(Slight) mystery NGK spark plug number...

[Deleted]

Short version first.
A specific question: Does anyone have any direct experience of using an equivalent spark plug to NGK ITR4A15 they can recommend as being the same heat range, same capability, but not an expensive Iridium tipped plug?

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Longer version with more context for the question...

My recently purchased new old car came with a set of 8 NGK ITR4A15 spark plugs installed. The NGK stock number is 5599. My plugs look like they may have been in there for some time and I'm thinking I might order a new set in, ready to swap them at the appropriate time.

So, I can go online and find NGK ITR4A15 on Amazon and Ebay, as sold by various sellers who have names like Zyeunchen and Chowfanloom, who all assure me theirs are the real deal legit NGK spark plugs and I shouldn't worry about them being fake because they are definitely not fake, okay?

But my usual, reputable go-to UK suppliers don't have this part number or stock number listed (eg Demontweeks, BurtonPower and others)

Furthermore, checking those numbers on NGK UK and NGK US also draws blanks. NGK do not list them as far as I can see. This I find odd given that NGK UK have a (user unfriendly) old/new x cheap/expensive part number comparison pdf available.

There clearly are legit NGK ITR4A15 spark plugs out there but I'm mystified by NGK's lack of representation in their own catalogues and product reference tools.

Thing is, these are gosh darn expensive spark plugs and I'm quite interested to find their equivalent plug... one that is not fancy Iridium tipped, and is simply a well performing standard spark plug for less than a tenner per plug (I need eight of them, see). For example, Green Spark Plugs have them listed bu with tax they are a whopping £14 each. None of the online spark plug cross reference tools list this plug so I can't find an alternative to use instead.

So I'm wondering if anyone out there has any info on NGK ITR4A15 and any potential alternative plugs at a more reasonable price I could swap out for (but based on experience, not random opinion, thanks)

Green Spark Plugs are reassuringly expensive ...



A.N.Othersan's worryingly reassuring offer with charmingly 1980's Kodak Disc camera packshot....

[Deleted]

What I do know, to save the sleuths amongst us a bit of time is that this plug is Iridium Tipped, a Resistor type plug, it's heat rating is 4 on NGK's scale, and the plug gap is 15.

What I don't know is what the A could imply, and also whether the gap is demonstrably different between a dinky little iridium tip and a more standard square top tipped plug.

But scrub that, my question is... does anybody have a recommendation for a cheaper alternative to NGK ITR4A15 they can recommend based on user experience?

[Woofwoof]

Just for your own reference there's plenty of fake NGK Iridium plugs for sale. Nearly fell into that trap not so long ago when buying long life plugs. Some seller's with 'strange names' were offering them @ 20 bucks for four.

See here: www.ngkntk.com/press-media/social-news/emea/fake-products-how-to-avoid-them/?fb=EMEA&cHash=cbfc902e74e78b90ea24f2a12d8b62c0#targetText=What's%20the%20difference%20between%20the,iridium%20on%20the%20centre%20electrode.

[Woofwoof]

Just had quick look and NGK don't list those plugs for cars only boat engines, Mercruiser & Volvo-Penta.

www.ngkntk.com/part-finder/produktfinder/////ITR4A15//

[Deleted]

Oct 29, 2019 12:50:38 GMT Woofwoof said:

Just had quick look and NGK don't list those plugs for cars only boat engines, Mercruiser & Volvo-Penta.

www.ngkntk.com/part-finder/produktfinder/////ITR4A15//

Oh cool. At least you've actually found them on an official part finder*. I couldn't find them. Gives me something to go on. Might find them at a local Chandlery or somesuch, or cheaper on a boat supplier's website. Cheers.

(and no, I'd never buy any plugs via an unaccredited reseller. It's just asking for very expensive trouble!)



* Ha. Maybe not. The link goes to a 404. The mystery apparently continues!

[gtviva]

Would you not be better speaking to one of the Merican car parts places to see what they recommend for that engine?

[Deleted]

Oct 29, 2019 13:09:35 GMT gtviva said:

Would you not be better speaking to one of the Merican car parts places to see what they recommend for that engine?

It's not a standard manufactured engine. It's a performance-based rebuild. The engine builder recommends NGK ITR4A15, and everyone I've asked who runs this engine uses NGK ITR4A15 too as a result. I'm just curious to know whether anybody happens to have switched between the NGK plug and another non-Iridium NGK plug or another brand's non-iridium plug. It's just on the off-chance somebody can recommend another plug for me to go and read about to see if it would suit my needs.

[welshpug]

I'd be looking up the dimensions and cross referencing to a standard ngk myself, gsp have details for most plugs and can do the x-ref o n the website

[Deleted]

Oct 29, 2019 14:34:05 GMT welshpug said:

I'd be looking up the dimensions and cross referencing to a standard ngk myself, gsp have details for most plugs and can do the x-ref o n the website

Unfortunately this plug doesnt come up on plug cross-referencing tools for whatever reason. GSP seem to only allow searching by car details, and my engine is a non-standard jobbie.

[Woofwoof]

I reckon this plug is somewhat unique as it's recommended for marine engines (probably large bhp too) and there's no cross reference back to a standard non Iridium plug. Well, I say that judging by the NGK website.

Probably, wise just to use the same plug again or equivalent from Bosch etc, after all they are a longlife plug so possibly no more expensive in the long term?

[Deleted]

Error post deleted

[Deleted]

Oct 29, 2019 15:20:12 GMT Woofwoof said:

I reckon this plug is somewhat unique as it's recommended for marine engines (probably large bhp too) and there's no cross reference back to a standard non Iridium plug. Well, I say that judging by the NGK website.

Probably, wise just to use the same plug again or equivalent from Bosch etc, after all they are a longlife plug so possibly no more expensive in the long term?

Yes that's where I'm panning out with this too. I'm also thinking that at those prices I wont be changing my spark plugs on a weekly basis

[Darkspeed]

Are you changing out these long life plugs because they have already done 10's of thousands of miles/hours and are breaking down or because you think they should be changed for one reason or another? The reason these things are expensive is that they are pretty well supposed to last the life of the engine at thousands of running hours. Change them if the breakdown not if you just "think" you need new plugs.

I would take the time to recommend a stock NGK/Bosch etc. plug but there is little point as you would just ignore it anyway. They are $8 at Summit so at least you can think you are getting a bargain and buying a performance item - Until shipping and duty that is - and it dawns that this is just a stock plug sold for high miler yank tin and nothing to actually do with "Performance".

[Deleted]

Oct 29, 2019 17:31:09 GMT Darkspeed said:

Are you changing out these long life plugs because they have already done 10's of thousands of miles/hours and are breaking down or because you think they should be changed for one reason or another? The reason these things are expensive is that they are pretty well supposed to last the life of the engine at thousands of running hours. Change them if the breakdown not if you just "think" you need new plugs.

Here's an answer to your first part, which is quoted from my opening post above...

Oct 29, 2019 11:55:13 GMT @spookytim2 said:

My plugs look like they may have been in there for some time and I'm thinking I might order a new set in, ready to swap them at the appropriate time.

If you'd like me to elaborate on that, I'm merely exploring options for cheaper plugs by asking the question on RR to see what people might have had experience with. As the owner of a car I'm quite within my rights to consider such things and to ask such questions without having to actually defend and justify my question to somebody sat 100s of miles away on his computer who believes he knows best. You have absolutely no information to work with to determine that you know best. WHY I'm asking isn't really any of your business. You have the choice of answering, or not answering. You're going out on a limb though if you're hoping that I am going to go into great detail convincing you of my desire to look into spark plug options.

To your second part then...

Oct 29, 2019 17:31:09 GMT Darkspeed said:

I would take the time to recommend a stock NGK/Bosch etc. plug but there is little point as you would just ignore it anyway. They are $8 at Summit so at least you can think you are getting a bargain and buying a performance item - Until shipping and duty that is - and it dawns that this is just a stock plug sold for high miler yank tin and nothing to actually do with "Performance".

... what is the point of writing this?

My post is a simple enough question if you subtract the additional context provided in the hope of limiting the tangential questions and suggestions that can sometimes happen when asking a question. So what do you think you sound like when you take the time to reply to say you could actually suggest an alternative but you're not going to 'because I will ignore you'?

Are you really, honestly, at your age in life, still hanging on to some random, long forgotten by me and everyone else, instance (or couple of instances) where I had the temerity to not follow your advice when it was offered some time about something or other way way back in another thread? Because here's the thing... people don't actually have to follow advice. You don't have to offer advice either, but if you offer advice and it was listened to but not acted upon, that's okay. It's not reasonable to hold a grudge about something like that. Advice is not a currency we can use in this way. It's goodwill and offered unconditionally.

If you offer advice that is tangential and not exactly an answer to the question asked, that's to be expected. Nobody offering advice should ever take umbrage to quite the extreme that you have done so on numerous occasions and for such an extended period of time, without wondering if maybe they're getting things a little out of perspective. If it offends you when people don't snap immediately to taking your advice, you should do yourself a massive favour and stop handing out advice. You'll feel much better for it.

And to that end, it seems clear to me that you personally would have been much better off not including the second part of your post, because you took the time to write it in order to tell me you wont be taking the time to offer anything useful... which is frankly bizarre and embarrassing to read. You sound like a seven year old who's been told he can't have any more crisps. I know that because I've got kids and when they were younger they would have little strops like this.

This is the moment where you go off in a huff, if my memory serves me well.

Cheers

Oh PS: any reference to "performance" is merely there to highlight the fact that I can't simply look up the make and model of my car and get a plug ref. The engine has been rebuilt. Now, if I just say "the engine has been rebuilt" people could say "But just rebuilding an engine doesn't mean you have to use different plugs", so I'm clarifying that it's not a stock rebuilt engine and doesn't have a stock plug listing (other than the one recommended by the builder). So to keep the conversation on track and to simply see if anyone has anything to offer based on the description of the plug, and not a description of the engine, I have referred to the rebuilt engine as being 'performance'. It's a short-hand for not factory spec, not the same cubic capacity, not the same heads, not the same cam profile... not the same in any way that means it can simply be looked up in a list. Irrespective of your personal views and your derogatory nature, it is an engine that has been rebuilt as a 'performance' upgrade engine. It is reasonable to use that word to describe it, as much as it rankles you up there on your tall horse at the top of your ivory tower.

[Deleted]

Anyway, thread closed, I have found an alternative plug to try should I need to change them.

[Deleted]

Hahaha, the ad at the top of this thread page is for design engineers. 'Design Engineer' implies a level of precision and attention to detail that is somewhat betrayed by the typo within the ad...

[Darkspeed]

Oct 29, 2019 18:00:06 GMT @spookytim2 said:

Oct 29, 2019 17:31:09 GMT Darkspeed said:

Are you changing out these long life plugs because they have already done 10's of thousands of miles/hours and are breaking down or because you think they should be changed for one reason or another? The reason these things are expensive is that they are pretty well supposed to last the life of the engine at thousands of running hours. Change them if the breakdown not if you just "think" you need new plugs.

Here's an answer to your first part, which is quoted from my opening post above...

Oct 29, 2019 11:55:13 GMT @spookytim2 said:

My plugs look like they may have been in there for some time and I'm thinking I might order a new set in, ready to swap them at the appropriate time.

If you'd like me to elaborate on that, I'm merely exploring options for cheaper plugs by asking the question on RR to see what people might have had experience with. As the owner of a car I'm quite within my rights to consider such things and to ask such questions without having to actually defend and justify my question to somebody sat 100s of miles away on his computer who believes he knows best. You have absolutely no information to work with to determine that you know best. WHY I'm asking isn't really any of your business. You have the choice of answering, or not answering. You're going out on a limb though if you're hoping that I am going to go into great detail convincing you of my desire to look into spark plug options.

To your second part then...

Oct 29, 2019 17:31:09 GMT Darkspeed said:

I would take the time to recommend a stock NGK/Bosch etc. plug but there is little point as you would just ignore it anyway. They are $8 at Summit so at least you can think you are getting a bargain and buying a performance item - Until shipping and duty that is - and it dawns that this is just a stock plug sold for high miler yank tin and nothing to actually do with "Performance".

... what is the point of writing this?

My post is a simple enough question if you subtract the additional context provided in the hope of limiting the tangential questions and suggestions that can sometimes happen when asking a question. So what do you think you sound like when you take the time to reply to say you could actually suggest an alternative but you're not going to 'because I will ignore you'?

Are you really, honestly, at your age in life, still hanging on to some random, long forgotten by me and everyone else, instance (or couple of instances) where I had the temerity to not follow your advice when it was offered some time about something or other way way back in another thread? Because here's the thing... people don't actually have to follow advice. You don't have to offer advice either, but if you offer advice and it was listened to but not acted upon, that's okay. It's not reasonable to hold a grudge about something like that. Advice is not a currency we can use in this way. It's goodwill and offered unconditionally.

If you offer advice that is tangential and not exactly an answer to the question asked, that's to be expected. Nobody offering advice should ever take umbrage to quite the extreme that you have done so on numerous occasions and for such an extended period of time, without wondering if maybe they're getting things a little out of perspective. If it offends you when people don't snap immediately to taking your advice, you should do yourself a massive favour and stop handing out advice. You'll feel much better for it.

And to that end, it seems clear to me that you personally would have been much better off not including the second part of your post, because you took the time to write it in order to tell me you wont be taking the time to offer anything useful... which is frankly bizarre and embarrassing to read. You sound like a seven year old who's been told he can't have any more crisps. I know that because I've got kids and when they were younger they would have little strops like this.

This is the moment where you go off in a huff, if my memory serves me well.

Cheers

Oh PS: any reference to "performance" is merely there to highlight the fact that I can't simply look up the make and model of my car and get a plug ref. The engine has been rebuilt. Now, if I just say "the engine has been rebuilt" people could say "But just rebuilding an engine doesn't mean you have to use different plugs", so I'm clarifying that it's not a stock rebuilt engine and doesn't have a stock plug listing (other than the one recommended by the builder). So to keep the conversation on track and to simply see if anyone has anything to offer for the plug, and not the engine, I have referred to the rebuilt engine as being 'performance'. It's a short-hand for not factory spec, not the same cubic capacity, not the same heads, not the same cam profile... not the same in any way that means it can simply be looked up in a list.

Okey-doke - glad you are sorted.

[Dez]

Personally, I think iridium plugs are sh1te and I won’t use them in anything. Copper every time. Even ones from reputable sources and brands seem to fail in an interesting variety of ways well before their supposed service life. Given you can usually buy about 4 sets of copper ones for the price of iridium, I’d rather do that and service more regularly, especially as it give opportunity to check how they’re actually working.

When it comes to choosing an appropriate plug, you’re probably making it a bit more complicated than it is. Wether the engine is stock or modified doesn’t really matter, as long as the plug physically fits correctly, and is the right heat range. I’d assume even with modified heads they’re not so wildly far from stock that the plug has changed in size or length? So match the thread size and length first (obviously too short is bad and too long could be catastrophic), then pick the appropriate heat range. Heat range isn’t as hard and fast as you think, you could have the same engine with two different heat range plugs just tuned mildly differently, and never notice the difference. Although with assumed higher CR and more cam overlap (again assumed), you’d probably be looking a heat range or two higher than stock . You’d only notice if it’s a long way out.

[Deleted]

Oct 29, 2019 19:23:07 GMT Dez said:

Personally, I think iridium plugs are sh1te and I won’t use them in anything. Copper every time. Even ones from reputable sources and brands seem to fail in an interesting variety of ways well before their supposed service life. Given you can usually buy about 4 sets of copper ones for the price of iridium, I’d rather do that and service more regularly, especially as it give opportunity to check how they’re actually working.

When it comes to choosing an appropriate plug, you’re probably making it a bit more complicated than it is. Wether the engine is stock or modified doesn’t really matter, as long as the plug physically fits correctly, and is the right heat range. I’d assume even with modified heads they’re not so wildly far from stock that the plug has changed in size or length? So match the thread size and length first (obviously too short is bad and too long could be catastrophic), then pick the appropriate heat range. Heat range isn’t as hard and fast as you think, you could have the same engine with two different heat range plugs just tuned mildly differently, and never notice the difference. Although with assumed higher CR and more cam overlap (again assumed), you’d probably be looking a heat range or two higher than stock . You’d only notice if it’s a long way out.

I've never chosen iridium plugs before so I cant comment on whether they are sh1te or not but I certainly don't intend paying for them

But yes theres an equivalent NGK I can use, probably a few others too, but I tend to go with NGK in general out of pure habit.

[Dez]

NGK are one of the ‘ok’ brands these days, if a little overpriced.

Champion are the ones to avoid.

I tend to find Bosch and Denso best, with motorcraft
And ACdelco also being perfectly acceptable.