any spark plug experts here?

[chad8]

I bought a set of 4 ngk bcpr6eix last night from an auction for $1 last night. They are listed for a saab , etc...
They are the same 14mm 3/4 reach as most Japanese 4 cylinder plugs except they are jis standard instead of iso and the heat range is one set colder . this means .10 shorter and I am not sure how much cooler the heat dissipation and is. They are gapped at .30 and my engines are gapped a little wider.
Now my question is that will the jis plugs fit ? will being one heat range colder affect much because these are iridium plugs and my 95 corolla currently has copper plugs(BKR5EIX in iridium)? don't they fire hotter? I also have a Aerio(BKR5EIX-11 in iridium) that takes a similar plug . Do you think its worth a try in either . Really , the only difference i see is the 1 heat range colder,.10 length and gap from .30-.44.

 

[Tegger]

I see from NGK's Website that they do not recommend opening the gap more than .008" from the as-shipped setting. You'd have to open yours .013", well above the limit.

Going from a "5" heat-range to a "6" increases the probability of carbon fouling. It's not a great idea unless you spend the bulk of your time on the highway at high-revs in the summer. A Corolla is geared fairly high, so you're not likely to be running at 4,000rpm on a regular basis.

I also see that your BCP number indicates a projecting insulator, which your BK lacks (this spec is independent of thread-reach). This means that the BCP ground-electrode will protrude further into the cylinder than the manufacturer intended, possibly contacting the piston or a valve, which could be destructive to the engine.

Since the BCPs are the taller JIS standard, your spark-plug boots won't sit tightly enough to the valve cover; there will remain a gap that may admit moisture and dirt into the spark-plug tube. On vehicles with waste-spark systems, it may not be possible to bolt the coils to the valve cover.

In my experience, I see no difference in longevity, performance, mileage, or emissions between platinum or iridium. I do note that iridium is notably less expensive than platinum, so its use may have roots in product cost-control, rather than in performance.

If I were you, I would not use the BCP plugs in engines that call for the BK plugs.

 

[Kestas]

I've read that platinum tipped (and probably iridium tipped as well) plugs have a wider heat range that standard plugs. This was a selling point to distributors who didn't need to stock the same variety of plugs with platinums.

 

[wiswind]

The emissions label under the hood of your Toyota should list a brand and number of the plug to be used.
Most Toyotas can use either a NGK or DENSO plug.
My owner's manual lists both a NGK and a DENSO number.
It is BEST to stick with exactly that number.

If you don't have an owner's manual, you can get access to one online for FREE.
Go to the TOYOTA website and find the "for owners" tab.
You can register your car for FREE and you will have access to the owner's manual, repair history for all repairs done at a Toyota dealership and any open recalls for your vehicle.
You will need your VIN to register.

A slight variation from the plug listed for your vehicle may cause no problem or cause lots of problems.
In my case, the listed plug is rated for up to 120K miles or more.
There is a plug that claims to increase performance with its smaller diameter electrode (Denso Power plus) but a lot of reading on the DENSO website finds that the Power Plus plugs are only rated for 30K miles by DENSO.
That is not an upgrade for me.

 

[GMBoy]

In any case I wouldn't be putting suspect $1 plugs in my car especially as it appears that they are not the correct plugs. I think Tegger summed it up well - you are risking possible internal engine damage due either to plug/piston interference or carbon build up and who knows what else.

Spark plugs are cheap - go get the right ones.

 

[mechtech2]

What part is 0.10" shorter?
The threads? The total length? The insulator?

If the threads are the same, you might as well use them since you paid for them. Gap them up to your original specs first.
See how she runs and yank one or two in a month for a visual.
There is a possibility of fouling with a colder plug. But they have a LOT of latitude.

 

[chad8]

Originally Posted By: mechtech2
What part is 0.10" shorter?
The threads? The total length? The insulator?

If the threads are the same, you might as well use them since you paid for them. Gap them up to your original specs first.
See how she runs and yank one or two in a month for a visual.
There is a possibility of fouling with a colder plug. But they have a LOT of latitude.


Mechtech, you are the only real mechanic who answered as a mechanic would. The car is a 93 corolla with 300000+ miles. i don't care if it blows. ,and of course I would check any differences when i pull the first plug. If the tip length matches , I already know that the threads are exact and the length is .1 difference. The protruding plug issue is just insulator length. That might be a non issue too if the wires fit tight over the holes.
I really wanted to access anybody who might have done something similar or would like to learn about spark plug design and nomenclature. There is a pdf that shows how the manufacturers have entirely different numbering systems for heat ranges. A ngk 6 might be a champion 19. It is just stupid and it took a while for me to understand it. I spent a few hours learning a lot and posed the question to share what I learned.

 

[PandaBear]

It is more than just the heat range that you need to be concern about. The ground electrode protrusion is also important so you will not have a piston clearance issue, make sure you check the dimension very well before you put it in.

I know a lot of people having to go to a colder plug when they advance their timing. What you may be able to do to avoid carbon build up in a colder plug is to advance your timing a bit and see how it runs. You might gain more power at the expense of fuel economy.