spark plugs... make sure they are correct!!!

[Klink]

I assumed my factory plugs came with the correct gap.

Well, they do. Generally speaking, new factory plugs come electronically gapped at 0.8 MM/.032" This is the factory specification for most MB engines since the late '70s. Experience has shown however that low load smoothness is enhanced by wider gaps.

Decades ago, I saw a cartoon. I think it was in "Road and Track", or something like that. In this cartoon there was a mechanic saying to a customer, "For $100 I can make it run like new. For $300 I can make it run right".
This is one of those situations, except that no extra money is required...

 

[gerryvz]

ALWAYS check gap when installing new plugs, even factory ones.

 

[gerryvz]

ALWAYS check gap when installing new plugs, even factory ones.

 

[modzona]

I hope this is a correct place to say this.

Was at my local dealer today and ordered som MB F8DC4 plugs. They had 15 left in storage i Norway and when they where gone they would not be replaced with the bosch f8dc4. But with some Beru plugs. Didn't catch the name on them. And as i understood it the f8dc4 could not after that be ordered from Germany.

Anyone know if this is the case world wide?

 

[gsxr]

I hope this is a correct place to say this.

Was at my local dealer today and ordered som MB F8DC4 plugs. They had 15 left in storage i Norway and when they where gone they would not be replaced with the bosch f8dc4. But with some Beru plugs. Didn't catch the name on them. And as i understood it the f8dc4 could not after that be ordered from Germany.

Anyone know if this is the case world wide?

If that is true - it would royally suck. Klink? Any word on supply of the genuine F8DC4's?

Martin - did you inquire about this part number? 003-159-67-03-26

 

[modzona]

If that is true - it would royally suck. Klink? Any word on supply of the genuine F8DC4's?

Martin - did you inquire about this part number? 003-159-67-03-26

Just missing the 26 on the end in EPC on my e420. Otherwise the same number.

A0031596703

 

[gsxr]

Just missing the 26 on the end in EPC on my e420. Otherwise the same number.

A0031596703

0031596703 had been superceded to p/n 003159670326. The dealer's systems should have shown that... but anyway, check on the other number with the -26 suffix and see if they have stock of those.

 

[Klink]

There are over 5000 F8DC4 plugs in USA inventory alone as part number 003-159-67-03-26, and billions and billions more worldwide...

 

[modzona]

There are over 5000 F8DC4 plugs in USA inventory alone as part number 003-159-67-03-26, and billions and billions more worldwide...

Aha.. maybe something was added wrong to the system or something.


Yep it was the 003159670326 number. It goes automatically to that number then you put in the short number.

 

[E500star]

Many time gone

What are the available non-resistor sparks now?

Maybe someone can share experiense?
What about NGK BKR5E /BKR5EIX/ BKR5EGP ?

My regards!

 

[nocfn]

You can get plugs via Mercedes for about as much as the NGK, and they will be proper.

 

[E500star]

You r right! Ordered a0031596803 - no problem. 2$ for the each !)))

 

[gsxr]

You r right! Ordered a0031596803 - no problem. 2$ for the each !)))

Those are factory plugs made by Beru, complete with MB Star logo, and should be excellent quality.

On a side note, the OE MB Bosch F8DC4 plugs went NLA in the past few weeks. If you place an order, it will be superceded to the Beru number (003-159-68-03), and you will receive Beru plugs. At the moment this appears to be a permanent NLA/supercession, but I guess we'll see as time goes on if the Bosch ever come back. If anyone prefers OE Bosch over OE Beru (or aftermarket Bosch), you better snag the last few available from Gerry or eBay. There are none of the Bosch left in any MBNA / USA warehouses.

 

[gerryvz]

I am all out of factory "Made in Germany" Bosch MB F8DC4 plugs. Shipped my last set out earlier this week.

I will continue to supply plugs, but as GSXR says they will be whatever subcontracted manufacturer MB is using at the current time.

I will put in another order for 200 plugs in the near future.

Bosch F8DC4 plugs that are made either in Russia or Brazil, which DO NOT have the MB star and are NOT made in Germany, are still available on the aftermarket.

For the MB plugs, it's hard to beat my price of $24 per set of eight, shipped via Priority Mail. ($7.15 of this price is the shipping, so do the math on the actual cost of the plugs).

Cheers,
Gerry

 

[MikeinTampa]

Is there a difference in the OE MB logo "made in Germany" plugs and the other F8DC4 plugs? I noticed a couple weeks ago the local Autozone here had them in stock so I bought a set at about $2.50ea. but they are the "made in Russia" plugs. I have not installed them yet..

 

[gsxr]

Is there a difference in the OE MB logo "made in Germany" plugs and the other F8DC4 plugs? I noticed a couple weeks ago the local Autozone here had them in stock so I bought a set at about $2.50ea. but they are the "made in Russia" plugs. I have not installed them yet..

Pics attached. The Brazil plugs are long gone AFAIK, Bosch moved production to Russia a few years back.

Functionally, I'm sure they are all fine. The OE ones are just cooler, lol. The new OE Beru plugs have minor differences compared to OE Bosch, but I don't have photos yet.

 

[MikeinTampa]

Functionally, I'm sure they are all fine. The OE ones are just cooler, lol. The new OE Beru plugs have minor differences compared to OE Bosch, but I don't have photos yet.

Hopefully they'll be fine. I pulled one of the plugs from the car just to check what's in there and it currently has the "made in Germany" F8DC4's. What's the ideal spark plug gap on these cars? I'm trying to get to the bottom of a slightly low idle issue. Can feel a slight shake or "mis" when engine is hot.

 

[gsxr]

Hopefully they'll be fine. I pulled one of the plugs from the car just to check what's in there and it currently has the "made in Germany" F8DC4's. What's the ideal spark plug gap on these cars? I'm trying to get to the bottom of a slightly low idle issue. Can feel a slight shake or "mis" when engine is hot.

Spec is 0.8mm but as discussed earlier in this thread, preferred gap is 1.0mm (max 1.1mm). This may help the hot-idle misfire.

However, check the records for when the engine mounts were last replaced. If they are more than 50-75kmi old, measure them as shown here:
http://www.500eboard.com/forums/showthread.php?t=593

 

[MikeinTampa]

However, check the records for when the engine mounts were last replaced. If they are more than 50-75kmi old, measure them as shown here:
http://www.500eboard.com/forums/showthread.php?t=593

Thank you. I will look into the mounts as well.

 

[doolar]

Ordered plugs from the dealer and received them today, they are made in France (Beru?) with p/n A 003 159 68 03.

 

[gsxr]

Ordered plugs from the dealer and received them today, they are made in France (Beru?) with p/n A 003 159 68 03.

Correct: the Bosch OE / dealer / Star-logo plugs are NLA.

If you order Bosch, you'll receive the replacement p/n which are Beru with Star logo, made in France. They are still good plugs, no concerns about using them.

 

[doolar]

Correct: the Bosch OE / dealer / Star-logo plugs are NLA.

If you order Bosch, you'll receive the replacement p/n which are Beru with Star logo, made in France. They are still good plugs, no concerns about using them.

They have a star-logo though That's the essential performance right there.

 

[JC220]

Spec is 0.8mm but as discussed earlier in this thread, preferred gap is 1.0mm (max 1.1mm).

Quick question (Apologies in advance if this is a stupid one!) is the 1.0mm Plug Gap recommendation still relevant to the M104 motors with Coil Packs? (M104.992) About to install new plugs just now

 

[gerryvz]

Yes, a 1mm gap is fine.

 

[Lynch]

I'm embarking on a journey to use the best parts on my M119, I know this goes against a lot of traditional/conventional thinking and believe me, I am a purist at heart and prefer to keep things the way it was original designed by the OEM but will not shy towards progress and reasonable upgrades, as long as it is reliable and will not cause any harm.

I used my limited language skills and discovered that some Japanese E500/500E owners are using high quality silicon ignition wires, without any built-in resistors, with resistor plugs and I don't know how good or bad it is, just that it is a popular option, as seen in their photos.

These ignition wires aren't cheap and they're built much better than what Beru and Bosch currently offers. In short, they're well-insulated, consistent in resistance and less prone to any changes than the Beru ones, as well as uniform in resistance (0.5k Ohm across each wire).

I've done my research and pinged Dave a few years back regarding this, and have finally taken the plunge to order them in.

Using the same limited language skills, I discovered that NGK Japan makes a line of ruthenium plugs, which is their top-of-the-line plugs that has ruthenium coated on the tip, with platinum coated on the pad, with resistor, which is usually 3-5k Ohm.

The main benefits or Ruthenium, according to the marketing copy and countless Japanese reviews for other cars (not M119), is that it acts even better than Iridium, lasting longer with better idle characteristics and reported fuel economy in direct comparison. This seems like a good thing to me, as Dave recommends gapping the spark plugs wider to decrease rough idle and misfires.

Summarized research notes:
1) Japanese E500/500E owners have been using this combination for some time without any real issue.

2) NGK resistor plugs are specced around 3-5k Ohm, which is slightly higher than what Dave mentioned is in the spark plug boot (2k or 2.4k Ohm).
The ignition wires I purchased are very high quality, equal length, uniformed resistance across each cable, with a max resistance of 500 Ohm.

3) Putting the plug and wires together gets me around 3.5k to 5.5k Ohm max, with consistent resistance regardless of engine/wire temperature as well as better idling/misfire reduction. This doesn't seem to be a problem and hopefully will not cause any electrical issues such as frying the EZL.

I think it's worth trying out, as I wouldn't be the first one to do this and would be happy to report back on how it is.

Questions:
My only question that I'm hoping to get some input with is whether I should gap to 0.8mm or 1.0mm? I know these plugs have better and smoother idle characteristics, so does that mean it will be better than the copper-core OEM ones already and be fine at the OEM spec of 0.8mm?

I think it was Gerry that also mentioned doing 0.9mm, which is an in-between of the two gap choices in one of his DIYs.

I have a W463 G500 which has the M113 and the spec for that is 1.0mm I believe, although that's a whole different engine so not sure if it's comparable.

Hopefully I can get some input, using logic and reasoning, whether to use 0.8mm, 0.9mm or 1.0mm gap for my specific case of ruthenium NGKs and upgraded ignition wires.

 

[Efraim]

Hello,

I ordered F8DC4 plugs. They came from Germany as none available in Finland. The plugs are nowadays sold only in pack of 10 plugs. The local big Bosch dealer told that I was the first one to order non-resistor ones for a several years. Sure the reason is the Bosch catalog that has replaced resistor free plug to more common with resistor ones.

Prior to installation I'd like know why the forum suggests to gab them to 1mm? What is the rational behind this hint?

 

[gerryvz]

The 1mm gap has been proven by some very experienced MB techs here (@Klink) to help the cars run and idle better, as opposed to the stock 0.8mm gap.

 

[Efraim]

Okay, so experimental testing by famous Mr Klink. Thanks.
Wonder if there are Bosch plug F8DC4 with 1,0 mm gap, probably not.

 

[gsxr]

New plugs are pre-gapped to 0.8mm.

 

[Efraim]

Hello, After replacing the spark plugs to re-gapped and non resistor ones I notices that the random hickups has vanished and the engines more smoothly. Very many thanks for the 500Eboard for the hint.

I also ponder if the extra resistor (=FR8DC) in spark lines could cause the famous misfiring/distributor caps syndrom?

 

[gerryvz]

I also ponder if the extra resistor (=FR8DC) in spark lines could cause the famous misfiring/distributor caps syndrom?

I do not believe so. I found that my car had the FR8DC4's in it since 2009, when I last had the plugs replaced by a shop that I had do my work just after I moved to Texas. I ran those plugs for 11 years, and never had the misfire / distributor cap problem.

The 1mm gap can make a difference in smoothing things out just a little bit. I am already seeing it after driving my own car after replacing the plugs and gapping them to 1mm.

 

[357Magnum]

Hi Folks, i just bought new plugs for my 400E from my MB Dealer. PartsNo: A003 159 6803. So, as i understand, they are made in France and its Beru. Correct?

Like to see, that @gsxr told us that these plugs can be used too. I set the gap on the 1.0mm from standard 0.8mm. Will replace them the next days and maybe surprised how (much) better the M119 will run.

Greetz from Germany

 

[gsxr]

Yup! Current dealer plugs are Beru, made in France. Those should be the correct non-resistor plugs.

BTW, welcome to the forum!

 

[The Emperor]

Hi Folks, i just bought new plugs for my 400E from my MB Dealer. PartsNo: A003 159 6803. So, as i understand, they are made in France and its Beru. Correct?

Like to see, that @gsxr told us that these plugs can be used too. I set the gap on the 1.0mm from standard 0.8mm. Will replace them the next days and maybe surprised how (much) better the M119 will run.

Greetz from Germany

Isn't a .357 Magnum illegal / verboten in Germany ?!?

 

[357Magnum]

Surprise surprise.... yesterday i decided to install the new sparkplugs. I was wondered that the "correct" plugs F8DC4 were already installed. So i just set the gap to 1mm and put them back. Now i got 8 brandnew plugs here... spareparts.

 

[gerryvz]

Surprise surprise.... yesterday i decided to install the new sparkplugs. I was wondered that the "correct" plugs F8DC4 were already installed. So i just set the gap to 1mm and put them back. Now i got 8 brandnew plugs here... spareparts.

Keep them. Always good to have at least one set of spares. I generally will run a set of M119 plugs for 50,000 miles / 80,000 km.