Today's Message Index:
----------------------
1. 01:24 PM - Bassackwards Lycoming (Fiveonepw@aol.com)
2. 02:24 PM - Re: Bassackwards Lycoming (Archie)
3. 02:33 PM - Re: Bassackwards Lycoming (Hal / Carol Kempthorne)
4. 02:59 PM - Re: Bassackwards Lycoming (Scott Derrick)
5. 03:46 PM - Marks lyc (Wes Hobbs)
6. 04:58 PM - Re: Bassackwards Lycoming (Fiveonepw@aol.com)
7. 05:00 PM - Re: Bassackwards Lycoming (Fiveonepw@aol.com)
8. 05:05 PM - Re: Marks lyc (Fiveonepw@aol.com)
9. 06:17 PM - Re: Bassackwards Lycoming (Kent Ashton)
10. 07:05 PM - Re: Bassackwards Lycoming (Archie)
Message 1
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| Subject: | Bassackwards Lycoming |
--> Engines-List message posted by: Fiveonepw@aol.com
My E3D Lyc (150hp) has a disturbing trait of late- on shutdown, it will
sputter along, barely running at full idle cutoff, then stop for an instant, then
turns backwards against a cylinder compression stroke and continues to run
backwards for as much as 1 or 2 seconds.=A0 The engine runs fine otherwise with
all
temps in the normal range.=A0 I had the carb apart before intial running, and it
seemed the cutoff valve was a little sloppy in the bottom of the float bowl
making me wonder just how well it could really shut off the fuel flow.
It seems this would not go in the "good" category.=A0 I already surmise that I
am still leaking some fuel past the cutoff valve which is supplying enough
fuel, and that perhaps a lower vapor pressure in the mogas (regular grade) I am
running may contribute, particularly at higher OATs, in the high 80s/low90s
lately.=A0 I tried running engine to 1200 rpm, then slowly pulling mixture back
to
stumble, then quickly full back to allow the engine to suck the last fuel from
the intake at higher rpm, but that still didn't help.=A0 I am running a 3-blade
wood core composite prop.=A0 I'm also curious if this is bad for stuff like=20the
mags, lifters, accessory gears, oil pump etc.=A0
How serious is this and other than checking mixture cable/lever for full
travel, what else can I do?
Thanks for any and all advice-
Mark Phillips, Columbia TN - RV-6A, 950 TT on '73 engine, 83 since first
flight Jan. 31.
Message 2
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| Subject: | Re: Bassackwards Lycoming |
--> Engines-List message posted by: "Archie" <archie97@earthlink.net>
Sounds like you may even have multiple problems.
Check spark plugs and especially combustion chambers for carbon build up.
Do you have CHT probes? If not, how is the oil temp?
The spark plugs can tell more than you may suspect, especially
if there are indications of cement boil.
Archie's Racing Service
Message 3
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| Subject: | Re: Bassackwards Lycoming |
--> Engines-List message posted by: Hal / Carol Kempthorne <kempthornes@earthlink.net>
Is ignition timing right on? A plug firing before TDC by too much can
drive the piston down before it ever reaches TDC. That would rotate the
engine backward tho not many firings I'd think.
hal
Message 4
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| Subject: | Re: Bassackwards Lycoming |
--> Engines-List message posted by: Scott Derrick <scott@tnstaafl.net>
cement boil?
At 03:24 PM 7/14/2004, you wrote:
>--> Engines-List message posted by: "Archie" <archie97@earthlink.net>
>
>Sounds like you may even have multiple problems.
>Check spark plugs and especially combustion chambers for carbon build up.
>Do you have CHT probes? If not, how is the oil temp?
>The spark plugs can tell more than you may suspect, especially
>if there are indications of cement boil.
>Archie's Racing Service
>
>
"Those who sacrifice freedom to get security, deserve neither."
- Benjamin Franklin
Message 5
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--> Engines-List message posted by: "Wes Hobbs" <weshobbs@starband.net>
Mark , all of the guys are correct, including you. I agree ,you need a tighter
ICO, and the right mag. has no impulse, so on shut down the right mag. will be
firing @ 25 deg BTC. A good reason the engine will turn backwards a few revs.
About the only thing it might hurt is the dry vacuum pump, if it has angled vanes-----Wes
Message 6
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| Subject: | Re: Bassackwards Lycoming |
--> Engines-List message posted by: Fiveonepw@aol.com
In a message dated 07/14/2004 3:25:36 PM Central Standard Time,
archie97@earthlink.net writes:
Do you have CHT probes? If not, how is the oil temp?
Highest CHT (all 4 monitored) is #2 at 425 or less in climb, less that 390 in
cruise, with usually about 60 degree spread from coldest to hottest. Oil
temp never higher than 190...
What should max CHT on this engine be?
Thanks Archie! - Mark
do not archive
Message 7
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| Subject: | Re: Bassackwards Lycoming |
--> Engines-List message posted by: Fiveonepw@aol.com
In a message dated 07/14/2004 3:34:30 PM Central Standard Time,
kempthornes@earthlink.net writes:
Is ignition timing right on?
Not sure- will have to check. It's been running so well otherwise, I hadn't
even considered checking.
Thanks Hal
Mark
do not archive
Message 8
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--> Engines-List message posted by: Fiveonepw@aol.com
In a message dated 07/14/2004 4:46:54 PM Central Standard Time,
weshobbs@starband.net writes:
Mark , all of the guys are correct, including you. I agree ,you need a
tighter ICO, and the right mag. has no impulse, so on shut down the right mag.
will
be firing @ 25 deg BTC. A good reason the engine will turn backwards a few
revs. About the only thing it might hurt is the dry vacuum pump, if it has angled
vanes-----Wes
Thanks, Wes- until I can check the plugs & ICO, will kill right mag with
mixture pull- all electric so not sucky thing!
Mark do not archive
Message 9
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| Subject: | Re: Bassackwards Lycoming |
--> Engines-List message posted by: Kent Ashton <kjashton@vnet.net>
Could you be mistaking what's happening here? To run backward, it would
have to be sucking in gas from the exhaust pipes and pumping air out the
carb, wouldn't it? I could see a kick back or half a turn but several
revolutions? hard to believe but then I've been wrong before.
--kent
> From: Fiveonepw@aol.com
> Reply-To: engines-list@matronics.com
> Date: Wed, 14 Jul 2004 16:23:43 EDT
> To: engines-list@matronics.com
> Subject: Engines-List: Bassackwards Lycoming
>
> --> Engines-List message posted by: Fiveonepw@aol.com
>
>
> My E3D Lyc (150hp) has a disturbing trait of late- on shutdown, it will
> sputter along, barely running at full idle cutoff, then stop for an instant,
> then
> turns backwards against a cylinder compression stroke and continues to run
> backwards for as much as 1 or 2 seconds.=A0 The engine runs fine otherwise
> with all
> temps in the normal range.=A0 I had the carb apart before intial running, and
> it
> seemed the cutoff valve was a little sloppy in the bottom of the float bowl
> making me wonder just how well it could really shut off the fuel flow.
>
> It seems this would not go in the "good" category.=A0 I already surmise that
I
> am still leaking some fuel past the cutoff valve which is supplying enough
> fuel, and that perhaps a lower vapor pressure in the mogas (regular grade) I
> am
> running may contribute, particularly at higher OATs, in the high 80s/low90s
> lately.=A0 I tried running engine to 1200 rpm, then slowly pulling mixture
> back to
> stumble, then quickly full back to allow the engine to suck the last fuel from
> the intake at higher rpm, but that still didn't help.=A0 I am running a
> 3-blade
> wood core composite prop.=A0 I'm also curious if this is bad for stuff
> like=20the
> mags, lifters, accessory gears, oil pump etc.=A0
>
> How serious is this and other than checking mixture cable/lever for full
> travel, what else can I do?
>
> Thanks for any and all advice-
> Mark Phillips, Columbia TN - RV-6A, 950 TT on '73 engine, 83 since first
> flight Jan. 31.
>
>
>
>
>
>
Message 10
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| Subject: | Re: Bassackwards Lycoming |
--> Engines-List message posted by: "Archie" <archie97@earthlink.net>
> --> Engines-List message posted by: Scott Derrick <scott@tnstaafl.net>
>
> cement boil?
The center electrode in spark plugs is cemented in place.
when the cement boils, or burns out, it is an indication of
overheating the plug, This can be caused by many factors,
but if the porcelain is speckled, it may be due to detonation
or pre ignition.
Archie's Racing Service
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