SoCal Jet Boats
Tech Talk => Engine Mechanical / Electrical => Topic started by: Tio Pancho on May 28, 2009, 04:11:47 PM
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So we decided to install a rail kit in Bebo's Hondo. My question is how do I find the elevation that the horizontal part of the rail gets installed at? I assume that some vertical distance can be made up in the mounting plates, so a little too low is better than a little too high.
Second question, the angle for the mount is aluminum, but the flat bar bracing on the outside of the stringer is steel (less cash), will this cause a problem due to disimilar metals? We will be using SS bolts.
Thanks
Frank
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install the rails level with the stringers.
the motor plates need to be ground down or wedged where they rest on the rails in order to adjust the motor angel to align it with the pump, but dont make it perfectly straight. the drive line needs a degree or two of angel in it to give it a little bind or it will make all sorts of noise and vibrate.
if i remember correctly, if you zero out the boat at the stringers, your pump sits at 4 degrees....so put your motor in at 3 or 5 degrees.
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I am not sure what you mean by "zero out the boat at the stringers". Do you mean making the stringers level fore and aft and using that as the starting point? Thanks for the info BTW.
Frank
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yes....use the stringers as a zero point.
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pics Frank pics
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No action yet, just planning and staging materials. We are still only as far as removing the bad fiberglass and foam (previous thread).
Any input on the different metals....?
Frank
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Hey Tio..are we working on a jet ??? Fwiw I wouldn't drill all the holes until you know you have it sitting right.
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Yeah its a jet. Don't plan on drilling until I understand it well. Still don't quite know how to figure the elevation, ie even with top, or how far below top of stringer for best fit/function.
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My rails are as low on the stringers as they can get... IMO there is no way to know where until you mock it up.. 8)
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Second question, the angle for the mount is aluminum, but the flat bar bracing on the outside of the stringer is steel (less cash), will this cause a problem due to disimilar metals? We will be using SS bolts.
Technically?... yes those are 3 slightly different metals that after 10 years might have some galvanic corrosion.
Practically? No. There's places on most motors where alum is mating up with steel and stainless sprinkled around here and there. If you wanted peace of mind then slather all the contact surfaces with silicone when you put it together after mock up. That will block both water and air and give you 30 years instead of 10! ;D
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if i remember correctly, if you zero out the boat at the stringers, your pump sits at 4 degrees....so put your motor in at 3 or 5 degrees.
When I was dorking with my driveline and motor mounts, I got paranoid about just taking for granted what the factory castings were supposed to be, so I eventually came up with a fairly EZ way to measure what angle the pump was set at relative to the stringers.
I don't like the REAL EZ way which is to use a protractor/level - FWIW there's only 6 inches worth of contact to try to get an accurate reading on a very shallow angle. Not a good situation in my opinion.
Like Brad sez, zero out your hull so the top of stringers are level. Then, clamp some kind of straight edge vertical onto the face of the pump flange where the splined shaft is sticking out. I had a 3' piece of 3/4 x 3/4 alum angle that worked well for this. Then I took a 24" long carpenters level and held it up so it was along side (forward) of the angle/straightedge. With the bottom of the level touching the straightedge and the level perfectly vertical, I measured the distance (gap) at the top between the level and the straightedge. I was holding the level with one hand and a tape measure with the other.
Then I just trigged out the angle on a calculator that had "arctan" (aka tan-1) of gap distance/24"
I'm sure that I was accurate to within a 1/4 of a degree which satisfied my inner nerd.
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Frank we do this routinely , call if Josh or I can help Tom
(https://www.socaljetboats.com/proxy.php?request=http%3A%2F%2Fi147.photobucket.com%2Falbums%2Fr319%2Fjetboatperformance%2Fbryan%2FHondo-037S.jpg&hash=0fe56a9cef9bfc4441ca7e38ae322dbcb865597c)
(https://www.socaljetboats.com/proxy.php?request=http%3A%2F%2Fi147.photobucket.com%2Falbums%2Fr319%2Fjetboatperformance%2Fbryan%2FHondo-039S.jpg&hash=4fbc5e6fa0319ead2bdec1f2ec4cca83b3855ccd)
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heres some pics of rail kit installs ralph and i have done so you can get an idea.
I suggest you measure 5 to 500 times and cut/drill/grind/etc once. I remember when we did the rail kit in the raspberry, we dropped that motor into the boat and set it on the rails over and over...everytime we put it in, it was at a different angle. :screwy:
(https://www.socaljetboats.com/cpg/albums/userpics/10041/DSC04910.JPG)
(https://www.socaljetboats.com/cpg/albums/userpics/10041/brads_liberty_014.jpg)
(https://www.socaljetboats.com/index.php?action=dlattach;topic=1453.0;attach=7180;image)
(https://www.socaljetboats.com/index.php?action=dlattach;topic=1453.0;attach=7182;image)
(https://www.socaljetboats.com/index.php?action=dlattach;topic=1453.0;attach=7184;image)
(https://www.socaljetboats.com/index.php?action=dlattach;topic=1453.0;attach=7186;image)
(https://www.socaljetboats.com/index.php?action=dlattach;topic=1453.0;attach=7220;image)
(https://www.socaljetboats.com/cpg/albums/userpics/10041/flyweel_instal_006.jpg)
(https://www.socaljetboats.com/cpg/albums/userpics/10041/flyweel_instal_009.jpg)
(https://www.socaljetboats.com/cpg/albums/userpics/10041/DSC05096.JPG)
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Thanx for the pics Brad they really help. Bebo and I are going to do our best to limit our "do overs" and make it work and look at least decent.
Frank
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Frank
The motor plates went down to Azusa with my son on Monday. I'll have him give you a call over the weekend.
Mark--"Sanger Pete"
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Excellent, I hope they work out ;D.
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I was exactly where you are about a year ago. For some reason I had started to think there was a ton of Calculas (sp?) and black magic voodoo shit in doing this. As it was, it was damn easy and the folks here on the board and Tommy talked me through this with no drama. I mounted my rails a touch under the tops of the stringers just cuz I didnt want to muck up a beautiful radius the top of my stringers had. Go for it and we're all here to help
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Thanks for the vote of confidence. We are cleaning up the engine bay and filling the old stringer holes right now. We should be starting the install after we get back from our vacation.
Frank
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What size bolts do you guys use for through bolting the rails? I was thinking 1/2". Also should the holes through the rails be the same size, or do you oversize by say 1/16"?
Frank
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What size bolts do you guys use for through bolting the rails? I was thinking 1/2". Also should the holes through the rails be the same size, or do you oversize by say 1/16"?
Frank
I would say 3/8" grade 8 is more than adequate, I would rather see you use more fasteners than larger ones....
As far as the oversize thing, the tighter the better, .003 or .004" is more than enough, the tighter the bolt fits in the metal, the less it can move around hogging out the stringers.... :sly:
GT
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X2 with what Glenn said. I went with 5 3/8" bolts per side. Likely to rip the stringers out before you shear those bolts.
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What spacing do you go between the bolts on the rails?
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What spacing do you go between the bolts on the rails?
space them evenly
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space them evenly
X2
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also, use stringer washers and make sure you use a flat bar on the outside of the stringer.
too many times i have seen regular washers on the outside of the stringer and thats it...and they are sunken into the stringer over time. my southwind is done this way and this winter i will be pulling the motor out to fix it. :banghead:
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We bought 2" flat stock for the back side of the stringers, and we were planning on making large washers from the extra flat and angle stock for both sides.
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Sounds like you have a great plan and ditto what Brad said. For what it's worth, I set the first bolt 2" back from the end of the rails and then ran them every 10".
Good luck
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a better way to do it is start from the outsides ...drill holes 2" in....then measure 1/2 way between those holes...then 1/2 way between the middle hole and the outside holes...keep on dividing it up until you have enough holes.....8-10 inches between bolts is good......this way they will be divided up evenly
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a better way to do it is start from the outsides ...drill holes 2" in....then measure 1/2 way between those holes...then 1/2 way between the middle hole and the outside holes...keep on dividing it up until you have enough holes.....8-10 inches between bolts is good......this way they will be divided up evenly
An additional .02c...Put a dab of caulking or silicone on the holes in the wood before final assembly. This keeps water from getting to the exposed wood and allowing dry rot to take hold.
Don't use elastomeric silicone though, you'll never get it apart.... :banghead:
GT
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Thanks for all the input guys, we really appreciate it. Thanks GT for the silicone info. Sounds like a good thing to do. We will probably be installing this in just over 2 weeks when we get back from vacation. Will update and post pics.
Frank