Hurth Vs Borg ?

[MOP]

Starting to kick around ideas for trannies and mounting the Arneson on the 22. I am leaning toward a Hurth due to it being shorter than a borg and it should do away with most of of the shaft angle. Has anyone put any power & RPM to a Hurth? Thinking of the 1.5 drop unit.

[BUIZILLA]

Your going to do WHAT?

[MOP]

Jim I bought Teds drive, depending on the condition of the transom on the 22 when I get it apart I will either go re-do of the transom or extension box. Not sure which will produce the best results. I have a few Borgs available but I am leaning toward a Hurth with the drop as the drive has no drop. If my measurements are fairly close the engine will not move much if any forward, the Hurth is pretty short. For now the Tempest will do, but who knows what is in the future. Don't need to go as quick as some but 50 cruise is my present goal. Right now I am gathering thoughts from those that have been there! Major Learning Curve! Have been intrigued with the A drives for many years.

Phil

[McGary911]

Hmmmm.....Do I detect an old dog zeroing in on some new tricks? wink No wonder you're feeling the waters for a 16 price. 22 with an arneson would be sweeeet. What kind of power are you thinking? BBC, or staying with Ford power? And how much of it?

[MOP]

Boats got a 300 Tempest SB, I am very partial to SB's. Tempest is in good shape will do for now, all I want is 50 mph cruise, will shoot for 75+ later. Got an eye on 377 385, should be enough to make me smile. Above that is for the the young LIONS we know who fits into that elite group!

Phil

[BigGrizzly]

I can answer that question. the borg is much stronger! there are a couple of botgs as you know the 10-17 ia 5 1/2 inches shorter than the 10-18 but is at least 25% stronger tham the hurth in stock form.

[CDMA]

Go Borg or go home....

[MOP]

Ok now leaning toward the Borg, need to do some research on getting things low enough for the drive, Ted says 15 degrees off straight into the drive is max. I am thanking my lucky stars that a few of the members can give me A drive help. Since I have an Alpha hole and a straight drive I will have to have a box fabbed. When Chis get caught up a bit I will enlist his help with that issue. Thats what he gets for living so close!

[rustnrot]

As for high rpm, I'd go Hurth ZF. Toyota used Hurth reductions in their (now abandoned) ski boats with the Northstar engine. And www.rotarypowermarine (http://www.rotarypowermarine) uses it behind their marinized Mazda rotaries (of which I have one sitting here in the garage waiting on a project boat....anybody got a spare Baby 14?) Both the aformentioned engines are high rpm engines, the Hurth is good for a sustained 6k-6.5k rpm.

[MOP]

Thanks Griz Tom for more inputI spent awhile looking over the Borgs, it does not appear that they drop as low as the Hurth/ZF which is a major issue with the straight A drive. I can cut the angle down a bit with a box and longer shaft but am concerned about CG. Weight, drop and length. Low and strong, boy do I need HELP! :confused:

[Forrest]

Hay MOP, I wonder if Chris, or GEOO, or some other Arneson guru knows the answer to this: Can your non-drop-box style ASD-6 be economically converted to a drop-box style ASD-6? That would solve your crank/transmission output height problem.

[CDMA]

Forrest,

I think the tailshaft is the same but the transom part is not the same and not easily converted.

Chris

[MOP]

HP600 says it can be done with the Hurth, he has a buddy doing it in boat he builds. I have not ruled out any option, am also looking into Aquadrive couplings. I want to keep the CG as far aft as possible and have a good strong drive train for a bit more power later. I do like the Borgs many of the boat I worked on over the years had 20 year old units still ticking.

[ZF-Mac]

MOP,

Hurth is now Zed F. I run a factory branch for ZF in Port Canaveral Fl. If I can be of any help, Let me know. There are many varations of the Hurth line, many pump choices, and even some units that have shot peened gears. Look at our web site. zf-marine.com. Look at the zf80 and the zf 80a for a down angle. You can also download drawings from the site. Toyota was using zf 63's and 80's with a high speed pump to lower cavatation at high RPM's in the hyd system. Let me know if I can help. tim.mcfarland@zf.com