What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Setting gap on Tempest fine wire plugs

rvanstory

Well Known Member
I just installed new Tempest fine wire plugs. But I have SureFly EI and both they and Tempest say the standard gap for plugs is too small when using electronic ignition. So, tomorrow I am setting the gap wider.

I have the Champion fine wire gap tool, so may make things a little easier. But Tempest warns against changing gap on your own. Since iridium is so brittle, the don't want you breaking the electrode.

My question is this, who has reset the gap on Tempest fine wire plugs? Any words of caution or advice to watch for? These plugs are too dang expensive to break, because if I do, no warranty.
 
I just installed new Tempest fine wire plugs. But I have SureFly EI and both they and Tempest say the standard gap for plugs is too small when using electronic ignition. So, tomorrow I am setting the gap wider.

I have the Champion fine wire gap tool, so may make things a little easier. But Tempest warns against changing gap on your own. Since iridium is so brittle, the don't want you breaking the electrode.

My question is this, who has reset the gap on Tempest fine wire plugs? Any words of caution or advice to watch for? These plugs are too dang expensive to break, because if I do, no warranty.

I think the wider gapping is an option, and not required.

https://www.surefly.aero/copy-of-home said:
Aviation spark plugs – gapped .016 to .032

https://www.surefly.aero/copy-of-home

Just curious, why not run auto plugs?

https://www.surefly.aero/faq
 
I think the wider gapping is an option, and not required.
Bill at Surefly gave me the wider gap advice because the engines smoothness was not as good with the fine wires. Not sure why they don't say this on the website, but was definitely his advice yesterday.

Just curious, why not run auto plugs?

Didn't know until recently you could get a wire harness for auto plugs using SureFly. Surefly doesn't make one (like many other of the EI MFG do). At this point, I already own a set of fine wires from Tempest, so, I'll stick with aviation plugs for now.
 
did 4 of my Tempest fine wire plugs when i got my Surefly ignition and took my time and never had a problem. It was a little nerve racking but no issues.
 
I would definitely widen the gap, as it will give a stronger spark that is more tolerant of high altitude and lean mixtures.

Are you sure that the ground electrodes are not just carbon steel? I would suspect that only the center electrode is iridium. However, I have never seen one.
 
Tempest Spark Plug Manual

Section 4.3.9 indicates the wire material is iridium and is only to be "tweaked" with pliers once, and then with great care - as broken wires are not covered under factory warranty.

HFS
 
Sounds like tempting fate.... I wouldn't risk it.

What I didn't mention in my OP is that the engine ran terrible at altitude LOP. So, I have to "tempt fate" and do something. Current engine smoothness with factory gap was not acceptable.
 
I purchased a fine wire gapping tool from ACS. Just be gentle when you regap

CHAMPION CT-457 FINE WIRE GAP SETTING TOOL
 
did 4 of my Tempest fine wire plugs when i got my Surefly ignition and took my time and never had a problem. It was a little nerve racking but no issues.

Follow up....

I used the Champion fine wire gap adjustment tool for this and it was a non-event (Like Brian's experience above). Gapped the SureFly plugs at .026 and the Slick plugs at .020. As soon as weather clears, I'll test fly to see the results.
 
Back
Top