V drive vrs. straight drive

arks

Lieutenant Commander
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Nov 7, 2002
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1,936
I'm looking at a variety of inboard cruisers in the 30- 34' range and wonder if there's any significant advantage with one over the other. The only thing I can think of is the more centralized weight distribution with the straight shaft. Is maintenance an issue with V drives? They look tough to service without pulling the motors. All the vessels I'm considering are used.
 

Ryoken

Petty Officer 2nd Class
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Nov 22, 2003
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Re: V drive vrs. straight drive

V drive allows for the running gear to start closer to the bow which can help hull design from what i understand. allows prop to be placed further under boat. i'm not big on hull design/prop performance and weight distribution so maybe someone will chime in with that info... <br /><br />shaftlogs are generally much more of a nuisance on V's(going dripless is advised). as can be coupling/running gear work depending on what your doing.<br /><br />jackshafted/seperate v drive setups have been notorious for corrosion issues..<br /><br />no additional maintence other than fluid changes, tho the Hurth V does have a replacable filter.<br /><br />from my experience V-drives tend to be much more durable (i'll replace 6 to 10 straight drives a year, can't remember the last bad v-drive i've seen). but V's are not as mechanic friendly sometimes..<br /><br />hope that helps some... i just got done with a rear seal on a Hurth in a 36 Cruisers actually. sheared coupling bolts and they in turn took out the seal.. had to pull shaft, tip motor on front mounts to be able to drive a new seal... unusual, first one of those i've ever seen. ;)
 

rodbolt

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Sep 1, 2003
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Re: V drive vrs. straight drive

hello<br /> the borg warner V drives use a standard 72 or 71 series clutch that is very good. you cant just lump all v drive together. just as you cant lump all inline drives together, from a maint standpoint its all but impossible to properly maintain a v-drive, the shaft alignment needs to be checked at least on a yearly basis. remember that the shaft normally wont come out of the coupler and its very difficult to do shaft log maint on v drives. so crawl around and see what you or the tech that will work on it has for room<br /> good luck and keep posting
 

Ryoken

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Nov 22, 2003
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179
Re: V drive vrs. straight drive

its all but impossible to properly maintain a v-drive, the shaft alignment needs to be checked at least on a yearly basis. remember that the shaft normally wont come out of the coupler
you lost me Rodbolt... theres no difference in alignment between a v and straight. no reason for it to "change" anymore than a straight would.. and all inboard shafts are removable from couplings, whether taper-fit or straight-cut, Borg-Warner or Hurth.....
 

arks

Lieutenant Commander
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Nov 7, 2002
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1,936
Re: V drive vrs. straight drive

Wow, I thought the straight drive would be the least problematic (fewer parts, easier access). I'm really surprised at Ryoken's comment about the V drives being more durable.<br />The V drive boats I'm most interested in are Silverton 34's from '84-'87. Not sure what brand drives they have.
 

rodbolt

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Re: V drive vrs. straight drive

hello <br /> there are at least 5 maybe 6 types of v-drives. alinment needs to be checked annually . some manufactures reccomend every 100 hours. motor mounts sag, stringers move. most boats have misaligned shafts. if the shaft has not been out of the coupler in a few years ,its all one piece and will have to be cut out. I cut 20 to 30 a year then use a 30 ton press to drive out the cut part from the coupler if the coupler is reusable.<br /> and while there is no difference in the theory of shaft alignment of a v-drive to a straight drive it takes 3 times as long and usually is much more difficult to access a v-drive,I just had the pleasure of doing the alignment on a 33 wellcract st tropez with a pair of 7,4 mercs and merc/borgwarner v-drives. it took almost 5 hours to get the stbd engine within .005". the shafts have never been out of the couplers. its a second owner boat. boat is a 1986 model. the couplers and the shafts are mated for life. if I ever need to remove the shaft it will be cut. shafts are very expensive. a pair of 1 1/4 x 72 inchers are about 700 a piece new. I dont do used or straightened, if my customer goes that way I send him down the street and let it be someone elses headache. <br /> so there are a lot of things to consider when buying a used inboard or any used boat.I also have a 33 CC with a pair of cummings that the shafts are bent .009. looks like some one placed the lifting straps wrong at a haulout. the guy has no complaints and both shafts are bent the exact amount, sooner or later though it will cause a problem . pay me now or pay me later. all things you must look for. hire a surveyor.<br /> good luck and keep posting.
 

Ryoken

Petty Officer 2nd Class
Joined
Nov 22, 2003
Messages
179
Re: V drive vrs. straight drive

hey Rod, all those alignment "issues" are the same with straight trannies tho... <br /><br />i do 20 to 30 a year myself and rarely have to cut a shaft. any tapered shaft can be removed, any... straight cuts biggest issues are generally the set screws. but drillable usually if need be.. i'd rather waste a $70 coupling than a $1000 shaft.. i can usually press any shaft out in the boat. do you use hydraulics or a Prop Off knocker?<br /><br />and i can certainly sympathize with alignments on an older St Tropez. i can see that one being a painful one. :( mated BW V's are the worst. remote and Hurth are much easier. got a bad one of those BW's from the factory once. output flange was cut bad. talk about some screwy feeler gauge readings. :eek: <br /><br /> tho any gas setup pales in comparison usually to an old Detroit shim setup. ;)
 

rodbolt

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Re: V drive vrs. straight drive

we use a hydraulic kit. most boats dont have enough room to use any power pullers. mostly shamrocks,albermarles and Carolina classics. agghhhhh not the oily nasty detroit shim method. I am glad we have none here. I do a few chris-crafts with dodge 6's that has wedges :) :) . and yes straight drives dont get the proper maint usually either. but I have found that on equipment that is impossible to access no maint gets done until something breaks. Oregon inlet is hard on props,rudders and shafts.<br /> but I have had no sucess with trying to press the shaft from the coupler in the hull. all the stuff we do is usually 1 1/2 " or less. and usually its so hard to access the coupler it never gets anything. so when it goes aground I am usually changing a bent one anyway<br /> good luck but I was just trying to tell Arks about small overlooked things that cost a lot of money. I looked at a 33 cruiser inc a year ago that was outrageos to access the engines. both vdrives were leaking from the coupler shaft. but the only way I could even touch them was to hjave a dockhand hold my feet and go down the engine hatch head first. a 15 year old saltwater pair of crusaders and everything so rusty I was amazed it still was on the mounts. I was soooo happy the guy took it someplace else:) :) <br /> good luck and keep posting
 

Ryoken

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Nov 22, 2003
Messages
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Re: V drive vrs. straight drive

understandable... always interesting to hear others experience with like things... they can be h$ll to work on sometimes. and come on, didn't you want to play with those highly engineered plastic adjusters on the Crusaders? ;) <br /><br />we get a good amount of running gear damage too. tho, around here, i'd attribute it to stupidity :eek: :D matter of fact i have a 46 Sportfish due in next week with glass struts he ripped out and almost sank. wants to convert over to bronze. big job, deck, tanks, glass, geometry, etc, etc.. should be fun. i'll take some pics ;) <br /><br />we have some pretty good methods and tools these days. one thing about my boss, he'll buy tools. our new shop rocks.<br /><br />best i had last season was some guy who snapped a shaft. ok, i check running gear, clean and straight. go inside, yup, yup, broken shaft right behind coupling. hey wow check the motor mts laying on the stringers :eek: the bottom 1 1/8 jamb nuts had worked there way all the way down on BB mercs. <br /><br />"Say mister? have any vibes with this boat?" <br /><br />too funny, that alignment started out at a 1/2" feeler reading ;)
 

18rabbit

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Nov 14, 2003
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3,202
Re: V drive vrs. straight drive

Royken – I would be interested in seeing the pix. I love boat fixing pix. :) But, you might want to get the owner’s permission before posting pix of their boat on the internet. Besides courtesy and a good business practice, there are possible legal ramifications you shouldn’t have to tangle with. Only one time have I been told not to take pix. It involved a boat-meets-unmovable-solid-object scenario shrouded in politics, jobs, big $$$.
 

Ryoken

Petty Officer 2nd Class
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Nov 22, 2003
Messages
179
Re: V drive vrs. straight drive

hmmm, you bring up an interesting thought there Rabbit....<br /><br />over the last couple years i've taken to documenting jobs quite a bit with the digital camera. i keep my spare PC down at work in our research room.. its not only been valuable for insurance claim stuff but helpful for showing customers unseen damage on jobs that they never saw initially once opened up..<br /><br />just had a customer in the shop the other day showing him some shots of his job. he wanted me to email him the shots to add to the documentation of the boat and the repairs it has recieved.<br /><br />but i can certainly see how someone might have a prob if it was an "embarrasing situation". think i'll check into adding some sort of clause to our release form that requires a signiture prior to starting a job pertaining to photos.
 

rodbolt

Supreme Mariner
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Sep 1, 2003
Messages
20,066
Re: V drive vrs. straight drive

hello<br /> hahaha the crusader nasties. yep I had to remove the plastic mount assy from an old 80's model dusky with a pair of 350 crusaders. I finnaly had in in the vise heating the cast iron ring around the nylon. it finally broke the nylon anyway. thats when I found that crusader has changed the mount pin diameter. the small 7/8ths pin is no longer availible. had to remove the block mount and send it off to have it reamed to the new 1" pin size. it all sounds so easy if you say it really fast :) :) .<br /> kinda like 17,000 a pair for new motors. its easy if ya say it real quick :) :) <br /> I try to take pics of anything that is out of the ordinary.and I write everthing down even if its just something I see that I dont think is correct. that way when the port engine blows I dont have some one going well ya just worked on the genset and now the port motors blown you must have done something.<br /> good luck and keep posting
 
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