Allison Teen
Member
Looking for some opinions, and insight, into the best way to install a Bob's nose cone on a gearcase, and any geometry, tweaks, modifications that should be done.
I'm currently building a 2.0 V6 to replace the inline 6 1500 on my 15R Allison, after 10 years of running that, its time for something new. The V6 is being built from the ground up, 15" mid, mild powerhead mods, and coned 200 case is what I've decided on with research to be a good lower unit to start with.
I've got a 200 C1 big bearing gearcase, and a new Bob's nose cone. The cone needs to be notched to clear the big trim ram, the installation and welding will be done by a certified welder under my guidance, not gluing it on. I am an engineer and machinist, so fixturing and aligning the cone isn't out of my league.
I'm looking for insight from you guys, as to where best to position the cone, and any modifications and shaping that work well on these Vee's. Currently from some reading I've done elsewhere, positioning the cone dead center is obvious. Height wise I've seen mention of the cone being 1/16" higher than the propshaft centerline, or 3/16" lower. I also just found reference on S&F that the Red Book, from Allison, states a CLE blows out around 90mph, and to install a cone 3/8" below the prop shaft CL.
I would appreciate some insight on this topic. If you are someone that has secret tricks, send me a message.
Thanks
I'm currently building a 2.0 V6 to replace the inline 6 1500 on my 15R Allison, after 10 years of running that, its time for something new. The V6 is being built from the ground up, 15" mid, mild powerhead mods, and coned 200 case is what I've decided on with research to be a good lower unit to start with.
I've got a 200 C1 big bearing gearcase, and a new Bob's nose cone. The cone needs to be notched to clear the big trim ram, the installation and welding will be done by a certified welder under my guidance, not gluing it on. I am an engineer and machinist, so fixturing and aligning the cone isn't out of my league.
I'm looking for insight from you guys, as to where best to position the cone, and any modifications and shaping that work well on these Vee's. Currently from some reading I've done elsewhere, positioning the cone dead center is obvious. Height wise I've seen mention of the cone being 1/16" higher than the propshaft centerline, or 3/16" lower. I also just found reference on S&F that the Red Book, from Allison, states a CLE blows out around 90mph, and to install a cone 3/8" below the prop shaft CL.
I would appreciate some insight on this topic. If you are someone that has secret tricks, send me a message.
Thanks
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