Null


Shortening driveline ? 1310 h bar

  • 3 Replies
  • 2126 Views

Nmiller02

  • Join Date: Apr 2013
  • *
  • Full Member
  • ***
  • Posts: 130
  • Karma: +1/-0
  • Registered User
    • View Profile
  • Liked:
  • Likes Given: 0
« on: April 13, 2014, 04:26:11 PM »
Anyone ever had to shorten a driveline ? Looking for some help.... I have a 1310 h bar that measures what I believe to be standard size at 7 1/2". I'm needing about 7" of driveline only, not including PTO, or 7 1/4" tops.   

Thanks




Sent from my iPhone using SoCalJetBoats mobile app


Flusher

  • Join Date: Sep 2011
  • Location: Colton, CA
  • *
  • Macho Member
  • ******
  • Posts: 2,054
  • Karma: +71/-0
  • The Machinist
    • View Profile
  • Liked:
  • Likes Given: 26
« Reply #1 on: April 13, 2014, 05:39:45 PM »
That is a common problem.  You want 1/8” clearance between the yoke and the snap ring in front of the thrust bearing.  You can shorten the splined yoke.  I would recommend not shortening to the point that the spline length is less than one shaft diameter.  That means that you want the actual spline engagement to have at least 1-3/8” engagement.

Before you cut anything, may I ask, what is the cause for the need to shorten the drive line?  Did you change drivelines, change or move your engine, reset your pump, add a Jetaway, etc.?  If the driveline is too long, flex in the boat will allow the pump shaft to push against the crank, killing the engine thrust bearing.

Actual cutting of the yoke can be done by various means based on what you have available to you.  I have machined them on both a mill and a lathe.  I have also cut them in a chop saw, with a die grinder cut-off wheel, and even with a hack-saw.  The material really isn’t that hard.  Ideally, you would like to make a nice straight cut, but the runout of the cut on the face is not critical at all.  The face of the yoke does (should) not contact anything.  All you want is to maintain clearance to prevent it from pushing against the crank shaft.  Don’t cut it too short or the splines could fail.

Cheers,

Joe
"I want to roll with my brother Joe" - Joe Bateman - January 29, 1950 ~ November 27, 2013

Nmiller02

  • Join Date: Apr 2013
  • *
  • Full Member
  • ***
  • Posts: 130
  • Karma: +1/-0
  • Registered User
    • View Profile
  • Liked:
  • Likes Given: 0
« Reply #2 on: April 13, 2014, 06:07:05 PM »

That is a common problem.  You want 1/8” clearance between the yoke and the snap ring in front of the thrust bearing.  You can shorten the splined yoke.  I would recommend not shortening to the point that the spline length is less than one shaft diameter.  That means that you want the actual spline engagement to have at least 1-3/8” engagement.

Before you cut anything, may I ask, what is the cause for the need to shorten the drive line?  Did you change drivelines, change or move your engine, reset your pump, add a Jetaway, etc.?  If the driveline is too long, flex in the boat will allow the pump shaft to push against the crank, killing the engine thrust bearing.

Actual cutting of the yoke can be done by various means based on what you have available to you.  I have machined them on both a mill and a lathe.  I have also cut them in a chop saw, with a die grinder cut-off wheel, and even with a hack-saw.  The material really isn’t that hard.  Ideally, you would like to make a nice straight cut, but the runout of the cut on the face is not critical at all.  The face of the yoke does (should) not contact anything.  All you want is to maintain clearance to prevent it from pushing against the crank shaft.  Don’t cut it too short or the splines could fail.

Cheers,

Joe


Great info, thank you much buddy !

Running a quarter stringer boat (78'challeneger) and the engine box is pretty tight, from the pump (berkely JG) in relation to the false floor bulkhead. My front 4 point motor plate has maybe an 1/8th clearance between it and the bulkhead at false floor.

The boat had a Rockwell driveline in it last year but replaced now with a PTO and 1310 to move engine forward the 2" I needed to get my drive line straighter. The angle was way out with the Rockwell because of its short length, my oil pan was interfering with the jet intake. So my solution was to go with a 1310 and PTO to achieve forward movement of the engine now I have 1/2" or so too much causing very close tolerances at front motor plate to bulkhead and drivline spline end to snap ring.

Make sense ? Lol








Sent from my iPhone using SoCalJetBoats mobile app

Flusher

  • Join Date: Sep 2011
  • Location: Colton, CA
  • *
  • Macho Member
  • ******
  • Posts: 2,054
  • Karma: +71/-0
  • The Machinist
    • View Profile
  • Liked:
  • Likes Given: 26
« Reply #3 on: April 13, 2014, 06:27:32 PM »
Yes, makes sense.  Just remember, thrust pushes the pump shaft forward in the suction.  All hulls have flex, some more than others.  Sounds like you got a handle on the driveline angularity.  Just make sure that you have about 1/8” clearance so the yoke doesn’t bottom out against the snap ring/thrust bearing at any time.
"I want to roll with my brother Joe" - Joe Bateman - January 29, 1950 ~ November 27, 2013

 


Website Security Test
Powered by EzPortal
Null

Website Security Test