SoCal Jet Boats
Tech Talk => Engine Mechanical / Electrical => Topic started by: spectralen on October 24, 2009, 08:05:29 PM
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I'm putting new engine stringers in my 21 Spectra 460 berkeley. It has the 3 point engine mount.
I'm wondering if I get one of those magnetic degree finder tools, get my angle of the pump from the shaft or the top of the bearing housing, and maybe get the engine angle from the top of the valve cover?
What's the right way to install this thing?
Thanks, Lenny
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I'm putting new engine stringers in my 21 Spectra 460 berkeley. It has the 3 point engine mount.
I'm wondering if I get one of those magnetic degree finder tools, get my angle of the pump from the shaft or the top of the bearing housing, and maybe get the engine angle from the top of the valve cover?
What's the right way to install this thing?
Thanks, Lenny
There is actually such a thing as an alignment fixture, by far the easiest way.....But.... with the three point dealio, it is actually a no brainer.
You do not want the alignment to be "dead nuts", but actually have a small amount of misalignment, I prefer a slight down bubble from "0" at the shaft...I am a cheater when it comes to this process...I normally level the shaft by raising the stern of the boat until my level zero's and set it up so the front of the engine drops about 3/8" from level..
I have been using a yoke and flange that I made for getting to perfect alignment and drop the front...Not calling it right, but been working good for me....If the driveline is in perfect alignment, the joints wont live long and you will have a large amount of drivetrain vibration.......The needles need to roll to get lubrication to them.
GT
edit; welcome to the fun! ;)
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So GT,
It sounds like your saying to bring down the cradle mount just enough so the u-joint has a slight turn to it?
Any idea on how many degrees difference?
thanks
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So GT,
It sounds like your saying to bring down the cradle mount just enough so the u-joint has a slight turn to it?
Any idea on how many degrees difference?
thanks
You testing my calculus skills? :sly:
I would say no more than 2* off of the shaft angle, the joints just need to get a slight roll, left to right should be close to dead on balls accurate. ;)
GT
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I think, and I'm not totally sure on the short lengths of the drivelines on jet boats if this applies as it does in cars, Glen is trying to tell you that unless the centerline of the crank matches exactly up to the centerline of the pump shaft, AT ALL TIMES, you need an offset. (If it did you could just couple it direct).
In cars, we used to use the 180 degree rule. Dunno if this applies or not. Will find out on this Saguaro project soon enough, but the angles of the driveline measured down from centerline of the tailshaft (Crank centerline in this case) and up from the centerline of the pinion in the rear end (Pump shaft in this case), needed to equal 180 degrees. Either adding or subtracting, or median, depending how you measured it.
Hard to explain this, and I think I just confused things even more including myself, ;D
And dunno how you'd easily measure such a short driveline either, without disassembling it and measuring each yoke installed and using the median method.
I think Glens way is easier!
Ray
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I think, and I'm not totally sure on the short lengths of the drivelines on jet boats if this applies as it does in cars, Glen is trying to tell you that unless the centerline of the crank matches exactly up to the centerline of the pump shaft, AT ALL TIMES, you need an offset. (If it did you could just couple it direct).
In cars, we used to use the 180 degree rule. Dunno if this applies or not. Will find out on this Saguaro project soon enough, but the angles of the driveline measured down from centerline of the tailshaft (Crank centerline in this case) and up from the centerline of the pinion in the rear end (Pump shaft in this case), needed to equal 180 degrees. Either adding or subtracting, or median, depending how you measured it.
Hard to explain this, and I think I just confused things even more including myself, ;D
And dunno how you'd easily measure such a short driveline either, without disassembling it and measuring each yoke installed and using the median method.
I think Glens way is easier!
Ray
Ray, you're close, but....
The 180* rule wont work because there is only one point at which you want angular misalignment...If there were two like in a car, that would be an offset and I only recomend going with an offset if you have a section of driveshaft in between two joints (read; motor set forward, which is impossible with the three point deal).
I need to come up with a better way to 'splain stuff ::)
GT
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Nope, you're right Glen, I'm wrong in my lil brain.
I completely overlooked the fact that you cannot move the fixed pump shaft angle, and that with 3 pt mounts, you cannot move the crank flange from near perfect alignment with said shaft. Makes more sense to me now.
Ray
Drivelines more like a CV joint than anything else, thinking about it that way.
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So where on the engine and where on the pump do I set the angle finder?
Thanks
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So where on the engine and where on the pump do I set the angle finder?
Thanks
I use the oil pan rail. :thumbup:
GT