Jump to content

Cause of insulator erosion on Tempest fine wires

RobertE

By RobertE
in General Mooney Talk

 Share

Recommended Posts

alextstone Mentor

alextstone

Posted
Posted

I'm no expert but the internet allows me to pose as one....it looks to me more like deposits vs erosion.   Perhaps a cylinder that is too rich or oil bypassing the rings???

  • Like 2
kortopates Grand Master

kortopates

Posted
Posted (edited)

Agreed, it'll probably even clean up just fine. A couple possibilities - was it still firing? (if you have an engine monitor you'd know right away) Can't tell from the picture to see if the plug is actually fouled, i.e. is it shorted out so that it wasn't  firing at all when removed? If so, a good plug will look like that pretty quickly if its been cold in the cylinder and what we're seeing now doesn't necessarily mean anything other than a fouled plug. If so, clean and inspect including internal resistance (less than 5K ohms) and gap and re-install and carry-on. 

But on the other hand it could be sign of an excessively oily cylinder in which case would suggest borescoping the cylinder and you may well see oil pooling in the cylinder since that plug looks oily - not just carbon from being overly rich but excessive oil. If so, look for oil leaking past the rings and/or sucking it in from valve guides.

Also your bottom plug is going to be much dirtier than the top - so hope that is a bottom plug :) 

Edited by kortopates
  • Like 2
carusoam Grand Master

carusoam

Posted
Posted

Expect it to clean-up nice...

If it doesn’t we have a contact for tempest around here somewhere...

The last time, a center electrode found its way loose...

Best regards,

-a-

takair Grand Master

takair

Posted
Posted

Is it just the one plug or more?  Looks either very rich or oily as someone else said.  Also, are there two gaskets there?  Could be the picture, but looks like 2......never mind, zoomed in...looks like 1.

Yetti Grand Master

Yetti

Posted
Posted
1 hour ago, EricJ said:

There should be a button or switch on the cleaner that blows air only without the abrasive to clean the abrasive out.

I don't trust that.  I still run a sharp pointy thing around the base.   Black medium.   dark down there.

RobertE Proficient

RobertE

Posted
  • Author
Posted

I think my photo didn’t properly display the problem. All other plugs have insulators that have a flat surface from the edge to the center electrode.  This one has a concave surface (wasn’t this way when new) that has the effect of exposing more of the electrode than it should.  In fact, if you looke very closely you will see the wider part of the electrode at the base of the insulator, whereas only the narrow portion should be exposed.

To answer some of the questions, I’ve had no problem with the engine, all plugs are firing,.....basically zero observed problems.  The only oddity is the eroded electrode.

 

 

takair Grand Master

takair

Posted
Posted

Hard to tell, but is it eroded or did it crack away?  Cracking can be detonation or similar.  Is it a one time one plug or does it repeat?

Yetti Grand Master

Yetti

Posted
Posted

From the internet.   "Blisters on the insulator tip, melted electrodes, or white deposits are signs of a burned spark plug that is running too hot. Causes can include the engine overheating, incorrect spark plug heat range, a loose spark plug, incorrect ignition timing or too lean of an air/fuel mixture."

 

NAHa3dp9j2MASLBOSDfNbtJ8sDS6JAVLAe8WEWKE

 

 

EricJ Grand Master

EricJ

Posted
Posted
13 minutes ago, RobertE said:

I think my photo didn’t properly display the problem. All other plugs have insulators that have a flat surface from the edge to the center electrode.  This one has a concave surface (wasn’t this way when new) that has the effect of exposing more of the electrode than it should.  In fact, if you looke very closely you will see the wider part of the electrode at the base of the insulator, whereas only the narrow portion should be exposed.

To answer some of the questions, I’ve had no problem with the engine, all plugs are firing,.....basically zero observed problems.  The only oddity is the eroded electrode.

How did the other plug in that cylinder look?

carusoam Grand Master

carusoam

Posted
Posted

If the plug appears different from the others... something has changed, from what you are expecting...
+1 on contacting the Tempest guys...

Iirc... Yetti’s email contact above came from an actual Tempest plug issue...

I had a car plug insulator come loose... they will fire improperly, stop firing, or fire normally...depending on where it is at the moment... I also posted a pick of that plug too... :)

Best regards,

-a-

Yetti Grand Master

Yetti

Posted
Posted
1 hour ago, carusoam said:

If the plug appears different from the others... something has changed, from what you are expecting...
+1 on contacting the Tempest guys...

Iirc... Yetti’s email contact above came from an actual Tempest plug issue...

I had a car plug insulator come loose... they will fire improperly, stop firing, or fire normally...depending on where it is at the moment... I also posted a pick of that plug too... :)

Best regards,

-a-

We had a brush truck get a tune up at the Ford Dealership.  One of the techs did not feel for the click on the coil wire to distributor.   Ya it's that old.   The rubber boot disintegrated due to the ozone produced.  The truck kind of ran.  I think the dealership had to cough up a new coil wire.

  • Like 1
Yetti Grand Master

Yetti

Posted
Posted
5 hours ago, Marauder said:

 


I use walnut shells on my Tempest fine wires.


Sent from my iPhone using Tapatalk Pro

I use some kind of shells to polish my pistol brass.

Yetti Grand Master

Yetti

Posted
Posted
2 hours ago, N201MKTurbo said:

I see what you are talking about. I think there is normally a frit seal there. It looks like it wasn’t properly bonded and fell out.

I will just go ahead and tell the story.    Apparently for a batch of fine wires the outsourced the welding of the center electrode.   Then they brought that process in house.   but ya the center thing is missing.

Take a picture of the side of the plug with the batch code on it.

  • Like 1
Sandman993 Community Regular

Sandman993

Posted
Posted
On 10/29/2019 at 4:33 PM, EricJ said:

It looks like deposits to me as well.  If you have access to compressed air, plug cleaners are pretty cheap.   Most come with abrasive material, just make sure to use the non-silica, non-glass-bead stuff.

https://www.aircraftspruce.com/catalog/topages/1201684.php

12-01684.jpg

Am I crazy or did I read you’re not supposed to use this type of cleaning process on fine wires.

kortopates Grand Master

kortopates

Posted
Posted
8 minutes ago, Sandman993 said:

Am I crazy or did I read you’re not supposed to use this type of cleaning process on fine wires.

You can use the cleaning process, just not the standard glass abrasive that comes with them and commonly used with massive plugs. It will ruin them and can lead to damaging them - in fact it could responsible for the damage done to the above plug. For fine wires we should only use a much larger diameter material such as walnut shell material.

https://www.tempestplus.com/Portals/0/PDFs/Sparkplug Cleaning The Right Way 061212.pdf

Safe walnut shell abrasive for fine wires:

https://aircraft-tool.com/shop/detail.aspx?id=78W&AspxAutoDetectCookieSupport=1 

  • Like 3
N201MKTurbo Grand Master

N201MKTurbo

Posted
Posted

I still use glass beads to clean my plugs.

I have read all the articles about how bad it is and I haven't been able to reproduce anything they compline about.

I have looked at the plugs with a professional inspection microscope before and after cleaning with glass beads and just can't see what they are talking about. Some of the images in the articles show glass beads trapped in crevice's. Yes, they can look like that before you clean the glass beads off, but they are easily cleaned. I have found the glass beads are less aggressive than any other media except walnut shells and soda. but the glass beads clean better. 

Yes I'm calling bullshit on the glass beads OWT!

Let me see picture from your first hand experience?

  • Like 1
jetdriven Grand Master

jetdriven

Posted
Posted

Supppsedly it also strips the iridium coating off the fire wire plugs.  Have you run the fire wire plugs 500 hours like this to see if they erode? 
I don’t even clean them.  Done this for 600 hours.  I pick the lead out of  them and reinstall. 

  • Like 1
EricJ Grand Master

EricJ

Posted
Posted (edited)

Does nobody use the jackhammer thingie for lead deposits?   I cleaned up a bunch of plugs that were pretty awful, including what was supposedly some serious accumulation of silica (from dust ingestion, supposedly, not bead cleaning), and the knife/jackhammer worked really well.   This thing (but on a bench machine, supposedly the engravers work okay, too).

https://www.aircraftspruce.com/catalog/topages/t560sparkCleaner.php

12-00714.jpg

Edited by EricJ

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
 Share
Go to topic listing
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.