Boroscope Exhaust Valve Images

[alextstone]

Hi MooneySpacers!

A little background:  I recently purchased my fifth airplane, a Bravo in September, (prior aircraft: Piper Archer III, Mooney J, Mooney Ovation, Mooney Acclaim)   I have had a number of maintenance "surprises" since the purchase, some of which I have posted about on this forum. 

After recovering from the initial disappointment, I began to focus on answering these questions: "What can I learn?  How do I become a better pilot / owner as it relates to understanding my aircraft systems? How do I become confident that my aircraft is maintained to a safe standard?"

To that end, I reviewed the logbooks and with the help of PilotPartner.net , I recorded all AD's, inspections and service intervals for most components of my aircraft.  I now have a clear picture of what has yet to be done (deferred maintenance), what might need attention soon, etc.  

I have been reading a lot.  This forum.  Mike Busch on Engines. Owner Assisted Aircraft Maintenance.  The Mooney Bravo Service Manual.  The Lycoming Engine Operators Manual., etc.

 Today, I captured boroscope images of mainly the exhaust valves of each cylinder, with the exception of cylinder 5, for which I captured both exhaust valve images and what appears to be evidence of a leak past the piston ring (see below).  While I am not an A&P, I have a desire to more fully understand how to interpret this data and ultimately how to fly safely for years to come.  For those of you who are experts (or just want to learn along with me), would you please comment?    I've made some initial assumptions as to what I am seeing and your feedback will be helpful.  Thanks.

Cylinder 1, 46.6 hrs, 76/80

 

Cylinder 2, 1104 hrs, 72/80

 

 

 

Cylinder 3, 1104 hrs, 74/80

 

Cylinder 4, 81.4 hrs, 72/80

 

Cylinder 5,  324 hrs, 76/80

 

 

 

Cylinder 6, 1104 hrs, 74/80

 

[Cruiser]

those exhaust valve pictures look really good. 

What is in the bottom of the spark plug between the ceramic and the outside wall? About 11:00 in the images.

[Cody Stallings]

Looks like Lead Build up.

are these photos from Bravo 7TD?

[alextstone]

1 minute ago, Cruiser said:

those exhaust valve pictures look really good. 

What is in the bottom of the spark plug between the ceramic and the outside wall? About 11:00 in the images.

Not sure yet.  I plan to pull the bottom cowl next and find out.

[Andy95W]

4 minutes ago, Cruiser said:

 

What is in the bottom of the spark plug between the ceramic and the outside wall? About 11:00 in the images.

A lead deposit.  The old Texan IA I learned from used to call them "clinkers", no ida why.

[alextstone]

Just now, Cody Stallings said:

Looks like Lead Build up.

are these photos from Bravo 7TD?

No, Bravo 84U.  I have been running LOP since I installed GAMIs right after the purchase, so I assume the lead buildup predated that....seem reasonable?  Here’s what the top plugs look like:

 

 

[MooneyBob]

What borescope did you use?

[alextstone]

2 minutes ago, MooneyBob said:

What borescope did you use?

A Snap On BK8000

[Yetti]

3t plug looks a little oily.   1 looks like there is something on the insulator.  Inspect more and report back.  rest of the plugs looks good keep  doing what you have been.

[carusoam]

Klinkers... metal deposits found after cleaning out a furnace.... the sound they make when shaken around in an ash can...? 

 

Valve deposits that are perfect circles, look like a pizza are good... valves that are not transferring heat the way they should will have a specific colored area at the edge of the valve... sticking valves, don’t rotate as needed....

 

Lead deposits are most common when the pilot doesn’t actively lean on the ground... start-up, then lean as soon as practical... it may take warming up a minute or two in winter.... if you don’t lean actively after starting the engine... small lead balls will collect in the lower spark plugs... tiny shot like balls... if they form slowly over time, remove and plugs and put them back... the plug has plenty of space to have a few in there... they will short the plug out eventually... it will be obvious on the engine monitor as this happens... be familiar with how to perform a run-up looking for individual plug issues...

Leaning on the ground is more of a challenge when you don’t have a FF instrument or an engine monitor....

 

Nice work learning about your Bravo...

 

Spend some time researching exhaust system issues specific to the Bravo and typical of other TC’d birds...

There have been discussions regarding V-clamps and exhaust pipe thinning that are worth knowing...

Always helps to have a CO monitor in the cabin for Plan C...

 

MS also has a section specific to Bravos... in case you haven’t found it.

 

PP thoughts and stuff I read about on MS... this was meant to be helpful information, i’m No expert at writing...

Best regards,

-a-

[jackn]

Please switch to fine wires. I was skeptical at first, as they cost significantly more. My engine runs much smoother & cooler, the fine wire plugs last much longer than the massive. 

Also, when taking a borescope, try to get a wider view, it helps to see the big picture. 

[alextstone]

Please switch to fine wires. I was skeptical at first, as they cost significantly more. My engine runs much smoother & cooler, the fine wire plugs last much longer than the massive. 
Also, when taking a borescope, try to get a wider view, it helps to see the big picture. 

Fine wires are next on the list... Can't spend money fast enough it seems!

Sent from my XT1585 using Tapatalk

[wpbarnar]

cylinder 5, for which I captured both exhaust valve images and what appears to be evidence of a leak past the piston ring (see below). 

Are you referring to photo 10?  I think that is a shadow. 76/80 is not indicative of a leak

Bill

[Bravoman]

I do not have the expertise to interpret what  is depicted on the photos. But I’ll chime in on the fine wires. Very much a noticeable difference on smoothness and cooling. Never had a fouling issue with the Bravo so can’t say any difference there due to the plugs. The Gee Bee baffling also helped significantly with cylinder cooling. As I recall I installed both the baffling and fine wire plugs around the same time. No problem keeping CHTs below 400 deg even in extended climb when hot outside.

Edited January 15, 2019 by Bravoman

[alextstone]

1 minute ago, Bravoman said:

I do not have the expertise to interpret what  is depicted on the photos. But I’ll chime in on the fine wires. Very much a noticeable difference on smoothness and cooling. Never had a fouling issue with the Bravo so can’t say any difference there due to the plugs. The Gee Bee baffling also helped significantly with cylinder cooling. As I recall I installed both the baffling and fine wire plugs around the same time. No problem keeping CHTs below 400 deg even in extended climb when hot outside.

I ordered the Tempest Finewires tonight.  Baffling is on the list soon.  So, you did the baffling install and had an A&P bless the work?

 

Alex

[carusoam]

Alex,

Want to see a Gee Bee pic?  

There is a fresh one around here somewhere...

Cooling is so dependent on good sealing.  It helps to have proper materials without any extra holes...

Best regards,

-a-

 

[Bryan]

Here is my GeeBee baffles Installing about 9mnths ago. M20K 252

[Bravoman]

3 minutes ago, alextstone said:

I ordered the Tempest Finewires tonight.  Baffling is on the list soon.  So, you did the baffling install and had an A&P bless the work?

 

Alex

No Alex if you knew my mechanical ineptness you would be surprised that I could   even be taught to fly! I ordered it directly from the company and had my MSC install it. The owner of Gee Bee is on this forum and is a super helpful and knowledgeable guy.

[bradp]

@Bryan what’s the heat shield on your forward firewall? 

[Bryan]

Something that came from the factory. It is not aftermarket. It is thick fabric type stuff with metallic shielding.