Learning 'bout the drives

[DEL51]

Yes, the Q&A is back,Thanks to all who have responded before.I would to like some answers regarding transmissions and how they are used in V-Drive Applications.I have heard of automatic trannies,T-400,Powerglide,etc used.I assume torque converters are not used,how is the tranny coupled to the engine and drive?How does the hydraulic pump in the tranny provide pressure with no converter?Is a special tranny setup needed or can a stock auto unit work ? how is the fluid cooled?What is the better tranny for in this application? What about the manual Trannies and how are they coupled to the engine?Are all the gears used,1st,2nd,etc. Can someone explain an IN/Out Box? What should I look for if a boat as a transmission,is there a way to check out their condition.I have a good basic knowledge of automatic transmissions,less on the standard.Thanks Again!DEL51

[schiada96]

DEl51
I think I can help you on the trans questions. Transmissions civilize a v-drive boat docking, reverse. Most transmissions use a coupler available from art-carr or TCI, TCI also sells hollow converters. These couplers drive the pump on the front of the trans.A flywheel with a drive plate is used to turn the coupler. A stock transmission will work, but most of us use a manual valve body to reverse the shift pattern for saftey. It would be a bad thing to shift into reverse at speed. Transmission oil coolers are available from REX or Eddie marine I run a -10 pickup in the bottom of the boat to cool the trans and v-drive. First gear is a waste of time in my boat. In retrospect I would have used for a long first gear powerglide. I don't know how you would check a transmission in a boat except to smell the fluid or drive the thing.
I hope this helps
[This message has been edited by schiada96 (edited November 28, 2001).]

[Stab-n-Steer]

DEL51,
To add to schiada96's comments, there is an excellent article on AZ Don'd v-drive site about automotive transmissions in boats including parts list. It use to be free but now he charges $10 for the "VVDC" section. It is well worth the $10 if you are serious about this conversion. Go to www.v-driveboat.com (http://www.v-driveboat.com) and click on the VVDC section.
You also might want to consider a Velvet Drive if more than one forward gear is not important... A Velvet Drive is a tranny manufactured by Borg Warner and is used in all the tournament style ski boats. The advantage is that they are smaller and lighter (only 95lbs) than a Powerglide or a turbo. If driveline length is a problem,like it was for me, they are about 10" shorter than the PG's or turbos. They are a planetary gear box that shifts with fluid pressure but mechanically lock up when in gear so there is no slippage... There are two versions; a 71C and a 72C for high horsepower applications. They are pretty available used if you watch the classifieds.
An In-and-Out box is nothing more than a slider gear assembly that bolts to the output of the v-drive allowing a neutral position. You can usually kick it out of gear at an idle but the engine must be off to put it in gear...
Randy

[DEL51]

Thanks for the insight on the trannies.

[Jim S]

DEL51,
I have got a Velvet Drive trans in my ski racer. It looks like a stock 72C. They are rated for about 350 horsepower but I don't remember what the exact torque service is. Right now it is in front of a turbo 454 running about 12 psi of boost. It doesn't slip and the fluid remains nice and pink. If you run enough torque to slip the clutches there is a guy in Florida who sets these trans up for 100 ft-lbs or more.
Let us know if you need more info.
Jim

[Jim S]

DEL51,
I mean 1000 ft-lbs. Sorry for the mistake.
Jim

[Stab-n-Steer]

Jim,
Not to be a know-it-all (but hey I have the book!) The 71C is rated at 310hp and the 72C is rated at 475hp. I think those numbers are pretty conservative. I couldn't find the torque specs however...
Randy

[spectras only]

I have the 72C in my 1972 spectra with the 450 HP LS-6, Ace Champion v-drive ,14x13 prop. Tranny has never needed to be fixed http://free.***boat.net/ubb/biggrin.gif!Del, the 72C is more expensive than the 71C,the 71C was recommended up to 355CU in,the 72C was for BB's.My friend had a 21 schiada with the 71C/BBC LS-6 combo and never had a problem.Used to install a lot of 71C's with LS-6's in the seventies with no problem.Call Dave at california marine,Ph;604 278 1880.He can sell you either unit and give you more info.The 72C's were installed in a lot of log salvage boats with diesel power with tremendous torque with no ill effect.A cooler istallation is a must for longevity.
[This message has been edited by spectras only (edited November 29, 2001).]

[Stab-n-Steer]

Sprectras,
What type of cooler do you run? Is it a heat exchanger type with water running through it like the Mastercrafts, etc use. I have installed an auto tranny type cooler (air) but I'm not sure if that will be sufficiant. I have a temp gauge on the tranny fluid to watch it and I am going to run Red Line ATF which has a much higher temp rating than standard ATF... Since the boat is not quite finished yet I don't know what temp she will run...I guess I'll find out next spring.
Randy

[boatguy222]

schiada96
are shifting from 2nd to 3rd for a better hole shot with your t-400?
Thanks
Marc