Roger,
I can agree with a lot of what you said. Then you finish with a comment on
proven practices. My suggestion here is that the vast majority of Rotax
users have transferred their hot rod or home maintenance procedures to their
Rotax engines and have simply used anti sieze lube on thier plugs for at
least 75% of probably millions of flight hours.
Then there is the apples and oranges thing. Evans coolant has become one
of the latest Rotax recommendations (read rages). Evans is a high temp
coolant with a lower heat carrying capacity than the 50% blend traditionally
used. Why was it introduced? Because in some installations, the Rotax
engines have been found to run hotter than in other installations causing
vapor pockets and damaged engines. Rans, for example in some models, have
cooling issues especially in climb. I have followed some that used a
protracted step climb to get over high mountains where the Kitfoxes in the
flight simply climb to altitude. Do I feel a need for Evans Coolant, of
course not. My problem always was to get the oil temps to the recommended
212 to remove the moisture from the oil. I simply don't need a high temp
coolant.
I think this argument can also be made for the heat sink compound. Our
engines, at least in the Model IV (I have no personal experience with the
internal radiator found in the later models) Our engines run on the cool
side of the heat range. I don't watch my sodium intake because my Blood
Pressure runs on the low side. What I mean by that last comment, is that
there are very few pieces of advice where one size fits all. Take the 912UL
vs. the 912ULS, for example. I suspect with the higher compression, the ULS
will run a bit hotter. It might be appropriate to consider a heat
transferring lube on the plug threads, then again if my engine runs on the
cool side, what's the point. I had 900 hours on my old engine. I changed
the plugs at the recommended intervals and had the same boring insulator
colors that everyone else had. Did I damage my engine? I seriously doubt
it. But, then again, would I damage the water cooled head, or the $3.00
spark plug if it wasn't cooled adequately. And I repeat, Honda recommends
name brand gas in my wife's Civic Hybrid. The latest issue if AAA magazine
quotes a petrolium engineer to the effect that with the EPA mandates on
detergents etc. in all fuels, there is very little difference in brands and
likely no difference at all because even the independents purchase their
fuels on the open marked and might sell Chevron one day and Texaco the next.
I don't feel comfortable making decisions for others, but for me and my new
project - 912UL - I see no need to worry about one more thing.
Lowell
----- Original Message -----
From: "Roger Lee" <ssadiver1@yahoo.com>
To: <kitfox-list@matronics.com>
Sent: Monday, November 16, 2009 9:24 PM
Subject: Re: Rotax spark plugs
>
> First Rotax is the expert and Mfg. They have hundreds of thousands of
> hours of actual flight data and testing, not to mention millions of $$$ in
> testing and the Mfg of the 912 engine since late 1989.
> How much of this do any of us have? Who has the facilities here to run an
> engine day in and out and the instruments to collect the data?
> Second maybe the rest of the old timers haven't caught up to newer ideas
> and technology, which is definitely the case in a lot of GA stuff. If you
> make a change you are liable and you have to invest tons of money for
> testing and STC's. That's one big reason you don't see big progressive
> changes in the GA engine stuff.
> If anyone chooses to experiment with their $18.5K engine then it's ok.
> This is also where they get good data on things not to do, from the guys
> that like to experiment. I think spending $3 on a little tube of heat
> conducting paste makes good sense and a good investment.
> The plugs don't get hotter. All we are trying to do is make the heads and
> plugs heat and transfer of the heat the same. By doing so you get a better
> marriage between heads and plugs.
>
> I don't quite understand why people are so reluctant to follow proven
> practices from an MFG that cost so little and is so easy. We have all
> invested so much time, money and education in our hobby, why stop on our
> on going educational process.
>
> --------
> Roger Lee
> Tucson, Az.
> Light Sport Repairman - Maintenance Rated
> Rotax Service Center
> 520-574-1080
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=273255#273255
>
>
>
