Beru Plug Replacement 4 Defunct Bosch H9DCO - My Story
 

Several months ago it was learned by more than one member here that Bosch had decided to eliminate the production of non-resistor plug numbers H9DC & H9DCO. These "non-resistor" plugs were designed for use in many MBs made throughout the 80s and early 90s. The word has always been that many of the MBs from this era required a "non-resistor" plug. As far as I know, all 103 motors use them and if I'm not msitaken, the 102 line as well. There may be others.

Beru(a German parts mfg.) has made the single electrode equivalent for the Bosch H9DC/H9DCO for years. Some MBs once shipped from Germany with them in the motor.

The Beru plug in question here is -> 14 K-7 DFUO (Z18). It's a single electrode plug designed like the Bosch H9DC/H9DCO and again, is the equivalent of said Bosch plug(s).

My research revealed that there was ONE source for this plug in the U. S - kingsborne.com - owner - Warren Hartley. I contacted him on 6/12/06 and order a set. He told me it would be 7-10 days. 3 weeks passed - no plugs. Contacted Warren via email and got the "7-10 day story" again. 2 months passed and still no plugs. Contacted Warren again and no response. He stopped responding to me. I wasn't to concerned as he had not charged my CC account.

Checked the mail box upon returning home last Fri(9/9) and guess what? - 6 Beru plugs sittin' in the mail box - shipped from Kingsborne in California. Only took 3 months - not bad - huh?

I emailed Phil awhile ago and suggested that he load up on these for forum members. Bosch's "resistor" replacement for the H9DC/H9DCO aint' gonna fly if you believe all that's been written about the "non-resistor" requirements for 103 motors.

I'd also like to refer to something posted in another thread. The pointer to it is further down. In it, a member lists several U. S Dist. for Beru plugs. They are all wholesalers with the exception of Kingsborne, and will not sell to individuals.

You may still find the Bosch H9DC/H9DCO listed at the various WEB seller sites, but I have heard first hand from a few diyers that they've received the new Bosch "resistor" plug and not the H9DC/H9DCO plug after ordering the Bosch H9DC/H9DCO. If you can find the Bosch "non-resistor" plug - congratulations. The source is drying up. I've never seen the Beru single electrode equivalent listed at any WEB seller site.

Sorry for what may appear to be rant, but I wanted everyone here to know one persons expereicne in this matter.

http://www.peachparts.com/shopforum/tech-help/133719-where-buy-beru-plugs-usa.html?highlight=Beru

At Beru Web Site H9DCO translates to Beru 14 K-9 DUO
Same thing in W124 maintenance CD
http://www.beru.com/english/produkte/produktident.php

Beru contact:
http://www.beru.com/english/handel/international/adresse.php?id=h&country=USA

This won't get you anywhere. The Beru dealer in Illinois sells to Kingsborne. You cannot order from the Illinois Beru dist. listed in your post. They'll point you at Kingsborne or the others that are listed in the URL at the bottom of my first thread and the "others" are whosesalers - they sell only to retailers or shops - not diyers. I called everyone of them. Presently, Kingsborne.com is the only U. S. source for diyers unless you know of someone who doesn't advertise on the WEB & who just happens to have an old stash.

I contacted Phil. All of his contacts have dried up. He's going to call both the Illinois dist and Kingsborne. With his bulk buying power, he may be able to generate more enthusiam than I got out of a "6 plug" order.

A good solution is NGK BP5EFS

Arthur - that's what I've been waiting to hear! I value your opinions and to HELL with the 3 month wait for Beru plugs! Problem solved.

Knowing this made coming up with a plug cross-ref site easy:

http://www.spark-plugs.co.uk/pages/technical/boschd6b-w4e2.htm

Thank your sir!

Hate to say it, but since Bosch plugs have been made in India, I have had nothing but troube with them
The last 2 sets I put in my 113 [ Bosch Supers, W8DC .plain Jane plugs] 4 out of the 12 had problems with the insulators actually turning in the plug casing.. they were replaced by bosch and the new ones did the same thing within 1K miles . Could actually spin the insulators by hand in the case .
When I brought them back , the counter guy knew it right off the bat, so I was not alone... but Bosch siad they never heard of such a problem. Said I must have torqued them incorrectly... Yeah, Right Pal, I have been changing plugs on Autos and Aircraft for 40 some years... get lost !!!!!
4 out of 12 was enough for me.............
Changed to NGK and problems solved....................

well, i've talked to bosch several times.
they say yes, they are resistor sp plugs
but not enough to be an issue. they said
we will not notice any differance.

george

That's a 3/4" reach gasketed plug with a 13/16" hex. The M103 requires a .708" reach taper seat plug with a 5/8" hex.

The NGK TR5 is a resistor plug equivalent to the HR9DC. NGK does not offer a non-resistor verision equivalent to the H9DC.

If one wants to stock up on H9DC or H9DC0, try dealers, but their prices are probably higher than the aftermarket - back when the aftermarket actually had them.

I found one set of H9DCs on the web and bought one at a dealer. I also have two 15K mile used sets that I ran through a spark plug cleaner that are serviceable for at least another 15K miles. At the rate I'm accumulating mileage I should be good for the duration...

Duke

well, you folks sufficiently scared me to order 6 more of the bosch from Arizona ******** with this months order... i have 6 new ones sitting in the shop... but with two cars, i decided to go ahead and get 6 more

h8dc @ 1.13 each


http://www.***************/search/productx.aspx?sid=altpr2m3uw0oew55ew0vapnt&makeid=800016@Mercedes&modelid=1193600@300CE&year=1989&ci d=25@Ignition%20Parts&gid=7212@Spark%20Plug

lee... I ordered from them 4 plugs for the 190E and they came and its the resistor type.

Should I worry? This is going into a M102 2.0 engine.:confused:

<<That's a 3/4" reach gasketed plug with a 13/16" hex. >>

Where did you get that info??

I can not find the specs.
Tnx

MBSHOP - I know you do this for a living and I'm not an electronics engineer, but what Bosch is telling us about not noticing any difference violates fundamental rules of electricity.

By switching to a resistor plug, they've modified the "ohm" side of the equation -> voltage - current - ohms.

A given amount of each of the 3 creates a specific circuit. Alter any of the 3 and the circuit changes.

I fail to see how we won't notice any difference. It would be nice if someone with a legitimate electronics background could contact Bosch and have someone there with same background explain how this is going to work.

I hoping Duke2.6 makes the call to Bosch - graduate degree in Mechanical Engineering. I suspect Duke could weed thru their story and decide if it's for real.

Once again - my 2 cents.

It kind of depends on relationship between wires and plugs.

Germans in past have liked nonresistor plugs and resistance in wires/plug connectors.

If a change to resistor plugs is accompanied by change in plug wires/caps, result can be the same.

The reason Benz prefers plug resistance in the connectors rather than the wires is b/c the R factor is equal to all plugs... with R wires , the OHM is per foot of wire and no wires are the same length.
Solid core wires w/R plugs will work , but R plugs w/R connecors is too much R factor.
Try R plugs on a 104 HFM/SFI waste spark ignition system ..common running faults/complaints.....samre goes for plats on these systems b/c the series spark has to jump out of polarity on the second plug, meaning from ground to the electrode...........Bosch Super , copper core work best here. And they are cheap...

i don't know what the 102 engine takes... probably non-resistor as well...

http://www.***************/search/productx.aspx?sid=c0sou055xgtkwayad3c0y455&makeid=800016@Mercedes&modelid=1192621@190E&year=1987&cid =25@Ignition%20Parts&gid=7212@Spark%20Plug


probably in the owners manual...

there may be a lot of hype here on this one...

any non-resistor may work well... you just NEVER here of problems with Bosch copper core

That makes sense, but as far as I know, there is no "alternative" set of wires for 103 systems that work with Bosch's new "R" plug? I supppose there could also be a need for a redesigned dist. cap & rotor?

If anyone knows of a new set of wires being offered for 103 motors that will be compatible with the new Bosch "R" plug, do let us know.

I ordered from there.. but the resistor plugs came instead. If you still haven't recieved your plugs, you'll notice the labeling when you get it.

I'm not the only one that recieved it either.

...from my NGK catalog. My Cosworth Vega uses the same plug as M103, but a resistor type. I use the TR5 in my CV - just bought new set - on sale at Pep Boys.

The kid didn't understand what "TR5" meant - not on the computer, so I asked him if he had a paper catalog (I didn't bring mine). He did - so I looked up the four digit stock number for a box of four - 2238 I think it was.

Then he was able to order them.

It's just pathetic!

Duke

<<The kid didn't understand what "TR5" meant - not on the computer,
It's just pathetic! >>>



" Fries with that ???? "

I don't know how bad resistor vs non-resistor plugs would be. Bosch doesn't think it would be a problem, and I can't beleive that they would recommend a misapplication of one of their products, resulting in poor performance and a bad reputation for them. That being said, the service manual for an 86 560SL (probably the same technology as most other MB's of that era) says the following:

- The load at the high voltage end of the system must be at least 2K - the wires= 1K and the distributor cap (surprise!) = 1K. Damage to the ECU (EZL) could otherwise result.

-Don't install a 5K resistance rotor


So:
<2K resistance, bad.
2K resistance, good.
7K resistance (1+1+5)=bad, probably not enough spark.

So ignition coil to dist cap (0 ohms) (I checked, it is NOT a resistance wire)+distributor cap (1K ohms)+wire from dist to plug (1K) +0K non-resistor wires = 2K, as per the manual.

So, I SUPPOSE that it would be possible to install a 1K plug (my Bosch resistor plugs come in at ~1K), no resistance wires, and get nearly exactly the same running results from the same 2K load (although there MAY be an effect on the waveform of the spark, would actually have to look at an oscilloscope).

But, here's the problem with the above. Ignition wires generally fail by leaking and arcing to grounded metal (the engine, some part of an accessory, etc). I've always seen the distributor to plug wires fail before the ignition coil to distributor wire.

With no-resistor wires, a shorted distributor cap to plug wire would result in ONLY a 1K resistance to the grounded plug, beyond the original specs and possibly resulting in overloading/overheating/damaging the output transistor of the ECU, which is a pretty expensive part. It might not be good for the coil either.

My conclusions (not backed up by oscilloscope waveforms, voltage readings, RF spectrum analyzer, etc):

1. Use of a resistor plug in a system designed for non-resistor plugs will add 50% total resistance per circuit, not good, but probably OK if you can deal with the plugs becoming marginal with age-related wear sooner - you might have to change them more often or gap them a little more tightly to start with)

2. Use of resistor plugs and non-resistor wires would probably work, but could POSSIBLY result in expensive damage to the ECU should the wires fail (which they certainly eventually will do unless proactively replaced). It MAY also result in increased RF and radio interference.

On the other hand, if the resistor in resistor wires is in the shell of the spark plug "socket" then this concern may not exist, because a shorted "resistor" wire and a shorted "non-resistor" wire would present the same resistance to the coil - the 1K of the distributor cap only.

Does anyone get this?

PS: I was lucky enough to get the last 8 Bosch non-resistor plugs NAPA had locally in addition to the 8 non-resistor plugs I got. They checked their inventory and I got the last 8 within a 30-mi radius, apparently (and by accident, I picked the right store). But they were all at a good price (like, $1.20 ea). Bottom line, looks like we'll be using resistor plugs in the future...

non-resistor plug sourcing
 

There must be some out there still. Anyone know anyone who sources hard to find parts for a living? There has to be plenty left for us to hoard. I could use a set right now. Will buy a few sets when I find them.

Jason

..as Strife, I ave always had good luck finding Bosch Coppers at NAPA stores

Here's a guy in Canada with H9DC plugs listed on EBay, but he has a minimum $50.00 order. That would be $.50/plug, so anyone interested in a bulk buy?http://cgi.ebay.com/ebaymotors/BOSCH-PLATINUM-SPARK-PLUGS-SUPER-BOSCH_W0QQcmdZViewItemQQcategoryZ33693QQihZ019QQitemZ8052274663QQrdZ1QQsspagenameZWD1V

I've started picking up the Beru copper equivelents.. I have two sets for my m117's coming up from the warehouse...Hope to try some out shortly and I'll report back.

I've pulled Many resistor plugs from MB's (most often V8's) to find that installing a proper non-resistor plug solved their idling issue.

Jonathan

I've emailed arizona ********... to see if they will be sending me Bosch non-resistors for my w124's...

i ordered 12 yesterday...

As a follow-up to my previous post, the resistance of Bosch W9RDC plugs in my hands is 6K. Considering that the 107 MB manual SPECIFICALLY cautions against using a 5K resistance rotor, it seems that resistor plugs are BAD in this engine with the stock ignition system.

Nice to know!!!! Thanks:)

Jonathan

Warren at Kingsborne checked into the Beru plugs a couple weeks ago for me. He said they were coming out with a new non-resistor plug in October that would be a direct substitute for the Bosch plug. He said it would be part # Z240.

In his contacts with Beru and whoever he spoke to in Germany, they told him that you should absolutely NOT use a resistor type plug in the M103 ignition system.

I hope Phil will look into this and become a mass distributor of the new plugs.

NGK has been my first choice for thirty years and the choice of most MB mechanics here in Ca. My mechanics and I have installed thousands of them and never had a problem. I prefer them to Bosch and will pay the extra money if Bosch is cheaper. As I've stated in many oil threads, I don't give a rats ass what brand of oil I put in my cars as long as it's a name brand and it'e the cheapest, but I am particular about my spark plugs.

My apologies. I must have misread my catalog.

BP5EFS is a correct replacement for the Bosch H9DC - non-resistor, correct geometry, equivalent heat range.

Duke

Correct ...........

Is the NGK BP5EFS a regularly stocked plug at any US distributor?

All NGK plugs are available at most of the mass marketer auto parts stores. Good independents will carry them as well.

I've never had trouble finding NGK plugs.

This is a better alternative to the 3 month wait for Beru non-resistors that I just went thru.

I just noticed on the Australian NGK plug finder:

http://www.ngkspark.com.au/part_index.htm?http://www.ngkspark.com.au/PartFinder/spark_plug_vehicle_type.htm

It lists BP6EFS as the plug for the 300 SEL, SE etc, and the BP5EFS matches up with the 300 CE...

plugs
 

i just ordered plugs for a 1990 2.6 from local dealer and i got bosch h9dco.no resistor so apparently the dealers can get correct plugs.

Be careful of non USA sites. The cars use cooler plugs in those markets.

So for example a 300E in the USA uses H9dc/o while in Europe it uses H8dc/o
The M102 uses H8dc/o in the USA but an h7dc/o in Europe/ Australia etc.

I just went to the MB dealer today they offered to sell me HR9DC for 4.50 C$each.I declined and told the partsguy it is a resistor plug.He says that what MB's computer tell them to use..
I went to Partsource,offshoot of CanadianTire parts store,the kid at the service desk punch it BP5EFS,no they dont have it and cant order it either(they have a 20% discount on NGK plugs this week).He offered to sell me these iridium resistor plugs,plat resistor plug.
I will talk to my mechanic this week and see whether this plug is stocked in North America.
If they stock it,I find it very strange NGK's US partfinder site list TR5 as the correct plug(regular) and no mention of BP5EFS on the US NGK site.

i went to my mechanic today and also visited CanTire parts store.BP5EFS is not listed as available from the NGK Canadian catalogue.Crossover to H9DCO is listed as TR5, the same listed on the NGK US website.

It seems this plug is not ordinarily available.

I wrote to followup with Autohauz and got the following response:Can someone confirm whether this is non-resistor or RESISTOR plug before I go ahead and order.
Response from Autohauz:
We can get BP5EFS (sold under our part number FOR004770) but I think
this is now a resistor plug as well. We do not stock it and it would
ship directly from one of our importers, so I can't physically
inspect it, however they have notes with this part number stating
"V-Power Resistor".
I spoke to our purchasing manager about this issue and he said that
Bosch is currently not producing any plugs without resistors. He
also said that one of our importers indicated that NGK and Champion
are following the same philosophy and discontinuing non-resistor
plugs. I have had many customers state that they have heard that
this is a problem with many models, however I have had very few
customers actually use the new resistor style plugs and report
problems. Unfortunately, if these plugs do actually cause problems,
we do not have any options to still obtain the original non-resistor
types.

Best Regards,
Tom
******** AZ Winners Circle
Winners@*************** - http://www.***************

One more reason my Beru connection finally came through.. First rate plugs that don't muck up the ignition system.

Jonathan

"EF" = tapered seat 17.5mm/ 0.708" reach.
 

"E" only is 3/4" reach.

This is per NGk's `Desin symbol chart'.

What about the NGK BCP5ES? I can't seem to find the BP5EFS anywhere, but my local parts store thinks they can find some of the other NGK plug. Will these work?

None of the spark plug cross references I've been able to find so far list a direct, easily available non-resistor option for the H9DC...

they are only available outside North America.
In NA,i ve resigned to the fact the resistor NGK plugs # TR5 may be used as an alternative.

I started looking around for H9DC plugs.

www.********.com has them I think.

And here are two places that seem to have them listed online.

http://www.internationalfilters.com/products/sprkplugs.html
International Filters
3451 Galazy Place, Oxnard CA 93030
800. 872. 2333
Internet sales Jim Mars and Ken Anderson
srammij@internationalfilters.com
kenander@internationalfilters.com

http://market.autopartsfair.com/mercedes-engine_parts/catalog-item-248001.html
this is a link at Auto Parts Fair to a catalog number F10000-37610/BOS
Its for the 1988-89 300 CE motor:103.983
And it's the Bosch H 9 DC plug

Let's see if these help. There were other leads out there. I'll look for some good ones in the event these dont turn up the right non-resistors.

Regards,
Jason

please report here if and when you DO receive an actual non-resistor plug.
On the bosch catalog,it is still listed in 2006.But when the parts dept of a major chain store here actually phoned Bosch direct ,they say it's not available any more.Ditto Dealership.
Prev MB owners has ordered from various places for the listed H9DC BUT later only to receive HR9DC.
Thanks

I picked up some BP5ES plugs; I hope they will work. There is some question as to whether BP5 or BP6 is really equivalent.

BERU UXF79 from Kingsborne
 

Hi
I ordered those, they are non-resistor copper plugs. They were on stock and do fine in my 300TE.
Bruno

What about Champion spark plugs? My manual list them along with bosch, and beru.

NGK is not even on the list!

Just got 6 Bosch H9DC0 plugs from an UK seller on ebay.11.50 pounds for 6 shipped to North America.Unused old stock.Paper carton a bit tattered but plugs fine.

:eek: :eek: Seem Bosch non-resistor spark plugs H9DC/ H9DCO are very hard to find in N/A for M103 engine...

The H8DC/H8DCO are very hard to find for M102 engine as well.

Lucky, i still have new 16's H8DC Bosch spark plugs left in my garage for my M102 engine (190E 2.3). :rolleyes: