Spark Plug Heat Paste for Rotax engines

[WestCoast]

It is my understanding that the Whacker P12 spark plug paste specified by Rotax is a combination of heat sink & anti-seize paste. Having listened to the "resident Rotax guru" on the Podcast link provided by Ozzie, I believe the paste available in the RotaxParts.net catalogue ( http://www.rotaxparts.net/scripts/prodView.asp?idproduct=245 ) is also a combination heatsink/anti-seize paste, but at a far more reasonable price. I tend to agree with Nev that the electronic heat sink paste alone may not be satisfactory for spark plug applications.

 

Dave

 

 

[Guest Maj Millard]

Lots of interest in this one !. I have inserted many (Probabily hundreds, possibly thousands !) of spark plugs into GA engines, and also many into Rotax engines over the years. I have always used a silver-coloured nickle anti-seize paste. As mentioned before, you put it onto the uppermost two or three threads only, and not down lower, to keep it away from the electrodes. Plugs always come out easy and trouble free, if this is used. If not, (watch out !) the plug can come out hard, and sometimes pulls out the helicoil with it. (Many GA engines are helicoiled as standard).

 

With a rotax, worst case scenereo would be to strip out the aluminum threads.(huge pain in the Axxx) Basically in both GA and Rotax, you are putting steel against Alloy, add a bit of heat, and possibly a bit of moisture, and you will get disimiliar-metal corrosion, the anti-seize simply separates the two in a corrosive sense, whilst still allowing the plug to ground out, which it must do to fire.

 

In my opionion if the Rotax white paste has a heat transfer role, it would be to a miniscule degree, and is probabily something dreamed up by the Krauts to sell more fancy and expensive white paste.

 

 

[Modest Pilot]

I would use Champion anti-seize sold by Aircraft Spruce. It's T S O'd and has a history going back many years. The gasket is probably more important for plug heat than heat sink paste. Don't reuse, consider anealed copper washers; available in various thickness from Champion USA. The thread should not protrude into the combustion chamber, and with plug ring type thermo couples (CHT probes) gaskets of the right thickness should be used to set the plugs.

 

 

[Guest ozzie]

Would the small size length and dia., plug be an issue to require the use of this paste achieve optimum heat transfer on the rotax engines, compared to the larger more efficient Lyc/Cont plug that uses the paste just for anti-seize.?

 

IE maybe to increase plug life or such.

 

Ross, sounds like you did quite a lot during your time in the States. After visiting Airventure i finally realised just why so many Aussies went over back then and stayed to take up the many opertunities and experiences that we just don't have here.

 

I can vouch for Maj Millards quality of workmanship to perform perfectly over the long term, made from harness webbing and a polished heavy chest strap buckle, it has never failed in keeping my pants up since he made it for me in 1976.best thing about it is that is i adjust it to the same point as back then:laugh:

 

regards

 

ozzie

 

 

[facthunter]

Conductivity- heat transfer.

 

The smaller plugs pick up less heat due to the smaller surface area, so have less heat to dissipate through the gasket (washer) and the threads. I would say that Rotax have an arrangement with the recommended supplier which is beneficial to both.

 

I'm with Maj on this . any TSO'd antiseize should be OK, in fact being liquid cooled the requirements should be less demanding that would be the case with aircooled engines, some of which run at temps significantly higher than the Rotax. Nev..

 

 

[Yenn]

To settle the argument, if it can be called an argument. There must have been a few people by no who have used different pastes or even no paste. Has anyone had any problems with what they are doing and if so what? Has an increase in plug defects occured, or is there any change in the torque required to remove plugs?

 

 

[Guest Lee Schaumberg]

Spark Plug Antiseeze

 

Hello All

 

This section was read by me because I didn't know what heat paste is. Nobody said go to an airport and ask an A&P mechanic what they use and where they get it. A&P mechanic= Airframe and powerplant mechanic in the USA. Worked for an engine manufacturer as a field service engineer for many years and didn't know that some people put in plugs without antiseeze. The engines I worked on were small to medium gas not gasoline engines only up to 5000 hp. Spark plugs lasted about 1 month (720 hrs). Any way I have used nickel and copper based antiseeze.

 

 

[Guest Maj Millard]

Thanks Ozzie for the great compliment, I occasionally wonder where all that stuff ended up, and it's quite a trip to hear that somebody is still actually enjoying it !!!! Glad you enjoyed Oshkosh, we made the big trip back in '87 and it is really like you have died and gone to pilot heaven !!.would you agree ? A lot of us went to the States back in the 70s for the big jumping, and were not disappointed. We did of course take advantage of the opportunities once we got there .....Cheers Ross.

 

 

[jetboy]

FWIW my work involves electronics and heat transfer paste which is usually zinc oxide based with an oily or silicone grease binder. When run hot (like over 75 deg C) it usually dries up and cannot be re-used. In the ealier days the best heat transfer used beryllium oxide we dont want to go there.

 

When I got my (new) J2200a I dont recall seeing any antiseize on the plugs. Must have removed at least one to fit a CHT ring. I checked the condition of one plug in each cyl. at the specified interval (to avoid unecessary disturbance of the threads and seal washers, been there done that). By 150 hrs I found they did not unthread easily, due to buildup on the plug threads scraping away at the head threads.

 

I replaced all plugs at 200 hrs and now use an antiseize paste. Wont know the outcome till next check. Another note - if new plugs go in too loosely get some calipers and measure the thread dia. - should be 11.80 mm not 11.56 mm as a batch of NGK D9EA supplied in NZ was found to be.

 

On the original question of Rotax requirements, I thought the special stuff was for the 912s, the stuff our club use is pinky colour and smooth silastic RTV looking, unlike any electronics paste I've seen.

 

Ralph

 

 

[ZULU1]

HKS Advisory spark plug pastes

 

I have read this thread with interest and as I own a HKS I discovered this "bulletin". Obviously the HKS has a oil cooled head and advises Iridium plugs but they do advise a anti seize material.

 

Very useful thread and discovered this document as aresult.

 

Thanks Paul

 

2008-12-15_Spark_Plug_Replacement_v1-02.pdf

 

2008-12-15_Spark_Plug_Replacement_v1-02.pdf

 

2008-12-15_Spark_Plug_Replacement_v1-02.pdf