I've been a hard core Inboard guy for years, the I/O is a stretch for me & the O/B is beyond a stretch for anyone who knows me thinking I might own an outboard. But lifes boring without experimenting a little. This little boat is #3 in line of projects but it could be a great economical little ski boat again with some creative thinking.
My comment was based on your comment that you were considering converting to an O/B! Here is food your thought: A 250/260 HP Merc I/O (small block V-8) weighs 950 pounds. A Merc 300X outboard with 300 HP weighs 505. You could have 600 outboard HP for the weight of the I/O +60. That is what I have against I/O's. What is your problem with modern outboards? jim :mrgreen:
Modern 4 stroke outboards are nice but very pricey, I can build (3) 320HP inboards for the price of a singe 300 hp ob. But this boat is destined for economy & a lightweight 250 shaft hp V-6 inboard w/ZF gear coubled to a outdrive with locked in "forward" gears is an idea I have tossed around, I haven't heard of it being done before. My 320hp 5.7s with gear weigh in at 595#s
I don't know about the ZF part, but Merc made a forward only drive that required a transmission years ago for performance applications. I don't recall the name of it, and it has been out of production for many years. I think the Bravo made it obsolete. A bravo drive which has a clutch type shift would probably be lighter than the combo you mentioned with no fabbed parts required. You might want to check it out. I can build up a nice 200-250 HP outboard pretty cheaply too. If I choose my parts carefully it could weigh in at 350 or less complete. jim
One more thing, The non shifting outdrive was called a TRS. In those days you could not just lock a regular drive in forward and hook it to a transmission because they were all (Merc) ratcheting drives. The 888 and 898 are ratcheting drives. You will need a non-ratcheting drive and I know that some of the late model Merc outboards are non-ratcheting, but I have no clue about the I/Os. A ratcheting drive is a free wheeling gearbox and it would have no reverse if turned backwards. It would just free wheel. If the drive or outboard is in gear the prop cannot be turned either direction with a non-ratcheting set up. The ratcheting drive will turn in one direction and you will hear it click. jim
I did some more checking and it looks like that locking the outdrive in forward and using a transmission will not work with any Mercury alpha outdrive. The input shaft cannot handle the reverse thrust load and will allow to much clearance in the gears and the consensus is that it will tear itself up. The input shaft would need something like a double tapered roller bearing set up like a car wheel and it does not have that. I suspect the Volvo is the same, but I don't really know how to check. jim
When I looked inside the Alpha drive that came with this boat I came to the same conclusion, this is because of the type of gears used. The input shaft is not the concern its the gears at the foot 1 forward 1 reverse, I think it would work but reverse thrust would be limited or it could tear itself apart. The selection process is based on trying to get rid of a number of "junk" items around here & trun it into something usefull. I have no outboard componets around here.
My Mercury guru just called back this morning. After thinking about it last night he said don't do it. The input shaft will jump up .025 immediately in reverse with no load and there is no provision to carry the upward axial load in the input shaft/bearing. Not to mention the excess bearing clearance right off the bat. It would need a double tapered roller bearing system like on the input shaft of a differential to work. I have always thought that an LS-1 would make a great inboard engine. They are nice and light and the late model alpha drives will handle it. There are marine exhaust manifolds available for that now. jim
Hey Dyners, New guy here. My father bought our dyne new in 1967 (I think). So many of the memories that I associate with childhood include that boat. We skied competitively and performed ski shows behind the dyne throughout the 60's, 70's and 80,s. I learned to ski behind her as a child and now my wife and children have done the same. Unfortunately, my father passed away a few years ago and I gave into the inboard craze. The dyne has been under water several times and has been sitting outside in the elements for several seasons now but for some reason I just couldn't talk myself into letting her go despite pressure from my mother and the rest of the family. Then, I discovered Hydrodiners.Com and must say what a refreshing and unselfish bunch you are. I've been reading many of your posts and have been inspired to do a full restoration on my Hydrodine. Being your typical type-A personality, it will take a while. Mark
