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  #71  
Old 12-10-2017, 11:48 AM
skylor's Avatar
skylor skylor is offline
 
Join Date: Aug 2009
Location: Southern California
Posts: 631
Default Aeroshell Plus

Quote:
Originally Posted by Jpm757 View Post
The only "Lycoming" approved additive is LW-16702 Anti scuffing agent. It adds about $35 to the cost of an oil change. However there are several "FAA" approved additives such as Avblend,
The Aeroshell Plus grades (i.e. W100+) contain LW-16702 so you don't have to buy a bottle of additive separately.

Skylor
RV-8
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  #72  
Old 01-03-2018, 10:51 PM
Frank Jackson Frank Jackson is offline
 
Join Date: Mar 2009
Location: Grass Valley
Posts: 4
Default Wish I had read ths sooner.

I should have looked at this sooner. Yesterday the #2 exhaust valve on my Lycoming IO360 stuck completely and bent the pushrod. Fortunately I was in the pattern at a nearby airport and immediately landed. It's now at the FBO at the same field getting a rebuilt cylinder. It had been running rough at idle and low power settings but smoothed out at runup power and higher. The engine had only 380 hours on it. I'll be doing a wobble test on the other cylinders.
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  #73  
Old 01-04-2018, 06:59 PM
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scrollF4 scrollF4 is offline
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Join Date: Jan 2010
Location: Flower Mound, TX
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Default

Quote:
Originally Posted by Frank Jackson View Post
I should have looked at this sooner. Yesterday the #2 exhaust valve on my Lycoming IO360 stuck completely and bent the pushrod. Fortunately I was in the pattern at a nearby airport and immediately landed. It's now at the FBO at the same field getting a rebuilt cylinder. It had been running rough at idle and low power settings but smoothed out at runup power and higher. The engine had only 380 hours on it. I'll be doing a wobble test on the other cylinders.
Frank,
I'm like you. I never paid attention to this post until your write-up today, because it happened to me this week.

My factory-new-plus-400 tach hours IO-360-M1B suddenly got rough under 1350 RPM along with an associated total drop of EGT on cylinder #4. I immediately showed it to Randy Richmond (aka Monk, our local 52F totally awesome expert of everything RV). He ran a compression check (there was none....0 inches, with a loudly audible hiss from the exhaust pipe). Diagnosis: Stuck exhaust valve.

Apparently, many (most?) mechanics will simply tell you the jug must be removed and sent to some repair house somewhere. Also, apparently, few will take the trouble to work the problem on-engine, if it can be properly worked on-engine. Randy actually conducted something akin to endoscopic surgery to clean the valve and inspect the pushrod.

All is Code 1, no bends, compression is good, and a cleaner valve. Of course, if the bits and pieces showed anything beyond mere carbon (or other gunk) buildup causing the stuck valve, he'd have elevated the level of repair.

I can't thank Randy "Monk" Richmond and Richmond Aviation enough. KELLI GIRL flies again!
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52F Aero Valley Airport, Roanoke TX (home of DR's Van Cave)
"KELLI GIRL" N260KM RV-7A tipper, YIO-360M1B with dual PMAGs, dual SkyView, GTN-650, VPX, EarthX LiFePO.
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90% done, 90% to go...
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  #74  
Old 04-26-2018, 08:56 AM
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bullojm1 bullojm1 is offline
 
Join Date: Feb 2006
Location: Baltimore, MD
Posts: 1,009
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Over the last few flights I noticed the #1 exhaust valve might be sticking. When the engine was warming up, it ran rough under 1,000 RPM and the CHT and EGT were low on #1 (CHT was 150 where others were 200+, EGT was 700 where others were in the 900's). As soon as I increased the throttle past 1,000 RPM, CHT and EGT increased to their normal places.

The timing of this was fantastic, as I was just starting the conditional inspection.

Yup, definitely a stuck #1 exhaust valve. If you're wondering about the bracket I have installed on the cylinder, it's what I used to pivot my home-made valve compressor on (see http://www.vansairforce.com/communit...2&postcount=59).


1/2 way through reaming out the guide, I took a pic with my borescope of what the inside of a guide looks like that's gunked up.


And after! Like night and day.



The only thing I changed from my original write-up (besides my new and improved valve compressor) was my method of keeping the exhaust valve seating for installation. Originally I used the "Rope Trick". One thing pointed out to me was there is a small chance of the rope forming a knot inside the jug, and then you have to yank it to get it out. So this time I tried using compressed air, delivered through the differential compression tester. I rotated the prop until the #1 piston was at the bottom of its stroke and the intake valve was closed. 60 psi of pressure seemed to be the right amount to keep the exhaust valve forced tight enough against the seat to install the springs.



All back together and ready for the next adventure! The whole process took me a little over an hour, including dropping and reinstalling the exhaust.
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  #75  
Old 04-26-2018, 05:19 PM
RV7 To Go RV7 To Go is offline
 
Join Date: May 2011
Location: Ontario, Canada
Posts: 101
Default Valve Sticky

I think this is a great reference thread on something that seems to come up regularly. Any chance of the moderator making it a Sticky in this category or maybe in the Traditional Engines section?
Al
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  #76  
Old 04-26-2018, 05:43 PM
painless painless is offline
 
Join Date: Jan 2005
Location: Peshtigo, Wisconsin
Posts: 725
Default

So Mike, inquiring minds want to know......

How come your guides are getting gunked up?? This is the second jug to have the problem for you, correct?
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  #77  
Old 08-09-2018, 03:14 PM
cujet cujet is offline
 
Join Date: Apr 2008
Location: West Palm Beach, Florida
Posts: 46
Default

As DOM for a small fleet, we see this issue from time to time.

A couple of notes:

After reaming the guide and cleaning the valve's stem, it's possible to (very sparingly) use valve grinding compound along with a rubber hose on the valve stem hooked to a battery drill to very slowly, carefully and intermittently (I know you guys understand this) clean off the valve face and seat via an "in place lapping" . Apply a tiny quantity of valve grinding compound (half a drop) through the exhaust port with a Q-Tip. Cleaning up afterwards takes some time, but it's possible to correctly ensure no valve grinding compound remains.

The reason to do this has to do with heat transfer. The valve will remain slightly cooler if it has a good heat path at the valve seat area. Leading to fewer problems with valve sticking.

Aeroshell 15W-50 use seems to result in fewer events. In fact, the only time we've experienced it (not so for others) is with an oil other than AS 15W-50.

Also, a very lean taxi seems to help.

Last edited by cujet : 08-09-2018 at 03:20 PM.
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