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| Propeller Selection with a difference |
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Message |
    
Bruce Reynolds
Member
Username: the_tassie_devil
Post Number: 90
Registered: 02-2009
| | Posted on Wednesday, October 28, 2009 - 06:01 am: | 
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G'day All,
I have a quandry as to which Propeller to use, when I get my Boat into the water.
I have a choice of three, but two are Aluminium, Light weight, and one is Brass, really heavy.
Seeing as the engine is an Odd-firing 155 HP Buick V6, and has an extremely HEAVY Flywheel, would the Heavy Propeller add to the smooth-running of the unit, or be a hindrance and a power-user?
Thanks,
Bruce. |
Morten Ringvold
Senior Member
Username: haffiman37
Post Number: 4319
Registered: 04-2006
| | Posted on Wednesday, October 28, 2009 - 06:21 am: |
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Brass prop on an OMC sterndrive and in salt water?
Guess You should add 'a ton' of zink as well!
I would anyway have stayed with the alu props.
The heavier the prop, the bigger risk of damaging the lower unit gears if you hit anything. |
Hy Stat
Senior Member
Username: hystat
Post Number: 1532
Registered: 05-2007
| | Posted on Saturday, October 31, 2009 - 10:59 pm: |
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aluminum only on electric shift. Anything heavier can break the clutch tangs during directional shifts. |
charlie
Member
Username: chollyjohn
Post Number: 86
Registered: 05-2008
| | Posted on Sunday, November 01, 2009 - 12:42 pm: |
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I see no reason why you would want to use a heavy weighted brass prop. Harder metal props are good to lessen any deflection under extreme workloads, and in your case, that is not happening. You are best to stay with a lighter prop and aluminum should work well for your needs. The prop would have nothing to do with making your engine run smoother. Basics of engine smoothness factors consist of engine timing, cam design, bore and stroke and # of cylinders, just to name a few. Don't confuse a heavy prop to do the job of a harmonic balancer; they are NOT the same animal. You say odd-firing?...maybe the engine was tuned or built to run in that fashion. Meanwhile, an alum prop keeps excessive weight off the bearings and should you hit something hard or hard bottom, its easier to fix a prop than the engine, gear housing or lower unit. |
Bruce Reynolds
Member
Username: the_tassie_devil
Post Number: 91
Registered: 02-2009
| | Posted on Monday, November 02, 2009 - 04:40 am: |
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Thank you all for the informative replies, and I was thinking on the same lines regards the lightness of the Aluminium Prop, but the Brass one does really look nice.
The Brass one is a Michigan SMC Casting, and fits the Leg exactly the same way as the Aluminium ones, so the next question is if Heavy Props are bar, why would then make them?
But for Charlie, Buick built two types of V6 engines. The first one was a shortened version of the 300 Inch "Nail Head" V8, and it is referred to as being an "Odd-firing" Ignition, because it has an "Odd" firing sequence. They had to install a Flywheel that weighed in at 48 Lbs. to smooth things out. It had common Big End Journals
The next V6 had off-set Big Ends on the same Journals, and use different Bearing Shells, and have a separating "Ring" between opposing Connecting Rods. This engine is referred as to the "Even Firing V6". These engines are smoother-running than the earlier ones and I believe are still being used today.
Bruce. |
Hy Stat
Senior Member
Username: hystat
Post Number: 1535
Registered: 05-2007
| | Posted on Monday, November 02, 2009 - 07:15 am: |
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why would then make them?
I doubt they make them anymore, they would have been made long before your clutch tangs were fatigued from 30 years of shifting
and even then, I suspect a brass omc stringer pin type prop would have been a rare item.
I've seen stainless before, but not brass. |
Bruce Reynolds
Member
Username: the_tassie_devil
Post Number: 92
Registered: 02-2009
| | Posted on Monday, November 02, 2009 - 07:06 pm: |
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Well, looks like I might then have a rare thing, for once.
Maybe I had better bight the bullet and strip down the bottom of the Leg and investigate the condition of the stuff down there as everything else has given me strife, and I haven't even had the thing in the water or going yet.
Bruce.
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Scott Dickson
Advanced Member
Username: corsair23
Post Number: 159
Registered: 11-2006
| | Posted on Monday, November 09, 2009 - 11:57 pm: |
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Stick with the Aluminum Prop. Have it cupped to change the pitch, if so desired. Like I've mentioned, I went from a 16 to 18 pitch.I like the result. |
Bruce Reynolds
Member
Username: the_tassie_devil
Post Number: 95
Registered: 02-2009
| | Posted on Tuesday, November 10, 2009 - 07:33 pm: |
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I will be sticking with the Aluminium ones I have, and at least I have a spare Aluminium one. The Brass one looks like being a really last-resort spare.
Bruce. |
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