Bosch Platinum 4+ ordering number

[m_steenbrugge]

Does anybody have the correct ordering number for the Bosch Platinum 4+ spark plugs? Can't seem to track it down.

[Delorean Industries]

Does anybody have the correct ordering number for the Bosch Platinum 4+ spark plugs? Can't seem to track it down.

save yourself the headache and you 4031 hr6 bosch plugs.

[Jack]

Why do people not like the 4+.
Is it a quality control issue or is it performance related?

[Delorean Industries]

Why do people not like the 4+.
Is it a quality control issue or is it performance related?

Both

[David T]

The platinum plugs are mainly for reduced wear for extended service intervals. Unless you are putting a LOT of miles on the car they are not worth the expense (and maybe not even then). The other issue is too often we see blow-by between the shell and the porcelain. Makes the car run rough when 1 cylinder is leaking combustion gases. No one is recommending them for the Delorean anymore. Besides, the platinum plugs don't make the car run any better even if they don't leak.
David Teitelbaum

[m_steenbrugge]

OK guys

Thanks for the info

[Evildeli]

Are the 4031 hr6 bosch plugs already gaped or do you have to gap them yourself?

[Delorean Industries]

Are the 4031 hr6 bosch plugs already gaped or do you have to gap them yourself?


They come with a gap in the mid twenties. Always a good idea to check though prior to install.

[David T]

You ALWAYS gap your plugs. At the very least you check it. If the plugs got banged around or you drop one they need to be gapped. The gaps they are shipped with are not application specific. The plug is used on many different cars and the gap on each is not the same. A wire gapping gauge is not expensive. Do not use a feeler gauge or that cr-ppy give away key chain thing. Try to gap all the plugs so that they are very close to the same gap, 0.025 inch.
David Teitelbaum

[Ron]

Does anybody have the correct ordering number for the Bosch Platinum 4+ spark plugs? Can't seem to track it down.
According to Bosch, they do not have a suitable Platinum +4 plug for a delorean.

16894

And in any case:
"Most Bosch Spark Plugs are factory pre-gapped for popular vehicle applications. The gap measurements are indicated either on the box, or by the part number located on the spark plug shell.

X suffix = .044"
Y suffix = .060"
Z suffix = .080"

Gaps should never by adjusted on Platinum+4 or Platinum+2.
Bosch Platinum+4 and Platinum+2 have factory pre-set gaps, and should never be gapped by the installer"

============================

$.02
Stick with the OEM Bosch Silvers
Bosch HR 6 DS

[Dangermouse]

You have me curious. What's wrong with a feeler gauge (apart from it being useless for +4s if we are still talking about that) ? Assuming it is a decent one of course.

I've used a feeler gauge for years.

[Ron]

I don't know why a feeler gauge would be bad (I have used them to check, but not spread, for decades. But I like the tool with the notches to bend with and wire gauges best tho...).
As for the "key chain thing", one slides it through the gap using the pressure against the center electrode to bend the ground electrode, a No-No.

From Bosch site-

16895




To widen the electrode gap, use a tool that only pulls back the ground electrode, without applying pressure to the center electrode. The tool must not be wedged between the electrodes as that may cause damage to the insulator nose.
To close the electrode gap, carefully tap the plug, electrode first, on a hard surface, as shown in the illustration.

[David T]

Because the ground electrode and the center electrode are not perfectly parallel you are not really measuring the gap accurately with a feeler gauge. Unless you file everything so it is flat and parallel (and nobody does that anymore, besides, you will remove any coating and wear the electrodes prematurely) only a wire gauge can accurately measure the gap. I was not aware that Bosch doesn't want you messing with the gap on their platinum plugs. Bummer if you drop one!!!!!!! Even if you order them you don't get them in the correct gap for a Delorean. Maybe that's why we are seeing failures, messing with the gap is damaging the plugs? Bottom line here is forget using the Bosch platinum plugs and you must at least check the gap in the plugs you are installing using only a wire gauge.
David Teitelbaum

[Ron]

I think you meant perfectly "perpendicular"...

Also, the platinum plugs with the tiny center electrode (the name/type escapes me) usually don't use the factory gap spec even when it is pre-gaped and specifically called out as a replacement...But I have good luck with them (non-Delorean).
And when it comes to the new "longer burning" "surface spark" plugs, you'd have to study alchemy and believe in magic :tongue2:

[David T]

I actually meant parallel. If you look at the center electrode the tip is flat. If you look at the ground electrode it also presents a flat surface above the center electrode. On too many plugs the ground electrode is not flat, when it was manufactured and was cut the end is not square so you can't accurately gap it especially with a flat feeler gauge. Back in the day, we would file the surfaces square with a small needle file, especially if we were regapping a used plug to clean up the rough surfaces. Now no one even cleans plugs anymore, they are considered disposable.
David Teitelbaum

[Ron]

Ah, got ya. I've often wondered why they didn't sheer it off in the other direction so that the lip would be on the other side...just assumed the machine cut it and bent it in one process or something similar.
{No Dear, I haven't seen your metal nail file. }