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Wow! Really good stuff!

I just hope I eventually get around to doing it... Have the parts.

cal 67 wrote: ↑Thu Jun 08, 2017 6:43 pm Ray, as I mentioned on The Samba, they're not AMC castings. They have no markings on them. They're completely new AA-made castings, NOT of AMC origin. They're bare, without any parts intalled.

Thats super nice to have confirmed! Somehow I missed that in the Samba forum. The confusion from their site...they speak of the 914 heads...yet at the same time all of their complete 914 heads for sale are all welded and are stated as such....thats why I was confused as to whether these were cast in configuration or modified by welding. Thanks! Ray

Piledriver wrote: ↑Fri Jun 09, 2017 2:41 am Actually a better plug existed, but they don't make them anymore.
There is nothing special in the electrode design...

I can still find stocks of Iridium Pulstars every now and then, the inconel "replacements" don't work as well or last as long as $3 Bosch Supers or Autolites for that matter... IIIRC they changed the capacitor design to make them harder to break when installing. Made the new ones ~worthless, or at least not worth the price..

All else being the same, I can pull 23:1 AFR smooth as glass with BE1i (iridium) pulstars, with any other plug ~18:1 is into lean surge/misfires. (tried most types/brands) the DTCs work better than anything other than the old iridium pulstars.

I had to richen up my cruise AFR targets when it cooled down under ~80F or it overcooled.

Probably not worth one extra HP at WOT, but for cool CHT and economy they rocked pretty well.
The electrodes were worn back into the insulators ~1/4" at ~50K miles, it still ran just fine but it started getting lean misfires... LS2 coils rock.

I wish they made an iridium/pulse discharge version of the Bosch triples though... even if it was just cladding or a long life alloy.

Yes...I truly love iridium plugs for what they are and how uniform they stay over time. I have thought the same thing.... that an iridium triple would be just the ticket. There "may" be some iridium double electrodes that might get close. In reality the two features of the triples (DTC's and ET's) are as you mentioned ...the extended nose...and....the "cage" around the central electrode which is excellent for flame kernel with high compression/lean burn.

The one interesting thing I am digging into right now is the "actual" difference (if any) between the Bosch Super series and the Bosch Super plus series which advertises a Yttrium alloy with the copper center electrode. My Golf Mk6 uses those. They do seem to get longer mileage than straight coppers should do with these kind of coils....but I am just not "sure" if Bosch has always had Yttrium alloy in the super series and just started advertising it....which is what I suspect (that or lack of vendor knowledge)....as many sites that advertise W7DTC...are calling them "Super Plus" with Yttrium.

If I remember correctly....the original Bosch "Super" plugs were copper core with a high chrome content nickel alloy plated center electrode. In theory ...if going by the Bosch nomenclature/numbering chart....a triple electrode, 7 heat range plug with copper/yttrium alloy (a Super-Plus)...should be called a W7DTE. Ray

IIRC the copper electrode core (for heat transfer) is the driver of the "copper/super" moniker.
AFAIK the Bosch DTCs always had the yttrium alloy bits, as well as the copper core.

Had been using the NGKs as I can walk in and buy them locally, they seem to last ~as long.

Back on heads...QSCs website used to show similar bare castings as well as 910-alike castings, in two different port sizes.
Don't seem to be shown on their site any longer, AA may have an exclusive deal.
Was considering getting some of the faux 910s, set up for T4 and adding water jackets...

Piledriver wrote: ↑Sat Jun 10, 2017 11:02 am IIRC the copper electrode core (for heat transfer) is the driver of the "copper/super" moniker.
AFAIK the Bosch DTCs always had the yttrium alloy bits, as well as the copper core.

Had been using the NGKs as I can walk in and buy them locally, they seem to last ~as long.

Back on heads...QSCs website used to show similar bare castings as well as 910-alike castings, in two different port sizes.
Don't seem to be shown on their site any longer, AA may have an exclusive deal.
Was considering getting some of the faux 910s, set up for T4 and adding water jackets...

Thanks Pile....thats an interesting confirmation. See over the decades of using DTC's....and Supers in general...I somehow missed the yttrium ingredient.

They were always directly advertised in literature as "nickel/copper". I knew about the copper core....and...virtually all of the high quality plugs...even iridium ...have copper cores. Only the electrode portion exposed to the combustion chamber gasses are high alloys like iridium, yttrium, platinum etc.

The first time I saw yttrium actively advertised as an ingredient was about 2004 when I was in the Philippines and the Super-Plus moniker plugs with combination grounding were washing over the Asian market and advertised everywhere. I even bought a set that fit nothing I own (still have them)...since they only cost me about $2 in the Philippines.....just to see what they looked like.

Yes....no head castings at all on the QSC site. Interesting, Ray

The main problem with yttrium is if you use it in a sentence, most folks think you are pulling their leg.

They're 14mm... butttt.... cal 67 and I did score a few sets of German w7dtc's

There really are quite a bit of Bosch W7DTC out there. You just need to shop around and spend a few dollars in advance. Think ahead.

If its a busy week and you cannot get to the bar to have 3-4 beers with friends....you just saved $20. Thats when you jump on line even on your phone...and spend that $20 you were planning to!

On Ebay there are a ton of W7DTC...including some good deals like at this link....

https://www.ebay.com/p/Spark-Plug-OE-Sp ... C/75988256 In singular buying the prices range from $2.59 to $684 each....but there is a deal on a box of 10 for $21 and another for $35 at this link.

I also cannot get a definitive answer just from reading here an there...as to whether this plug has actually been discontinued. We all assumed itw as years ago when Bosch went to the four digit codes and there did not seem to be one for the W7DTC....but overall the supply out there still seems to be fairly large...yes realizing it could all be NOS.

This site..... https://www.sparkplugs.com/learning-cen ... park-plugs Listing supposedly all the discontinued Bosch spark plugs (have no idea how up to date it is)...DOES NOT list the W7DTC...but it does list the W8DTC at the very bottom of the listr. Ray

That's where we picked up a few boxes of 10 at the 21 dollar rate. Thanks for posting my honey hole Ray...

Well, I took that as a mini challenge to search the Bosch catalogue & cross reference etka.

The latest version of W7DTC (there are a number with different 10 digit bosch part numbers), was discontinued late in 2016 with no replacement version.

The VW part number which appears to match is 101000005AB.

That is still listed on the online ETKA as current but that may be out of date.

One use of that part number is the VW golf cabrio 1.8 up to 1993. Checking that model in the Bosch catalogue gives you a number of options but only one version has multi electrodes and that is WR78. It doesn't list W7DTC.

Screenshot of the catalogue PDF (URL added in case it's too big for the forum)

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[IMG]//uploads.tapatalk-cdn.com/201706 ... 56c2a7.jpg[/IMG]

Thanks Bruce. I have two boxes. I think I'll buy some more just in case.

By the way Bruce, nice to see you're still lurking! I rarely see you on Samba.

Interesting yttrium is not listed... Is there another version?
Maybe only in the side electrodes?

NGK1263 (BP6ET) still exists an has always worked ~identically AFAICT.

There also (possibly more common) equivalents from Bosch and NGK in 5/8" hex... Maybe those are still made?
(Don't have the part#s memorized tho)
I generally prefer those, easier to get in/out with the smaller socket.

Hmmmm.
OK, Nippondenso actually makes iridium electrode, triple ground plugs, ALSO with platinum tips on the 3 ground straps, for $15... 2 side electrodes and one over the top (std location)
Just need to figure out 'densos completely different part# system...

Almost, the lexus plug is 26mm reach, they use the same code for multiple things grrr...