Spark plug alternatives.

[falcor]

My engine builder recommended NGK BP7ES for my 2276 engine but my ECU needs to run a resistor plug but NGK doesnt seem to make a BPR7ES, only BPR6ES. Any recomendations for alternative resistor plugs in the 7 heat range?

['77 Westy]

BPR7ES is a common plug and should be readily available; Amazon has them and so does Spark Plugs.co.uk http://www.sparkplugs.co.uk/ngk-spark-plug-bpr7es

[falcor]

Lol, wow look at that. Wierd that my local parts store couldnt find them in their catalogue.

[Piledriver]

I've run 14x19mm 5/8" hex NGK resistor plugs in iridium that are the equivalent. bkr6eix or bkr7eix
There is also an NGK extended nose triple electrode in 5/8" hex. bkr6 (or 7) et
Makes plug changes easier, and leaves more room around the plug for TCs etc.
Base is same but socket clearance needs are much smaller.

I have found NGK -6 or -7 heat range both work fine YMMV.

Don't forget the Milk of Magnesia on the threads...
(That's a Jake Raby recommendation and it works great, also on WBO2 sensors)

[falcor]

Thanks Pile, ordered one set of each.

[aircooledtechguy]

I run the NGK Irridiums in both my engine's with good results. With the LS2 coils, they last about a year of abuse.

[falcor]

I run the NGK Irridiums in both my engine's with good results. With the LS2 coils, they last about a year of abuse.

Cool, if yours last a year of daily driving I should see at least 3 or 4 years from mine.
I doubt I'll ever do more than 3-4000 miles in a season in the 914.

[aircooledtechguy]

They lasted about 10K miles. Admittedly, I didn't check them for about the last 7K ('cause they're Irridium, right?) until I began to develop a ping under load. I yanked the plugs and found that the electrode was gone on all of them; as in down to the porcelain! The gap was somewhere around .120"+!! It ran perfect except for a slight ping under hard load. . . Gotta love that EFI!! Swapped them out and it was back to normal.

I'm left guessing that once the irridium coating wore-off, the tiny electrode disintegrated quickly.

[falcor]

Wow, I figured they'd last at least 20k or so, maybe thats only in newer engines?

[raygreenwood]

Its not an iridium "coating". Its a small solid iridium tip. The iridium in plugs is useful because it has a very high temp range and they "generally" wear very slowly. They do not make any bigger or better sparks.....they just last a long time and stay very even from plug to plug within an engine....which is very important in modern injection/ignition systems that use ion sensing to not only adjust coil ouput but have some input into fueling on some systems.

That being said.....the same rules apply for iridium plugs. You need to have the right heat range, nose length and design for your apllication....and it sounds like you did not have something right in yours.

That being said.....the OEM habit of running iridium plugs to extreme miles.....VW now quotes 70-80k before plug change......is simply so they do not have to mess with them during any warranty they offer.

This has been.....for over a decade now....causing LOT of problems especially with VW/Audi cars and I am sure with others. The plug gaps DO wear...even though its slow. With most VW ignition since at least 2000 maybe earlier......as the plug gap wears, the ignition ECU ramps up coil output to keep spark uniform. After a certain point.....the coils are over driven and they overheat.

You start burning out coils....and you start burning out modules. It was a common issue....outside of the module placement issue they had on the early turbo 1.8s. Around 65-70k miles.....cars were dropping a coil. Replace coil. Three weeks later....another coil drops off. Dealer says plugs are fine because they are still "even" in gap, within the 80k mile range and the engine runs smooth and with good power.

You can see the telltale by looking at the ABS hard sheath on the wire harnesses to the individual coils. It will be shrinking a nd distorting from the coils that are overheating. If you catch it early.....a plug change can prevent coil losses.

Typically I do not go over 50k miles with iridium plugs now. Not because the plug cant last....but because its hard on the system. Ray

[Wally]

Good infos Ray!

I also got some Iridium plugs (12mm) for my billet heads. Never used those, so I was wondering as you hear indeed many stories about them. Good to read your informative info!