VansAirForceForums  
Home > VansAirForceForums

-POSTING RULES
-Advertise in here!
- Today's Posts | Insert Pics

Keep VAF Going
Donate methods

Point your
camera app here
to donate fast.

  #1  
Old 03-07-2012, 08:34 PM
Ironflight's Avatar
Ironflight Ironflight is offline
VAF Moderator / Line Boy
 
Join Date: Jan 2005
Location: Dayton, NV
Posts: 12,839
Default Firewall Forward at 1450 Hours




I mentioned on another thread that I am essentially doing a ?Top Overhaul? on the Valkyrie right now due to significantly increased oil consumption and dropping compression. Of course, having everything opened up and removed is a great time for an in-depth inspection, so here are a few things that I have found:

1) The baffles are quite remarkable ? no cracks at all! These were built from the ?old? non-pre-punched kit (which came with a mimeographed set of hieroglyphics for instructions) and required a lot of fabrication. My previous experience with baffles on used spam cans had me expecting cracks and wear early in their life, so I am extremely impressed with their performance. I think the key, like with all assemblies, is to keep the pre-load on parts low or zero ? if the fasteners are used to pull parts together, then the assemblies will constantly try to pull themselves apart.




2) Those long aluminum tube spacers that you use to keep the flanges on the oil cooler apart? The ones with the long steel bolts going through them? Yeah?.aluminum and steel ? they tend to corrode together. I think I?d look for some 4130 in the same size and make them that way next time.

3) Speaking of oil coolers ? mine is dead. Or I should say, the flanges are dead ? cracked at the mounting bolts. They weren?t cracked (that I could tell) at the last annual. I talked to Pacific Coolers, and they said that the cost of repair would be the same as buying a new one (about $260) ? but they did have some used, zero-timed Niagara?s for sale for $200 outright! I have a new one on the way.




4) The little carb heat box that attaches to the exhaust had really worn itself to death. I have a spare, but seriously ? it really doesn?t add much heat to the carb. I think if I really was depending on carb heat, I?d use a real heat muff next time.

5) Hoses, exhaust, air box ? all in great shape after 6.5 years of flight.

6) I took the opportunity to remove the primer system completely. I had disconnected it last year when I saw a crack in the connecting line from the solenoid (even with a triple coil, it had cracked). In the five years it was active, I used it exactly once ? to test it during phase one. With an accelerator pump in the carb, I find it?s just an added complication, and this was an easy time to take it out and re-do Adel clamps to be more efficient.

New cylinders should be here in a couple of days, but I have some traveling to do, so it might be a couple weeks before it?s finished up. I?m just glad that this came to a head AFTER the Rv-3 was flying?. 

Paul
__________________
Paul F. Dye
Editor at Large - KITPLANES Magazine
RV-8 - N188PD - "Valkyrie"
RV-6 (By Marriage) - N164MS - "Mikey"
RV-3B - N13PL - "Tsamsiyu"
A&P, EAA Tech Counselor/Flight Advisor
Dayton Valley Airpark (A34)
http://Ironflight.com
Reply With Quote
  #2  
Old 03-07-2012, 09:26 PM
Toobuilder's Avatar
Toobuilder Toobuilder is offline
 
Join Date: Jul 2009
Location: Mojave
Posts: 4,844
Default

Odd that you would have to "top" a Lycoming so early...

...Any thoughts as to why?
__________________
WARNING! Incorrect design and/or fabrication of aircraft and/or components may result in injury or death. Information presented in this post is based on my own experience - Reader has sole responsibility for determining accuracy or suitability for use.

Michael Robinson
______________
Harmon Rocket II -SDS EFI
RV-8 - SDS CPI
1940 Taylorcraft BL-65
1984 L39C
Reply With Quote
  #3  
Old 03-07-2012, 09:58 PM
Ironflight's Avatar
Ironflight Ironflight is offline
VAF Moderator / Line Boy
 
Join Date: Jan 2005
Location: Dayton, NV
Posts: 12,839
Default

http://www.vansairforce.com/communit...ad.php?t=83590
__________________
Paul F. Dye
Editor at Large - KITPLANES Magazine
RV-8 - N188PD - "Valkyrie"
RV-6 (By Marriage) - N164MS - "Mikey"
RV-3B - N13PL - "Tsamsiyu"
A&P, EAA Tech Counselor/Flight Advisor
Dayton Valley Airpark (A34)
http://Ironflight.com
Reply With Quote
  #4  
Old 03-07-2012, 10:03 PM
Kokemiller's Avatar
Kokemiller Kokemiller is offline
 
Join Date: Mar 2008
Location: Boone, IA
Posts: 145
Default

What did compressions drop to?

The cowl hinges appear to show little to no wear in the pix, is that representative of actual wear?
__________________
Kelley Kokemiller
9A sb N94KK 400hrs. and counting
Barrett O-320
Catto 3-blade
Panther tail complete
Reply With Quote
  #5  
Old 03-07-2012, 10:15 PM
erich weaver's Avatar
erich weaver erich weaver is offline
 
Join Date: Aug 2006
Location: santa barbara, CA
Posts: 1,754
Default

Any chance of some pictures of the wear on your pistons and rings you described in the other post? Exhaust valves too if possible. This could be educational...
Regards,
Erich
Reply With Quote
  #6  
Old 03-07-2012, 10:16 PM
Ironflight's Avatar
Ironflight Ironflight is offline
VAF Moderator / Line Boy
 
Join Date: Jan 2005
Location: Dayton, NV
Posts: 12,839
Default

Quote:
Originally Posted by Kokemiller View Post
What did compressions drop to?

The cowl hinges appear to show little to no wear in the pix, is that representative of actual wear?

Compressions dropped below 60/80. I am a believer in the "button it up, fly it, and try again" theory on low compressions - but you can't get stuck in an endless "DO"-loop - sooner or later, you have to admit that there's a problem. In this case, all the air was going into the crankcase, so I knew it was rings. I was just going to hone and re-ring, but after some significant study and consultation about the ECI nickel cylinders, that just didn't seem like a great option with this many hours on the jugs.

Yes, the cowl hinges are original - they can last a long time of you build them without any preload.

Quote:
Originally Posted by erich weaver View Post
Any chance of some pictures of the wear on your pistons and rings you described in the other post? Exhaust valves too if possible. This could be educational...
I've tried to take some, but with the camera I have, all I get are reflections that don't really show anything. If I get anything that is educational, I certainly will share it.

Paul
__________________
Paul F. Dye
Editor at Large - KITPLANES Magazine
RV-8 - N188PD - "Valkyrie"
RV-6 (By Marriage) - N164MS - "Mikey"
RV-3B - N13PL - "Tsamsiyu"
A&P, EAA Tech Counselor/Flight Advisor
Dayton Valley Airpark (A34)
http://Ironflight.com
Reply With Quote
  #7  
Old 03-08-2012, 10:21 AM
jrs14855 jrs14855 is offline
 
Join Date: Apr 2008
Location: Lake Havasu City AZ
Posts: 2,644
Default cooler

Here is what I do with the cooler:
4130 spacers machined to a length that allows a very slight push fit between the flanges. AN 970 washers with the edges trimmed to clear the cooler and installed between the flange and spacer tube would be desirable, obviously adjust the length of the spacer to allow for the washers.
AN 970 washers at both ends of the bolts.
Use all four outer attachment holes.
If the cooler flanges are slotted, as most are, adjust the location of the cooler so all bolts are in the middle of the slotted hole.
Reply With Quote
  #8  
Old 03-08-2012, 10:42 AM
Ironflight's Avatar
Ironflight Ironflight is offline
VAF Moderator / Line Boy
 
Join Date: Jan 2005
Location: Dayton, NV
Posts: 12,839
Default

Quote:
Originally Posted by jrs14855 View Post
Here is what I do with the cooler:
4130 spacers machined to a length that allows a very slight push fit between the flanges. AN 970 washers with the edges trimmed to clear the cooler and installed between the flange and spacer tube would be desirable, obviously adjust the length of the spacer to allow for the washers.
AN 970 washers at both ends of the bolts.
Use all four outer attachment holes.
If the cooler flanges are slotted, as most are, adjust the location of the cooler so all bolts are in the middle of the slotted hole.
That's pretty much what I had, except that I had normal sized washers. The cracks basically started right at the holes, so (like you) I am going to use larger washers, with a straight edge ground to make them fit, like you did. That should increase the bearing surface a bit. Making 4130 spacers this morning as well....
__________________
Paul F. Dye
Editor at Large - KITPLANES Magazine
RV-8 - N188PD - "Valkyrie"
RV-6 (By Marriage) - N164MS - "Mikey"
RV-3B - N13PL - "Tsamsiyu"
A&P, EAA Tech Counselor/Flight Advisor
Dayton Valley Airpark (A34)
http://Ironflight.com
Reply With Quote
  #9  
Old 03-08-2012, 12:43 PM
JonJay's Avatar
JonJay JonJay is offline
 
Join Date: Jan 2007
Location: Battleground
Posts: 4,348
Default

Quote:
Originally Posted by Ironflight View Post
That's pretty much what I had, except that I had normal sized washers. The cracks basically started right at the holes, so (like you) I am going to use larger washers, with a straight edge ground to make them fit, like you did. That should increase the bearing surface a bit. Making 4130 spacers this morning as well....
I did the same. So far, so good, 460+ hours. I think the large area washers and the support on the flange are the key.
I also sandwiched one layer of baffling material between the cooler and the baffle. I was told that this isolates the cooler thermally from the baffle and can help to reduce oil temps. There is also a theory that it reduces vibration into the flanges vs them being hard fixed to the baffle.
Something else to consider and it is really easy to do. I don't know if it works but I don't see any down side either.
__________________
Smart People do Stupid things all the time. I know, I've seen me do'em.

RV6 - Builder/Flying
Bucker Jungmann
Fiat G.46 -(restoration in progress, if I have enough life left in me)
RV1 - Proud Pilot.
Reply With Quote
  #10  
Old 03-08-2012, 01:51 PM
az_gila's Avatar
az_gila az_gila is offline
 
Join Date: Jan 2005
Location: 57AZ - NW Tucson area
Posts: 10,011
Smile

Quote:
Originally Posted by Ironflight View Post
That's pretty much what I had, except that I had normal sized washers. The cracks basically started right at the holes, so (like you) I am going to use larger washers, with a straight edge ground to make them fit, like you did. That should increase the bearing surface a bit. Making 4130 spacers this morning as well....
Paul,

Consider adding a 1/8 or so stiffener inside the flanges like the Grumman design.



It's probably easier than hacking washers and should be better support.
__________________
Gil Alexander
EAA Technical Counselor, Airframe Mechanic
Half completed RV-10 QB purchased
RV-6A N61GX - finally flying
Grumman Tiger N12GA - flying
La Cholla Airpark (57AZ) Tucson AZ

Last edited by az_gila : 03-08-2012 at 01:56 PM.
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 10:55 PM.


The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.