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Is this glazing ? What do I do next please ?

amerkarim

Active Member
Hi All,

I have a stock thunderbolt IO-540 supplied through Vans in my RV10 that I built 3 years ago. Engine time is 107 hours now.

I think I had a problem on break in. It was hot and at high altitude. Despite full rich, the engine got close to 400F at first flight, but then temps settled down quickly afterwards. Changed to AD oil after 10 hours.

Temps are now around 320F to 380F in cruise, 5 and 6 are the hottest cylinders. Oil consumption is about 1 quart every 6 hours. I keep the oil level around 6 to 7 quarts. Any more and it chucks it out sooner. Not getting any smoke or oil on the belly. Plugs were clean and not fowled at the last check.

My local mechanic said it sounded ok, but probably that break in was not completed, so to change back to mineral oil for the next 50 hours, and then see what happens.

I have been reading a lot of similar cases on the forum where this is glazing. Will the re-run for 50 hours on mineral oil achieve anything? or is the solution to re-hone, re-ring, and then do the break in again.

What should I do to confirm if this is the case, and if re-hone and re-ring is necessary, what parts and tools will I need to order to do the work, as I dont think anyone locally has the parts or tools.

Thanks and regards

Amer
 
Hi All,

I have a stock thunderbolt IO-540 supplied through Vans in my RV10 that I built 3 years ago. Engine time is 107 hours now.

I think I had a problem on break in. It was hot and at high altitude. Despite full rich, the engine got close to 400F at first flight, but then temps settled down quickly afterwards. Changed to AD oil after 10 hours.

Temps are now around 320F to 380F in cruise, 5 and 6 are the hottest cylinders. Oil consumption is about 1 quart every 6 hours. I keep the oil level around 6 to 7 quarts. Any more and it chucks it out sooner. Not getting any smoke or oil on the belly. Plugs were clean and not fowled at the last check.

My local mechanic said it sounded ok, but probably that break in was not completed, so to change back to mineral oil for the next 50 hours, and then see what happens.

I have been reading a lot of similar cases on the forum where this is glazing. Will the re-run for 50 hours on mineral oil achieve anything? or is the solution to re-hone, re-ring, and then do the break in again.

What should I do to confirm if this is the case, and if re-hone and re-ring is necessary, what parts and tools will I need to order to do the work, as I dont think anyone locally has the parts or tools.

Thanks and regards

Amer

The oil consumption likely is on the higher side of normal but nothing crazy. I would not consider doing anything major to the engine before running the mineral oil and most importantly talking to Lycoming. I would also run higher power settings with the mineral oil.
 
You could also run the Phillips 20W50 X/C. It is an approved break in oil. Try running at 25 squared for a bit and see if you can help it break in.

I doubt your cylinders glazed at those temps. A quick borescope look will help you get an answer. Also, perform a compression check and check for air coming out the dipstick tube. That will tell you if it is the rings.

1 qt in 6 hours for an IO-540 is not too terribly bad, but you should be able to keep more than 6-7 qts in it.

My IO-540 Thunderbolts uses 2-3 qts every 35 hours, when I change the oil.

Vic
 
First, engines will break in just fine with XC20W50. AD in mineral oil is OK for break in, additives are not. That oil is 100% mineral based and has no additives, just avoid their newer victory version with the additives NO synthetics for break in!

No way your rings haven't seated at 100 hours, so waiting for it to get better makes no sense. If they didn't seat correctly, more time won't make it happen at this point. You have a pretty limited amount of time for ring seating and once the window closes it won't happen. Most say that window is 10-15 hours, probably less. The critical temp for glazing is much higher than 400 CHT generally. However, glazing is based upon cyl barrel temp, not CHT. You never really know what the barrel temps are, just a guess, implied from CHT.

I would expect a minimum of 10 hrs/qt on a 100 hour engine with steel cyl's. Your level of oil consumption implies that something is not optimal in the cyl wall / ring interface and moderate glazing is a good possibility. Heavy glazing would leave pooling oil around the piston head and leave oily plugs. It is easy to check for. Pull both plugs and shine a flashlight in one hole and look in the other. Shinny, silver walls are not glazed. Any areas that have a tan, opaque coating are glazed areas. Glazing can also just be in patches. A borescope will give a more thorough examination, but if there is glazing, you will likely see some of it by looking through the hole.

A compression check would make sense also. On my 540, I had less than optimal oil consumption (much better than yours though) and at the first CI, found #1 50/80. Turned out to be a cracked compression ring, likely from installation. After replacement, consumption got much better.

Larry
 
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When I purchased my RV7A from the builder in 2015 the engine had recently gone through a tear down inspection due to a prop strike he had going into Airventure the summer before. Part of that inspection required new bearings, rings and honing of the cylinders. Not knowing any better when the A&P/IA asked me what oil I wanted (since he was also doing a condition inspection concurrent with the prebuy) I told him Aeroshell 15W50. That was not a good choice because of its synthetic properties and the engine had only ten hours on it since the inspection tear down.

The engine fowled plugs, especially the lower plugs, constantly. The A&P/IA at my local airport spent a lot of time ( and my money) investigating the problem. He eventually, after borescoping the engine decided the rings weren’t seated. Since,by that time, there was approximately 30+ hours on this engine since teardown he had me run straight mineral oil for over a year. The rings finally seated with oil consumption evening out at 8 to 10 hours per quart with plug fowling eliminated.

My aircraft is now at Myers Aviation at Oshkosh undergoing another repair process from a second prop strike while taxing in the grass at this year’s Airventure. I hit an unmarked concrete abutment in the grass with the nose gear and the aircraft nosed over resulting in it digging a trench with the prop. Popular Grove is now doing another tear down inspection and repair. This time I plan to use Philips XP 20w50 for break in and give it plenty of time for the rings to seat.

Bottom line: you can improve the seating of your rings by running mineral oil going well beyond the normal break in period. Change your mineral oil every 25 hours and do it for a year. Maybe you’ll never see the low oil usage rates some folks claim but as long as you’re not fowling plugs and blowing oil out the exhaust and have normal compression ratios who cares!
 
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the problem seems to be that there are no real hard rules. Finding a broken in engine with no sign of glazing is rather seldom.

The O-360 on my steed has 1'400 SOH, rust, some glazing, yet the compressions are ok, and the oil consumption is around 25 hours on a quart, or 0.04 quarts/hour.
Oil in the cylinders can also be caused by the valve guides.

Compression check yes. Borescope inspection, yes. Confirmed glazing, then what?
Will the re-run for 50 hours on mineral oil achieve anything?
Probably not, but since you have to have oil in the engine anyway, give it a try.

Then, since everything is still well within limits, I wouldn't bulge, but would keep a vigilant eye on any worsening parameter.

Regular compression, borescope, oil filter, oil analysis, Savvy, etc, are all health indicator tools, helping in assessing the actual condition of the engine. Correlating the results helps to decide on any form of predictive maintenance.
 
Is it me or is it the mechanic?

I am not a mechanic yet I would think to use some of the tools available to us to diagnose before say just go back to break-in procedure.

Can he look inside the cylinder, do a compression check, etc to determine if there is an issue to begin with.
 
Not advocating

Told to me by an old WWII AF mechanic and later Lycoming tech.

When all of the jugs on the old zillion cylinder engines wouldn't break-in in the field, they'd feed Bon Ami into the inlet at load to break the glaze. I assume there would be an oil flush system flush and oil change afterward but they didn't say.

Another example of tribal knowledge that is passed down but doubt you'll find it written anywhere. Makes one curious but probably would never try it. Would be an interesting personal experiment on a PP that was about to get scrapped or possibly torn down anyway.
 
Told to me by an old WWII AF mechanic and later Lycoming tech.

When all of the jugs on the old zillion cylinder engines wouldn't break-in in the field, they'd feed Bon Ami into the inlet at load to break the glaze. I assume there would be an oil flush system flush and oil change afterward but they didn't say.

Another example of tribal knowledge that is passed down but doubt you'll find it written anywhere. Makes one curious but probably would never try it. Would be an interesting personal experiment on a PP that was about to get scrapped or possibly torn down anyway.

Sure, bon ami will create scoring of the cyl walls and break the glaze and even starting a new ring seating cycle. Problem is that EVERYTHING it comes in contact with will also score, including the valve guides. What if it gets in the oil, say goodbye to the bearings; copper and tin are no match for that stuff. It is not that hard or expensive to pull the jugs hone it with a ball hone and install new rings. Couple days work.

I am sure this makes a lot of sense for getting a military plane back in the air out in a jungle somewhere, but not an approach I would take if I had other options.

Larry
 
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What should I do to confirm if this is the case, and if re-hone and re-ring is necessary, what parts and tools will I need to order to do the work, as I dont think anyone locally has the parts or tools.

Thanks and regards

Amer

Will need two barrel wrenchs ($25 from ACS) and a 5-1/8" ball hone. Will also need new rings and a ring compressor+ ring installer (basically reverse pliers). Install new o rings on cylinder before re-assmbly. Do some research on how to match drill RPM to stroke speed to get the correct cross hatch angle.

Larry
 
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Thanks for all your time and input.

I guess the next step is to boroscope the cylinders and see what they look like on the inside.

Will let you know what I find tomorrow

Many thanks and regards

Amer
 
@ Larry. Completely understood, Sir. Had always assumed it was tried and "worked" once for something that wasn't expected to have much of a life left or otherwise had an early demise. Since it wasn't known to be anything other than running fine at the time of its demise. Isn't that how many legends or superstitions are born?
 
@ Larry. Completely understood, Sir. Had always assumed it was tried and "worked" once for something that wasn't expected to have much of a life left or otherwise had an early demise. Since it wasn't known to be anything other than running fine at the time of its demise. Isn't that how many legends or superstitions are born?

Agreed. It is a clever solution to the problem, but doubt if anyone ever really looked or even cared about the potential consequential damage. We work pretty hard to filter air oil and gas used in the engine and have for 120 years. Just doesn't make a lot of sense to intentionally add a large quantity of abrasives into the engine and assume no negative consequences. If someone did this right before a tear down and analyzed the results, I would reconsider my position. Doubt this approach was ever taken by someone in that position.

I have heard of this trick before, but never from someone I trusted.

Larry
 
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Aww, Not that Bon Ami Thing Again

Many moons ago, a local guy I’ll cal Phil (his real name because he wasn’t innocent and besides, he’s long dead) built a round Warner for his Monocoupe. He did some pretty interesting things on it but short version, when oil consumption didn’t go down after a lot of running on the ground, he finally put some Bon Ami in and indeed the rings seated almost immediately, then wore out completely right after that. Aanndd, he removed the cylinders for the second time (first time was when he’d had them choke ground because he figured he knew better that the Warner Overhaul Manual.) Putting Bon Ami in an engine is a dumb idea.
 
Cylinders

Just under 400 should not glaze the cylinders. I don't like the change to AD oil at 10 hours. I don't like the Phillips for break in at high ambient temperatures.
There is 50 plus years of history with straight Aeroshell for break in and not changing to AD for at least fifty hours.
Clean plugs indicates you do not have a serious problem. I like you mechanic's advice to change back to straight mineral oil and would add to run it hard for 50 hours. There is no downside to waiting another 50 hours.
 
This

Just under 400 should not glaze the cylinders. I don't like the change to AD oil at 10 hours. I don't like the Phillips for break in at high ambient temperatures.
There is 50 plus years of history with straight Aeroshell for break in and not changing to AD for at least fifty hours.
Clean plugs indicates you do not have a serious problem. I like you mechanic's advice to change back to straight mineral oil and would add to run it hard for 50 hours. There is no downside to waiting another 50 hours.

Totally Agree with this.
 
Results of tests

Hi All,

Following up, did leak tests on the engine after warming up on the ground to operating temperature. Results below:

1=79/80
2=77/80
3=75/80
4=75/80
5=75/80
6=75/80

Plugs were dry.

Boroscope showed a little smear of oil in the cylinders, but the walls were still silver and shiny, and the cross hatch could be clearly seen on all the cylinder walls. I couldnt see any major areas of yellow discoloration or suspected glazing on the cylinder walls.

I dont think there is anything terrible here, so I'm going to run on mineral oil for another 50 to 100 hours, and keep a record of the the oil cumsumption. Hopefully things will settle down.

Thanks for all your input and advice.
 
We did what Vic suggested on our -10

Initially oil consumption was qt/2-3 hrs after break in ---- we switched to PhillipsXC, as recommended, and, over the next 30-40 hrs, oil consumption became qt/10-12 hrs.

Ron
 
Sounds like two things are commonly stated about cylinder glazing:

First, once it happens, the only solution is reconditioning the cylinders. Jugs come off, head to the shop, reinstall, conduct another break in period.

Second, there seems to be only one level of glazing... all or none. It's there or it's not and your oil consumption will suffer forever if it is.

The earlier comment about running Bon Ami through the intake adds an abrasive which helps the rings grind the glazing off the cylinder walls. Makes sense, just sounds like the patient may die from the surgery, but none the less, demonstrates (at least in theory) that operation while ingesting abrasive will clean up the cylinder walls.

The question is: will normal operation while ingesting normal amounts of "grit" in the air ever reduce "light" glazing? And is it worth the time it might take to allow it to happen naturally?

My point is that there seems to be some evidence (from all the different experiences posted) that not all is lost when light glazing happens. And it might depend on the kind of cylinders installed. The nitrided cylinders in my IO-360 had higher than desired oil consumption until at least 50 hours, but has since settled down to a normal rate. It had some areas with light yellowish patches early on, but they have since disappeared. Like the OP, I was concerned but any indication of glazing was so small that I decided to let it ride for a bit.

More thoughts?
 
Break In

I have 0 320 in Wittman Tailwind with Lycoming nitride cylinders, carb and Bendix mags. Break in was under very challenging conditions. 110 plus ambient temperatures. I had one very short excursion to about 410 CHT but got it below 400 very quickly. The CHT dropped slightly within 10 hours. The engine has never used oil. I change oil at 25 hours and have only added 1/2 quart a couple of times in between changes for 250 hours. At one point I had a slight leak at pipe thread on cooler fitting, and some small leaks from cylinder drain hoses. That probably accounts for the occasional 1/2 quart added.
Aeroshell straight mineral oil for 50 hours and Aeroshell 100W since.
I followed the Mahlon Russell protocol for break in.
 
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