Ignition wire boot

[cnoe]

I'm looking for a little help in locating an ignition wire boot (plug end) to replace a damaged one. Sadly I didn't snap a pic of the actual boot when I had everything opened up yesterday.

This would be one of the red silicone boots that goes inside the spark plug on my Lycoming IO360-A3B6D (dual-mag). The ignition leads are the silver-colored ones with the exposed shielding braid. This is for the larger (3/4") plug design. If I'm not mistaken the boot can be carefully worked off the end of the wire though the contact spring may have to be removed first.

I've looked through a pile of old wires at my mechanic's shop but he didn't have what I needed. I'd rather not have to purchase an entire new wire assembly if I don't have to.

So, if anybody knows where to buy a new boot, or has a pile of old wires laying around that I could rob one from I'd be most appreciative and would pay a fair amount for such.

Thanks,

Chuck

P.S. I'll send a pic of an installed wire from my ipad so you can see the type. And I'll snap a pic of the actual boot next time I'm at the hangar (perhaps this weekend).

[jetdriven]

i have a wire harness set from a pair of Bendix 1200s, perhaps you could rob one from that.  here is perhaps some additional useful info  http://www.tcmlink.com/pdf2/635.pdf

 

 

Edited March 25, 2016 by jetdriven

[cnoe]

Look like these?

Sent from my iPad using Tapatalk

[Guest]

4 hours ago, cnoe said:

Look like these?

Sent from my iPad using Tapatalk

Spruce sells individual parts.

http://www.aircraftspruce.com/catalog/eppages/slickharnessaccessories.php?clickkey=21664

Clarence

[N601RX]

Slick produced a service manual that shows all the combination of parts needed to repair both their 5/8 and 3/4 leads for both slick and bendix as well as how to replace the ends.  I remember having a very difficult time finding a download of it online but finally located it. I have a copy at work I can email you if you need it.  I found the toolkit for installing the ends on eBay, luckily no one else bid on it.  Otherwise it's the most expensive pair of vise grips you will ever buy.

the spring screws off the pin, the pin that sticks up inside the center conductor may come out with it if not careful.  There is usually NOS of these on eBay.

[cnoe]

Thanks guys; I couldn't find this myself on Spruce. I'm still looking for the literature but I think I can replace the insulator/boot/sleeve by simply removing the contact spring and carefully sliding the old one off, etc. I'm familiar with the spring replacement. Hopefully I won't have to replace or shorten the lead.

Interestingly the defect has caused no functionality or performance issues but was detected during a LOP mag check at altitude. And even then I wouldn't have caught it without reviewing my JPI data on the computer. That one cylinder exhibits a significantly higher (~100F) EGT rise than the other 3 cylinders when running on that one mag. Swapping wire positions top/bottom moves the problem to the other mag.

As I fly high and LOP often I want optimal spark returned to that plug.

No hurry, but if you have the Slick manual .pdf I'd love a copy for reference. I'll PM you my direct email address. At your convenience for sure.

Sent from my iPad using Tapatalk

[carusoam]

cnoe, Nice detailed description of your investigation and JPI data.  Thanks for sharing those details.

Best regards,

-a-

[cnoe]

I'll post a couple of graph screenshots and follow up with post-repair results. For me, diagnosis and repair tips top the list of what makes Mooneyspace great. Many helpful individuals here!

Sent from my iPad using Tapatalk

[cnoe]

FYI: I just posted a detailed report about this with graphics on a new post.

 

[bradp]

@cnoe I'm trying to trouble work through something somewhat similar now...  (I didn't do my in-flight mag check properly here because I didn't let settle, go back to both, then go to other single mag, but you can get the general idea).  Cyl #1 EGT always runs a little hotter when LOP, suggesting inefficient spark.  Rich Cyl#1 runs a bit richer than others when ROP, suggesting fuel / air ratio (i.e. intake valve) or spark.   A richer than normal mixture as a result of fuel metering to a single cylinder would be rare. 

 

I'm going to check that I don't have split mag timing (not suggested by the below graph as I would expect all cyls to have a delta between L and R mags, not just two.  Two individual leads or two individual spark plugs could result in the deltas shown, however.), but I'm down to doing a wobble test on #1 versus replacing my mag harness.  I can't find any indication that the harness was replaced at last overhaul.  There are, however, several areas where the metal shielding is frayed and I'm starting to get RFI through my headset that matches the mag induction changes during startup.  The resistances check fine, but I haven't had it high-voltage tested yet.  Might be more worthwhile to just replace the darn thing rather than go through the effort of troubleshooting further. 

 

I also need to educate myself on the delta-EGT that is considered significant for timing / ignition inefficiencies.  So much to learn about engine monitoring. 

 

Image key:  LOP operation.  Cursor is going between L mag and R mag before going back to both (I know I didn't do it right).  Will get a proper in-flight mag check done this week hopefully. 

 

If I didn't have a monitor or want to run LOP, I'd have no idea that there were some inefficiencies in the system.  I can get LOP -25 for cyl #1, but my leanest are hitting -75 and the engine starts running a bit rough at that point (altitude dependent, of course).  LOP ops certainly do stress the efficiency of the system in ways that, if ROP, I'd never notice.

 

In medicine we call this type of workup a result of being a "victim of monitoring". 

[cnoe]

Brad, there are others on MS much more knowledgeable than me about this stuff, but I do study it carefully and read all I can about it. The best you can do is make an educated guess and then test your hypotheses trying not to throw money away in the process. I'm not sure if you have the dual-mag or two singles but ignition lead sets can be quite expensive and they should last a long time unless you have specific damage (like my torn boot, or your chaffed shielding). If the shielding isn't too bad you may want to check your p-leads' shielding first as this should be grounded to the connector at the mag (mine has broken here before). Radio interference can be tough to nail down but that's an easy and inexpensive place to start looking.

Regarding your graphs, I wouldn't categorically state that your #1 EGT is higher than the others because of inefficient spark. Sometimes a cylinder will "consistently" be hotter than the others due to probe placement or other reasons. My #4 is always hotter than 1, 2, & 3 when under power. There will be some variation between cylinders as they reach peak etc. but I wouldn't consider your #1 to have a problem based only on it being the hottest. It does appear, though, that the large difference between #1 and the others running LOP shows you with a significant injector balance disparity. Can you state your GAMI spread, or fuel-flow delta between each cylinder at peak? The oft-stated target is 0.5 gph spread but my experience has been that it's still hard to get a smooth running engine at that level (with a 4 cylinder). I'd like to see 0.2-0.3 if possible.

I assume you have GAMI injectors installed? Some people are lucky to find they can run LOP with stock injectors; YMMV. But before you start swapping/replacing injectors I'd clean all four in Hoppe's #9 in an ultrasonic cleaner and then run a thorough GAMI test to get a baseline. If you're still way too rich on #1 after that I'd look at getting another #1 injector.

Now regarding your LOP test graph I don't see a significant difference between the EGT rises on #1, but it does look like you might have an issue with #2. It's hard to tell without redoing the LOP test with a "both" phase in there (as you stated) but it looks to me like #1 starts higher than the others and increases fairly smoothly. #2 on the other hand appears to make a fairly sharp rise from the lower end to a temp above #1. I'd suspect a weaker spark from #2. It also looks like #4 actually "drops" a little but a minor variance in timing between mags could account for that.

Again, all this is simply speculation on my part, but I don't see anything too dramatic. Once you run the test again with the "both" period you should get a better indication.

Indeed I can see the danger of over-monitoring but... In my case I'd previously seen my damaged my plug boot but since I couldn't identify a symptom I figured it was not a problem. It's really great to have all the data, though, to actually identify what's going on.