Spark Plug Cables

[wpw2511]

Hi everyone, I just bought new spark plug cables from Authentic Classics to replace my Beru ones. In addition, I also bought a set of NGK BP5ES to replace the Bosch WR9DC+ (Idk why the mechanic installed this on my car). Anyways, i’ve tried for an hour to fit the new cables on the new NGK but it just wouldn’t click or screw in. The new cables fit just fine with the Bosch WR9DC+ plugs. Any tips or advice??

Thanks!

https://www.authenticclassics.com/Mercedes-280SL-Ignition-Spark-Plug-Wire-se-p/auth-004612.htm

[Vander]

Did you screw the cap off the spark plugs?

[Mike Hughes]

There are two versions of NGK BP5ES non-resistor plugs.  One version has a solid cap and the other, labeled "BP5ES 7832" has a screw on cap.  Some spark plug sets have a lead that is only compatible with a plug from which the cap has been unscrewed, leaving just the threaded portion.

[WRe]

https://www.sl113.org/forums/index.php?topic=30874.msg224100#msg224100

[UJJ]

I tried to get the NGK BP5ES 7832 with the screw on cap, unfortunately the are NLA or not being made anymore by NGK. Perhaps there is some old stock out there?
I saw them on Amazon a while ago.

Best, Urban

[Leester]

I had a similar experience as the OP. I had the plugs with SAE tips and plug wires for the screw on plugs. After some thought I inserted the plug into my drill press and using a file milled down the SAE tip to about 4.5mm. Then using a 4mm die I took the tip down the rest of the way. Tedious?  Yes.  PITA? yes.  But it worked. The first plug probably took me an hour but the 6th one took me about 20 minutes.

Although I've "solved" my problem at least until the next plug change, I am wondering if anyone has identified the correct SAE 1K Ohm plug wires.  Lee 

[Shvegel]

Someone with a lathe could bang those out pretty quickly.  Especially if they built a mandrel that was threaded to hold the plug. 

[Benz Dr.]

I had a similar experience as the OP. I had the plugs with SAE tips and plug wires for the screw on plugs. After some thought I inserted the plug into my drill press and using a file milled down the SAE tip to about 4.5mm. Then using a 4mm die I took the tip down the rest of the way. Tedious?  Yes.  PITA? yes.  But it worked. The first plug probably took me an hour but the 6th one took me about 20 minutes.

Although I've "solved" my problem at least until the next plug change, I am wondering if anyone has identified the correct SAE 1K Ohm plug wires.  Lee

Best pug wire set I've found so far is those sold by K&K mfg.

[Pawel66]

I made mine myself, it is also an option, I could not find a good one at that time... Just avoid Beru plug connectors, go for Bosch.

[mdsalemi]

Someone with a lathe could bang those out pretty quickly.  Especially if they built a mandrel that was threaded to hold the plug.

Now there's a great starting project for my new to me, mini Unimat lathe...
When you remove the SAE cap on a spark plug to reveal the threads, anyone know the thread size? Have to see if I have the correct die.

Now, I'll have to go through my large inventory of NGK plugs to see if they have the SAE caps as "non removable".

[Benz Dr.]

I think it's a 4mm thread.

[Leester]

Good use for that Unimat lathe. As I said earlier I used a 4mm die but you may want to have a plug wire connector handy on the first go round and cut to about 4.5, check it, then cut a little more and check etc, etc.  Or if you have a die set you can cut to about 4.5 and use the die.  Good project.

[Mike Hughes]

Now there's a great starting project for my new to me, mini Unimat lathe...

Have toys, will play !   ;^)

[mdsalemi]

I made mine myself, it is also an option, I could not find a good one at that time... Just avoid Beru plug connectors, go for Bosch.

Out of curiosity, why "avoid" Beru and use Bosch? I don't know that one is any better than the other; I've seen nearly identical looking ones you could only tell apart by close examination. Also they've changed over the years, so the Bosch of today isn't the same as the Bosch of 1969 and the same holds true for Beru I'd imagine.

Have you had a quality issue with Beru?

[Pawel66]

I installed a set of Beru a couple of years ago, all of them are replaced with Bosch now. Breaking down one by one every couple of months - insulations got shot and i had spark between the connector and engine block. Maybe just faulty lot, but why take chances.

Separate from that I also had very bad experience with a couple of Beru distribution caps for M103 in my W463. Troubles stopped when i installed Baosch.

[Benz Dr.]

I've found that some Bosch wire sets contained carbon core coil wires which will not work well on our cars. You can save the boots and metal ends then just replace the wire which I've had to do on numerous cars that have come in. Not sure why Bosch would get something so elementary that wrong but that's what I've found too many times. A 12'' piece of carbon core ( coil ) wire will have about 10K ohms which really limits voltage at your spark plug.

[Pawel66]

I was not able to find Bosch copper core wire. The only one I could find to buy by meter was Beru.

[mdsalemi]

I installed a set of Beru a couple of years ago, all of them are replaced with Bosch now. Breaking down one by one every couple of months - insulations got shot and i had spark between the connector and engine block. Maybe just faulty lot, but why take chances.

Separate from that I also had very bad experience with a couple of Beru distribution caps for M103 in my W463. Troubles stopped when i installed Baosch.

Interesting. About 10 years ago or more, I had a set of wires made by someone in California. Beru solid copper wire, Beru ends. Never had an issue.
I've only seen Bosch distributor caps for the Pagoda. At the time I think the set was in the $150 price range but that would barely cover the cost of the Beru ends these days, without wire or fabrication.

As for Bosch selling carbon core wire, they don't really make a set for our car. They simply cross reference something that contains six wires of the appropriate length, and the distributor/coil wire, with no thought to the resistance of the caps or the wires. The good news is, when I bought a set years ago prior to my existing set, they were exceedingly cheap.

Not only is carbon core wire inappropriate for our car, it will break down. Solid copper will not.

[Pawel66]

Beru have always been a reputable parts provider in my geography. That is why I had no problem to buy Beru connectors and a cap (not for Pagoda). And they failed. So I stopped buying.

For years we were buying Gardena products for garden. Today they are junk (chineesium), so we stopped buying. It goes this way, I think.

Yes, I did not find a copper core wire from Bosh, they had, like you say, cross referenced sets. Same in Mercedes. The only copper w core wires I found were Beru - and there is nothing wrong with them, they work.

There are also brand perceptions that I have no clue what the origin might be. For example here most people think NGK spark plugs are junk. No idea why. I use NGK spark plugs as I read here everybody are using them. Where is this opinion in my country coming from - no clue.

[Benz Dr.]

After WW2 anything ' made in Japan ' was considered junk; kind of like China today. Now Japan makes high quality products because if your parts fail in Japan it's shameful.  Odds are, that's where this notion came from.

[ja17]

 "For example here most people think NGK spark plugs are junk. No idea why."

Pawel, NGK developed their high quality "copper core" non resistor plug for high rpm motorcycle engines many years before Bosch offered their "copper core" non-resistor, supper plug. In addition Bosch abandoned supplying non-resistor plugs some years ago while NGK continued to supply their non resistor plugs. These days NGK recently, has also abandoned supplying non resistor plugs and Bosch has begun re-supplying their non-resistor plugs again, which can be special ordered and are very pricey. Choices for non-resistor "original style" spark plugs are limited to us these days. As far as the quality of NGK spark plugs, they are good enough to be used by the Mercedes factory as original equipment in many new Mercedes AMG engines today.

[Benz Dr.]

Resistor plugs add about 5K ohms to each plug which is not really what you want. They'll work but not as well as non resistor.

[Raymond]

You can still find NGK BP6ES for motorcycles.  Are those hotter or colder than the 5ES? 

[ja17]

Hi Ray,

I assume you may find that your sources may be drying up on the non resistor NGK plugs these days. In most instances unless they have old inventories on hand, they automatically hand you resistor plugs (BPR6ES instead of the BP6ES). If you have upgraded to the hotter Bosch Red coil or the Bosch silver coil or the 123 distributor with the flame thrower coil then using resistor plugs is not such a big deal, but certainly not ideal!

[Benz Dr.]

You can still find NGK BP6ES for motorcycles.  Are those hotter or colder than the 5ES?

With Bosh plugs the higher the number the hotter the plug. With NGK it's the opposite.  A W7DC plug in Bosch is close the same BP7ES plug in NGK.  BP5ES is similar to a Bosch W9DC in Bosch.

I've found that the standard recommended plug ( BP7ES ) is usually too cold for most engines and the BP5ES is close to right for older or slightly worn engines. The BP6ES would be probably OK for a fresh rebuild. I leave the plug gap at the factory setting of .032"