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Rotax plugs

Cyclone

Active Member
I’m approaching a 200 hour spark plug change on my 912ULS
The factory plugs are Rotax double electrode compared to the NGK single
electrode referred to in search results. There’s a significant cost spread
which I’m okay with if there’s a performance difference. My existing
plugs have been trouble free and look like new. Any comparison results out
there?
 
The current version of the parts catalog from Rotax still lists the old plugs (with the Rotax part number, not with the NGK designation) with status s.v., that is "still valid".
Also from the parts catalog: "s.v. | still valid, part was replaced by compatible component and can not be supplied any longer by the producer. Existing stock may be used."

We have used the new plugs for a short period and not seen any performance difference. That was on a motorglider and a few ultralight planes. We have been switching back to NGK since then. Can't remember any problems with either type of plugs.

By the way, the most recent maintenance manual allows for 400 hours between spark plug replacements when using lead-free fuel. It doesn't specifically tell whether this applies only for the new plugs or also for the NGK plugs, so use that information at your own discretion.
 
I just switched out my Rotax-brand plugs at 200 hours. I run strictly mogas but 400 hours seemed like pushing it. Changed to the standard auto plugs. The connectors fit fine. Just don't mix and match Rotax and NGK plugs; it's all or none.
 
I'll be replacing the factory installed Rotax plugs in my 912iS soon with the NGK plugs. For those of you doing the same, are you torquing them to the original 177 in. lbs and not the 142 in. lbs specified for the Rotax plugs? Also, does anyone know why the torque value changed?
 
I use 15 ft Lb ...the range you posted is 12-14.75 ft lb make sure to use the recommended heat paste on the threads ...don't worry so much about such close torque values.
 
I use NTE303A as it's advertised as 0.8 W/mK thermal conductivity.. comparable to Wacker P12's "0.6 - 0.8 W/m.K" (according to the Wacker spec sheet).
 
So how does Rotax square with NGK which indicates anti seize / lubricant should not be used?

https://ngksparkplugs.com/en/resources/5-things-you-should-know-about-spark-plugs

I think when Rotax introduced the new, super expensive, dual-electrode spark plugs, they took it into account by specifying 142 in-lbs.. NGK says lubricating can have a 20% difference.. so 142 (11.8 in-lbs) x 120% = 14.16 ft-lbs .. which is safe. (NGK calls for 10.8-14.5 lb. ft.)

Rather than revising the recommendation on the Rotax-NGK plugs to 142, they just said.. well we are introducing this new dual-electrode plug anyway.. and people shouldn't be using the old plugs.. so.. here's the new, safer value.

After my expensive plugs had 100 hrs, I went back to the NGK's with the 142 in-lbs torque and its been fine.. no loosening, no difference as far as I can tell.

Just my 2 cents.
 
I got the heat paste from Lockwood, don't have the PN available right now but if you call they'll hook you up.
 
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