Today's Message Index:
----------------------
1. 07:14 PM - Oil Cooler Mount Cracking... (Matt Dralle)
2. 07:48 PM - Re: Oil Cooler Mount Cracking... (Linn Walters)
3. 07:51 PM - Re: Oil Cooler Mount Cracking... (Jhnstniii)
4. 08:03 PM - Re: Oil Cooler Mount Cracking... (mr.gsun@gmail.com)
5. 08:40 PM - Re: Oil Cooler Mount Cracking... (Vanremog@aol.com)
6. 09:11 PM - Re: Oil Cooler Mount Cracking... (Don)
Message 1
| INDEX | Back to Main INDEX |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Oil Cooler Mount Cracking... |
Dear Listers,
I took the cowling off the 'ol RV-8 today to have a look around at about the 112
TTSN hour mark. Most everything looked okay except for one major issue. The
outside, lower back mount on the oil cooler is totally cracked off. The outside,
lower front mount also has a long crack. At this point, the upper part
of the mount seems alright. Also the inside mounts show no signs of cracks.
The rear flange on the baffling has a small crack where the left rear part rivets
to the back baffle that the oil cooler is bolted to. No oil leaks of any
kind at this point. See attached pictures from my Cell Phone.
So what the heck? The engine shakes quite a bit on startup and shutdown (smooth
as glass during normal ops), but this doesn't really seem like rotational shake
damage. Although, it must be. Obviously I'm going to have to remove the
oil cooler and have it repaired (that can be done, right?). But just "fixing"
the mounting flanges isn't going to solve the "problem".
What are lister's opinion on what's going on here and what could be done to prevent
it?
Interestingly, I noted that the #4 grounding cable that is attached to a bolt hole
right underneath the oil cooler also had the lug sheered off. There is "service
loop" on the cable, but #4 isn't really flexible so its not particular
effective. Guess I need more. The point though, is, that it seems like the engine
shook pretty hard. I don't see any other signs of "issues" related. The
mounts and bolts seem solid and tight.
Thoughts?
-
Matt Dralle
RV-8 #82880 N998RV
http://www.mattsrv8.com - Matt's RV-8 Construction Blog
http://www.youtube.com/MattsRV8 - Matt's RV-8 HDTV YouTube Channel
Status: 112+ Hours TTSN!
Message 2
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Oil Cooler Mount Cracking... |
Wow Matt! Impressive photo's.
I'm going to guess that it isn't the startup/shutdown motion doing the
damage. I think it's vibration in cruise. Get the prop balanced if you
haven't already. Your airplane will love you for it. As a test, place
a glass of water on the glareshield and look at the ripples ..... change
RPM to see where the ripples are the largest .... and the worst
vibration. Vibration is very subjective.
As for the fix. Well, I'm not in favor of hanging the oil cooler on the
baffle for the reason you found. Things move around a lot. Check the
engine mount for signs that the oil cooler (or even the hoses being
tight) is hitting the engine mount. It looks close per the picture. You
might try to strap the oil cooler aft flange over to the valve cover
screws or over to the screws above the valve cover, or on the inside of
the cooler mount to the engine to stabilize the cooler. My Pitts has
only the corners mounted to the baffle under the air inlet ramp and a
brace up to the cylinder, and it's been trouble free.
I also noticed the spiral wrap prominent in the first picture. Might as
well get rid of it now as it'll dry out and crack off later on. :-P
Use lacing cord to tie the wires together, or real good ty-raps .....
the cheap ones will go the route of the spiral wrap.
Linn
On 10/17/2010 10:10 PM, Matt Dralle wrote:
> Dear Listers,
>
> I took the cowling off the 'ol RV-8 today to have a look around at about the
112 TTSN hour mark. Most everything looked okay except for one major issue.
The outside, lower back mount on the oil cooler is totally cracked off. The outside,
lower front mount also has a long crack. At this point, the upper part
of the mount seems alright. Also the inside mounts show no signs of cracks.
The rear flange on the baffling has a small crack where the left rear part rivets
to the back baffle that the oil cooler is bolted to. No oil leaks of any
kind at this point. See attached pictures from my Cell Phone.
>
> So what the heck? The engine shakes quite a bit on startup and shutdown (smooth
as glass during normal ops), but this doesn't really seem like rotational
shake damage. Although, it must be. Obviously I'm going to have to remove the
oil cooler and have it repaired (that can be done, right?). But just "fixing"
the mounting flanges isn't going to solve the "problem".
>
> What are lister's opinion on what's going on here and what could be done to prevent
it?
>
> Interestingly, I noted that the #4 grounding cable that is attached to a bolt
hole right underneath the oil cooler also had the lug sheered off. There is
"service loop" on the cable, but #4 isn't really flexible so its not particular
effective. Guess I need more. The point though, is, that it seems like the
engine shook pretty hard. I don't see any other signs of "issues" related.
The mounts and bolts seem solid and tight.
>
> Thoughts?
>
>
> -
> Matt Dralle
> RV-8 #82880 N998RV
> http://www.mattsrv8.com - Matt's RV-8 Construction Blog
> http://www.youtube.com/MattsRV8 - Matt's RV-8 HDTV YouTube Channel
> Status: 112+ Hours TTSN!
Message 3
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Oil Cooler Mount Cracking... |
Matt--Classic problem. Many have mounted the oil cooler on the firewall
to avoid it. Some may have come up with ways to beef up the mount/flange
s to keep it on the baffle and hopefully you will hear from them. The oil
cooler is heavy and the engine shakes a lot on start up and shut down.
Another option is to just move it to the firewall and no worries.
LeRoy Johnston RV-6A Esperanza 400 hrs
-----Original Message-----
From: Matt Dralle <dralle@matronics.com>
Sent: Sun, Oct 17, 2010 10:10 pm
Subject: RV-List: Oil Cooler Mount Cracking...
ear Listers,
I took the cowling off the 'ol RV-8 today to have a look around at about
the 112
TSN hour mark. Most everything looked okay except for one major issue.
The
utside, lower back mount on the oil cooler is totally cracked off. The
utside, lower front mount also has a long crack. At this point, the upper
part
f the mount seems alright. Also the inside mounts show no signs of cracks
.
he rear flange on the baffling has a small crack where the left rear part
ivets to the back baffle that the oil cooler is bolted to. No oil leaks
of any
ind at this point. See attached pictures from my Cell Phone.
So what the heck? The engine shakes quite a bit on startup and shutdown
(smooth
s glass during normal ops), but this doesn't really seem like rotational
shake
amage. Although, it must be. Obviously I'm going to have to remove the
oil
ooler and have it repaired (that can be done, right?). But just "fixing"
the
ounting flanges isn't going to solve the "problem".
What are lister's opinion on what's going on here and what could be done
to
revent it?
Interestingly, I noted that the #4 grounding cable that is attached to a
bolt
ole right underneath the oil cooler also had the lug sheered off. There
is
service loop" on the cable, but #4 isn't really flexible so its not partic
ular
ffective. Guess I need more. The point though, is, that it seems like th
e
ngine shook pretty hard. I don't see any other signs of "issues" related.
The
ounts and bolts seem solid and tight.
Thoughts?
att Dralle
V-8 #82880 N998RV
ttp://www.mattsrv8.com - Matt's RV-8 Construction Blog
ttp://www.youtube.com/MattsRV8 - Matt's RV-8 HDTV YouTube Channel
tatus: 112+ Hours TTSN!
Message 4
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Oil Cooler Mount Cracking... |
The oil cooler on my RV7 is mounted the same way. At about 180 hours I had
some similar cracking. Not as bad and not on the oil cooler itself, just on
the mounts. I've got the 180 hp Lyc so maybe mine doesn't shake as bad.
Anyway, the consensus I got locally was that the mass of the oil cooler way
out away from the center of rotation of the engine caused a lot of inertia
and forces and those four long bolts carry a lot of stress back and forth.
The fix for me was to stop drill the cracks and add a piece of angle
aluminum bracing to try to get some of the forces transferred to some more
sturdy components than the baffles. It is I've got over 500 hours and check
things every 50 hours. No changes, cracks stopped. I may add another
piece of bracing as well since I saw your photos.
PS: I just finished installing dual 10" Skyviews after my Blue Mountain
EFIS died. Painful but I really like it!!
do not archive
On Sun, Oct 17, 2010 at 7:10 PM, Matt Dralle <dralle@matronics.com> wrote:
>
> Dear Listers,
>
> I took the cowling off the 'ol RV-8 today to have a look around at about
> the 112 TTSN hour mark. Most everything looked okay except for one major
> issue. The outside, lower back mount on the oil cooler is totally cracked
> off. The outside, lower front mount also has a long crack. At this point,
> the upper part of the mount seems alright. Also the inside mounts show no
> signs of cracks. The rear flange on the baffling has a small crack where
> the left rear part rivets to the back baffle that the oil cooler is bolted
> to. No oil leaks of any kind at this point. See attached pictures from my
> Cell Phone.
>
> So what the heck? The engine shakes quite a bit on startup and shutdown
> (smooth as glass during normal ops), but this doesn't really seem like
> rotational shake damage. Although, it must be. Obviously I'm going to have
> to remove the oil cooler and have it repaired (that can be done, right?).
> But just "fixing" the mounting flanges isn't going to solve the "problem".
>
> What are lister's opinion on what's going on here and what could be done to
> prevent it?
>
> Interestingly, I noted that the #4 grounding cable that is attached to a
> bolt hole right underneath the oil cooler also had the lug sheered off.
> There is "service loop" on the cable, but #4 isn't really flexible so its
> not particular effective. Guess I need more. The point though, is, that it
> seems like the engine shook pretty hard. I don't see any other signs of
> "issues" related. The mounts and bolts seem solid and tight.
>
> Thoughts?
>
>
> -
> Matt Dralle
> RV-8 #82880 N998RV
> http://www.mattsrv8.com - Matt's RV-8 Construction Blog
> http://www.youtube.com/MattsRV8 - Matt's RV-8 HDTV YouTube Channel
> Status: 112+ Hours TTSN!
Message 5
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Oil Cooler Mount Cracking... |
Matt-
I doubt that I could recommend reusing the cooler, as local embrittlement
is likely to have occurred deeper into the oil cooler end cap than appears.
From your photo it is clear that this was a cyclic fatigue failure as the
break appears crystallized and embrittled on both sides of the point of
attachment. I believe you will find that the problem is due to the lack of
sufficient bearing surface in the original attachment. I would recommend
replacing the oil cooler and installing doublers on both sides of the flange
to arrest the standing wave in the area of the original attachment.
N1GV (RV-6A Flying 956TTAE Silicon Valley, CA)
A bronze-age myth concocted by goatherders probably isn't a really good
thing to base your life on.
In a message dated 10/17/2010 7:20:30 P.M. Pacific Daylight Time,
dralle@matronics.com writes:
Dear Listers,
I took the cowling off the 'ol RV-8 today to have a look around at about
the 112 TTSN hour mark. Most everything looked okay except for one major
issue. The outside, lower back mount on the oil cooler is totally cracked
off. The outside, lower front mount also has a long crack. At this point,
the upper part of the mount seems alright. Also the inside mounts show no
signs of cracks. The rear flange on the baffling has a small crack where
the left rear part rivets to the back baffle that the oil cooler is bolted
to. No oil leaks of any kind at this point. See attached pictures from my
Cell Phone.
So what the heck? The engine shakes quite a bit on startup and shutdown
(smooth as glass during normal ops), but this doesn't really seem like
rotational shake damage. Although, it must be. Obviously I'm going to have to
remove the oil cooler and have it repaired (that can be done, right?).
But just "fixing" the mounting flanges isn't going to solve the "problem".
What are lister's opinion on what's going on here and what could be done
to prevent it?
Interestingly, I noted that the #4 grounding cable that is attached to a
bolt hole right underneath the oil cooler also had the lug sheered off.
There is "service loop" on the cable, but #4 isn't really flexible so its not
particular effective. Guess I need more. The point though, is, that it
seems like the engine shook pretty hard. I don't see any other signs of
"issues" related. The mounts and bolts seem solid and tight.
Thoughts?
-
Matt Dralle
RV-8 #82880 N998RV
http://www.mattsrv8.com - Matt's RV-8 Construction Blog
http://www.youtube.com/MattsRV8 - Matt's RV-8 HDTV YouTube Channel
Status: 112+ Hours TTSN!
Message 6
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Oil Cooler Mount Cracking... |
Very true but Pacific will replace the entire flange. The comment about
lack of surface area is well taken care of by steel washers at the ends of
the tubes.
From: owner-rv-list-server@matronics.com
[mailto:owner-rv-list-server@matronics.com] On Behalf Of Vanremog@aol.com
Sent: Sunday, October 17, 2010 8:27 PM
Subject: Re: RV-List: Oil Cooler Mount Cracking...
Matt-
I doubt that I could recommend reusing the cooler, as local embrittlement is
likely to have occurred deeper into the oil cooler end cap than appears.
>From your photo it is clear that this was a cyclic fatigue failure as the
break appears crystallized and embrittled on both sides of the point of
attachment. I believe you will find that the problem is due to the lack of
sufficient bearing surface in the original attachment. I would recommend
replacing the oil cooler and installing doublers on both sides of the flange
to arrest the standing wave in the area of the original attachment.
N1GV (RV-6A Flying 956TTAE Silicon Valley, CA)
A bronze-age myth concocted by goatherders probably isn't a really good
thing to base your life on.
In a message dated 10/17/2010 7:20:30 P.M. Pacific Daylight Time,
dralle@matronics.com writes:
Dear Listers,
I took the cowling off the 'ol RV-8 today to have a look around at about the
112 TTSN hour mark. Most everything looked okay except for one major issue.
The outside, lower back mount on the oil cooler is totally cracked off. The
outside, lower front mount also has a long crack. At this point, the upper
part of the mount seems alright. Also the inside mounts show no signs of
cracks. The rear flange on the baffling has a small crack where the left
rear part rivets to the back baffle that the oil cooler is bolted to. No
oil leaks of any kind at this point. See attached pictures from my Cell
Phone.
So what the heck? The engine shakes quite a bit on startup and shutdown
(smooth as glass during normal ops), but this doesn't really seem like
rotational shake damage. Although, it must be. Obviously I'm going to have
to remove the oil cooler and have it repaired (that can be done, right?).
But just "fixing" the mounting flanges isn't going to solve the "problem".
What are lister's opinion on what's going on here and what could be done to
prevent it?
Interestingly, I noted that the #4 grounding cable that is attached to a
bolt hole right underneath the oil cooler also had the lug sheered off.
There is "service loop" on the cable, but #4 isn't really flexible so its
not particular effective. Guess I need more. The point though, is, that it
seems like the engine shook pretty hard. I don't see any other signs of
"issues" related. The mounts and bolts seem solid and tight.
Thoughts?
-
Matt Dralle
RV-8 #82880 N998RV
http://www.mattsrv8.com - Matt's RV-8 Construction Blog
http://www.youtube.com/MattsRV8 - Matt's RV-8 HDTV YouTube Channel
Status: 112+ Hours TTSN!
Other Matronics Email List Services
These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.
-- Please support this service by making your Contribution today! --
|