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Spark Plug Mania..

Posted: Apr Thu 28, 2011 7:18 pm
by squabeggs
First off...MKIV 2.0 AVH engine...

Seems to be a lot of mixed information out there on proper gap/gapping of spark plugs. I recently got a set of Denso plugs from MJM. Double platinum plugs that are pre-gapped to .044

I believe the NGKs for my engine are also factory gapped to .044

Vortex is full of people saying you either need to gap your plugs to anywhere from .032 to .044 Other people are saying you NEVER gap platinum plugs, just check them to make sure the pre-gap is correct. (I'm leaning toward this line of thought.)
Here is this link that has a fairly wide range of gaps...I believe 1.1mm is .044?
http://forums.vwvortex.com/showthread.php?2157409

What is the consensus here? for my engine type, just leave it at the .044 factory? Or should I close the gap down? and why?

Thanks

Re: Spark Plug Mania..

Posted: Apr Thu 28, 2011 8:02 pm
by Mikewire
My thoughts: don't buy platinum, the 2.0 will not like them and won't run as well as copper. Been there and done that.

Gap them at .032

Re: Spark Plug Mania..

Posted: Apr Thu 28, 2011 9:58 pm
by squabeggs
Hmm..the OEM plug in the AVH is an NGK PZFR5D-11, which is the Laser Platinum.

MikeWire, was your 2.0 a AEG ? (1999.5-2000..i think) I think those had the NGK BKUR6ET-10 Standard (Coppers). Unless I'm totally wrong, which is quite possible.

Anyway, I might try those coppers per your suggestion if these Denso plats end up sucking.

I read somewhere that the copper plugs produce a stronger spark with a smaller gap. A lot of the bad press, for the platinum, comes from people trying to use the recommended gap for the coppers on their platinum plugs. The platinum plugs produce a weaker spark at these smaller gaps and suck. So to compensate for this weaker spark the gap is opened up to strengthen the spark.

"Platinum should be gapped at 0.039in to 0.044in and Copper at 0.031in and 0.035in" -some internet chatter

Thanks for your suggestion. I'll let you know how these Denso platinum plugs work. I got them with some KarlynSTI plug wires from MJM ...they didn't have...or list...the coppers probably because I was looking for AVH specific stuff.

Re: Spark Plug Mania..

Posted: Apr Thu 28, 2011 11:48 pm
by Mikewire
Yep, I had the AEG with no smog pump and drive by cable. The AVH is slightly different that it has a smog pump and is drive by wire and I believe it got oil squirters. In the MKIV the two motor codes are nearly identical, including the manifold and head (IIRC) so they should accept the same or similar plug.

The NGK PZFR5D-11 is a single electrode platinum center plug, where the BKUR6ET-10 is a triple electrode center plug copper. Platinum simply gives more life to the plug because it's a "harder" material, has a higher melting point, and will wear less than copper, and will last longer. But you pay more because plat is a precious metal. Copper is cheaper, but will need to be changed more often.

I didn't run the triple electrodes because the three electrodes gives the spark three different paths to choose. As the plug and electrode material wear - electricity being similar to water...in that it takes the path of least resistance - the spark will migrate from one electrode to another, creating irregular, weaker spark patterns. So, I went with the single electrode copper plug and changed them every other oil change.

As far as gap goes, the plug will come pre-gapped from the factory with a specific set value. You need to set that value to what your engine's ignition system needs to run efficiently, and IIRC it is .032 on the 2.0L. You cannot effectively gap a double or triple electrode plug, which is another reason why I always went single electrode.

Again, these are just references to my ownership with the 2.0, so I think you should run what you want and don't be afraid to try different sets. There are as many opinions on plugs as there is oil weights and types, so my advice is to experiment and find what works for you, and go with it.

Re: Spark Plug Mania..

Posted: Apr Sat 30, 2011 12:41 pm
by squabeggs
Thanks. Do you happen to remember the model number for the single electrode copper you were running? NGKs?

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Re: Spark Plug Mania..

Posted: May Sun 01, 2011 2:20 am
by Mikewire
They are the V-power, model #7938, a.k.a. BKR5E.