D9EA plugs

[Yenn]

This is not an accident and hardly an incident.

 

I cannot get the required D9EA plugs for the Jabiru motor, with caps on the threads.

 

This morning the engine fired up and ran well and I conducted a mag check at low revs, then taxied to the holding point and when I did a proper mag test, I had a misfire on the right mag.

 

The cause was that the screw cap on a plug had come off and the lead was detached. The plugs were changed only about 2 hours before.

 

Does anyone know if it is possible to get the plugs with solid built in caps. My local retailers cannot get them. Failing that it would be safer to replace the plug leads with a different sort designed to fit the screw thread.

 

 

[facthunter]

Remedy.

 

Ian , crush the bottom of the nut till it is just oval enough to be a tight fit on the thread and wind it on carefully with pliers, and it should stay there. Don't try to undo it as you will probably pull the whole assembly out of the insulator. Nev..

 

 

[Captain]

Does anyone know if it is possible to get the plugs with solid built in caps.

Ian

 

 

 

I had exactly that discussion with an NGK rep and was told that it isn't possible. Furthermore if you tell them this is needed for an aircraft they get decidedly twitchy (I assume because it increases their liability over just a car or a bike) and they then declined to give me any specific recommendations.

 

 

 

I have the same issue on the engine in my sailplane and have been doing what Nev recommended for the last couple of years with ok results, but you have to deform the nut just the right amount.

 

 

 

Regards Geoff

 

 

[blueshed]

Is locktite or a liquid metal, which may let the spark passed, a possibility?

 

Cheers Guy

 

 

[old man emu]

Yenn,

 

I'll have a look at the plugs we fit to Jabirus when I get to work tomorrow. I haven't heard our AMEs say anything about loose HT leads, nor have the operators brought it to our attention (flying school).

 

Old Man Emu

 

 

[Guest J430]

I use the Irridium plugs and thought the caps were not supplied on them for some reason, but they must be available from somewhere.....how do they get there in the first place?

 

Have not had that problem in 610 hrs, mind you watch the leads in the distributer cap, they can come loose so open out or expand the conductor a fraction so its tight when you push the lead into the cap.

 

J:wave:

 

 

[Guest Graham Lea]

Maybe they take the cowling off and push the HT leads on as part to the DI :-)

 

I do this as part of the DI.

 

I used to crimp the top of the lead so it was tight on the plug cap (having screwed it onto the plug so that it was tight)

 

One way of telling if it isnot a good fit is to listen to the radio. if on transmission there is a lot of engine noise, it can be just this problem.

 

 

[Guest Graham Lea]

I forgot:

 

I *think* the dealers/importers are :

 

Precision 93166800

 

Botany

 

[email protected]

 

They should know...

 

 

[Guest brentc]

I find it a true pain in the butt. I have to remove them each time and re-attach which can't be a good thing. Once I changed them and instead of them coming off easily they took the thread out with them - very annoying! If I lost or dropped one in the change-over I would be very unhappy!

 

 

[old man emu]

Yenn,I'll have a look at the plugs we fit to Jabirus when I get to work tomorrow. I haven't heard our AMEs say anything about loose HT leads, nor have the operators brought it to our attention (flying school).

 

Old Man Emu

I checked with our AMEs, and they have not experienced the problem you mention. However, they did mention that putting the leads on the plugs involved a bit of a trick. You push the lead on until it feels firm, then push hard again till it sort of "clicks" into place.

 

The only problem we know of with HT leads is that they come loose from the "distributor" and have to be pushed back home to secure it. We do this every time the top cowl comes off.

 

Old Man Emu

 

 

[skybum]

Depending on how the HT lead has been manufactured, one alternative is to pull the rubber cover back far enough to present the actual connector. Push the connector onto the plug cap until click then push the protective cover back over the connector and plug. Sometimes the cover will go so far as to prevent the plug from mating with the connector. Another alternative is to source NGK propriatory connectors that will fit directly to the plug sans nipple. Very snazzy looking in black. 90 bend and in varying lengths to suit deep set plugs in motorcycle twin cam engines.

 

 

[Yenn]

My problem was not with the lead to plug connection. The plug cap unscrewed allowing the lead and cap to drop off. From your replies it seems that the plugs with caps are not available anywhere, although the packets show a cap in place on the plug. I will just have to be a bit more careful in future, maybe fit brackets to hold the lead in place to the plenum chamber, then even if it comes unscrewed I will still have a spark and also a lot of radio noise. This was the first time it happened in over 200 hours.

 

 

[Guest Nelson Smith]

Just for info,did a deal with Auto Barn for 6 boxes of D9EA spark plugs for $2.89 ea.best ever price I have had

 

Nelson

 

 

[Dieselten]

Got 100 of the plug end-nuts using the NGK part No. GSA quoted above, also a box of D9EA from my local Auto One store, took a couple of days only. 100 end-nuts cost me $15, the plugs were pretty reasonable too.

 

D9EA are not supplied with end-nuts as they are basically a motorcycle plug and most bikes use a lead-cap that requires the threaded shaft. You buy the plugs, you buy the end-nuts, you put one on t'other.

 

A Jab driver I know uses a smear of high-temp Loctite on the thread when he installs the end-nuts. Has had no problems with plugs as far as I am aware.