Today's Message Index:
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1. 06:02 AM - Re: Fretted Crankcase (dlelkins@juno.com)
2. 01:19 PM - Re: Fretted Crankcase (barrynorman@comcast.net)
3. 01:45 PM - Re: Fretting (barrynorman@comcast.net)
4. 01:57 PM - Re: Re: Fretting (Bob)
5. 02:15 PM - Re: Re: Fretting (freedom4life)
Message 1
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| Subject: | Fretted Crankcase |
How can I tell if my crankcase is fretted without a major teardown?Mine
is a 1995 model with almost 500 hours on it. Dan Elkins N96DE
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| Subject: | Re: Fretted Crankcase |
The problem years were 2005-2006. The engine is hard to turn over by hand after
flight. That's one indication. Mine also started leaking from crankcase bolts.
Barry
----- Original Message -----
From: dlelkins@juno.com
Sent: Tuesday, October 14, 2014 8:59:52 AM
Subject: RE: Pulsar-List: Fretted Crankcase
How can I tell if my crankcase is fretted without a major teardown?
Mine is a 1995 model with almost 500 hours on it.
Dan Elkins N96DE
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Message 3
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Your right on with the possible causes. My engine was never overheated.
I appreciate your offer to do an analysis but they are aware of the problem
. They've just been very quite about it. From what I hear, they have paid f
or the parts to repair it for some folks depending on how many hours were o
n it but not everyone. If it's anywhere near TBO, nothing is covered even t
hough the case isn't rebuild-able at that point. I suspect that they will t
ell me my engine is too old for any reimbursement because that's what they
are telling other folks in my situation. The problem production years were
2005-2006. Since it was a problem that slowly occurs over time and hasn't l
ed to a in-flight failure, they probably figured it would be best to let th
e engines run until symptoms of a problem showed up then deal with each iss
ue. Cheaper for them in the long run because they can pro-rate the amount o
f compensation based on how much use was provided by the engine. The redesi
gn of the crankcase, fasteners, torque values and stretch techniques is pro
of they knew there was a problem. As a mater of fact, my engine only had a
1200 hr TBO. The they expanded them to 1500 hr TBO, but the models with the
new crankcase, have a 2000 hr TBO and the dealers like Lockwood tell you t
hat once you install the new case, then your engine goes up to the 2000 hr
TBO.
I have sent pictures to the folks at Lockwood and they said they'll present
my case to Rotax but, I'll be surprised if they offer any relief.
Suggest everyone check the're engines for this periodically.
----- Original Message -----
From: "Bob Hartunian" <bobh5@earthlink.net>
Sent: Tuesday, October 14, 2014 11:56:13 AM
Subject: Fretting
Fretting Barry;
Viewed your pics and was really surprised at the amount of damage, consider
ing the relatively short operating life.
To get fretting, you need relative motion between mating parts and that mot
ion would come from relaxation of the joint clamping pressure. And that mea
ns that the bolt preload diminished over time or was too light to start wit
h; i.e, insufficient initial bolt torque.
Was engine ever overheated badly? That would relax bolt preload.
I have never separated case halves so I noticed in your pics that the blind
bolt holes had Helicoil inserts. It=99s possible that these inserts
relaxed slightly, reducing bolt preloads. I prefer Keenserts myself in tens
ion loading because they are steel with large threads into the case. If you
want me to write a technical analysis of the probable situation, I can, sh
ould you wish to pursue it with Rotax.
Bob H
Message 4
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FrettingIs there an accepted range of serial numbers that are at risk
posted anywhere?
Bob
From: barrynorman@comcast.net
Sent: Tuesday, October 14, 2014 1:43 PM
Subject: Pulsar-List: Re: Fretting
Your right on with the possible causes. My engine was never overheated.
I appreciate your offer to do an analysis but they are aware of the
problem. They've just been very quite about it. From what I hear, they
have paid for the parts to repair it for some folks depending on how
many hours were on it but not everyone. If it's anywhere near TBO,
nothing is covered even though the case isn't rebuild-able at that
point. I suspect that they will tell me my engine is too old for any
reimbursement because that's what they are telling other folks in my
situation. The problem production years were 2005-2006. Since it was a
problem that slowly occurs over time and hasn't led to a in-flight
failure, they probably figured it would be best to let the engines run
until symptoms of a problem showed up then deal with each issue. Cheaper
for them in the long run because they can pro-rate the amount of
compensation based on how much use was provided by the engine. The
redesign of the crankcase, fasteners, torque values and stretch
techniques is proof they knew there was a problem. As a mater of fact,
my engine only had a 1200 hr TBO. The they expanded them to 1500 hr TBO,
but the models with the new crankcase, have a 2000 hr TBO and the
dealers like Lockwood tell you that once you install the new case, then
your engine goes up to the 2000 hr TBO.
I have sent pictures to the folks at Lockwood and they said they'll
present my case to Rotax but, I'll be surprised if they offer any
relief.
Suggest everyone check the're engines for this periodically.
-------------------------------------------------------------------------
-------
From: "Bob Hartunian" <bobh5@earthlink.net>
Sent: Tuesday, October 14, 2014 11:56:13 AM
Subject: Fretting
Barry;
Viewed your pics and was really surprised at the amount of damage,
considering the relatively short operating life.
To get fretting, you need relative motion between mating parts and that
motion would come from relaxation of the joint clamping pressure. And
that means that the bolt preload diminished over time or was too light
to start with; i.e, insufficient initial bolt torque.
Was engine ever overheated badly? That would relax bolt preload.
I have never separated case halves so I noticed in your pics that the
blind bolt holes had Helicoil inserts. It=99s possible that these
inserts relaxed slightly, reducing bolt preloads. I prefer Keenserts
myself in tension loading because they are steel with large threads into
the case. If you want me to write a technical analysis of the probable
situation, I can, should you wish to pursue it with Rotax.
Bob H
Message 5
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Fretting
I believe the fretting problems were mostly related to the 912S 100 HP
engines. I have the 80 HP which would have been produced in about 1995.
It has now done 2,100 hours and has never had a problem. It is still
not using oil and I suspect I should get about 4,000 hours from it
before overhaul. I have run a product called Power Up in it since
almost new which I know has helped cut wear to a minimum.
Cliff
Your right on with the possible causes. My engine was never overheated.
I appreciate your offer to do an analysis but they are aware of the
problem. They've just been very quite about it. From what I hear, they
have paid for the parts to repair it for some folks depending on how
many hours were on it but not everyone. If it's anywhere near TBO,
nothing is covered even though the case isn't rebuild-able at that
point. I suspect that they will tell me my engine is too old for any
reimbursement because that's what they are telling other folks in my
situation. The problem production years were 2005-2006. Since it was a
problem that slowly occurs over time and hasn't led to a in-flight
failure, they probably figured it would be best to let the engines run
until symptoms of a problem showed up then deal with each issue. Cheaper
for them in the long run because they can pro-rate the amount of
compensation based on how much use was provided by the engine. The
redesign of the crankcase, fasteners, torque values and stretch
techniques is proof they knew there was a problem. As a mater of fact,
my engine only had a 1200 hr TBO. The they expanded them to 1500 hr TBO,
but the models with the new crankcase, have a 2000 hr TBO and the
dealers like Lockwood tell you that once you install the new case, then
your engine goes up to the 2000 hr TBO.
I have sent pictures to the folks at Lockwood and they said they'll
present my case to Rotax but, I'll be surprised if they offer any
relief.
Suggest everyone check the're engines for this periodically.
-------------------------------------------------------------------------
-------
From: "Bob Hartunian" <bobh5@earthlink.net>
Sent: Tuesday, October 14, 2014 11:56:13 AM
Subject: Fretting
Barry;
Viewed your pics and was really surprised at the amount of damage,
considering the relatively short operating life.
To get fretting, you need relative motion between mating parts and that
motion would come from relaxation of the joint clamping pressure. And
that means that the bolt preload diminished over time or was too light
to start with; i.e, insufficient initial bolt torque.
Was engine ever overheated badly? That would relax bolt preload.
I have never separated case halves so I noticed in your pics that the
blind bolt holes had Helicoil inserts. It=99s possible that these
inserts relaxed slightly, reducing bolt preloads. I prefer Keenserts
myself in tension loading because they are steel with large threads into
the case. If you want me to write a technical analysis of the probable
situation, I can, should you wish to pursue it with Rotax.
Bob H
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