designing engine accessory brackets
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  1. #1
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    Default designing engine accessory brackets

    anyone had to design and make brackets from scratch for engine accessories. i have some primative ideas but maybe someone has been there before and has better ideas. my retired architect customer, who thinks anything is possible when someone else does it, wants to remove existing alternator and a/c compressor (a6 - old GM iron) and install 2 non fitting marine alternators which both will require mounts inc different pulleys because, in his opinion, a v-belt will not be adequate.

    there is an aftermarket company that makes a serpentine setup. i suggested he get them to design and build. they walked of course.

    this guy is a cad expert. however getting critical measurements could be real time consuming me thinks

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    I'd put him on to the marine engine guys, ........... most marine engines are at least basically ''converted'' industrial or vehicle engines, so the marine guys are used to solving your sort of problem.

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    Quote Originally Posted by cg285 View Post

    this guy is a cad expert. however getting critical measurements could be real time consuming me thinks
    Then just let the customer spend endless amounts of time getting the CAD files right.

    You just make 'em to the print.

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    I've done a lot, with great success. Here are some tips:

    1) Use steel, not aluminum. Or, don't assume aluminum is the best choice because it's 'lighter'. It's also thicker and not as friendly to bending or welding.

    2) Avoid serpentine belts unless you are also incorporating a constant tension idler. The sole exception to that is if you are running a single, small load (like a power steering pump) all by itself. A V-belt does far better if you are using any arrangement that doesn't have a way of always self-adjusting the belt tension.

    3) Don't be afraid to make your own pulleys if it allows you to put everything else where you want it. Too many people make half-ass brackets just because they're not wiling to make the pulleys to suit.

    4) Use 1/3 belt wrap for most loads....the smaller the pulley, the more wrap you'll need. Nothing worse than seeing a 2" pulley on a 200 amp alternator with 20% wrap. The geniuses at March Pulleys are especially bad about that sort of thing.

    5) The three most important things about making brackets? Alignment, alignment, and alignment. If a belt is running true, it'll last forever and be quiet and never decide to seek its independence.img_0275.jpg

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    Quote Originally Posted by digger doug View Post
    Then just let the customer spend endless amounts of time getting the CAD files right.

    You just make 'em to the print.
    that was my thinking but he expects me to furnish the details

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    I suggest that you get him to watch Project Binky on Youtube and report back, as it will teach him all there is to know about designing, making and fitting brackets. Actually, there's always the hope that he'll get side-tracked and never come back.

    Project Binky - Episode 1 - Austin Mini GT-Four - Turbo Charged 4WD Mini - YouTube

    George B.

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    Quote Originally Posted by cg285 View Post
    that was my thinking but he expects me to furnish the details
    Refuse.

    Simply require a fully GD&T print, your not the designer.

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    When you "furnish the details" you are doing design/engineering work. Inform him that the going rate for engineering is $150/hr. And you will be marking up any outside sourced work by 15%.
    The hardest part of this is to measure the locations of all the mounting pads and bolt holes on the engine. That means you need a portable arm CMM to make accurate measurements. You can probably rent one, again mark that expense up.

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    I've made them for my own custom vehicle work. Usually I'll figure out how to anchor the main pivot bolt, then hang the accessory by that one bolt, and then cardboard templates are your friend for the rest. Round stock sitting in the V groove pulleys help you eyeball offset and alignment.

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    I’m interested in this as well, I have a ej20 that I’m doing a reversed intake manifold, FMIC and alternator relocation/ac delete.
    Removing the belt drivin PS pump for a all electric MR2 style pump, v mount radiator.
    Oil cooler under hood scoop. And so on, gonna need some brackets that no one sells ATM

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    For a prototype, I would use aluminum. It is a lot easier to work with so that will go faster and less expensive. Get the dimensions right first. Then worry about designing the permanent mounts.

    Heck, for starters, cardboard can be very useful just to see what may work. Wood could be helpful too.

    And for gosh sake, do not quote a fixed price. This is a classic example of a TIME and MATERIALS job. That $150 per hour may be a bit steep, if you actually want the job. But $75 an hour would not be out of the question.



    Quote Originally Posted by GregSY View Post
    I've done a lot, with great success. Here are some tips:

    1) Use steel, not aluminum. Or, don't assume aluminum is the best choice because it's 'lighter'. It's also thicker and not as friendly to bending or welding.

    2) Avoid serpentine belts unless you are also incorporating a constant tension idler. The sole exception to that is if you are running a single, small load (like a power steering pump) all by itself. A V-belt does far better if you are using any arrangement that doesn't have a way of always self-adjusting the belt tension.

    3) Don't be afraid to make your own pulleys if it allows you to put everything else where you want it. Too many people make half-ass brackets just because they're not wiling to make the pulleys to suit.

    4) Use 1/3 belt wrap for most loads....the smaller the pulley, the more wrap you'll need. Nothing worse than seeing a 2" pulley on a 200 amp alternator with 20% wrap. The geniuses at March Pulleys are especially bad about that sort of thing.

    5) The three most important things about making brackets? Alignment, alignment, and alignment. If a belt is running true, it'll last forever and be quiet and never decide to seek its independence.img_0275.jpg

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    Quote Originally Posted by digger doug View Post
    Then just let the customer spend endless amounts of time getting the CAD files right.

    You just make 'em to the print.
    that's what i ended up telling him. he's bouncing all over the place. threaded rod is one of his favorite commodities he keeps bringing up
    haha

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    "Anything is possible if you don't know what you are talking about" comes to mind.

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    Perhaps your not the right person for the job (no offense)

    I actually enjoy such work

    Ps I get paid by the hour

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    Quote Originally Posted by Hbjj View Post
    Perhaps your not the right person for the job (no offense)

    I actually enjoy such work

    Ps I get paid by the hour
    i would gladly send him your way except you appear to be on the other edge of the earth

    (and this is just 1 of his many projects for this vehicle)

  23. #16
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    Quote Originally Posted by Erich View Post
    That means you need a portable arm CMM to make accurate measurements. You can probably rent one, again mark that expense up.
    No you don't. You just need to know how to measure shit.

    And yes, I've done it. Its not easy, but its not hard.



    Simple alternator bracket.





    Making sure your stuff fits in the actual engine compartment is far harder than
    figuring out the brackets you need to attach it to the motor.

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    Measuring what was on the motor gives you numbers and offsets to work from.
    Yes a scan arm nice but not needed.
    A factory block print the ultimate along with crank and pulley but good luck getting those.
    Bob

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    Quote Originally Posted by Bobw View Post
    No you don't. You just need to know how to measure shit.

    And yes, I've done it. Its not easy, but its not hard.
    i might add this is in a motorhome and not on an engine stand
    but that may not be a problem for some.

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    "For a prototype, I would use aluminum. It is a lot easier to work with so that will go faster and less expensive. Get the dimensions right first. Then worry about designing the permanent mounts.

    Heck, for starters, cardboard can be very useful just to see what may work. Wood could be helpful too. "

    Yes, I was referring to the finished product. I make a lot of brackets out of trusty 1/8" aluminum for the sake of ease and speed. Then make the real version out of whatever thickness and material is proper.

    krc-pump-bracket.jpg

  28. #20
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    Do I see "retired architect" cad expert and marine use two alternators?
    I smell blood in the water.

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