mnm99
Well-Known Member
How many of you torque your inboard props? If so, What are the specs for a 1 1/2" shaft? If not , just crank it down???
Thanks
Thanks
How many of you torque your inboard props?
- Thread starter mnm99
- Start date
Woody
Well-Known Member
My owners manual has a prop nut torque chart for shafts 1" thru 2.5". For a 1.5" shaft it shows for 'bronze nuts'...prop nut 250-275ftlbs, jam nut 100ftlbs.
My shafts are 2" and that chart says 325-350ftlbs, I'm not getting them that tight but they don't loosen up. I just lap the props, and guesstimate the torque using 24" wrenches, some pulling, and some smackin' with a 3.5# hand maul.
mnm99
Well-Known Member
Thanks, I just found that in the manual. I have to see what my torque wrench goes up too. I don't think it's 250. Wonder how much a socket costs..lol. When I had my props done, my prop guy said wedge a piece of wood as close to the hub as possible and do not let it rest on the tip of the blades when tightening. They could bend the props when installing. I'm going to see how I can do that also.
mnm99
Well-Known Member
Just finished . In this order
-Large nut first to 250ftlb
-Remove large nut, install small nut, torque to 125ftlb
-a dab of 4200, install large nut and torque to 250 ft lbs
-Install cotton pin
I read a couple places about the 4200. I figure it would give accurate torque and also a little assurance to keep the nut on.
-Large nut first to 250ftlb
-Remove large nut, install small nut, torque to 125ftlb
-a dab of 4200, install large nut and torque to 250 ft lbs
-Install cotton pin
I read a couple places about the 4200. I figure it would give accurate torque and also a little assurance to keep the nut on.
shogun95
Member
Be careful if the 4200 acted like a lubricant to the large nut. Approximately 80% of torque goes to overcoming friction and 20% goes to stretching the shaft. If the 4200 acted like a lubricant, you may have significantly exceeded the shaft stretch and essential over torqued the nut.
mnm99
Well-Known Member
Good Thought. I torqued to 250 and the specs are 250-275. After I seated the prop with the large nut at 250, no lube or 4200 I installed the small nut to 125 then put a dab of 4200 and torqued the large again to 250. The spec is 250-275. I was able to get that with or without the 4200 pretty easy. I happen to have a 250lb torque wrench. Most people just crank them down and call it a day. Now you have me thinking....:smt009. I stress about things like this. How much more torque could it have put on?
I kinda went by this guy.
http://www.sbmar.com/articles/propeller-installation-big-nut-vs-little-nut/
And this guy
http://stevedmarineconsulting.com/propeller-installation/
Both use some sort of lubricant. :huh:
EDIT... I ended up removing both nuts and cleaning good. Reinstalled dry and re-torqued.
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