Valve Guide Reamer / Can't deal

[201Steve]

I am about to loose my mind over the insanity of the maintenance community. I caught the symptoms of a sticky exhaust valve on my IO-360 very early. Over the last year, I was seeing slightly elevating levels of Nickel in my oil analysis, with the last reading showing 10ppm. Fast forward to last week, I was having slight morning sickness over the duration of 3 starts. Roughness lasted approx 30 seconds.  Shot a boroscope into all cylinders. Arrived at #4 and found it stuck open a little bit.

PER LYCOMING SERVICE INSTRUCTION 1425A, they outline exactly the STANDARD procedure to first address this issue. Via the "rope trick" drop the valve into the cylinder, clean the valve guide with a hand reamer, and reinstall. A 45 minute job at best for someone who's experienced with it. Please... someone explain to me why the 4 mechanics I've talked to have never done this before? Want to immediately pull the cylinder? WHY! I explain to them that Lycoming addresses this in detail, as to what to do FIRST. Exhaust valve sticking may be the most common valve train item... yet they don't even know how to do the simplest of procedures. Mike Busch theory aside, it is a LYCOMING recommendation. It's not some back woods remedy.

All of that said, I can't deal. I'm ordering the stuff to do it myself with supervision. I'm pretty sure the reamer needed is 0.4995-0.5005 (.5000) for my engine.

Looking at https://www.mcfarlaneaviation.com/articles/valve-guide-cleaning-reamers-for-lycoming-engines/

Can anyone confirm this is correct size before I order? Also, any other suggestion on what tools to have handy in the process would be great!

77J

Lycoming IO-360 A1B6D

[Hank]

It's just like car mechanics now. No one fixes anything, many are just part swappers.

[alextstone]

I am about to loose my mind over the insanity of the maintenance community. I caught the symptoms of a sticky exhaust valve on my IO-360 very early. Over the last year, I was seeing slightly elevating levels of Nickel in my oil analysis, with the last reading showing 10ppm. Fast forward to last week, I was having slight morning sickness over the duration of 3 starts. Roughness lasted approx 30 seconds.  Shot a boroscope into all cylinders. Arrived at #4 and found it stuck open a little bit.
PER LYCOMING SERVICE INSTRUCTION 1425A, they outline exactly the STANDARD procedure to first address this issue. Via the "rope trick" drop the valve into the cylinder, clean the valve guide with a hand reamer, and reinstall. A 45 minute job at best for someone who's experienced with it. Please... someone explain to me why the 4 mechanics I've talked to have never done this before? Want to immediately pull the cylinder? WHY! I explain to them that Lycoming addresses this in detail, as to what to do FIRST. Exhaust valve sticking may be the most common valve train item... yet they don't even know how to do the simplest of procedures. Mike Busch theory aside, it is a LYCOMING recommendation. It's not some back woods remedy.
All of that said, I can't deal. I'm ordering the stuff to do it myself with supervision. I'm pretty sure the reamer needed is 0.4995-0.5005 (.5000) for my engine.
Looking at https://www.mcfarlaneaviation.com/articles/valve-guide-cleaning-reamers-for-lycoming-engines/
Can anyone confirm this is correct size before I order? Also, any other suggestion on what tools to have handy in the process would be great!
77J
Lycoming IO-360 A1B6D

Bam! That's EXACTLY what I do... Use my judgement as to what is appropriate, do the work with supervision. I can't tell you how many times this had worked out in my favor (lower costs, enhanced safety). For the record, a helpful IA oversees and inspects approves of everything.

Sent from my Pixel 3 XL using Tapatalk

[RLCarter]

1 hour ago, Hank said:

It's just like car mechanics now. No one fixes anything, many are just part swappers.

Yep, plug it in and see whats wrong

[David Lloyd]

Last year I needed to ream a stuck valve on my RV7. Used a .4995 reamer.  I used compressed air via a compression tester rather than rope to keep the valve seated while putting the keepers in place.  Being able to drop the exhaust system makes it a lot easier to get the valve back in the guide.  The mechanic at the airport said he thinks it is easier just to pull the cylinder and do the reaming on the bench. He has done it both ways.  Uh-uh, he won't be pulling one of my cylinders off to do this.  Search over on Vansairforce.net, there is an excellent blow by blow description with pictures how to do this. A few days ago a mechanic that contributes told that he always uses a ball hone as opposed to a reamer for better results.  On thing that many overlook is the need for the appropriate valve spring compressor.  Without the right one, the job is difficult at best. 

[Yetti]

.4995    We used the grabber things in the spark plug holes to maneuver the valve back into the guide.   Order a valve spring compressor.   rope is silly.  Never pass up an opportunity to acquire new tools.    Straight forward.   I only freaked out a little when he took a punch and hammer to knock the valve out.   Order the silicone gaskets for the valve covers.

[thinwing]

This is new to me...I’ve never heard you could completely drop the valve to access the valve guide...the rope trick I’ve seen is used to regrind the valve seat by preventing the valve from dropping into cylinder.

[201Steve]

Just now, thinwing said:

This is new to me...I’ve never heard you could completely drop the valve to access the valve guide...the rope trick I’ve seen is used to regrind the valve seat by preventing the valve from dropping into cylinder.

Check out Lycoming SI 1425A. It’s not what most people think when talking about rope trick, and apparently with the correct valve spring tool, you don’t actually need to use the rope here. But it’s been a common procedure item published by Lycoming originally in the early 80’s but of course 78% of mechanics are clueless about it. 

[Jim Peace]

5 hours ago, Hank said:

It's just like car mechanics now. No one fixes anything, many are just part swappers.

What would be the shop rate for fixing things vs swapping out parts?

[Guest]

7 hours ago, 201Steve said:

I am about to loose my mind over the insanity of the maintenance community. I caught the symptoms of a sticky exhaust valve on my IO-360 very early. Over the last year, I was seeing slightly elevating levels of Nickel in my oil analysis, with the last reading showing 10ppm. Fast forward to last week, I was having slight morning sickness over the duration of 3 starts. Roughness lasted approx 30 seconds.  Shot a boroscope into all cylinders. Arrived at #4 and found it stuck open a little bit.

PER LYCOMING SERVICE INSTRUCTION 1425A, they outline exactly the STANDARD procedure to first address this issue. Via the "rope trick" drop the valve into the cylinder, clean the valve guide with a hand reamer, and reinstall. A 45 minute job at best for someone who's experienced with it. Please... someone explain to me why the 4 mechanics I've talked to have never done this before? Want to immediately pull the cylinder? WHY! I explain to them that Lycoming addresses this in detail, as to what to do FIRST. Exhaust valve sticking may be the most common valve train item... yet they don't even know how to do the simplest of procedures. Mike Busch theory aside, it is a LYCOMING recommendation. It's not some back woods remedy.

All of that said, I can't deal. I'm ordering the stuff to do it myself with supervision. I'm pretty sure the reamer needed is 0.4995-0.5005 (.5000) for my engine.

Looking at https://www.mcfarlaneaviation.com/articles/valve-guide-cleaning-reamers-for-lycoming-engines/

Can anyone confirm this is correct size before I order? Also, any other suggestion on what tools to have handy in the process would be great!

77J

Lycoming IO-360 A1B6D

Have you considered paying one of them to read up on the procedure and then helping you with the process?

Clarence

[EricJ]

I think there's been a shift in practices since cylinder removal/replacement became cost effective compared to mitigating techniques like this that have lower success rates.   I'm in A&P school now and the wisdom seems to be that while many of these field techniques can be made to work, the quality of the work cannot match that done in a proper repair station with dedicated personnel and proper equipment.    Back when cylinders were expensive and lead times were longer, this stuff was done more often.

Another factor is liability.   A repair like this that fails later can have a far larger affect on the A&P than a replacement cylinder that fails.   My understanding is that the lower success rate of the field repairs aggravates this, or they aggravate each other, whichever.

So the why's of why people don't do this much any more seem fairly logical to me.

 

[201Steve]

24 minutes ago, M20Doc said:

Have you considered paying one of them to read up on the procedure and then helping you with the process?

Clarence

That’s the plan Clarence

[201Steve]

7 minutes ago, EricJ said:

I think there's been a shift in practices since cylinder removal/replacement became cost effective compared to mitigating techniques like this that have lower success rates.   I'm in A&P school now and the wisdom seems to be that while many of these field techniques can be made to work, the quality of the work cannot match that done in a proper repair station with dedicated personnel and proper equipment.    Back when cylinders were expensive and lead times were longer, this stuff was done more often.

Another factor is liability.   A repair like this that fails later can have a far larger affect on the A&P than a replacement cylinder that fails.   My understanding is that the lower success rate of the field repairs aggravates this, or they aggravate each other, whichever.

So the why's of why people don't do this much any more seem fairly logical to me.

 

Eric, I’m not asking them to diagnose, I’m not asking them to sign an inspection, I’m asking them to perform a procedure that’s been standard practice per the manufacturer since the 1980’s. 

Purchase Order: Clean my valve guide. 

Mechanics Entry: cleaned valve guide per SI1425a. 

So, liability wise, I’d say your well within a protection envelope. 

 

Practicality wise, there is such an extreme disparity between a cylinder overhaul and a valve guide cleaning. You can’t rightfully say that a $200 job isn’t worth trying before immediately attacking it with a $2,500 cylinder overhaul. For something you can physically verify the success of upon completion, it is a crime not to know about that option or perform that option. Again, this is not some shade tree procedure. It’s what the manufacturer says should be done. In black and white. 

[Yetti]

Well some more information.   I have 5 years on the two cylinders that we reamed the exhaust guides on.   Last two annuals they both did 79 compressions.   As far best path.  A cylinder replacement has a certain set of risks plus break in.  I would consider it more major surgery.   Reaming would be a  minor surgery.   Cylinder replacement has the risk of spun bearing and a broken case if things are not torqued properly.    A ream and a couple of wrenches and a screw driver.   No letters behind my name.  

Edited May 6, 2020 by Yetti