The "Hitchhiker's Guide" to the Maxi-Stream mod

[miatawnt2b]

My mod started to make a bit of noise again, so I pulled it apart again to visually inspect. I found that the imbalance of the propellor had caused the CF rod to wear the rigid airline so the hole is now oval.

OK, fair enough, so I need to rebuild, and this time balance the propellor. How do you guys do this? Do you balance the propellor itself or after it's assembled to the shaft and magnet?

THanks,
-J

[johnvu713]

when i take of the shroud the pump seems to push more water...but when i place the shroud back on the amount of water is drastically reduced?...what giveS?

[lessthanlights]

did mjmods raise their prices recently??

[lessthanlights]

double post

[dhnguyen]

Originally posted by johnvu713
when i take of the shroud the pump seems to push more water...but when i place the shroud back on the amount of water is drastically reduced?...what giveS?

Ah well you kinda answered your own question on that

Sounds like your shroud is too restrictive while not providing enough inlet area for the propeller to suck in water.

Less inlet=less flow.


D.

[dhnguyen]

Originally posted by miatawnt2b
My mod started to make a bit of noise again, so I pulled it apart again to visually inspect. I found that the imbalance of the propellor had caused the CF rod to wear the rigid airline so the hole is now oval.

OK, fair enough, so I need to rebuild, and this time balance the propellor. How do you guys do this? Do you balance the propellor itself or after it's assembled to the shaft and magnet?

THanks,
-J

I balance my prop by attaching it to the rigid airline tube and put that onto a drill and have it spin against some sandpaper.

Alternatively if you have a belt sander you can do this too.
http://s45.photobucket.com/albums/f9...t=DSCF1081.flv


D.

[Norboo]

What is the most reliable propeller for MJ 900 and 1200? I am not looking for super flow rate but rather more reliability (low maintenance).

…and where can I buy them?

Thank you.

[johnvu713]

Originally posted by dhnguyen
Ah well you kinda answered your own question on that

Sounds like your shroud is too restrictive while not providing enough inlet area for the propeller to suck in water.

Less inlet=less flow.


D.

My shroud is peppered with lot of holes...one more hole and it'll fall apart.
BTW i plugged it into a wavemaker and it wont restart..any remedies to resolve this?

[quangtam7]

No matter how well made is your shroud, you will not be able to achieve the flow of shroud less streamer, it is extremely powerful with Dumas 3004 prop.

[miatawnt2b]

Thanks!
Now that I can balance the prop, I have noticed that the magnet wobbles when spinning on the CF rod. When I built the mod, I used the break the impellor method.

I removed the tube from the magnet, and cut the back half off, so that it would fit halfway up the magnet. Then I jammed the rigid airline into the front end. The problem seems to be that the hole in the magnet is not only out of round, but it is also off center. Therefore, jamming the rigid airline method makes the entire thing off center and out of balance as far as the magnet goes.

What methods have been used to successfully fix this?

I have 2 ideas. Leave the impellor assembly in-tact. Then use flexible air line to connect the impellor to a CF tube where the prop attaches.

My second idea is much more involved, but may lead to a perfectly centerd magnet, and a rigid 1 piece propellor assembly.
I would to continue using the break the impellor method, insert the back half into the magnet, and fill the top half with epoxy resin. Then use a .98 bit to drill a pilot hole directly through the center of the magnet using the hole in the back half as the centering guide. (hope that makes sence) Then flip over the magnet, and drill a hole directly in the center of the epoxy resin that is the same diameter as the OD of the carbon fiber rod. This hole would be drilled halfway down the center of the magnet. Then epoxy the CF tube and prop assembly into the magnet. This should result in a perfectly centered magnet/prop assembly.

What do you think? is there a better way?

-J

[jl7854]

With the second idea would the hole you make possibly cut into the magnet. That seems like a bad thing to me if it does.

Jon

[Cuervo]

I noticed that not only was the hole through my magnet out of round, but the entire magnet itself was not perfectly round. I reckon with such a cheap pump/impellar, there's bound to be some imperfections.

I do think the problems with noise are from these things being slightly out of balance, which causes vibrations at high RPM's.

I was figuring on just ordering an extra impellar or two.

[dhnguyen]

Originally posted by Norboo
What is the most reliable propeller for MJ 900 and 1200? I am not looking for super flow rate but rather more reliability (low maintenance).

…and where can I buy them?

Thank you.

for MJ900 use Octura 1435
for MJ1200 use Dumas 3004 or Octura 1435

The Dumas 3004 is larger and will produce more flow.

Get the props from mjmods.com

[dhnguyen]

Originally posted by johnvu713
My shroud is peppered with lot of holes...one more hole and it'll fall apart.
BTW i plugged it into a wavemaker and it wont restart..any remedies to resolve this?

some photos would help.

Also as quangtam7 mentioned, a shroud of any sort will impede the inlet area somewhat so you will never be able to get as much flow from a shroud versus going shroud less.

As far as the restart problem what prop did you use?


D.

[MrZ]

Originally posted by nautilus808
Mjmods have stainless steel rods that are the same diameter as the rods used in a store bought maxijet. Why use the carbon rod when the identical Steel rod diameter is available

I was wondering the same thing, and actually found a pretty good reason. The smaller diameter carbon fiber rod spins near perfect in a matching carbon fiber tube. The outer diameter of the carbon fiber tube is the perfect size for mating it up to both the dumas 3004 prop as well as the magnet with the top plastic part bored out. In this setup there is a little bit of slop on the bottom plastic part of the magnet & carbon rod but you eliminate the majority of vibration with such a positive match on the topside of the magnet (closest connection to the prop).

I've built a few of these now from scratch and gluing the carbon fibre tube directly to the top of the magnet assembly can result in an almost silent system when I am careful to glue it in nice and straight. Much much better than the airline tubing solution IMO.

Best one so far is still running silent after 3 months with no service.

-Z

[Snarkys]

so basically we have 4 combinations

cf on cf
cf on plastic
ss on cf
ss on plastic

one of these combinations certainly has to be hands down better than the rest but it seems we all get such different results . you would think buy now we would have ruled at least two of these out.

Guess i have had luck with them all but SS and plastic tube has produced fantastic results for me almost every time, just need to take the time to find the right piece and make sure it is in strait.


I suppose part of the problem is not many of us have built more than a few and tried them all the different ways. Even myself , I've done them all but 95% of them are the SS and plastic because i have had so much success with it.

[RichConley]

Snarkys, I just put together some of yours, one SS on Carbon fiber, one SS on Plastic, and honestly can't tell the difference.

[Snarkys]

ya to be honest i think 95% people have no issues with this project and of that 5% that do have problems half figure it out one way or another.

The debate between different materials may very well be a mute point and they all work well. Reality is we are using a bunch of materials that were not in any way made to do what we are asking of them so there are just bound to be some issues here and there. kinda the nature of a DIY project like this i guess.

[dhnguyen]

IME the SS rod will be quieter than the CF rod. At least at first.

In time the CF will wear out smooth and won't be a problem anymore anyway.


D.

[dhnguyen]

Anybody used this powerhead before?

http://www.premiumaquatics.com/Merch...e=JBJpowerhead

It looks like it may be a good candidate for an MJ mod as well
The price is right that's for certain.

[Snarkys]

that would be slick if it was the same sized mount

[Snarkys]

looks like its stronger too : )

[dhnguyen]

So what do you say Snarkys? Wanna give those a try?

[dhnguyen]

Ah heck I'm probably gonna order all 3 and try them out anyway. Just because I'm a dork more than anything

I also emailed JBJ asking about the wattage ratings on them.


D.

[JohnL]

This thread was automatically split due to performance issues. You can find the rest of the thread here: http://archive.reefcentral.com/forum...hreadid=968876