S-Bend drivelines

[Mike Starrett]

When you setup an S-Bent driveline, do you normaly run an inner liner from front to back or just before and after the s-bend?

Thanks, Mike

 

[Jeff Cowey]

Hey Mike~

I'm sure you will get varied opinions on this one. I personally run a teflon liner from front to back in the stuffing box. Liners will slide towards the rear as the engine runs. If you look at the wind direction of your flex cable and consider the fact that gas and nitro engines turn in a counter clockwise direction, everything inside the stuffing tube gets forced toward the rear of the tube. If you lube your flex with grease you will notice a big grease stain on the bottom of the hull at the end of the stuffing tube. For this reason if you use a two piece liner inside, chances are they won't be in the same place you installed them after you run. Some guys don't use a liner at all. But something has to wear...the flex cable or the tube. My advice ~ use a one piece liner from front to back and cy glue the last 1/2" at the rear.

Regards Jeff~

 

[SayMikey]

Hey Mike~

I'm sure you will get varied opinions on this one. I personally run a teflon liner from front to back in the stuffing box. Liners will slide towards the rear as the engine runs. If you look at the wind direction of your flex cable and consider the fact that gas and nitro engines turn in a counter clockwise direction, everything inside the stuffing tube gets forced toward the rear of the tube. If you lube your flex with grease you will notice a big grease stain on the bottom of the hull at the end of the stuffing tube. For this reason if you use a two piece liner inside, chances are they won't be in the same place you installed them after you run. Some guys don't use a liner at all. But something has to wear...the flex cable or the tube. My advice ~ use a one piece liner from front to back and cy glue the last 1/2" at the rear.

Regards Jeff~

No liner here just brass. Ive used straight and sbend and see no difference in performance or wear. If you can wear out a shaft or tube quit using vasoline and get some good grease

 

[John Knight]

Absolutely no liner, just brass. If the shaft and tube develops a hot spot, the liner can melt and you have a glorious mess in the tube that you cannot get out. You have to replace the tube. It actually narrows the ID of the tube anyway and can bind or create more friction on the shaft.

I agree with Mike, I have used both straight (actually slightly bent) and S bend and have not noticed any appreciable difference.

 

[Mike Starrett]

Absolutely no liner, just brass. If the shaft and tube develops a hot spot, the liner can melt and you have a glorious mess in the tube that you cannot get out. You have to replace the tube. It actually narrows the ID of the tube anyway and can bind or create more friction on the shaft.

I agree with Mike, I have used both straight (actually slightly bent) and S bend and have not noticed any appreciable difference.

Ok, So I guess I worded this wrong. Let me be a little more specific. I intend to run a brass liner. If you run the liner full length, how do you get the liner up thru the s bend? Do you need to anneal the liner and/or stuffing tube? I have done a few drivelines but always just used a gentle bend. I would prefer to do that but in this Whiplash 40 I'm working on I need to set the motor down in order to get clearance for the cowling and still be able to get the starter belt out from under the flywheel. Thanks for your answers, Mike

 

[misshydro]

Most racers dont run liners because in times it will melt and freeze your cable up and snap it or might do damage to you motor..Just run the brass tube and keep that cable well lube....

 

[Bill Gibson]

Absolutely no liner, just brass. If the shaft and tube develops a hot spot, the liner can melt and you have a glorious mess in the tube that you cannot get out. You have to replace the tube. It actually narrows the ID of the tube anyway and can bind or create more friction on the shaft.

I agree with Mike, I have used both straight (actually slightly bent) and S bend and have not noticed any appreciable difference.

Ok, So I guess I worded this wrong. Let me be a little more specific. I intend to run a brass liner. If you run the liner full length, how do you get the liner up thru the s bend? Do you need to anneal the liner and/or stuffing tube? I have done a few drivelines but always just used a gentle bend. I would prefer to do that but in this Whiplash 40 I'm working on I need to set the motor down in order to get clearance for the cowling and still be able to get the starter belt out from under the flywheel. Thanks for your answers, Mike

Mike, are you talking about a liner or a stuffing box for the shaft tube??

 

[opio]

I think he is talking about a stuffing box. When I did mine I used as short of a piece as possible for the perment section. It was basiclly straight. Then ran the "inside" tube from strut to final location by motor collet.

 

[Tom Foley]

STUFFING BOX = SHORT PIECE OF BRASS PERMANENTLY INSTALLED IN HULL THAT THE SHAFT TUBE FITS IN

SHAFT TUBE = BRASS TUBE 2 TUBE SIZES LARGER THAN ACTUAL SHAFT SIZE , TUBE FITS TIGHT INTO STRUT.

IMHO NEVER USE TEFLON BS =UNNECESSARY PRODUCT :lol:

 

[Bill Gibson]

STUFFING BOX = SHORT PIECE OF BRASS PERMANENTLY INSTALLED IN HULL THAT THE SHAFT TUBE FITS IN

SHAFT TUBE = BRASS TUBE 2 TUBE SIZES LARGER THAN ACTUAL SHAFT SIZE , TUBE FITS TIGHT INTO STRUT.

IMHO NEVER USE TEFLON BS =UNNECESSARY PRODUCT :lol:

Hey "Go Fast"...do everyone a favor....quit beatin around the bush and GET TO THE POINT.....WILL YA?? :lol: :lol:

 

[Mike Starrett]

STUFFING BOX = SHORT PIECE OF BRASS PERMANENTLY INSTALLED IN HULL THAT THE SHAFT TUBE FITS IN

SHAFT TUBE = BRASS TUBE 2 TUBE SIZES LARGER THAN ACTUAL SHAFT SIZE , TUBE FITS TIGHT INTO STRUT.

IMHO NEVER USE TEFLON BS =UNNECESSARY PRODUCT :lol:

Opio is right, that's about the same way I do it. And thanks Tom for clearing up the terminology. The only difference is I always run a brass liner inside the shaft tube and it,s I.D. is the same as the shaft size(ie 3/16"). That way everything is replaceable easily. I was trying to find out how do you guys normally get those 2 tubes bent into the "S"? Do you put them thru the stuffing box together and then bend them or do you not even use the second inside tube leaving only the bearing in the strut to support the shaft? Seems like it would wobble really bad if that's the case. Oh, and lets clear this up...There will be no teflon liner in this system. They may work fine, but I don't use them.

Thanks for your patience and understanding, I'm just trying to learn something here. Mike

 

[Kez]

I have found that if I used a straight or slight bend in the tube, the cable can whip at certain RPM.

I have tried an S bend. While it works very nicely to eliminate the whipping, and at the same time place the engine at a better angle, having an S bend will make it almost impossible to remove the tube from the stuffing tube (the permanent tube that you glue to the hull).

Kez

 

[Mike Starrett]

I have found that if I used a straight or slight bend in the tube, the cable can whip at certain RPM.

I have tried an S bend. While it works very nicely to eliminate the whipping, and at the same time place the engine at a better angle, having an S bend will make it almost impossible to remove the tube from the stuffing tube (the permanent tube that you glue to the hull).

Kez

Thanks Kez, That's enough of an answer to make me rethink this whole s-bend thing. I'll figure out a way around it. Thanks to all who answered, Mike

 

[Tom Foley]

I have found that if I used a straight or slight bend in the tube, the cable can whip at certain RPM.

I have tried an S bend. While it works very nicely to eliminate the whipping, and at the same time place the engine at a better angle, having an S bend will make it almost impossible to remove the tube from the stuffing tube (the permanent tube that you glue to the hull).

Kez

Thanks Kez, That's enough of an answer to make me rethink this whole s-bend thing. I'll figure out a way around it. Thanks to all who answered, Mike

Guys , this is really simple ...the s bend occurs aft of the stuffing box which is merely a very short (2 " maybe ) section of tube glued into the hull . The whole brass liner thing that is the next size up from the shaft is WRONG !! Please save yourself from doing it twice !! There needs to be "room " for the grease , oil , in the shaft tube . By using that liner you will have too close a fit in the shaft tube .. The S Bend is VERY SLIGHT and gradual . 29 years and countless boats later it's very simple !! Also in the event of a wreck you just remove the strut/shaft tube assembly , heat strut , remove tube , bend new tube ..RACE and WIN !! Merry Christmas...don't drive yourself nuts overthinking this stuff :lol:

Just trying to help !!!!

 

[Bill Gibson]

Yep.....thats the advantage to using the stuffing box..... quick replacement of the shaft tube in the event of a OOPPPSS! As with others who posted on here and other racers that ive talked to, im pretty indifferent to the S bend thing, maybe with a very long shaft it makes a difference... for me personally, i cant see any big effects either way, except that its easier to set up the shaft tube/stuffing box in a new boat without a shaft tube that has a very pronounced S bend....i also know racers who swear by em, so there ya go..to each thier own! P.S. Tom, the Darwin thing you E-mailed me...HILERAEOUS! Judy and I laughed our tails off!

 

[Norm Doerr]

I have tried "S" bends with and without the liner... Now I goe as straight as possible with no liner and the big tube only a slight bend. AND I am very picky on the bend part..

OR What Foley said.. I can testify that I have a few accomplished boaters that come over to the shop and they do the same thing as Foley. Not only is it easier but there "seems" to be a lot less drag.

Just my 2 pennies.

Norm Doerr

 

[Mike Starrett]

I have tried "S" bends with and without the liner... Now I goe as straight as possible with no liner and the big tube only a slight bend. AND I am very picky on the bend part..

OR What Foley said.. I can testify that I have a few accomplished boaters that come over to the shop and they do the same thing as Foley. Not only is it easier but there "seems" to be a lot less drag.

Just my 2 pennies.

Norm Doerr

Norm, Thanks for your reply. What you and Tom said are exactly what I was looking to find out. I always installed the liner because I thought the shaft would wobble badly but as I understand it now, the grease and the shape of the bend will keep it in place.

Mike

 

[Norm Doerr]

I have tried "S" bends with and without the liner... Now I goe as straight as possible with no liner and the big tube only a slight bend. AND I am very picky on the bend part..

OR What Foley said.. I can testify that I have a few accomplished boaters that come over to the shop and they do the same thing as Foley. Not only is it easier but there "seems" to be a lot less drag.

Just my 2 pennies.

Norm Doerr

Norm, Thanks for your reply. What you and Tom said are exactly what I was looking to find out. I always installed the liner because I thought the shaft would wobble badly but as I understand it now, the grease and the shape of the bend will keep it in place.

Mike

Yup.. I have several feet of that plastic teflon stuff that I have no real use for It was a PITA to deal with.

 

[kcvnd]

Look in my U-10 gallery you will see my s-bend set up. The link is in my signature below...

 

[steve wood]

I have found that if I used a straight or slight bend in the tube, the cable can whip at certain RPM.

I have tried an S bend. While it works very nicely to eliminate the whipping, and at the same time place the engine at a better angle, having an S bend will make it almost impossible to remove the tube from the stuffing tube (the permanent tube that you glue to the hull).

Kez

i have removed countless stuffing tubes from a bent stuffing box, with no problem. just grab with a pair of pliars and twist and pull em out. install new the same way. make the new one long enough to cut off the smashed end and lube well, and push and twist and they go right end.