Today's Message Index:
----------------------
1. 07:36 AM - Compression (BobbyPaulk@comcast.net)
2. 07:49 AM - Re: Compression (Martin Hone)
3. 08:33 AM - Re: Compression (Garth Knowles)
4. 10:14 AM - Re: Compression (FLYaDIVE)
5. 11:12 AM - Re: Compression (Pete Krotje)
6. 02:08 PM - Re: Compression (Gary Aman)
7. 03:15 PM - Re: Compression (BobsV35B@aol.com)
8. 03:22 PM - Re: Compression (BobsV35B@aol.com)
Message 1
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List,
I just finished a differential compression check of my 3300 for it's Conditional
Inspection.
It has 125 hrs and has been broken in correctly and oil changed regularly.
3 cylinders have dropped to the low 60's over 80. #3, 4 & 5 are down from the mid
70's. #3 was below 70 at last conditional but now I have two more following
suit. The #3 & 4 are not the hottest cylinders but #5 is second hottest. Engine
was cold for 2 days at time of check. At this rate I don't know if it will
make Top OH.
The compression is being lost through the rings as it can be heard thru the oil
dipstick tube. Has anyone had a similar problem and is there any thing I can
do about it. I am going to add Marvel Mystery to the fuel but I think that would
be just a band aid on a more serious problem. How low should the compression
get before I get alarmed??
Bobby Paulk
601 XL N131BP
Jabiru 3300 S/N 1141
Message 2
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Hi Bobby,
This sounds all too familiar. From memory, my Jab manual says that you need
to pull the cylinders if the reading is 60/80 or less, but I would strongly
suggest doing the test again but on a warm engine before getting too
excited.
Cheers
Martin
On Tue, Sep 13, 2011 at 12:31 AM, <BobbyPaulk@comcast.net> wrote:
>
>
> List,
> I just finished a differential compression check of my 3300 for it's
> Conditional Inspection.
> It has 125 hrs and has been broken in correctly and oil changed regularly.
> 3 cylinders have dropped to the low 60's over 80. #3, 4 & 5 are down from
> the mid 70's. #3 was below 70 at last conditional but now I have two more
> following suit. The #3 & 4 are not the hottest cylinders but #5 is second
> hottest. Engine was cold for 2 days at time of check. At this rate I don't
> know if it will make Top OH.
> The compression is being lost through the rings as it can be heard thru
> the oil dipstick tube. Has anyone had a similar problem and is there any
> thing I can do about it. I am going to add Marvel Mystery to the fuel but I
> think that would be just a band aid on a more serious problem. How low
> should the compression get before I get alarmed??
>
> Bobby Paulk
> 601 XL N131BP
> Jabiru 3300 S/N 1141
>
>
> *
>
> *
>
>
Message 3
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>From my experience, when doing both leakdown and compression checks, engine
temperature can make a significant difference.- Jabiru says "warm to hot
" for a leakdown test where the max 25% drop would apply.- You may not ha
ve an issue at all.=0A=0A=0AGarth=0A=0AFrom: "BobbyPaulk@comcast.net" <Bobb
yPaulk@comcast.net>=0A>To: jabiruengine-list-digest@matronics.com=0A>Sent:
Monday, September 12, 2011 10:31:19 AM=0A>Subject: JabiruEngine-List: Compr
ession=0A>=0A>=0A>=0A>=0A>List,=0A>I just finished a differential compressi
on check of my 3300 for it's Conditional Inspection.=0A>It has 125 hrs and
has been broken in correctly and oil changed regularly. =0A>3 cylinders hav
e dropped to the low 60's over 80. #3, 4 & 5 are down from the mid 70's. #3
was below 70 at last conditional but now I have two more following suit. T
he #3 & 4- are not the hottest cylinders but #5 is second hottest. Engine
was cold for 2 days at time of check. At this rate I don't know if it will
make Top OH.=0A>The compression is being- lost through the rings as it c
an be heard thru the oil dipstick tube. Has anyone had a similar problem an
d is there any thing I can do about it. I am going to add Marvel Mystery to
the fuel but I think that would be just a band aid on a more serious probl
em. How low should the compression get before I get alarmed??=0A>=0A>Bobby
============== =0A>=0A>
Message 4
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Bobby:
MMO - Not to the fuel, but in to the CYLINDER. Remove the plug, squirt MMO
all over the inside of the cylinder (about 1 oz per cylinder) and let it sit
over night. If luck is on your side you may just free up some sticky rings.
If you want to add some MMO to the oil - - - ONE HOUR BEFORE AN OIL CHANGE.
DO NOT RUN WITH MMO MORE THAN THAT.
You will see a cleaning of all internal parts.
MMO in the fuel is pretty much wasted. The ratio of fuel is so high and the
flow rate so fast that it really does nothing. Been there - Done that.
Barry
On Mon, Sep 12, 2011 at 10:31 AM, <BobbyPaulk@comcast.net> wrote:
>
>
> List,
> I just finished a differential compression check of my 3300 for it's
> Conditional Inspection.
> It has 125 hrs and has been broken in correctly and oil changed regularly.
> 3 cylinders have dropped to the low 60's over 80. #3, 4 & 5 are down from
> the mid 70's. #3 was below 70 at last conditional but now I have two more
> following suit. The #3 & 4 are not the hottest cylinders but #5 is second
> hottest. Engine was cold for 2 days at time of check. At this rate I don't
> know if it will make Top OH.
> The compression is being lost through the rings as it can be heard thru
> the oil dipstick tube. Has anyone had a similar problem and is there any
> thing I can do about it. I am going to add Marvel Mystery to the fuel but I
> think that would be just a band aid on a more serious problem. How low
> should the compression get before I get alarmed??
>
> Bobby Paulk
> 601 XL N131BP
> Jabiru 3300 S/N 1141
>
>
> *
>
> *
>
>
Message 5
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Bobby,
Before you start adding mysterious additives please do what the manual says
and warm up your engine thoroughly before the compression check. The engine
should be as hot as practical to work with. We can take any engine cold and
get very inconsistent compression results!
Pete Krotje
Jabiru USA Sport Aircraft, LLC
931-680-2800
www.usjabiru.com
From: owner-jabiruengine-list-server@matronics.com
[mailto:owner-jabiruengine-list-server@matronics.com] On Behalf Of FLYaDIVE
Sent: Monday, September 12, 2011 12:12 PM
Subject: Re: JabiruEngine-List: Compression
Bobby:
MMO - Not to the fuel, but in to the CYLINDER. Remove the plug, squirt MMO
all over the inside of the cylinder (about 1 oz per cylinder) and let it sit
over night. If luck is on your side you may just free up some sticky rings.
If you want to add some MMO to the oil - - - ONE HOUR BEFORE AN OIL CHANGE.
DO NOT RUN WITH MMO MORE THAN THAT.
You will see a cleaning of all internal parts.
MMO in the fuel is pretty much wasted. The ratio of fuel is so high and the
flow rate so fast that it really does nothing. Been there - Done that.
Barry
On Mon, Sep 12, 2011 at 10:31 AM, <BobbyPaulk@comcast.net> wrote:
List,
I just finished a differential compression check of my 3300 for it's
Conditional Inspection.
It has 125 hrs and has been broken in correctly and oil changed regularly.
3 cylinders have dropped to the low 60's over 80. #3, 4 & 5 are down from
the mid 70's. #3 was below 70 at last conditional but now I have two more
following suit. The #3 & 4 are not the hottest cylinders but #5 is second
hottest. Engine was cold for 2 days at time of check. At this rate I don't
know if it will make Top OH.
The compression is being lost through the rings as it can be heard thru the
oil dipstick tube. Has anyone had a similar problem and is there any thing I
can do about it. I am going to add Marvel Mystery to the fuel but I think
that would be just a band aid on a more serious problem. How low should the
compression get before I get alarmed??
Bobby Paulk
601 XL N131BP
Jabiru 3300 S/N 1141
ist" target="_blank">http://www.matronics.com/Navigator?JabiruEngine-List
tp://forums.matronics.com
_blank">http://www.matronics.com/contribution
Message 6
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Bobby,
Sometimes you can get the pressures up by slowly taking the piston over top
center a few degrees and then bringing it back up to tdc WHILE HOLDING THE
PROP FIRMLY THROUGH THIS MOTION!! It made a big difference on my Continent
al O200;s and IO470's
G.Aman
-----Original Message-----
From: BobbyPaulk <BobbyPaulk@comcast.net>
Sent: Mon, Sep 12, 2011 11:11 am
Subject: JabiruEngine-List: Compression
List,
I just finished a differential compression check of my 3300 for it's Condit
ional Inspection.
It has 125 hrs and has been broken in correctly and oil changed regularly.
3 cylinders have dropped to the low 60's over 80. #3, 4 & 5 are down from t
he mid 70's. #3 was below 70 at last conditional but now I have two more fo
llowing suit. The #3 & 4 are not the hottest cylinders but #5 is second ho
ttest. Engine was cold for 2 days at time of check. At this rate I don't kn
ow if it will make Top OH.
The compression is being lost through the rings as it can be heard thru th
e oil dipstick tube. Has anyone had a similar problem and is there any thin
g I can do about it. I am going to add Marvel Mystery to the fuel but I thi
nk that would be just a band aid on a more serious problem. How low should
the compression get before I get alarmed??
Bobby Paulk
601 XL N131BP
Jabiru 3300 S/N 1141
Message 7
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Good Afternoon Bobby,
The Comparative Compression Check has been proven to have many faults. So
many such that Continental Motors now recommends that when the Compression
gets below the ancient 75 percent rule, further investigation be used before
a cylinder is pulled.
They specify that the valves be looked at via a Borescope. If the coloring
is equal all the way around. The valves are not being "burned" and can
remain in service.
In your case where you feel there is a ring problem, They recommend that
oil consumption be monitored. As long as such consumption is normal
(Whatever that is?) the engine is OK.
CMC recommends that no cylinder be removed on strictly a low compression
number.
See Continental Service Bulletin SB03-3.
My take is that the same principles will apply to the Jabiru.
Happy Skies,
Old Bob
Stearman N3977A
Downers Grove, IL
LL22
In a message dated 9/12/2011 4:08:23 P.M. Central Daylight Time,
zeprep251@aol.com writes:
Bobby,
Sometimes you can get the pressures up by slowly taking the piston over
top center a few degrees and then bringing it back up to tdc WHILE HOLDING
THE PROP FIRMLY THROUGH THIS MOTION!! It made a big difference on my
Continental O200;s and IO470's
G.Aman
-----Original Message-----
From: BobbyPaulk <BobbyPaulk@comcast.net>
Sent: Mon, Sep 12, 2011 11:11 am
Subject: JabiruEngine-List: Compression
List,
I just finished a differential compression check of my 3300 for it's
Conditional Inspection.
It has 125 hrs and has been broken in correctly and oil changed regularly.
3 cylinders have dropped to the low 60's over 80. #3, 4 & 5 are down from
the mid 70's. #3 was below 70 at last conditional but now I have two more
following suit. The #3 & 4 are not the hottest cylinders but #5 is second
hottest. Engine was cold for 2 days at time of check. At this rate I don't
know if it will make Top OH.
The compression is being lost through the rings as it can be heard thru
the oil dipstick tube. Has anyone had a similar problem and is there any
thing I can do about it. I am going to add Marvel Mystery to the fuel but I
think that would be just a band aid on a more serious problem. How low should
the compression get before I get alarmed??
Bobby Paulk
601 XL N131BP
Jabiru 3300 S/N 1141
Message 8
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HMMM---
One more thing Bobby,
I should have mentioned that the Borescope inspection should include
looking at the cylinder wall to check for scratches which may indicate a broken
ring.
Happy Skies.
Old Bob
AKA
Bob Siegfried
Ancient Aviator
In a message dated 9/12/2011 5:15:55 P.M. Central Daylight Time,
BobsV35B@aol.com writes:
Good Afternoon Bobby,
The Comparative Compression Check has been proven to have many faults. So
many such that Continental Motors now recommends that when the Compression
gets below the ancient 75 percent rule, further investigation be used before
a cylinder is pulled.
They specify that the valves be looked at via a Borescope. If the coloring
is equal all the way around. The valves are not being "burned" and can
remain in service.
In your case where you feel there is a ring problem, They recommend that
oil consumption be monitored. As long as such consumption is normal
(Whatever that is?) the engine is OK.
CMC recommends that no cylinder be removed on strictly a low compression
number.
See Continental Service Bulletin SB03-3.
My take is that the same principles will apply to the Jabiru.
Happy Skies,
Old Bob
Stearman N3977A
Downers Grove, IL
LL22
In a message dated 9/12/2011 4:08:23 P.M. Central Daylight Time,
zeprep251@aol.com writes:
Bobby,
Sometimes you can get the pressures up by slowly taking the piston over
top center a few degrees and then bringing it back up to tdc WHILE HOLDING
THE PROP FIRMLY THROUGH THIS MOTION!! It made a big difference on my
Continental O200;s and IO470's
G.Aman
-----Original Message-----
From: BobbyPaulk <BobbyPaulk@comcast.net>
Sent: Mon, Sep 12, 2011 11:11 am
Subject: JabiruEngine-List: Compression
List,
I just finished a differential compression check of my 3300 for it's
Conditional Inspection.
It has 125 hrs and has been broken in correctly and oil changed regularly.
3 cylinders have dropped to the low 60's over 80. #3, 4 & 5 are down from
the mid 70's. #3 was below 70 at last conditional but now I have two more
following suit. The #3 & 4 are not the hottest cylinders but #5 is second
hottest. Engine was cold for 2 days at time of check. At this rate I don't
know if it will make Top OH.
The compression is being lost through the rings as it can be heard thru
the oil dipstick tube. Has anyone had a similar problem and is there any
thing I can do about it. I am going to add Marvel Mystery to the fuel but I
think that would be just a band aid on a more serious problem. How low should
the compression get before I get alarmed??
Bobby Paulk
601 XL N131BP
Jabiru 3300 S/N 1141
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