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Stan this is more directed to you and Jeremy. We have the G engine/prop and not the GSP full feather engine/prop arrangement, as does Jeremy's boat. The pitch control is mounted in the cockpit. The prop pitch lever neutral position is vertical. For the discussion, let's call this zero degrees. The prop pitch control lever can moved in a "forward arc" of about 120 degrees and 120 degrees "aft arc" when the prop is reversed, i.e. the lever travel from full forward to full reverse is about 240 degrees. At present there is no pitch stop screw on the engine, hence I ordered one from Bill Miller. I believe I have been "over pitching" the prop. When you have the engine rpm set at 1500, where do you set the lever for your G engine? I believe the best pitch for our engine/prop is when the lever is either 90 degrees forward or 90 degrees aft.
After I wiped "egg off my face" the other day, I tested the engine and experimented with the prop setting. When the lever is pushed to the full 120 degree forward position, engine rpm would not exceed 1200 at full throttle even though the engine exhaust was not sprewing black smoke. When I decreased the pitch setting to 90 degree forward control, I was able to obtain 1800 engine rpm. I did the test at the dock and need to repeat the test underway but for now, your input is appreciated.
I know you will ask about "egg on my face." When I replaced the water pump diaphragm in March, I used the old diaphragm orientation to the engine as a guide. After carefully reading the manual, I discoved this was backwards. The letters on the diaphargm should face the engine. I did this work in conjunction to the check valve work. Norway Sabb, works at their schedule, hence I turned down one of the check valves from 23 mm to 22.5 mm diameter so it fit the recessed seat in the valve body. I also lapped both plactic valves to the check valve housing with very fine grinding compound. By lapping the valves in place I was able to achieve a very good fit, i.e little if any blow-by of air when I blew into the assembled check valve.
After I installed the pump and check valve assembly, I ran the engine for 30 minutes at the dock. If I do not "over pitch" the propeller, the engine temperature stays in the green at all engine rpm when under load. At 1500 rpm and 90 degree setting on the prop pitch control, the engine is moving water aft for an estimated distance of 40 ft. based on the surface eddies in the water.
Because I am unfamiliar with the Sabb engine, I know I have many questions and wish to thank Jeremy and you for your time to replie to my questions.
Fair Winds,
Rod
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Rod,
I do not have a tachometer, so I cant place my performance with regard to RPM. I generally found myself using different prop pitches depending upon conditions and engine load. When motoring in flat conditions I usually used full forward pitch. When motoring into seas, I sometimes backed of the pitch, but not as far back as 90 deg. When reversing, I always use significantly less pitch, say 45-60 deg. These three cases indicate that slip is a factor in selecting optimum pitch; that is the relative speed of the prop in the water. When motoring while the refrigeration compressor is engaged or the alternator was working hard, I use something near 90 deg. I did install an alternator field disconnect for times where I wanted all available horsepower for the prop. In choosing pitch I considered RPM (gauged by ear), engine temperature, exhaust gas color, and exhaust water color.
Regards,
Jeremy
-----Original Message----- From: Rod Bruckdorfer [mailto:seagypsy@att.net] Sent: Thursday, August 23, 2001 4:27 PM To: bcc@yahoogroups.com Subject: [bcc] Sabb Prop Pitch - To Pitch or Not To Pitch, That Is The Question .....
Stan this is more directed to you and Jeremy. We have the G engine/prop and not the GSP full feather engine/prop arrangement, as does Jeremy's boat. The pitch control is mounted in the cockpit. The prop pitch lever neutral position is vertical. For the discussion, let's call this zero degrees. The prop pitch control lever can moved in a "forward arc" of about 120 degrees and 120 degrees "aft arc" when the prop is reversed, i.e. the lever travel from full forward to full reverse is about 240 degrees. At present there is no pitch stop screw on the engine, hence I ordered one from Bill Miller. I believe I have been "over pitching" the prop. When you have the engine rpm set at 1500, where do you set the lever for your G engine? I believe the best pitch for our engine/prop is when the lever is either 90 degrees forward or 90 degrees aft.
After I wiped "egg off my face" the other day, I tested the engine and experimented with the prop setting. When the lever is pushed to the full 120 degree forward position, engine rpm would not exceed 1200 at full throttle even though the engine exhaust was not sprewing black smoke. When I decreased the pitch setting to 90 degree forward control, I was able to obtain 1800 engine rpm. I did the test at the dock and need to repeat the test underway but for now, your input is appreciated.
I know you will ask about "egg on my face." When I replaced the water pump diaphragm in March, I used the old diaphragm orientation to the engine as a guide. After carefully reading the manual, I discoved this was backwards. The letters on the diaphargm should face the engine. I did this work in conjunction to the check valve work. Norway Sabb, works at their schedule, hence I turned down one of the check valves from 23 mm to 22.5 mm diameter so it fit the recessed seat in the valve body. I also lapped both plactic valves to the check valve housing with very fine grinding compound. By lapping the valves in place I was able to achieve a very good fit, i.e little if any blow-by of air when I blew into the assembled check valve.
After I installed the pump and check valve assembly, I ran the engine for 30 minutes at the dock. If I do not "over pitch" the propeller, the engine temperature stays in the green at all engine rpm when under load. At 1500 rpm and 90 degree setting on the prop pitch control, the engine is moving water aft for an estimated distance of 40 ft. based on the surface eddies in the water.
Because I am unfamiliar with the Sabb engine, I know I have many questions and wish to thank Jeremy and you for your time to replie to my questions.
Fair Winds, Rod
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Rod, I go along with Jeremy on pitch. My engine does
have a pitch stop screw but I have it backed all the
way off and set the pitch by conditions.
I’m afraid I’m not much help here because I have
neither temp gauge or rpm meter. I generally set the
speed and pitch by ear (very fast rpm is only for
emergencies)and vibration. Its what I call a ‘happy’
setting, i.e. least vibration and pleasant sounding
rpm.
I did borrow a hand held tach once and ran the engine
up to 1800. Scared the hell out of me. Sounded like a
sewing machine. I have no doubt I’m running the engine
too slow for its own good. I’d guess it to be in the
neighborhood of 1200 to 1400 with enough pitch to
motor in calm seas at 5 knots.
This probably isn’t very helpful information. But keep
in mind the engine is extremely sturdy. If you keep
oil in the pan to splash around, fuel to the injector
and enough water to keep it below boiling the thing
will run forever.
Were you aware that the reason almost all lifeboats on
passenger ships used to carry Sabb engines was the
requirement the engine had to be capable of starting
while the lifeboat was still in its davits and run
without overheating for three minutes without damaging
the engine.
fair winds,
Stan
— Rod Bruckdorfer <seagypsy@att.net > wrote:
Stan this is more directed to you and Jeremy. We
have the G engine/prop and not the GSP full feather
engine/prop arrangement, as does Jeremy’s boat. The
pitch control is mounted in the cockpit. The prop
pitch lever neutral position is vertical. For the
discussion, let’s call this zero degrees. The prop
pitch control lever can moved in a “forward arc” of
about 120 degrees and 120 degrees “aft arc” when the
prop is reversed, i.e. the lever travel from full
forward to full reverse is about 240 degrees. At
present there is no pitch stop screw on the engine,
hence I ordered one from Bill Miller. I believe I
have been “over pitching” the prop. When you have
the engine rpm set at 1500, where do you set the
lever for your G engine? I believe the best pitch
for our engine/prop is when the lever is either 90
degrees forward or 90 degrees aft.After I wiped “egg off my face” the other day, I
tested the engine and experimented with the prop
setting. When the lever is pushed to the full 120
degree forward position, engine rpm would not exceed
1200 at full throttle even though the engine exhaust
was not sprewing black smoke. When I decreased the
pitch setting to 90 degree forward control, I was
able to obtain 1800 engine rpm. I did the test at
the dock and need to repeat the test underway but
for now, your input is appreciated.I know you will ask about “egg on my face.” When I
replaced the water pump diaphragm in March, I used
the old diaphragm orientation to the engine as a
guide. After carefully reading the manual, I
discoved this was backwards. The letters on the
diaphargm should face the engine. I did this work
in conjunction to the check valve work. Norway
Sabb, works at their schedule, hence I turned down
one of the check valves from 23 mm to 22.5 mm
diameter so it fit the recessed seat in the valve
body. I also lapped both plactic valves to the
check valve housing with very fine grinding
compound. By lapping the valves in place I was able
to achieve a very good fit, i.e little if any
blow-by of air when I blew into the assembled check
valve.After I installed the pump and check valve assembly,
I ran the engine for 30 minutes at the dock. If I
do not “over pitch” the propeller, the engine
temperature stays in the green at all engine rpm
when under load. At 1500 rpm and 90 degree setting
on the prop pitch control, the engine is moving
water aft for an estimated distance of 40 ft. based
on the surface eddies in the water.Because I am unfamiliar with the Sabb engine, I know
I have many questions and wish to thank Jeremy and
you for your time to replie to my questions.Fair Winds,
Rod
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