Engine alignmenet

[jimmaki]

So I might need to yank my 787 engine out of the SPX and rebuild the lower end. If I keep all the shims where they are, do I need to buy an alignment tool and yank the pump? Or will the same engine go back in the original ski close enough for govmint work? If I send my engine to a place like SES that uses your case, same question on alignment on reinstall. While I'm at it, has anyone here used SES to rebuild an engine or crank and was it a good (or bad) experience?

 

[Coastiejoe]

If the mounts fit over the studs and have ZERO play in them, then I would think you would be ok. But, if the holes in the mounts allow for movement, then you will need to align the engine. Putting pressure on the PTO wears the shaft splines faster as well as puts a lateral load on the pump bearings and tends to move the impeller to one side as well.

 

[CReynoldsMIZ]

Do a search, the two questions you have asked have been asked a lot. SES is hit or a big miss, do what you like on the driveshaft, the pros will say yes align, but you can get by but do it at your own caution.

 

[jimmaki]

I'm wondering if I it would be possible to support the driveshaft somehow and just leave the pump and driveshaft installed, remove the mounts and slide the engine forward and up, then reverse the process on installation. it would more or less self align .... I hope.

 

[jimmaki]

Do a search, the two questions you have asked have been asked a lot. SES is hit or a big miss, do what you like on the driveshaft, the pros will say yes align, but you can get by but do it at your own caution.

Some communities have allegiances to certain commercial interests as I'm finding out, so asking for recommendations takes some sorting out of these relationships. Not necessarily a bad or good thing, just something to be aware of. I knew sea-doo.net was tied to Perry, but I didn't find out until recently that pwctoday was sponsored by watercraft magic.

SBT seems to have a lot of fans as well as enemies. But the fans say they are fast and their stuff generally is good enough to be reliable. On the other hand, SES reviews say they are a lot slower and the customer service callbacks can take days. SES doesn't seem shy about dissing SBT for using Japanese bearings and welding on cranks. SBT has higher shipping charges but they're only about 1-1/2hours from me, I'm in Orlando.

At this point I'm not even sure I need a rebuilt engine. My plan is to start disassembling from the top down with it in the ski and see if a) I can tell what is making the rattling noise, and b)make sure the spring isn't in the engine and c) see how the piston/sleeve/heads look and if any metal has gone through and damaged them. Hopefully I won't break any bolts which is my worst fear.

 

[Coastiejoe]

If you unbolt the mounts from the ski and do not remove them from the engine, I would think that this would be the "best" odds of not needing to align the engine.

 

[jimmaki]

I agree but it seems most rebuilders want everything removed from the engine.

That would include the flywheel and based on how I plan to take apart the engine from the top down, if I end up having to take of the flywheels, I'm not going to have a piston/exhaust to stick a rag into to keep the crank from turning. I guess I'll have to temporarily reassemble the jugs if it gets down to that unless there's some other trick to getting the flywheel nut off i'm not aware of. Ditto on the PTO end.

 

[soccerdad]

I'm wondering if I it would be possible to support the driveshaft somehow and just leave the pump and driveshaft installed, remove the mounts and slide the engine forward and up, then reverse the process on installation. it would more or less self align .... I hope.

I don't think it matters what you do with the pump. You can take it off. It is the motor that gets aligned and the pump theoretically goes back on the same each time. But having it in when you slide the motor in may help target you in.

Time for me to put on my helmet because I see rocks in the air coming.... OK ready... I honestly don't completely understand the motor alignment needs. I get that the hulls are fiberglass and molded from the outside. Therefore shims are needed to get everything correct when the mounts are installed. But if they are installed correctly, then a motor should go back in the same spot it came out of. And I will go one step further. The motors and mount points are all machined/fabricated in what I would expect to be pretty precise. I watched that video posted on them building skis. They way they do it, I cannot imagine the factory mounting an alignment plate, installing the motor and then adding and taking away shims until it is correct. So, with all that said, I think the real alignment and shimming is to get the mounts in the correct place, and then they add any motor. BUT I COULD BE WRONG. Just knowing modern manufacturing, I don't think they shim after a motor is put in.

I pulled the motor and reinstalled it in my GSX without a jig. The shaft went right in, with no bind. The carbon seal sits fine and does not suck air. It has only been in there a year, so who knows. The drive shaft is made for some movement as it has convex splines. So all of that said, an alignment tool is safe and will correct for any hull sags or someone that replaced a mount or moved shims in the past. Also if the motors are actually significantly different, it will get it all right. I will not say what I am going to do when I replace the motor in my GTX. I have not completely made up my mind yet....

 

[mikidymac]

If you loosen the engine mount bolts and try to move it you will see that there is actually a lot of movement possible. It is easy to get it out of wack. There is also play in the drive shaft splines and when the pump goes back in there is a lot of movement possible there too. You might get it close by eye and have no problems but if you can get access to the tool you will sleep better.

On the 1997+ XP's and HX's with the two piece drive shafts you really need to get them in alignment.

 

[Nike12000]

if shims are the same and its the same block toss it back in and bolt up if you mess up the shims at all or you get diff block then deff align

 

[Coastiejoe]

I think if I was going to do the gamble,, I would leave the mounts tight to the block and trace the outline of the mounts in the hull. Label all shims by location and how they were facing..

 

[racerxxx]

I'll sum it up.

It's a long ass swim back dragging your ski behind you.

 

[Coastiejoe]

I'll sum it up.

It's a long ass swim back dragging your ski behind you.

its ALWAYS a long swim back even without the ski...

 

[jimmaki]

I'm not sure one way or the other either. Logically, the same engine should go back in the same boat the same way. I realize there's more than zero tolerance between motor mount bolts and holes but there's also more than zero tolerance between the alignment tool mounting holes, the retaining bolts and the alignment shaft and the bore it slides through. The engine location error on it's mounting bolts is close to 1:1 but any alignment tool true position error on its mounting holes, dirt wear or distortion error on the shoe and/or angular play of the alignment shaft in the alignment plate tube is coordinately multiplied by the length of the alignment shaft, I would think.

Having said all that mumbo jumbo, it's also true the alignment tool is expensive, has a singular usefulness (for me), and appears to be a pain in the ass to use. While watching a video of an SBT tech remove the pump, and hammer on the tool ... I'm thinking what a pain to use and how is he going to get that plate off that he just hammered on without using the alignment shaft as a rocking/bending tool or hammering it off from the inside beating on the tube with a socket or something.

If the pump has to be removed anyway, why can't a hole be drilled in the end of a $15 impeller removal tool parallel to the splines and an inexpensive $10 laser pointer inserted in the hole pointed toward the center PTO flywheel. Since the tool is probably hardened it would be even easier to mount the laser pointer in a socket that fits the hex on the tool. Three small threaded holes 120* apart on the socket could snug it down on the tool aligning the laser to centerline. Even with some small error, by rotating the impeller, the laser dot will subscribe a circle on the PTO flywheel. So it's just a matter of moving the engine so the circle centers on the driveshaft receiver.

If this has a chance in hell of working ... patent pending.

 

[jimmaki]

Once we ran totally out of gas about 100' from the dock so I told my wife to hop off the back of the SeaDoo we were riding and kick us in pushing from the back while I steered.

 

[Lake Sailor]

jimmaki, you think an alignment tool is expensive, try a new driveshaft, impeller & maybe PTO flywheel

 

[soccerdad]

Wow, that is innovative thinking! It would be hard to get the laser mounted dead center, but as you noted, if you got close, you would have a circle target. I would love you to try it! It may not work, but I love outside the box thinking!

It would likely cost just as much as the real tool, but I would think you could get a shaft with the OD turned to the ID of the pump splines. A good snug fit. The other end would fit the PTO splines ID. The put in the shaft in the pump, install pump then install motor, slide back to see a good fit, shim if needed. So now you tool is just a shaft. But I think there are different shaft lengths so it would not be a "universal" tool. But it would work for one model ski. We have TONS of 96-97 GTXs and 96 XPs out there. The only downside would be it is tough to move the motor back and forth while you are checking.

 

[soccerdad]

Thinking about it more, I think the laser may have an issue. It will get the rear hole in position, but the yaw of the motor (tilting up or down front to back) may still be off. Thinking of my idea, a telescoping shaft would work and be more universal. But more complex and require tighter tolerances. I may have to make one and test it in a ski that my motor has not been out of.

 

[jimmaki]

Wow, that is innovative thinking! It would be hard to get the laser mounted dead center, but as you noted, if you got close, you would have a circle target. I would love you to try it! It may not work, but I love outside the box thinking!

It would likely cost just as much as the real tool, but I would think you could get a shaft with the OD turned to the ID of the pump splines. A good snug fit. The other end would fit the PTO splines ID. The put in the shaft in the pump, install pump then install motor, slide back to see a good fit, shim if needed. So now you tool is just a shaft. But I think there are different shaft lengths so it would not be a "universal" tool. But it would work for one model ski. We have TONS of 96-97 GTXs and 96 XPs out there. The only downside would be it is tough to move the motor back and forth while you are checking.

Well, you could just buy a used but straight driveshaft with good splines and cut it in half or wherever the splice best fits, and reconnect them with a precision fit tube so the two pieces can be telescoped. Of course you would shorten the drivewshaft at the splice so the telescoping half would slide in and out of the PTO.

Another thought I had was to temporarily support the PTO end of the existing driveshaft a bit back from the PTO using a pillow block bolted to the hull or bolted to a block of wood glassed to the hull. Once the engine is reinstalled, the pillow block to can be opened and the base removed. A split alum tube or rubber or plastic grommet could be fabricated to hold the driveshaft in the pillow block precisely. You would place this support in an area where there are no bearings supporting/touching the driveshaft.

 

[jimmaki]

Thinking about it more, I think the laser may have an issue. It will get the rear hole in position, but the yaw of the motor (tilting up or down front to back) may still be off. Thinking of my idea, a telescoping shaft would work and be more universal. But more complex and require tighter tolerances. I may have to make one and test it in a ski that my motor has not been out of.

Good point on the yaw alignment. You could take another impeller tool, chuck it up and face it off dead square and polish it. When the laser reflects back to the origination point, you're dead on at double accuracy. You know you're dead on when you can't see the returning beam because it's boresighted right back at the laser or it prescribes the same diameter circle around the rear impeller tool. Well, actually it would be twice the diameter. But anyway, I would mount the laser or led pointer in such a way that I could make it dead center using three axis screw adjustments the same way they zero in laser gunsights.

 

[jimmaki]

jimmaki, you think an alignment tool is expensive, try a new driveshaft, impeller & maybe PTO flywheel

If you're out that far you could probably add bearings and seals to the list... and mounts ... the engine .... fillings ...

 

[soccerdad]

The problem with using a drive shaft (and the entire reason for this thread...) is that the splines are convex and allow for misalignment. So you could use the shaft, but it may be at the edges of the "travel" But you don't want to eat up all of the tolerance the convex gives you, so the motor must be in straight. If the splines were straight, you would use the shaft to align the motor. But if they were straight, ANY misalignment (static or from dynamic flex) would eat the splines and kill the bearings in the pump and maybe the motor. So a tool that moves in the ID of the splines at both ends, or a shaft with straight splines at both ends should work. Unless I am missing something.

Actually this is exactly what the SBT tool does, but it mimics your pump. In a way, this would be better since it uses your pump.

 

[jimmaki]

Thinking about it more, I think the laser may have an issue. It will get the rear hole in position, but the yaw of the motor (tilting up or down front to back) may still be off. Thinking of my idea, a telescoping shaft would work and be more universal. But more complex and require tighter tolerances. I may have to make one and test it in a ski that my motor has not been out of.

Sounds good! Make two, one for me please (providing it doesn't cost more than the SeaDoo tool!)

 

[Coastiejoe]

Unless the laser was mounted in such a way that it was proven or known to be square to the engine, it would not help.

In theory, you are looking to get the laser on a DOT on the other end. Getting the dot of the laser in place would be easy as you would learn or tilt the engine as needed. But in reality, you could be off by many inches as it is like a gun. I can be square to the target or off by 10 feet to the left and still hit the bulls eye...

 

[6hoppy6]

I made a tool to aline mine, 1995 xp 717. I had a spare pump i removed the impeller, shaft and seal from. Then i bought some 7/8 to 3/4 brass bushings to slip in the pumps bearings to adapt it to 3/4 inch and to protect the bearings from the shaft i used. I then bought a straight piece of 3/4 inch steal shaft and had one end turned down on a lathe to fit inside the splines of the pto and used it like the factory/sbt tool to hold one end of the shaft square in the pump and test fit the other end in the pto. (i really had my friend with the lathe turn both ends of the shaft one end just a little bit smaller then the aliment end so i could tell when i was close and i had him use the splines of the impeller as a guide on how to machine the ends of the shaft since it was portable and the splines were the same size as the pto).