Dec 2010/Jan 2011 Annual
Dec 2010/Jan 2011 Annual
I decided to annual my 7 a bit early to set up future winter annuals so I'm not down for an extended time in the summer...so, I put up a page on my website that will get updated each day (already has three entries) as I progress thru it...
http://www.chadandbrittne.com/December% ... annual.htm
The first thing I want to point out is something that matches exactly what Brian (Chesteen) ended up with after the first several hours...cracked baffling at the oil cooler. I noticed mine was cracked about a half inch after the 5 hour oil change, but between then and hour 25, it had progressed to about two inches. From 25-30, it ended up like this...
I'd say another hour or two, and the oil cooler would've been dangling off the back! I should've fixed it at the 25 hour oil change, but for reasons I can't remember, I didn't.
The other big squawk (I have several small issues to address, but only two big ones), and it's not really even a squawk, technically...the compression on cylinder 3 was "only" 62/80. All the others were 72+. This raised my eyebrow, and even tho it is within Lycoming limits, I wanted to investigate further. After a day and a half looking at it with a borescope (every A&P in the shop had a look), we determined that it was not a burned valve, and that it was probably some carbon built up on the seat. That may still be the case, but we found the hydraulic lifter for the exhaust valve had some "gunk" in it that wasn't allowing the valve to seat fully. After that time consuming journey, we did a cold compression check, and it's up to 68 pounds, which should translate to somewhere back in the 70's when hot. The diagnosis is to fly it 5-10 hours, and check it again.
Just an fyi...if ya care to know what I'm doing instead of flying for a couple of weeks...
http://www.chadandbrittne.com/December% ... annual.htm
The first thing I want to point out is something that matches exactly what Brian (Chesteen) ended up with after the first several hours...cracked baffling at the oil cooler. I noticed mine was cracked about a half inch after the 5 hour oil change, but between then and hour 25, it had progressed to about two inches. From 25-30, it ended up like this...
I'd say another hour or two, and the oil cooler would've been dangling off the back! I should've fixed it at the 25 hour oil change, but for reasons I can't remember, I didn't.
The other big squawk (I have several small issues to address, but only two big ones), and it's not really even a squawk, technically...the compression on cylinder 3 was "only" 62/80. All the others were 72+. This raised my eyebrow, and even tho it is within Lycoming limits, I wanted to investigate further. After a day and a half looking at it with a borescope (every A&P in the shop had a look), we determined that it was not a burned valve, and that it was probably some carbon built up on the seat. That may still be the case, but we found the hydraulic lifter for the exhaust valve had some "gunk" in it that wasn't allowing the valve to seat fully. After that time consuming journey, we did a cold compression check, and it's up to 68 pounds, which should translate to somewhere back in the 70's when hot. The diagnosis is to fly it 5-10 hours, and check it again.
Just an fyi...if ya care to know what I'm doing instead of flying for a couple of weeks...
Chad,
I had heard of others having the baffles crack so I reinforced mine like this. So far, after 165 hrs no problems...
Hope this helps![/img]
I had heard of others having the baffles crack so I reinforced mine like this. So far, after 165 hrs no problems...
Hope this helps![/img]
Bret Smith
9A Flying (N16BL)
Blue Ridge, GA
http://www.FlightInnovations.com
APRS Tracking: http://www.flightinnovations.com/tracking.html
9A Flying (N16BL)
Blue Ridge, GA
http://www.FlightInnovations.com
APRS Tracking: http://www.flightinnovations.com/tracking.html
-
- Chief Rivet Banger
- Posts: 4013
- Joined: Thu Oct 14, 2004 8:40 pm
- Location: Baltimore, MD
- Contact:
Very interesting Chad. It really shows how vibrations and our brittle aluminum can interact. Thanx for showing us whats up.
Spike
Spike
http://www.rivetbangers.com - Now integrating web and mail!
Current Build: 2 years into a beautiful little girl
Current Build: 2 years into a beautiful little girl
Chad, sorry to see this crack. There is another way I have seen guys use to prevent this. A support rod, or aluminum angle is attached to the engine lift point (the bolt and loop amidships of the engine) and then attached to the baffle upper outside corner where the cooler is mounted. Should work with your plenum. This would give your baffle more support and rigidity.
Chill'n in southern Cal...... Literally!!! Go Bucky.
Chill'n in southern Cal...... Literally!!! Go Bucky.
Jeff Orear
RV6A N782P
Hatz Classic, Welding fuselage
Hatz build log. https://eaabuilderslog.org/?blproject&p ... GNCwv&sid=
Peshtigo, WI
RV6A N782P
Hatz Classic, Welding fuselage
Hatz build log. https://eaabuilderslog.org/?blproject&p ... GNCwv&sid=
Peshtigo, WI
- Mike Balzer
- Class E
- Posts: 147
- Joined: Tue May 20, 2008 11:18 pm
- Location: Saugus, CA
Chad,
some 5052-h32 aluminum would be less prone to cracking and maybe you could make a doubler out of .125 and rivet it to your baffle and stop drill the crack so it does not continue.
2024-t3 aluminum is brittle and when subject to vibration and stress will cause it to crack.
I also recommend adding Marvel Mystery Oil to your fuel at about 4-6 ounces per gallon on one tank and fly it. This will help bring up compression also. It helps remove the lead and carbon build up on the valve seats and cant hurt.
We did this on a friends o-235 that has little time left on it and it brought compression up to specs when it was well below specs before.
During compression test could you tell where the Loss was. EX: intake valve, exhaust valve or crankcase? This may help determine what the cause is.
Happy New Year,
Mike Balzer
some 5052-h32 aluminum would be less prone to cracking and maybe you could make a doubler out of .125 and rivet it to your baffle and stop drill the crack so it does not continue.
2024-t3 aluminum is brittle and when subject to vibration and stress will cause it to crack.
I also recommend adding Marvel Mystery Oil to your fuel at about 4-6 ounces per gallon on one tank and fly it. This will help bring up compression also. It helps remove the lead and carbon build up on the valve seats and cant hurt.
We did this on a friends o-235 that has little time left on it and it brought compression up to specs when it was well below specs before.
During compression test could you tell where the Loss was. EX: intake valve, exhaust valve or crankcase? This may help determine what the cause is.
Happy New Year,
Mike Balzer
It is better to be on the ground wishing you were in the air, then being in the air and wishing you were on the ground. N78MB
- Wicked Stick
- Class B
- Posts: 1000
- Joined: Wed Feb 09, 2005 10:00 pm
- Location: KEWB
Chad,
Get some .125 aluminum angle stock and fabricate two pieces like you see here below. One on each side. This worked out great for me and really makes it bullet proof. It should work fine with your plenum.
Also I noticed on your photo that you don't have the 3/4 brace down the side of the baffle either? Add one there too if you don't have it.
Get some .125 aluminum angle stock and fabricate two pieces like you see here below. One on each side. This worked out great for me and really makes it bullet proof. It should work fine with your plenum.
Also I noticed on your photo that you don't have the 3/4 brace down the side of the baffle either? Add one there too if you don't have it.
Dave "WS" Rogers
RV-8 (125 hrs & counting)
N173DR
RV-8 (125 hrs & counting)
N173DR
- Mike Balzer
- Class E
- Posts: 147
- Joined: Tue May 20, 2008 11:18 pm
- Location: Saugus, CA