Checking Spark Plugs

[Roger Lee]

Jim M,

 

I remember when:

On two different occasions on another forum you liked my comments (under a different name ) on a particular subject, but on this forum with the same subject you found them lacking. You even brought it up on this forum once that we should look at the other forum post by no other than because that guy's post was better. They were one in the same. I also write tech articles that are published under a different name and you liked one of those controversial articles too.

[Jim Meade]

Go ahead and post the examples, Roger, and we'll work it out.

 

As for you being John The Baptist foretelling the coming good news - I'm not buying it. It is simply inconceivable that ROTAX would use that way to disseminate information.

 

BTW, does Eric work for Rotax? Directly, as an employee? Do you know of any of the instructors who are Rotax employees?

[FlyingMonkey]

It was just a simple spark plug question...

[Jim Meade]

The current Rotax Line Maintenance manual says to set plugs for 0.6mm-0.7mm (0.23-0.27 thousandths) for new installation and the wear limit is 0.9mm (0.35).

 

There is one entry that discusses plug gap as an issue in winter operations. It does not specify a value.

 

From what I can find out, a wider gap will increase the voltage needed to fire the spark. It increases tip temperature. A wider gap will give a better spark that will result in better fuel burn.

 

One can see that if battery performance in winter is marginal that a wider gap requireing more voltage may make starting more difficult.

 

My immediate impression is that if your airplane starts OK, a wider or "summer" gap setting is preferable. There is some very interesting reading in spark plug technology. The following is for cars but much of the information is generic and should be useful for airplane engines.

 

http://www.ngksparkplugs.ca/tech-info-spark-plugs.cfm

http://www.ngksparkplugs.com/techinfo/spark_plugs/installation.asp

http://www.globaldenso.com/en/products/aftermarket/plug/basic_knowledge/spark/conditions.html

http://vdlfuelsystems.com/?p=273

http://www.carcraft.com/howto/116_0703_spark_plug_guide/viewall.html

 

 

 

 

[Roger Lee]

A leap of faith and trust in our fellow mankind when documentation isn't our first guide shouldn't be hard to swallow..

 

Rotax has no direct instructors from the factory. Master distributor instructors go back to the factory for training.

 

"As for you being John The Baptist foretelling the coming good news - I'm not buying it. It is simply inconceivable that ROTAX would use that way to disseminate information.'

 

 

Believe it, it happens and other LSA Mfg's do it too. I just got back from 912is training and the books aren't quite correct. How do you think so many instructors hear or teach things that aren't quite the same as the manual? How do you think the distributors get info before it becomes public? And here lies the rub, John The Baptist knew nothing about Rotax. I'm still predicting a major SB no one knows about in a few weeks time and I think it might even cover aircraft in the late 2009 or 10 time period. Time will tell and you'll know it when you see it.

 

" I'm not buying it."

You should, it happens all the time and in every industry. Things change faster than some documentation happens and sometimes no documentation ever gets generated for years.

The main Rotax distribution hubs know stuff at times long before the smaller distributors and certainly before the public. There are different master distributors for certain regions of the world. People like Eric Tucker of Kodiak (master distributor) in Nassau for all the Americas and Rob Seaton of Rotech (master distributor) for Canada and other regions. There are others in the world (22 of them), but I don't know those people. The thing is Jim you aren't in the system so you don't know the system or its inner workings. What you don't know may surprise you, it did me. So as you said you're a non believer. An individual you could never hope to know and it takes years and thousands of hours to get to know these people and the inner workings.

 

Here is the an example: For MANY years in the line maint. manual under the carb sync it was written to screw the stop screw to increase idle rpm counterclockwise. But in Rotax school they taught to screw the stop screw clockwise. It just got fixed in writing this last manual update. There are other things in the manuals that aren't up to current teachings too.

 

 

Here is another example: What's the magnetic oil plug torque as it is listed in the oil change section of the Line maint. manual? Kind of a trick question because it isn't listed in the Line maint. manual where you find all the other oil change items. It is in the Parts manual. Listed under the crankcase parts section. Most will tell you it's 200 in/lbs, but it's really 222 in/lbs or 18.5 ft/lbs.

But here's the problem. That is a cold dry torque. No where does it tell you what a wet warm torque is to be. Where do you get that info. Rotax school. Use 150 in/lbs for a warm wet torque. Lockwood will tell you the same if you want to call them.

 

So the questions are where, how and who do want get info from because I can go on and on about non documented items or things that have changed, but aren't in writing yet. You get your info from the instructors, schools, tech centers or mechanics that work closely with the Mfg's and tech centers, but not John the Baptist. Sorry you brought him up first.

 

Here is another prediction. You may see in the future a new Rotax class that will be better than the existing Service class and teach how to do proper annuals, service and better documentation, but that's just a dream I had last night. Two others may have had the same dream so I better hook up with them before I forget my dream.

 

My point Jim isn't to give you a hard time or shoot anyone down, it is to help let you know that things do go on behind the scenes from all our LSA Mfg's and engine Mfg's that isn't public knowledge and word of mouth is usually the way it gets out from anywhere to a week and up to years in advance of any documentation and it shouldn't be a huge leap of faith to trust some of these people. There are even private invitation only forums that these people chat on without being open to the public. I didn't make the system I like everyone else live and work within the system. I just choose not to fight it and get left outside.

 

I think we have pretty much beat our horse to death and should probably get back to plugs.

 

 

How about: How to make a compression test extension to reach down inside the plug wells?

Documentation and pictures included.

[Roger Lee]

Hey Andy,

 

You sure generate some interesting post and with the simplest questions! :lol:

I can't wait to see what happens when you ask a complicated question. I might have to take a few days off for those. Wait these post should qualify for time off. I'm headed to Mexico next week. No really I am going Friday.

 

Give me a call about your brakes.

 

Have a nice Sunday.