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[rebel-builders] The continuing V8 SR Saga

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Ken

[rebel-builders] The continuing V8 SR Saga

Post by Ken » Sun Feb 19, 2012 11:16 am

Mike Kimball wrote:
Hope I'm not boring too many of you but I thought I'd keep everyone up to
date on my progress. Especially since I keep getting such great ideas and
comments.

58 degrees outside this morning, in October, and here I am stuck at work! I
don't think I mentioned it before but on the day of my first flight my prop
controls weren't working. But the prop was at fine pitch and I decided to
go anyway. Pretty stupid now that I know how bad a prop with too fine a
pitch can be. A little ignorance can get you into a world of trouble.
Anyway, I think I finally figured out what was wrong. The wires that
control the prop connect to brushes with crimp on paddle connectors. For
some reason, the connectors I was able to get locally fit quite loosely.
For that reason I added solder to the connectors then ground them down until
they fit tightly. Unfortunately, the solder fell off on one connector. I
knew I couldn't trust them to stay put so I slathered silicon around them to
keep them in place. I must have used the wrong kind of silicon because it
never hardened up. But the connectors were still in place. Why didn't the
prop work? I pulled the connectors out and cleaned off all of the silicon.
While fiddling with them one of the connectors broke off with very little
pressure applied. I wonder if applying the solder heat treated the metal
and made it brittle. Perhaps it was ready to break already and wasn't
making a good connection. I'm going to try to find new connectors that fit
better today. Then I'll apply Household GOOP which I've used before for
stuff like this. I know it will harden up and stay put.

I'm enjoying your adventure Mike!
Heating and cooling metal in air normally removes heat treating. It's
the fast cooling in oil or water that usually hardens metal. For tricky
stuff the new solders seem to have much better fluxes in them than my
20+ year old rosin solder. I like the PIDG series of connectors from
AMP. Mostly I just crimped them but they do solder easily. The push on
ones lock onto spade terminals very well.
I cleaned off the spark plugs and ran the engine again yesterday. I was
able to get it started easier but it still seemed like it was loading up,
running too rich, even when I leaned until I got an RPM reduction and EGT
increase. Could be my imagination but I'm going to fiddle with things a bit
more. I may get new spark plugs one number hotter.

My calculations for compression ratio comes out to 9.7 to 1. I wonder if I
should be running higher octane fuel? I am using regular unleaded right
now. I don't know much about how much compression ratio is too much for
regular unleaded. I don't detect any detonation or pre-ignition. No
knocking at low RPM or during my first flight running high power settings.
Despite high EGT the engine seemed to be running smooth as silk.

9.7 is exactly the CR of the soob as well and it is fine on regular
mogas which it was designed to run on but with a knock detector that
will retard the ignition if needed. So far the knock sensor has not
activated. Some 9.7 engines will require high octane fuel as combustion
chamber design and things like ignition timing have significant effect.
Some guys put the original knock sensor in and measure its output with a
voltmeter or dedicated display. Lots of guys just put high octane in
whether there is a need or not and I'd probably do the same with a
modified engine without other's experience to draw on or a knock sensor.
With regular gas it probably makes sense not to advance the ignition
timing too far and not to emply vacuum advance. I might also go easy on
the throttle when the temps are high but that is intuitive for operating
any engine.
I had to re-read Ken's note about high EGT with a too rich mixture since
it's contrary to what usually happens with mixture and EGT. Normally, as
you lean, EGT rises, and as you enrichen, EGT decreases. But I hadn't
thought about the condition Ken describes about an excessively rich mixture
causing unburned fuel (not burned in the combustion chamber) to continue
burning in the exhaust increasing EGT. That does seem like a reasonable
possibility.

The engine quitting on the landing roll-out was definitely my throttle stop.
I was able to reproduce it. Simple fix.

Mike
044SR

I did see some indications that I loaded up the cylinders a bit during
ground running but all has been fine since I started flying it. A very
cheap oxygen sensor and voltmeter will also confirm that you can adjust
the mixture back and forth across the 14.7:1 range but you need a
reasonable length exhaust stack to use one. The plugs don't lie though,
if they continue to carbon up you know it is too rich.

Ken






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Bob Patterson

[rebel-builders] The continuing V8 SR Saga

Post by Bob Patterson » Sun Feb 19, 2012 11:16 am

Hi Mike !

I'm enjoying the adventure too ! We're all learning a bunch as
we go !!! I've recently (re-)learned that high engine temps can be caused
by lean mixture from loose bolts holding the injector assembly to
the manifold ! This also reduces power ... :-(

Just wondering - can your engine be run with BOTH pumps OFF - just
on gravity feed ??? This would tell you if it's the pumps putting
in too much fuel .... Would mean cleaning plugs, running up, and
pulling a few to check - might be worth it. If that's ok, the next
suspect might be the manual mixture setup - possibly too rich by
default, or maybe jets ..

--
......bobp
http://bpatterson.qhealthbeauty.com
http://apatterson2.qhealthzone.com
http://apatterson2.qbeautyzone.com

-------------------------------orig.-------------------------
On Monday 09 October 2006 09:38 pm, Ken wrote:
Mike Kimball wrote:
Hope I'm not boring too many of you but I thought I'd keep everyone up to
date on my progress. Especially since I keep getting such great ideas and
comments.

58 degrees outside this morning, in October, and here I am stuck at work!
I
don't think I mentioned it before but on the day of my first flight my prop
controls weren't working. But the prop was at fine pitch and I decided to
go anyway. Pretty stupid now that I know how bad a prop with too fine a
pitch can be. A little ignorance can get you into a world of trouble.
Anyway, I think I finally figured out what was wrong. The wires that
control the prop connect to brushes with crimp on paddle connectors. For
some reason, the connectors I was able to get locally fit quite loosely.
For that reason I added solder to the connectors then ground them down
until
they fit tightly. Unfortunately, the solder fell off on one connector. I
knew I couldn't trust them to stay put so I slathered silicon around them
to
keep them in place. I must have used the wrong kind of silicon because it
never hardened up. But the connectors were still in place. Why didn't the
prop work? I pulled the connectors out and cleaned off all of the silicon.
While fiddling with them one of the connectors broke off with very little
pressure applied. I wonder if applying the solder heat treated the metal
and made it brittle. Perhaps it was ready to break already and wasn't
making a good connection. I'm going to try to find new connectors that fit
better today. Then I'll apply Household GOOP which I've used before for
stuff like this. I know it will harden up and stay put.

I'm enjoying your adventure Mike!
Heating and cooling metal in air normally removes heat treating. It's
the fast cooling in oil or water that usually hardens metal. For tricky
stuff the new solders seem to have much better fluxes in them than my
20+ year old rosin solder. I like the PIDG series of connectors from
AMP. Mostly I just crimped them but they do solder easily. The push on
ones lock onto spade terminals very well.
I cleaned off the spark plugs and ran the engine again yesterday. I was
able to get it started easier but it still seemed like it was loading up,
running too rich, even when I leaned until I got an RPM reduction and EGT
increase. Could be my imagination but I'm going to fiddle with things a
bit
more. I may get new spark plugs one number hotter.

My calculations for compression ratio comes out to 9.7 to 1. I wonder if I
should be running higher octane fuel? I am using regular unleaded right
now. I don't know much about how much compression ratio is too much for
regular unleaded. I don't detect any detonation or pre-ignition. No
knocking at low RPM or during my first flight running high power settings.
Despite high EGT the engine seemed to be running smooth as silk.

9.7 is exactly the CR of the soob as well and it is fine on regular
mogas which it was designed to run on but with a knock detector that
will retard the ignition if needed. So far the knock sensor has not
activated. Some 9.7 engines will require high octane fuel as combustion
chamber design and things like ignition timing have significant effect.
Some guys put the original knock sensor in and measure its output with a
voltmeter or dedicated display. Lots of guys just put high octane in
whether there is a need or not and I'd probably do the same with a
modified engine without other's experience to draw on or a knock sensor.
With regular gas it probably makes sense not to advance the ignition
timing too far and not to emply vacuum advance. I might also go easy on
the throttle when the temps are high but that is intuitive for operating
any engine.
I had to re-read Ken's note about high EGT with a too rich mixture since
it's contrary to what usually happens with mixture and EGT. Normally, as
you lean, EGT rises, and as you enrichen, EGT decreases. But I hadn't
thought about the condition Ken describes about an excessively rich mixture
causing unburned fuel (not burned in the combustion chamber) to continue
burning in the exhaust increasing EGT. That does seem like a reasonable
possibility.

The engine quitting on the landing roll-out was definitely my throttle
stop.
I was able to reproduce it. Simple fix.

Mike
044SR

I did see some indications that I loaded up the cylinders a bit during
ground running but all has been fine since I started flying it. A very
cheap oxygen sensor and voltmeter will also confirm that you can adjust
the mixture back and forth across the 14.7:1 range but you need a
reasonable length exhaust stack to use one. The plugs don't lie though,
if they continue to carbon up you know it is too rich.

Ken


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Mike Kimball

[rebel-builders] The continuing V8 SR Saga

Post by Mike Kimball » Sun Feb 19, 2012 11:16 am

It wouldn't run on gravity feed in my shop using a jerry can with 5 gallons
of fuel sitting on a ladder a bit higher than the wing tanks. The pressure
gauge at the carb inlet showed no pressure at all. But it would be an
interesting test to see what happens anyway - on the ground. I don't know
if I have the guts to try it in flight just yet. It would be hugely
comforting if it does run with both pumps off.

As long as the fuel pumps are not overcoming the floats in the carb float
bowls I sorta thought the fuel pumps wouldn't be supplying too much fuel.
They just keep the float bowls full of fuel. Of course, with the engine
running at high power settings the fuel is likely drawn out of the float
bowls so fast that the float needles are continuously off the seat. Too
high a pressure from the pumps under those conditions probably would be a
problem. The funny thing is, I started having a problem with flooding and
too rich a mixture during taxi tests. The first few taxi tests showed no
problem. Then later ones started giving me starting problems and rich
mixture indications. Maybe the early ones were OK because I hadn't
sufficiently fowled the plugs yet. I was rarely over 2000 RPM for taxiing
so I would have thought there would have been normal float operation. Of
course, a pressure regulator is a cheap and easy addition. Maybe I'll just
go get one.

My mixture plate on the primary side is definitely an experimental mod to
the carb and could be the problem. There aren't any primary jets because of
the plate unless you count the secondary metering plate which has fixed
orifices instead of replaceable jets.

Mike

-----Original Message-----
From: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com] On Behalf Of Bob
Patterson
Sent: Monday, October 09, 2006 5:54 PM
To: rebel-builders@dcsol.com
Subject: Re: [rebel-builders] The continuing V8 SR Saga


Hi Mike !

I'm enjoying the adventure too ! We're all learning a bunch as
we go !!! I've recently (re-)learned that high engine temps can be caused
by lean mixture from loose bolts holding the injector assembly to
the manifold ! This also reduces power ... :-(

Just wondering - can your engine be run with BOTH pumps OFF - just
on gravity feed ??? This would tell you if it's the pumps putting
in too much fuel .... Would mean cleaning plugs, running up, and
pulling a few to check - might be worth it. If that's ok, the next
suspect might be the manual mixture setup - possibly too rich by
default, or maybe jets ..

--
......bobp
http://bpatterson.qhealthbeauty.com
http://apatterson2.qhealthzone.com
http://apatterson2.qbeautyzone.com

-------------------------------orig.-------------------------
On Monday 09 October 2006 09:38 pm, Ken wrote:
Mike Kimball wrote:
Hope I'm not boring too many of you but I thought I'd keep everyone up to
date on my progress. Especially since I keep getting such great ideas
and
comments.

58 degrees outside this morning, in October, and here I am stuck at work!
I
don't think I mentioned it before but on the day of my first flight my
prop
controls weren't working. But the prop was at fine pitch and I decided
to
go anyway. Pretty stupid now that I know how bad a prop with too fine a
pitch can be. A little ignorance can get you into a world of trouble.
Anyway, I think I finally figured out what was wrong. The wires that
control the prop connect to brushes with crimp on paddle connectors. For
some reason, the connectors I was able to get locally fit quite loosely.
For that reason I added solder to the connectors then ground them down
until
they fit tightly. Unfortunately, the solder fell off on one connector.
I
knew I couldn't trust them to stay put so I slathered silicon around them
to
keep them in place. I must have used the wrong kind of silicon because
it
never hardened up. But the connectors were still in place. Why didn't
the
prop work? I pulled the connectors out and cleaned off all of the
silicon.
While fiddling with them one of the connectors broke off with very little
pressure applied. I wonder if applying the solder heat treated the metal
and made it brittle. Perhaps it was ready to break already and wasn't
making a good connection. I'm going to try to find new connectors that
fit
better today. Then I'll apply Household GOOP which I've used before for
stuff like this. I know it will harden up and stay put.

I'm enjoying your adventure Mike!
Heating and cooling metal in air normally removes heat treating. It's
the fast cooling in oil or water that usually hardens metal. For tricky
stuff the new solders seem to have much better fluxes in them than my
20+ year old rosin solder. I like the PIDG series of connectors from
AMP. Mostly I just crimped them but they do solder easily. The push on
ones lock onto spade terminals very well.
I cleaned off the spark plugs and ran the engine again yesterday. I was
able to get it started easier but it still seemed like it was loading up,
running too rich, even when I leaned until I got an RPM reduction and EGT
increase. Could be my imagination but I'm going to fiddle with things a
bit
more. I may get new spark plugs one number hotter.

My calculations for compression ratio comes out to 9.7 to 1. I wonder if
I
should be running higher octane fuel? I am using regular unleaded right
now. I don't know much about how much compression ratio is too much for
regular unleaded. I don't detect any detonation or pre-ignition. No
knocking at low RPM or during my first flight running high power
settings.
Despite high EGT the engine seemed to be running smooth as silk.

9.7 is exactly the CR of the soob as well and it is fine on regular
mogas which it was designed to run on but with a knock detector that
will retard the ignition if needed. So far the knock sensor has not
activated. Some 9.7 engines will require high octane fuel as combustion
chamber design and things like ignition timing have significant effect.
Some guys put the original knock sensor in and measure its output with a
voltmeter or dedicated display. Lots of guys just put high octane in
whether there is a need or not and I'd probably do the same with a
modified engine without other's experience to draw on or a knock sensor.
With regular gas it probably makes sense not to advance the ignition
timing too far and not to emply vacuum advance. I might also go easy on
the throttle when the temps are high but that is intuitive for operating
any engine.
I had to re-read Ken's note about high EGT with a too rich mixture since
it's contrary to what usually happens with mixture and EGT. Normally, as
you lean, EGT rises, and as you enrichen, EGT decreases. But I hadn't
thought about the condition Ken describes about an excessively rich
mixture
causing unburned fuel (not burned in the combustion chamber) to continue
burning in the exhaust increasing EGT. That does seem like a reasonable
possibility.

The engine quitting on the landing roll-out was definitely my throttle
stop.
I was able to reproduce it. Simple fix.

Mike
044SR

I did see some indications that I loaded up the cylinders a bit during
ground running but all has been fine since I started flying it. A very
cheap oxygen sensor and voltmeter will also confirm that you can adjust
the mixture back and forth across the 14.7:1 range but you need a
reasonable length exhaust stack to use one. The plugs don't lie though,
if they continue to carbon up you know it is too rich.

Ken


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Locked