Experiences - Comparison "new" Rotax spark plugs vs NGK

Ken Ryan wrote:

I think the important question is, do the expensive plugs perform better in any meaningful manner?

That is the real question.  Is the engine going to run any smoother, make more power, or last longer, as a result?  If each and every plug change with BRP over NGK extended the TBO by 1%, it still wouldn't be worth it.  Perceivable changes in performance, or real reductions in overall cost, or real improvements in reliability are things I can get behind.  If the only place it shows up is a fractional blip on some dyno....then not so much.

Hi all: 

Most of the readers have missed a key factor with this thread.  

First, the new plug is superior in durability.  Note that the NGK was 100 hour replacement with Avgas and 200 hour with unleaded fuels.  The Rotax plug is double...yes double.  You can go 200 hours on Avgas and 400 on unleaded fuels.  (Line Maintenance Manual, current editions) 

Second, the NGK is not approved by NGK and you can only get NGK via 3rd party suppliers who are not in the Rotax system.  While this may not bother you fine however any operators who operate under a TC I believe they must use parts that are approved.  Indeed for a TC engine, say fitted into a certified glider or Part 23 aircraft, the operator must have a log entry and the parts used have to be approved and sold with documentation verifying they are from Rotax.  

I know that some want to use the NGK, nothing can stop you on an experimental or amature built aircraft.  I think that the validation from Rotax is shown very well in the Line Maintenance Manual in the time to change.  

Cheers

What's "the Rotax system"?  Lockwood sells lots of NGKs for Rotax engines.  It seems clear that any engine that was originally supplied with NGKs can continue to use them.

OK the new plugs are twice as durable (at least on paper), so you replace them half as often but at seven times the cost...

What exactly is it about them that makes them more "durable"?

Hi Tyler...what is the Rotax system, good question.  Rotax, like most  manufacturers, have quality control standards that they follow.  Rotax is an ISO company and any supplier must also work to the QA system to ensure compliance to the design and performance of the part they make.  

Rotax has not sold any NGK spark plugs since the introduction of the new private label plugs.  Sales of the NGK were allowed by Rotax but only for the inventory that was on the shelf at the time of the change.  Given that Rotax will no longer supply NGK any supply still coming from a Rotax iSC, independent Service Center, might still be old stock.  That is a question for Lockwood as I have no information on how they still have supply at this time.  It is common knowledge that most spark plugs sold are from 3rd party suppliers that are not concerned with if it is approved by Rotax or not.  

Your question on what makes the Rotax plug more durable is easy, it is the tip design itself.  A multi tip plug has more ground points to select when it fires therefore reducing the buildup of carbon.  It also is less prone to wear of the main pin as the plug will alternate grounds randomly as it is in operation, hence longer life.  

Nothing can really help us with the price on the new plug, it is a commerchail problem with having to use a private label for supply and the relatively low volume used.  I would suggest you try to extend the interval also, there is no mandatory change of the plug required if you are experimental.  Actually in the case of the fuel injected Rotax I rather think the lean burn they have will greatly extend plug life.  Time will tell. 

Cheers

PS...a link to what is ISO 9001 QA systems

https://www.iso.org/iso-9001-quality-management.html

Seems to me, the whole 912 ULS sparkplug maintenance topic is a bit of an overkill.  Pulling the 8 plugs for typically 75-100 hr &-or annual insp. & conducting compression checks on an engine that burns zero oil ... is a gross overkill, much like doing it on your auto @ every synthetic oil change ( 7.5 k miles ! ). 

Seems like rotax ought to helicoil each plug hole for such continual use & abuse!  Never mind the constant weakening of the wire connector socket. 

Attached is a gr8t  .pdf  that newer members may have not seen.

Salud /