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Posted

Hi all,

 

At the risk of getting my head bitten off, are there alternative Spark plugs you can use in a 503.

 

Yes I know Rotax recommend NGK BR8ES plugs, I was just wondering if I have an option.

 

Regards,

 

Mike

 

 

Posted

Having thought about this a bit more, I seem to recall that the Rotax supplied plugs aren't standard NGK BR8ES so the equivalent from other manufacturers might not be suitable anyway.

 

John

 

 

Posted

I just bought a box of 10 BR8ES. $33 for 10. On the box there is a symbol of a microlight trike with a slash through it which I assume means that they are not for ultralight use.

 

Anyone else noticed this? Is it a liability thing?

 

Phil

 

 

Posted

Dear newairly

 

It seems that all NGK spark plugs are boxed with the same warnings.

 

The most important thing is that the terminal [on the porcelain end] is 'solid'.

 

Easily obtained BR8ES plugs often have threaded terminal caps that can corrode or fall off. $3.30 for each plug sounds 'cheap', although you may have a bargain.

 

Safe flying, Paul.

 

 

Posted

Dear Paul,

 

I bought the plugs at a local auto parts store. They had to order them. The individual price was about a dollar more than the whole box price. I figured I would need them all eventually anyway.

 

I am aware of the issue of solid vs screw on tips.

 

 

Posted

The NGK plugs I have bought in the past from Bert Floods as well as California Power Systems are DCPR8E (described as 912S spark plug - new style) but I guess the 503 may use a different plug to the 912.

 

Dave

 

 

Posted

The main reason I asked the question was that my local car part shop won't stock them and will only order them in when I request them. On top of that it takes 3-4 days to get them in! He was telling me the Bosch WR4CC'S are an alternate according to his cross reference book, and he actually stocks them.

 

I am just a bit dubious deviating from the manual. If all else fails I guess I'll buy a box and hopefully remember to order them when I use the last ones.

 

Mike

 

 

Posted

Mike,

 

Be aware, corrosion and ends coming loose are not the only issues with the aluminium screw top plugs. The main issue is aluminium dust created from the plug cap spring wearing on the screw top, collecting in the plug cap and causing tracking of the current - in effect, bypassing the sparkplug.

 

This is more prevalent with the old metal shielded spark plug caps, but is still relevant.

 

My advice is, if it's not a steeltop and the correct number, don't use it. The correct plugs may seem an unnecessary expense, but consider how much an engine failure could cost you.

 

Bertfloods can normally get most things to you by express post - usually next day.

 

Fly Safe

 

Kev.

 

 

Posted

Dear newairly,

 

Thanks for the tip. I have been paying a 100% mark-up to somebody.

 

I suppose specifying a certain item on safety grounds can leave yourself open to profiteering when you live far away from a major centre.[ I had to wait a week and a half for them as well.]

 

Thanks again, Paul.

 

 

Posted
Mike,My advice is, if it's not a steeltop and the correct number, don't use it. The correct plugs may seem an unnecessary expense, but consider how much an engine failure could cost you.

 

Kev.

Not disagreeing at all here - but to help with my learning - if you are testing both plugs (in each cylinder) on run-up, then even if one plug fails, surely the other will get you home?

 

Cheers,

 

Chris

 

 

Posted

When you consider the price of them, how can plugs be considered expensive? For my first car plugs cost the equivalent of 50 cents and I was earning $25. They were nowhere near as good as they are now, so I consider them cheap. I cannot buy D9Ea's over the counter anywhere in Gladstone which likes to promote itself as the powerhouse of Queenland, and it is impossible to buy them with a solid top, even when specifying them.

 

 

Posted

Mike,

 

No problem - feel free to disagree or challenge an opinion at any time. Some opinions will be more or less qualified than others, but the main thing is that they are free and you can take them or leave them.

 

The short answer to your question is yes, the other ignition circuit should get you home, unless of course the other plugs/plug caps are in the same condition and about to suffer the same failure. Assuming that all of the plugs were serviced/replaced at the same time, this is probably more likely.

 

I personally know of at least a couple of trike flyers who use the screwtop plugs on a 582 quoting something like 'Iv'e used them on my trail bike for 15 yrs and never had a problem', and indeed as far as I know they haven't had problems, but there is something else worth considering - You, or whoever is doing your servicing is signing for doing so iaw the Rotax servicing manual. Fitting the incorrect spark plugs would contravene those instructions. If you were to have an accident under these conditions, would you still be covered the HGFA/RAAus insurance?

 

Safe flying

 

Kev.

 

 

Posted

I have contacted the NGK help-line and enquired about plugs for my Trike.

 

The response was that NGK DO NOT recommend the use of their Spark Plugs for light aircraft and that is why the warnings are on the box. I then explained that the importer supplies NGK for these Engines. After taking my number they returned my call in about ten minutes with the response.-

 

The specific order number is BR8ES-SP .

 

They have plentiful stocks in Melbourne and are readily available for dispatch to Repco, Autopro and other NGK stockists.

 

Cheers, Paul.

 

 

Posted
Mike,

The short answer to your question is yes, the other ignition circuit should get you home, unless of course the other plugs/plug caps are in the same condition and about to suffer the same failure. Assuming that all of the plugs were serviced/replaced at the same time, this is probably more likely.

 

Safe flying

 

Kev.

Guys,

 

With my 2 Rotax 912uls's I change the top set of plugs at 100 hours, bottom set at 200 hours, top set at 300 hours, bottom set at 400 hours etc.

 

This method over time uses no more plugs than doing all 8 of them every 200 hours.

 

By doing this I always have a set of plugs with less than 100 hours of use. I also always have a proven set of plugs in.

 

Call me paranoid :hittinghead:, but I prefer not to buy my plugs in bulk, that way if there happens to be a dud batch come out hopefully I will not be effected with more than one set.

 

Cheers

 

Mick

 

 

Posted

Mick,

 

sounds like a really good way to ensure the engine ignition system stays good. I assume the 912uls's was a typo and that you meant 912UL which has a 200hr plug life. The 912ULS only has a 100hr plug life.

 

Safe Flying

 

Kev

 

 

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