Ayuh,......... I Know,........ But, Just How Crazy Is It.??

[Bondo]

On this refit I'm doing on My Old Town, Atlantis,.... I'd Really like to move the engine Forward,.. 2'....<br /><br />Well,... In the Bone Piles that I've been able to forage thru, a Jackshaft system is Really Hard to Find,.. Much less a Jackshaft drive for a SBC/ Alpha 1 drive..............<br />I've toyed with the Idea of building it from the ground Up,.. But,.. Man, It's ALOT of Work....<br /><br />Well,... During 1 of My regular ebay searches, I found this.....<br />

<br /><br />Granted,.. It's Only 1' longer than stock,.....<br />But, It got Me to Thinking,.... Again...... <br /><br />Why can't I cut,+ Splice in a 2' stick into the middle of a stock driveshaft.......<br />I'm pretty tight with the fella who runs 1 of the local Driveshaft Shops here,.. I could do the welding on his lathe to keep it straight,+ Balance it when done....<br /><br />It would make Aligning the motor a Royal Pain,.. But, I Think I can do it.....<br /><br />I Think I could Loose a couple of Bearings,+ a couple of U-joints........<br /><br />Even though this pc. is to move the Drive Back,...<br />Can anybody think of any Reasons I can't use something like it to move the engine Forward ?????

 

[craze1cars]

Re: Ayuh,......... I Know,........ But, Just How Crazy Is It.??

Of course it can be done. This is not much different than creating a stretch Lincoln or Hummer limo...just make a longer driveshaft. Many of these conversions involve multiple driveshafts/u-joints...but you're only talking 2 feet, not 20 feet, so I'm sure you can easily keep it a single. Sounds like you have lots of patience and fabrication skills. That's all it takes. Since you'll be flying by the seat of your pants, you can expect problems along the way.<br /><br />Proper balance will be absolutely critical, but if you have access to driveshaft manufacturer's shop, you can lick that no prob. The only suggestion I might have is that you'll maybe need to fabricate some type of support for the middle of the driveshaft (like a second gimbal bearing, maybe?) Then again, 2 feet is not that much of a stretch...and if this is a solid driveshaft, you may not need the support either. But a center support would also help with your alignment challenge. Maybe just relocating the one gimbal bearing further back? I dunno...give it a go...<br /><br />Do it, man!

 

[Laddies]

Re: Ayuh,......... I Know,........ But, Just How Crazy Is It.??

Bondo, I'm not sure on an I/O but what would take up the alingnment problems cause by tramsom flex--Bob

 

[rabidfish]

Re: Ayuh,......... I Know,........ But, Just How Crazy Is It.??

I think you could do it also, but I agree with Crazee, get another carrier bearing on it. <br /><br />If you put it close to your repair, you would be assured the only force on it is torsion. I am certain a good welding job can handle that. I am not as certain of tension, but again that can be solved by holding the shaft straight.<br /><br />I would also recommend you take the boat out and run it hard before giving it back to your customer... just for safety's sake...

 

[TilliamWe]

Re: Ayuh,......... I Know,........ But, Just How Crazy Is It.??

I am in the "carrier bearing" crowd. Just a little support in the middle of a long straight shaft, can't hurt, can it?<br />On semi trucks, they put a carrier bearing & a second driveshaft. While two shafts might be a little too complicated for your tastes, maybe it would solve some problem in the long run? I mean, I don't know, but is Bob's concern valid? A lot of transom flex? Two shafts with a CV joint would help that. Good luck

 

[tommays]

Re: Ayuh,......... I Know,........ But, Just How Crazy Is It.??

i would say based on machinery driveshaft repiar its going to break if welded we have never been able to weld one that lasted the weld just seams to stress it self out like a dog chaseing its tail<br /><br />and thats two welds you have to worry about <br /><br />even when we make new ones if we dont start with a stress relieved shaft they will fail much faster<br /><br />i think the u-joints and standard tube drive shaft would be much stronger<br /><br />tommays

 

[flashback]

Re: Ayuh,......... I Know,........ But, Just How Crazy Is It.??

Pretty neat idea Bondo, I don't know anything about welding so what I'm about to say may be dumb, but, can you get a good weld on a 1 inch+ solid shaft? wonder how hard it would be to make a solid shaft to start with and then just weld the yoke on? Wish I could help ya more..

 

[Don S]

Re: Ayuh,......... I Know,........ But, Just How Crazy Is It.??

With a normal length splined shaft like that, the back of the engine is mounted on the transom shield and only the front of the engine is used for alignment. With the loooooooong shaft, you will also need a loooooooong alignment bar and have to be Very, Very, accurate in the alignment.<br />ANY vibration at all in the coupler would probably be amplified and things may start coming apart at higher rpms.<br />Looks scarry to me.

 

[bluewater19]

Re: Ayuh,......... I Know,........ But, Just How Crazy Is It.??

I think that stingray did a jackshaft/alpha drive combo on their 20' center console.<br />You could try talking to a stingray tech.<br />Just a thought.

 

[newport dave]

Re: Ayuh,......... I Know,........ But, Just How Crazy Is It.??

Some of the go-fast offshore type boats with mutliple engines have a forward mounted engine. Maybe you could get some tips by researching how they do it.<br /><br />Dave<br /><br />

 

[cc lancer]

Re: Ayuh,......... I Know,........ But, Just How Crazy Is It.??

Bondo:<br />I have the utmost faith that you can make it work, may be a pillow block in the middle for support.<br />I have heard of broken cranks welded back together and lived. There are shops that balance drive-shafts here to over 200 MPH. If people didn't experiment things would never be invented.

 

[flashback]

Re: Ayuh,......... I Know,........ But, Just How Crazy Is It.??

maybe the rear axle out of a differential will fit.

 

[Bondo]

Re: Ayuh,......... I Know,........ But, Just How Crazy Is It.??

Well guys,......A Couple Days ago,.. I had the time to type out a Looong reply to the feedback that you've given....... <br />Before I clicked "Add Reply",.. I needed a new window to look at something else,.. More Info for My ideas,... <br /><br />Ayuh,.................Clicked the "Back Button" Instead....... POOF,.. Gone..... I Gave Up.....<br /><br />After talking with some Buds,.... You Guys are Right......<br />Bad Idea.... That shaft is Extremely Expensive.... And Only ava. 1' over length.....<br />Custom Built would the Twice the Money for the extra Foot.........<br /><br />The day after I posted this thread, I was looking over some different Bellhousings I have around.......<br />I found 1 that wasn't a Merc.,.. No rear motor mounts....<br />Just a round hole,+ 6 studs.....<br />Bob stopped over about that time,+ mentioned he thought that he pulled that off an old OMC that was junked out a few years ago......Might have been a Cobra, or King Cobra......<br /><br />Anyway,.. Later that day, Bob was down to Chris's Marina, talking boats,+ parts with Chris...... He mentions to Chris what I'm looking to do,+ they went,+ checked on a 2' shaft,..... That's where I got the Price Info.......<br />So,.. further into the conversation, Chris finally tells Bob, He's got 1/2 of what I'm looking for, On his Shop Floor,..... <br />$200.00, Out the Door............. <br /><br />Now,.. I've Got the Jackshaft, the Bearing Carrier,+ the Coupler pc. that connects the Input shaft on the outdrive........<br />Everything, Up to the Forward Jackshaft Flange.........<br /><br />What I'm still in need of is Everything Between the engine Flywheel,+ the Jackshaft.........<br />Which should include the Pilot Bushing, Proper Coupler, Flywheel Housing , the Bearing Housing,+ the Output Shaft that connects from the coupler to the jackshaft......<br /><br />Which brings Me to the Next Question I have,............<br /> <br />This Flywheel housing I've got, with the 8 1/8th" Hole in the center, with 6 studs at 9 1/4" centers, in a pattern that would suggest it should have 8 bolts, but the top 1,+ the bottom 1 is missing...........<br /><br />Is this some sort of "Standard" bolt pattern for inboard transmissions,+ the like ????<br /><br />Thanks Again Guys.............