Short driveshaft alignment

[ngerk]

I just want to talk this one out to make sure my thinking is correct. I’m going to align a 155 pump in a KDX. The engine is set back an inch but still uses a SJ midshaft so the shaft just gets pressed into the housing further. So this means the driveshaft doesn’t even protrude inside the hull so when you bolt up the cold fusion tool, it makes it useless.

What I’m thinking, since I already rebuilt and assembled my pump, is to use my wear ring and reduction nozzle along with a buddies stator section. He has a 155 that hasn’t been touched yet so it still has a couch shaft in it. I plan to align it like this and keep up with how many shims I need and leave my wear ring bolted in place and remove the rest. Does this sound ok or is there a better way?

 

[McDog]

Should work close enough but the midshaft/driveshaft plan seems wrong to me. I would think that you need an extended driveshaft and a shorter midshaft instead.

 

[iQRTurbo]

Do just as you mentioned and it should remain aligned. Depending on the midshaft your planning to use you may need to machine the OD on it to get your depth without bottoming the bearing on the shelf on the shaft

 

[ngerk]

Should work close enough but the midshaft/driveshaft plan seems wrong to me. I would think that you need an extended driveshaft and a shorter midshaft instead.

I did think about this but this is how the hull was ran before I got it so I was just going the same route. I think if I wanted to, I could use a 28” shaft and 122mm midshaft unless I figured that wrong.

 

[ngerk]

Do just as you mentioned and it should remain aligned. Depending on the midshaft your planning to use you may need to machine the OD on it to get your depth without bottoming the bearing on the shelf on the shaft

Thanks. The midshaft has been machined. I’m actually pressed in 55mm right now. I figured the standard 19.5mm + 25.4mm setback + extra 10mm for losing engagement from the 155 pump. I’ve got extra washers behind the coupler. May not be the best but I don’t see why this shouldn’t work.

 

[hornedogg79]

I would rather not have the driveshaft/midshaft engagement outside the bearing housing. It will blow out eventually. Splines need the outer support of the bearing race. Those washers are a little sketchy too. Maybe use an FX1(140mm) or gp800(127.5mm) midshaft and swap for the correct driveshaft. Rrp motor mounts come slotted for some adjustment or you could slot yours.

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[jo5hi3]

If this is the hull I think it is, it's an early kdx. The way he is setting it up is the way it was ran for years and the way xscream said to set it up.

 

[ngerk]

I would rather not have the driveshaft/midshaft engagement outside the bearing housing. It will blow out eventually. Splines need the outer support of the bearing race. Those washers are a little sketchy too. Maybe use an FX1(140mm) or gp800(127.5mm) midshaft and swap for the correct driveshaft. Rrp motor mounts come slotted for some adjustment or you could slot yours.

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You thinking the splines or the bearing will take a beating? I figured someone would say something about the washers, haha. I may only need 1 or 2 extra; I’m only holding them there so I don’t misplace them. There’s plenty of threads engaged.

 

[ngerk]

If this is the hull I think it is, it's an early kdx. The way he is setting it up is the way it was ran for years and the way xscream said to set it up.

It’s the hull you think. Only difference is going to a 155 pump. He had the midshaft pressed in somewhere around 46mm I think which is why I went to 55mm. It’s a guess until I check spline engagement.

 

[ngerk]

Just updating here. So, just 1 extra washer worked for the coupler. My problem is even with the midshaft pressed in to 55 mm, I still lack somewhere close to 17 mm for correct spline engagement with a 26 & 3/16” driveshaft. On paper, pressing 10mm extra on the midshaft should have worked but that’s assuming that it was always correctly splined before which I have no clue. It could have been lacking spline engagement before and I could have lost a couple more mm with the pump shoe swap as well (it had to be shimmed a little). My brother in law has a GP760 midshaft so I plan to get a driveshaft long enough to use that midshaft. Should be in the neighborhood of 28.25”to 28.5”.