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Discussion Starter · #1 · (Edited)
I'm the guy that's been running my homebuilt water jet pack off my Berkeley. In the beginning of the testing stages this summer the first few hours we had no problems with air or seizure, just a matter of time, finally had a small seizure. I've been using the standard berk white ropes. Should I use graphite? Which is the best. Since I'm using the pump in a static mode, of course I'm battling the packings overheating, I over heated them this last weekend, may need to replace the shaft again because Its getting harder to keep air out. I know this is brutal on that packing gland. If I keep them loose then we suck air in, at least I think that's where the air must be coming from. Not so good when I'm 20 feet up in the air and enough air enters the pump. Some time ago I read somewhere online of someone running a water tap off of the high pressure engine cooling line at the pump, and feeding water into the packings via a drilled hole into the packing housing. I would think one would want to have a sand/debris trap tho. Seems to me this might work somewhat especially if I keep the packings loose...? Make a hole in the packing down to the shaft might lube and replace the air with water too. I'm in a pickle here trying to make this work. This is a very interesting challenge. Like Tom at Jet Boat Performance said, I'm in uncharted territory. I'd sure like to find a way to beat this. We never turn more than 2000 rpm's. I've heard of those cartridge seals, but dont' have the funds for a new shaft just yet, maybe after tax time! And my packing housing bore has a bit of pitting so I may have problems with the outer cartridge o-ring seals. I had thought about using silicone to seal the cartridge in against the pitting. I've also read that the shaft/o-ring interface are sensitive to dirt and grime. I'd love to hear your ideas, or tell me if you think I'm crazy lol. :)sphss
 

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seal

Check with John Crane. Look for a mechanical seal, made of ceramic. Not cheep, but will work for you for sure.
 

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Duane has a nice mechanical seal. We run one.
 

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I think what ever you end up with, it will require seal water in the packing and a latern ring . Typically taken from the perssure side of the system.
 

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Discussion Starter · #8 · (Edited)
Duane has a nice mechanical seal. We run one.
What kind of maintenance do they require? I am going to need a new shaft with that kind of seal right? Does the shaft/seal interface need any maintenance? What kind of life expectancy do those have? I'll post pictures of the pitting that the bore has which might shoot this whole mechanical seal down. I think I could use some kind of sealant during installation to seal the outer o-rings against the pitting...?
 

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Discussion Starter · #9 ·
I think what ever you end up with, it will require seal water in the packing and a latern ring . Typically taken from the perssure side of the system.
Does anyone make a lantern ring for packing rope type seal? I could try to make one. Hell if I can make that darn Jet Pack I should be able to make a lantern ring. I can visualize how it should be made, but hooking it to a water supply would be tricky thru the housing. Plus I'd need a sand trap.
 

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Discussion Starter · #10 ·
Heck we can darn near run our boats (or water craft) here in San Diego year round Lol, Winter doesn't necessarily mean we have to shut down here in S.D.! :thumb:.
 

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What kind of maintenance do they require? I am going to need a new shaft with that kind of seal right? Does the shaft/seal interface need any maintenance? What kind of life expectancy do those have? I'll post pictures of the pitting that the bore has which might shoot this whole mechanical seal down. I think I could use some kind of sealant during installation to seal the outer o-rings against the pitting...?
If the pitting or corrosion in the housing bore is significant it may not seal or center properly (where packings will expand and conform under marginal conditions) that housing bore could however be bored and sleeved , similar circumstances apply to the pump shaft surface where the seals will ride, cannot be scored, worn or rough else it will damge the seal lips very quickly

 

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Here's a couple pics of the packing bore pitting in my suction piece. I'd imagine I'd have to have this honed and sleeved? Seems this might be bad enough to be part of my air suction problem. The pitting seems to be about 1/32 and 1/16th inch deep in places.
Hope you dont take offense but that suction is done , time to recycle Rick
 

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Discussion Starter · #14 · (Edited)
The rest of the suction is in darn near new condition... this can't be saved? That's the only problem with it is that pitting. There's no way I could afford another suction piece.... What kind of price is a good used one?

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Discussion Starter · #15 · (Edited)
I'll try to find a way to make this work, maybe I dont know what I'm talking about but there's no way this suction piece going to the trash. Hell it's good enough to run the boat without problems if nothing else. I'll eventually find another way to power the jet pack.......I've been running the boat with that bore like that for years without problem. Its only when I started using it for the jet pack that Im running into problems.
 

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Looks like the salt water had its way with the bore on that suction housing. Would deffinately think thats not helping the situation.
 
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