Problems with NGK R5671A-8 plugs..

[prj]

Only plugs I've had repeatedly fail are f5dpor's.

Out of interest what failed on the F5DPOR's?

Oh, nothing important. Just the spark plug electrode separating, falling into the cylinder and blowing up the engine.

[Carfreak]

Oh, nothing important. Just the spark plug electrode separating, falling into the cylinder and blowing up the engine.

ouch... that´s not good at all! I´m glad that I changed em out for NGK BCPR7ES-11
My car is runnin great now.. now missfiring at all on idle

[K Simmonds]

Oh, nothing important. Just the spark plug electrode separating, falling into the cylinder and blowing up the engine

That's not good at all, I've dealt with such damage on a Two stroke bike engine once, in that case just the head and piston were damaged beyond repair, the thought of it happening to a four stroke engine is scary. Not a problem I'd heard of, or encountered with the Bosch plugs, however I'll take your's and JP's advice over most peoples !!! Think I'll start using the NGK race plugs instead.

[JP]

Realistically bkr7eix normal ngk's are fine for normal application. Bkr8eix for 400+ application. Bkr9-eix for 550+.

Race plugs are different territory in the price bracket at £35 each

[andy10v]

That's not good at all, I've dealt with such damage on a Two stroke bike engine once, in that case just the head and piston were damaged beyond repair, the thought of it happening to a four stroke engine is scary. Not a problem I'd heard of, or encountered with the Bosch plugs, however I'll take your's and JP's advice over most peoples !!! Think I'll start using the NGK race plugs instead.

Couple of failures mentioned in this thread

http://www.s2forum.com/forum/showthread.php?t=56638&highlight=spark+plugs

I will also be following JP's advice and ditching the Bosch (although I have had great use from them so far, its a bit much of a risk if they are now known to fail).

[JP]

The f5dpor's used to be the plug to have but I believe they changed factories of recent years and then the problems started to occur. My favourite was when they were hot if you held the metal nut with a pair of pliers you could spin the whole ceramic centre round with your fingers.

[Carfreak]

Changed to BCPR7ES with 0,5mm gap today.. started the engine, everything is fine till the temp reached +90C and then it starts to missfiring every 2-3 sec :s
What the hell could it be ? is it possible that one of my coils is bad after 1 earth cable got lose from the connector ?

Should I try a different gap on the plugs ?
Could it be my stock fuel pump that won´t reach the right pressure on idle ?

I also noticed that it´s difficult to hold a steady rpm.. if I have a constant pressure on the throttle pedal at around 2500RPM, the RPM goes up a little by it self, what could that be ?
Could it be the o2 sensor ?

Please help me out!! Need to fix the car for MOT!

[JP]

Why are you running such a small gap? When gap is too small there is not a big enough spark to ignite all the fuel properly.

The bigger the gap the bigger the spark the more fuel it can ignite. Up until the problem where the voltage from coilpack is not enough to make the gap so you use stronger coilpacks.

Regap them to 0.6mm or even try 0.65-0.7mm then see if the problem is still there.

[Carfreak]

Why are you running such a small gap? When gap is too small there is not a big enough spark to ignite all the fuel properly.

The bigger the gap the bigger the spark the more fuel it can ignite. Up until the problem where the voltage from coilpack is not enough to make the gap so you use stronger coilpacks.

Regap them to 0.6mm or even try 0.65-0.7mm then see if the problem is still there.

ohh okey.. i´ll try 0.6-0.7 then! Hopefully it works!

0.5mm was the gap I was recommended by other audi tuners with 1,8T ignition!

I´m gapping with a feeler gage, should it be a tight fit when checking the gap ?

[JP]

Gaps will vary depending on the plug material too. 99% of plugs nowadays are pregapped from factory to be suitable as a drop in application. If using a feeler gauge interference fit.

[Carfreak]

Gaps will vary depending on the plug material too. 99% of plugs nowadays are pregapped from factory to be suitable as a drop in application. If using a feeler gauge interference fit.

Okey, I´m running the BCPR7ES-11, I guess they have 1,1mm gap from factory but I was recommended to go down to 0.5mm. Maybe I should regap them to 1,1mm and start from there and go down to see what gap is best ?

[K Simmonds]

Realistically bkr7eix normal ngk's are fine for normal application. Bkr8eix for 400+ application. Bkr9-eix for 550+.

Race plugs are different territory in the price bracket at £35 each

Thanks for the info JP, I'll start using the NGK range you suggest on my own car as well as others. So BKR7EIX it is for standard and chipped stuff.

At 170 odd quid a set one needs a good reason (like 500BHP+) to shell out for those race plugs.

[JP]

Okey, I´m running the BCPR7ES-11, I guess they have 1,1mm gap from factory but I was recommended to go down to 0.5mm. Maybe I should regap them to 1,1mm and start from there and go down to see what gap is best ?

I would gradually go up rather than start at max and go down. Because if they were 1.1mm stock they were obviously for a completely different application. Makes me wonder whether they protrude the correct distance into the combustion chamber to enable a correct flame front.

[Carfreak]

I would gradually go up rather than start at max and go down. Because if they were 1.1mm stock they were obviously for a completely different application. Makes me wonder whether they protrude the correct distance into the combustion chamber to enable a correct flame front.

Okey, will do that!

Allmost every Audi here in Sweden is driving with the bcpr7es plugs.. all from 230hp to 800hp!

[Carfreak]

Prob found the problem
I´ve totally missed that u have to cut some of the rubber off the 1,8t coils to correctly fitment on AAN

I´m crossing my fingers and hoping all my problems is gone when this is done

Update: Nothing wrong with the hight of the coils Maybe the are damaged by the ground cables that had come loose from the coils... ?