HKS spark plugs, any good?

[Laeeq]

I was in need of replacement spark plugs so ordered some HKS iridium + platinum plugs from rhd Japan.  They turned up today after 10 days of ordering. The heat rating on these are 10.

My question is: are these any good with single turbo setup of mine?  I had NGK Iridiums 11\'s all round before with no problem till they are tired now, the HKS ones are highly recomended for Rotary engines according to RHD and HKS.

Although HKS, these also have NGK JAPAN marking on them.   Who makes these plugs? and if NGK do? then how could these be different???Confused.com i am + how good are these???

Anyone???

Many thanks

[BlitzBoy]

Made by NGK my man, I would have went colder personally on a single turbo running high boost

[Laeeq]

I know but with the colder weather setting in these are in between with 10 heat ratings.  I had 11\'s all round before.  Well, only one way to find out...:burnout :burnout

[John Yorke]

There were reports of these plugs having failed and losing the electrode into the engine:2eek  I was advised to steer clear of these and stick to the standard ones, would have thought a mix of 10\'s and 11\'s would be a good option. When you change these plugs every 3k miles I dont think the Iridiums are worth the extra $$

[Laeeq]

There were reports of these plugs having failed and losing the electrode into the engine:2eek  I was advised to steer clear of these and stick to the standard ones, would have thought a mix of 10\'s and 11\'s would be a good option. When you change these plugs every 3k miles I dont think the Iridiums are worth the extra $$

Oh just great....:mad:

spent 70quid and these are no good then??? surely recomended by HKS can only be a good thing??

So, where can i get NGK 10\'s and 11\'s from?  Reworx only sell iridium ones in that range with over 20 quid per plug.  I want to use standard as they will do the job and don\'t mind changing every service at a half the cost...:yes

[907]

I emailed NGK recently about the iridium plugs and this was the reply.

Thank you for your enquiry passed to me today.
Unfortunately the two plugs you mention (R7420-10 and R7420-11)are not UK kept spark plugs.  The only alternative we have is R6725-10.5.

Although I have no Idea how much these are or if they are any good.
I shall pop down to lucas tomorrow and find out a price.

Neil

[maximtaylor]

Same price I\'m afraid!

[kev-yorks]

Running B9EGV\'s and B11EGV\'s now as opposed to the iridium\'s with no issue\'s at all. I swapped over at the start of the year using the EGV\'s for both the Thor dyno day and rotorstock and they seem to work just as well but at a fraction of the price. Do a search on Ausrotary for more on these plugs.
Kevin

[K1HKS arse]

As John said, i have had an HKS plug destroy an engine(rear rotor).

Mind you that was about 3-4 years ago,they might have improved the plug since then.

[clive]

Hi Laeeq,

Please have a read of the comments I made on this thead ( below), also I delivered some NGK plugs to TDI last night and in conversation they told me they have HKS problems in piston things as well, and they are THE official HKS people in the UK!!  

http://www.mazdarotaryclub.com/forums/showthread.php?t=12310&highlight=denso

[Laeeq]

interesting reading there....

These HKS iridium+platinum plugs are a new range of "M" series according to HKS USA site, made by NGK as it has clear marking on them.  The HKS site also recommend these for rotary engines...

There was "S" series plugs also by HKS and was not recommended for rotarys.  I do\'nt know what to do now...Can someone tell me where i can get some NGK 10\'s and 11\'s then?  dont wana kill my engine as yet.

I must say one thing though, after putting these new "M" series HKS in the car; idles and drives much better with cold and warm start without any problem and boost\'s fine too.....:2Rolleyes

[banned advertiser]

The old HKS plug was made by Denso but the new by NGK so cant see there being a problem with the new ones. Find it hard to believe that from the millions of plugs sold by the 2 biggest producers in the world that probably the smallest of percentages that go wrong can turn people off them. I would not have thought that NGK or Denso for that would make a new plug  with new technology just for HKS, probably a plug to HKS spec but using a plug they already have in stock but with a different label on it.
If Im wrong, and we cant use HKS, Denso and NGK who can we use.
Had HKS plugs in the yellow car and never a problem, and have had customs buy and use HKS without trouble.
Could bad tuning be down to creating a fault with the plugs that have failed.
To date I have only heard of 1 UK car failing with HKS plugs, what does that percentage work out from the millions sold.

[Laeeq]

Thanks for that Gary...

feelin a bit better..i have e-mailed HKS and rhd japan, see what the respose is? if any?

[Laeeq]

This is the answer i got from the rhd japan:




Laeeq,


that is the exact reason we have made these plugs available, they are not prone to losing their tips. and this is the exact information our tuning shop told us when we were deciding on the plugs to carry.


All of the items that are listed on our site are requests or recommendations from tuning shops here in Japan. We have many customers who know exactly the best item for their vehicle and then make the items available upon their research and requests. We do not list the S Series plugs on our site, there is a reason for this.


We could easily list every product in every catalog as many of the other suppliers do however we know that no matter how good the company is each company does produce inferior to not so good items. We cannot endorse these items.


If you do not want to use the plugs on your vehicle that is your call and we highly recommend doing the necessary research for each item you decide to place on your 13B-REW before purchasing them.


Patrick Antell
Russell Hobbs
RHDJapan
Phone:  +81-3-3487-1415
Mail: rhdjapan@rhdjapan.com
Web: //www.rhdjapan.com

[Mazdarotaryparts]

Hi Laeeq and all,

Got to the bottom of this one ,

If the numbers start with 5000 they are HKS made by NGK

If the numbers start with 5408 they are HKS made by Denso.

Also found out that HKS Europe have no plans at present to bring over the NGK equivalent