Manual automotive transmission usage?

Discussion in 'DIY Marinizing' started by DennisD, Jan 1, 2014.

  1. rwatson
    Joined: Aug 2007
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    Location: Tasmania,Australia

    rwatson Senior Member

    Oh, that was a question for PDW, as he did a lot of the custom machining himself. Very impressive work.
     
  2. whitepointer23

    whitepointer23 Previous Member

    i have also read somewhere that fisherman in florida used to run chev v8's in their boats complete with truck fan . radiator and gearbox.
     
  3. pdwiley
    Joined: Jun 2008
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    Location: Hobart

    pdwiley Senior Member

    If you are talking about an SKF 22208 EK type bearing and housing, then I have to say you'd better calculate the max thrust before relying on it. I did the sums and decided that the chance of the shaft slipping in the tapered inner was higher than I wanted to risk. There are ways of dealing with this but just relying on friction isn't one of them.

    If you're referring to some other type of bearing, your information is actually useless to anyone unless you quote a bearing reference so we know what you're talking about. So can you please quote the make and manufacturer part number of the bearing so we can actually have information we can use?

    WRT my machining time, it's irrelevant as I don't charge by the hour and no longer do work for anyone other than myself. I just use my boat building as an excuse to buy more big toys.

    PDW
     
  4. SamSam
    Joined: Feb 2005
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    Location: Coastal Georgia

    SamSam Senior Member

    If you need a thrust bearing for forward, you need one for reverse too.
     
  5. rwatson
    Joined: Aug 2007
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    Location: Tasmania,Australia

    rwatson Senior Member

    I was hoping you could provide a time estimate for people who may have to pay for the work to do a similar job.
     
  6. pdwiley
    Joined: Jun 2008
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    Location: Hobart

    pdwiley Senior Member

    It'd be a totally misleading number because I'm slow, lazy and inefficient.

    Also dependent on what type of machinery you have (or the shop has). It's basically a lathe job with tolerances a bit better than 0.001" for bearing fits and runout held to the same levels but a CNC lathe would do it a lot faster than a manual machinist, so......?

    PDW
     
    1 person likes this.
  7. whitepointer23

    whitepointer23 Previous Member

    i don't have a part number but can probably get it when i have time. i am talking from first hand experience i don't keep records. i have a shaft in the shed right now that has a plummer block thrust bearing. that one took the thrust of a 240 hp holden v8 with a reduction gear no problem at all. it seems that i am pushing **** up hill here. i wil let you blokes discuss how it is impossible to do something i have done for years and leave it at that.
     
  8. CDK
    Joined: Aug 2007
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    Location: Adriatic sea

    CDK retired engineer

    You sure do. Two tapered roller bearings back to back can do that, but as pdwiley pointed out, some means to keep them in place -other than friction- are necessary.
    A new shaft can be machined to provide a collar for fwd thrust, an existing one must get a sleeve or thrust ring, fixed with pins or set screws. It is also possible to use a thin sleeve with a 2 part compression ring around it.
    If the thrust bearing is followed by an U-joint, that part can take up the reverse thrust.
     

  9. pdwiley
    Joined: Jun 2008
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    Location: Hobart

    pdwiley Senior Member

    Brendan, I wasn't saying it was impossible. What I was saying is, telling someone it can be done is useless information unless you ALSO tell them HOW it was done. The specifics are important, there are many thousands of bearings with different characteristics for axial and radial load ratings.

    I spent quite a bit of time tracking down a specific SKF bearing that someone sent me a reference to, only to find out that it was a non-standard item made on demand. It would have been perfect for what I wanted, but it turned out to be unobtanium unless you were very lucky and as for spares sometime in the future, good luck with that. I had to do a lot of searching on the SKF Web site to even get to that point.

    So do me a favour and stop being so sensitive, start providing useful information such as the bearing manufacturer and bearing code number. You might save someone a lot of time and trouble.

    PDW
     
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