaced 5&6 with the hotter BP5ES plugs and kept BP6ES in the front 4, I haven’t had any problems since doing this.

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12 hours ago, Richard Crawley said:

I've had my TR since 1975 so know all about "choke" control but the PI doesn't have a choke on the air supply, as in the old conventional style, it has an excess fuel lever on the MU which isn't quiet the same; that said, I appreciate over-fueling can foul the plugs & I appreciate firing up the car between infrequent runs is not ideal. My TR does have an uprated MU, supplied by the PI "Godfather" himself, which was regulated in line with my state of engine tune & the + fuel setting at higher revs probably isn't helping but exhaust pipe & plugs don't show signs of excessive richness &, having spent all that money, I'd be reluctant to down-tune the fuel supply & loose the extra power the engine tune has given. It's always been mainly cylinder 5 that gets the problem which may indicate some other underlying problem with the MU, distributor or induction but I'm not about to rip things apart to investigate what is really just a minor annoyance. My particular circumstances are not ideal I admit but everything else is fin & I'm just looking for a plug that might cope better, what ever configuration or heat range.

I have always had trouble with cylinders 5 & 6 the plugs coming out very black from new. I took advice from SAH and fitted a hotter plug in those 2 cylinders a grade 5 and not 6, problem gone! That was 40+ years ago!!!!

Bruce.

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3 hours ago, Kevo_6 said:

Hi Richard

I had a fouling problem with cyls 5 & 6 so I copied a few on here and replaced 5&6 with the hotter BP5ES plugs and kept BP6ES in the front 4, I haven’t had any problems since doing this.

Oh thats interesting; I now seem to remember reading a post about this some years ago, maybe I'l try it.

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Hello Marco

                    This is what I mean and I had a set of each and I check the gaps and it is correct.

This was from the Sideways forum

Hi Roger

the wr78x has en increased distance between the 4 mass electrodes and the center electrode.

i think itś 1,1mm for the x and 0,9mm for the standard -but dońst nail me on the values.

i use the x with megasquirt/ edis coil and the standard wr78 in my sons fast road spitfire engine with 123ign and golden lucas coil ( which is is not tuned yet…)

cheers

Patrick

Roger

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9 minutes ago, rogerguzzi said:

Hello Marco

                    This is what I mean and I had a set of each and I check the gaps and it is correct.

This was from the Sideways forum

Hi Roger

the wr78x has en increased distance between the 4 mass electrodes and the center electrode.

i think itś 1,1mm for the x and 0,9mm for the standard -but dońst nail me on the values.

i use the x with megasquirt/ edis coil and the standard wr78 in my sons fast road spitfire engine with 123ign and golden lucas coil ( which is is not tuned yet…)

cheers

Patrick

Roger

I did not notice that,

I have 2 spare sets and will measure

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