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78_Tahiti
07-05-2012, 11:01 AM
Since I'm not very good at sitting still for very long. I decided to experiment with an idea I had. I took an old Panther Impeller that had a few nasty nicks in it, and reshaped the intake side of the vanes, to make them a little more agressive! Heres some pics.

I increased the fin angle a 1/16", to give it a little bigger initial bite in the water.
5729

here's the hole it resides in.
5730

The clearance to the bronze sleeve is .010".
5731

Now maybe a little test at the river tomorrow to see what happens!

T8er S.
07-05-2012, 04:16 PM
Like a boss!:rooster:

78_Tahiti
07-06-2012, 11:10 PM
Wow! So far, I'm very pleased with the results! Took it out to the Sacramento river today for a couple of hours. GPS says 58mph at 4800 Rpm. My planing RPM is also lower. I can cruise at 23mph at 2800rpm. http://www.youtube.com/watch?v=SYdPacK4Kqg&feature=youtu.be

"THE ADVOCATE"
07-07-2012, 08:26 AM
Nice vid of the "split tail" as well!

freudian Slip
07-07-2012, 08:33 AM
Awesome!

roblock
07-11-2012, 08:50 PM
Interesting... care to clarify exactly what you did there?

78_Tahiti
07-12-2012, 01:40 AM
notice the angle of the blades on the impeller. The left is stock, the right side, the blades are now about 1/4" longer. This causes a bigger byte on the water in the pump!

roblock
07-12-2012, 05:34 AM
Ah, so you ground down the blade faces nearing the shaft? Or did you build up the outside?

78_Tahiti
07-12-2012, 02:30 PM
I cut a pie shaped piece out of each leading edge. This added the angle.

roblock
07-13-2012, 05:45 PM
Got it... have to rebalance the impeller afterward?

So you now get the same basic speed with lower rpms?

78_Tahiti
07-13-2012, 09:21 PM
Got it... have to rebalance the impeller afterward?

So you now get the same basic speed with lower rpms?
will take to my local machine shop to have the balance checked. I wanted to see how much it changed first! Impeller cut vs RPM works out on a curve. not a straight line, its more like, the thrust at 2000rpm was (this is simply an example) say 500psi, now its 540psi. At 3000rpm 850psi, now its 920psi, at 4000rpm was 1120psi now its 1210psi. I would have to measure the actual pressure difference, as well as the intake pressure, to give exact figures. Flying by the seat of my pants, GPS and RPM currently!

Jet Mad
07-14-2012, 07:40 AM
Nice vid of the boat running, don't know if saw correctly, but does the boat start to porpoise?

Wikus

roblock
07-14-2012, 09:37 AM
Flying by the seat of your pants??? Looks to me like your flying by the nozzle of your jet :biggrin:

How did you cut or grind the impeller?

78_Tahiti
07-14-2012, 12:46 PM
Thanks Wikus! It runs pretty good for a 20' boat! About the porpoising, I was running up river, coming up on a big cruiser displacing a lot of water!

I used a die grinder Rob, with a very thin cutoff wheel. then contoured the end closest to the shaft, with a flame shaped burr.

roblock
07-14-2012, 01:07 PM
Alright... I'm keeping all of this in mind. If I ever have the problem of extra impellers lying around, maybe I'll experiment myself (based on your trial and error of course :biggrin: ).

Jet Mad
07-14-2012, 01:07 PM
Thanks Wikus! It runs pretty good for a 20' boat! About the porpoising, I was running up river, coming up on a big cruiser displacing a lot of water!

I used a die grinder Rob, with a very thin cutoff wheel. then contoured the end closest to the shaft, with a flame shaped burr.

She does run nice, the way the water exists the nozzle looks like a Hamilton Jet disperses the water. I used to rework the brass impellers on those by hand, and it was a hassle getting the sharpening angle correct on the leading edge of the blades.

Wikus

78_Tahiti
07-14-2012, 01:15 PM
I bet Wikus! If the leading edge isn't shaped right. You would have an excellent cavitation maker! A Panther is similar to a Hamilton, Both are Axial Pumps.

Jet Mad
07-14-2012, 01:30 PM
I bet Wikus! If the leading edge isn't shaped right. You would have an excellent cavitation maker! A Panther is similar to a Hamilton, Both are Axial Pumps.

I have read your whole thread now, and looking at the pics where you cut the pieces out actually lessens the bite of the impeller, you are making the surface of the blade smaller.

On the Hamilton Jet impeller what we want is a 90* angle from the base of the impeller, with a 4* cutting edge. That is what made the impeller more efficient. The tips of the impeller blade also needs to be a sharp edge and not rounded.

Wikus

78_Tahiti
07-16-2012, 11:39 AM
I think why lengthening the blade works on the Panther impeller, may be the overall impeller shape. When compared to a Hamilton model. If you take the blades off, and just look at the shape of the cone. The Hamilton is shaped a little differently. Then looking at the exit side of the blade. The Hamilton Impellers seem broader. I know Hamilton Impellers are available in different pitches. Panther has only One. I'll put up a couple drawings of what I mean. Maybe you can see the methodology behind how I trimmed this style impeller. Are the Hamilton Impellers cupped at all?

Jet Mad
07-16-2012, 01:09 PM
I think why lengthening the blade works on the Panther impeller, may be the overall impeller shape. When compared to a Hamilton model. If you take the blades off, and just look at the shape of the cone. The Hamilton is shaped a little differently. Then looking at the exit side of the blade. The Hamilton Impellers seem broader. I know Hamilton Impellers are available in different pitches. Panther has only One. I'll put up a couple drawings of what I mean. Maybe you can see the methodology behind how I trimmed this style impeller. Are the Hamilton Impellers cupped at all?

Here is a picture of a 7 Series Multi Stage impeller.

They are for the 2 and three stage units.

I got the pic of the net, but will post some pics of the different style ones if you want, and how to sharpen the leading edge.

Wikus

78_Tahiti
07-16-2012, 04:16 PM
Please do Wikus! I love learning about the different pumps, and the different ways optimize flow,or setup for different HP ratings, then they are originally. I see the center hub is straight (front to rear) the Panthers hub is cone shaped, the blades are also much longer (front to rear) on a Panther. The exit side of a Panther Impeller is much narrower, in respect of the distance between hub and pump housing.

78_Tahiti
07-17-2012, 01:35 AM
Here's what I meant about taking a bigger Initial bite, with a Panther Impeller. By back cutting the hub end of the blades by an 1/8" (.125") the cut a straight line to the original tip location, creates an edge that is almost 3/16" (.1875") the reason this works in this application (at least seems to make sense) as the cone center, expands outwards, towards the rear of the impeller. The blades get shorter, and farther apart. I believe, the area at point of entry, must be slightly smaller, then the area, at the point of exit. Since water doesn't compress, This seems to make sense.

5872
see how the blade gap gets wider, as it gets shorter towards the exit (bottom)

5873
Here you can see the difference in the biting edge of the blade.

5874
This is the exit area. notice here as well, the blades are not at 90* in relation to the shaft. It appears that the blades are quite a bit longer, on these impellers, then they are on a Hamilton, as well. Any thoughts or Ideas, are greatly welcomed!

78_Tahiti
07-17-2012, 01:46 AM
For my next experiment with my Panther. I may take, another fairly beat up impeller I have, and cut the leading edge back at the tip end, and see what happens! Panther claims they have tested numerous Impeller profiles, However, this data seems to have been misplaced, or otherwise unavailable to the general public.

Jet Mad
07-17-2012, 02:25 AM
Here's what I meant about taking a bigger Initial bite, with a Panther Impeller. By back cutting the hub end of the blades by an 1/8" (.125") the cut a straight line to the original tip location, creates an edge that is almost 3/16" (.1875") the reason this works in this application (at least seems to make sense) as the cone center, expands outwards, towards the rear of the impeller. The blades get shorter, and farther apart. I believe, the area at point of entry, must be slightly smaller, then the area, at the point of exit. Since water doesn't compress, This seems to make sense.

5872
see how the blade gap gets wider, as it gets shorter towards the exit (bottom)

5873
Here you can see the difference in the biting edge of the blade.

5874
This is the exit area. notice here as well, the blades are not at 90* in relation to the shaft. It appears that the blades are quite a bit longer, on these impellers, then they are on a Hamilton, as well. Any thoughts or Ideas, are greatly welcomed!

I basically understand what you are trying to achieve.

Example: On a 751 Hamilton (single stage) you have 3 impeller profiles to suit different HP engines.

The higher the HP the more aggressive the pitch is on the impeller and the blade lengths are a bit shorter.

If I look at the profile of the Panther impeller it looks like one opening is bigger and it tapers off to a smaller size.

It might work what you are trying to do.

Wikus

78_Tahiti
07-17-2012, 03:22 AM
It would be real interesting to see the difference in the 3 Hamilton Impellers, compared to each other. Do the single stage impellers have a significant size entrance as this impeller?

Jet Mad
07-17-2012, 04:21 AM
It would be real interesting to see the difference in the 3 Hamilton Impellers, compared to each other. Do the single stage impellers have a significant size entrance as this impeller?

Maybe this will help.

Just a correction on a previous post.

The longer the blade length the more aggressive the bite of the impeller.

Wikus

78_Tahiti
07-17-2012, 10:21 AM
Thanks Wikus! Thats great info! I don't see many Hamilton Jets, in this part of California. So. I really enjoy learning what I can about them.

Jet Mad
07-17-2012, 10:40 AM
Tahiti,

I know that changing the nozzle size on the Hamilton makes a huge difference in performance, being an axial flow pump.

They had different shapes and sizes, you had one for skiing, one for speed and one for manoeuvring etc.

Wikus

roblock
07-17-2012, 08:04 PM
Here's what I meant about taking a bigger Initial bite, with a Panther Impeller. By back cutting the hub end of the blades by an 1/8" (.125") the cut a straight line to the original tip location, creates an edge that is almost 3/16" (.1875") the reason this works in this application (at least seems to make sense) as the cone center, expands outwards, towards the rear of the impeller. The blades get shorter, and farther apart. I believe, the area at point of entry, must be slightly smaller, then the area, at the point of exit. Since water doesn't compress, This seems to make sense.

5872
see how the blade gap gets wider, as it gets shorter towards the exit (bottom)

5873
Here you can see the difference in the biting edge of the blade.

5874
This is the exit area. notice here as well, the blades are not at 90* in relation to the shaft. It appears that the blades are quite a bit longer, on these impellers, then they are on a Hamilton, as well. Any thoughts or Ideas, are greatly welcomed!

Well I think I get it now... (I've been scratching my head for some time). The reason the blades get further apart is because the cone shape displaces some of the space available up front. The increased blade spacing makes up for it toward the exit. And now I see that by cutting back the leading edge, you are allowing more water in to begin with because the cone is narrow there.

78_Tahiti
07-19-2012, 08:24 AM
Exactly Rob! If you think of it this way, take a chunk of water, that would fill the empty space, between 2 blades of the impeller, from the leading edge to the trailing edge. During 1 revolution, I have opened up, the intake side, enough to pass a slightly bigger chunk of water during 1 revolution! Does that make sense?

roblock
07-19-2012, 05:44 PM
Exactly Rob! If you think of it this way, take a chunk of water, that would fill the empty space, between 2 blades of the impeller, from the leading edge to the trailing edge. During 1 revolution, I have opened up, the intake side, enough to pass a slightly bigger chunk of water during 1 revolution! Does that make sense?

Yes, that's what I had in mind. And obviously the rear of the impeller can handle more water as well or it wouldn't pass (since water doesn't compress). Since it seems to work, we must conclude the stock angle is not optimum... at least as it concerns your engine, and boat.

Did you actually pick up a little speed too, or did you just bring the rpms down?

78_Tahiti
07-19-2012, 06:22 PM
I'll know more as I go. best before 56 gps, now 58 gps! as I drive it more I'll know! If it hits 60 gps its done!!!!!

roblock
07-19-2012, 07:12 PM
I'll know more as I go. best before 56 gps, now 58 gps! as I drive it more I'll know! If it hits 60 gps its done!!!!!

Right on... and you save wear and tear by briging those rpm's down. Nice result...

60 is my target too. I hope that by cleaning up the pump a little and going a bit richer on the WOT end of the primary metering rods I'll be there next outing. Got 52 up at 4800 ft elevation and was running on the 'rich side of perfect' after jetting down for that elevation. But last year 52 is what we had at 2500 ft. We'll be back about 2500 next outing and I've jetted back up the secondaries to where they were. Now for testing the richer primaries. I think I am dialing in on the perfect jetting.

Let the tinkering continue.....

78_Tahiti
07-20-2012, 01:47 AM
There is obviously a lot more variables, when setting up a Berkley Style mixed flow pump. There are also hundreds of different aftermarket bits and pieces available. There are very few accessories for a Axial Flow Panther. Most of it having to with "It works fine, the way it is" kind of attitude, Panther seemed to have then. That's My opinion though. Like most small companies, I'm sure they went through some incredible growing pains & downsizing pains. I'm just glad Panther is Still in Business, so owners of their pumps like us, can still get parts! I have enjoyed accomplishing a couple of the goals I have had for my Big Tahiti and its Panther. I wanted to be able to trim the boat & sport a decent Rooster Tail. I have accomplished that goal, by making a few mods to their Panthervator. I've almost reached my second goal of 60mph with less then 400 horsepower, in my cruiser. This means fully rigged, as I take it to the lake! Anchor, vests, ropes, Bimini Top, Towels, cooler, 2 batteries, stereo, gas, my Lady! LOL! Then its time to build a little Lake Hot Rod! That's a different thread!

Jet Mad
07-20-2012, 04:44 AM
Tahiti,

Some nice footage on You Tube.

Couple of questions:

1. What carburettor are you running?
2. Distributor?
3. Timing curve?
4. Plug type and gap.
5 Normal altitude you use your boat.

Wikus

78_Tahiti
07-20-2012, 10:56 AM
Tahiti,

Some nice footage on You Tube.

Couple of questions:

1. What carburettor are you running?
2. Distributor?
3. Timing curve?
4. Plug type and gap.
5 Normal altitude you use your boat.

Wikusin order,
barry grant 750 cfm Mighty Demon Mech secondary carb.
recurved prestolie marine, with pertronix itniter III, msd blaster II coil
15 degrees initial advance, total 34 degrees all in at 3000 rpm
NGK platinum, gap .038"
elevation beyween sea level and 2000'

:biggrin:

Jet Mad
07-20-2012, 12:47 PM
Tahiti,

I am going to go the Barry Grant Carburettor route, 770 Holley Street Avenger just don't cut it.

I am running a MSD Ready to Run Marine Dizzy, got a couple of extra springs for advance adjustment, still running as it came out the box.

Thanks for sharing.

Wikus

roblock
07-20-2012, 07:25 PM
Questions... When you sharpen the impeller blades up front, how do you do it? I don't just mean what tools you use... but also whether you shave the top (or front) of the blade face, or underneath, or both? Put another way, do they come to a point like a needle ideally or is it beveled like most razor blades? Does it matter?

I have some small dings on the face of the blades on mine...

78_Tahiti
07-21-2012, 04:32 AM
Tahiti,

I am going to go the Barry Grant Carburettor route, 770 Holley Street Avenger just don't cut it.

I am running a MSD Ready to Run Marine Dizzy, got a couple of extra springs for advance adjustment, still running as it came out the box.

Thanks for sharing.

Wikus
2 things Wikus, The Demons are great carbs. Go with at least a "Mighty Demon" a 750 to 780 cfm. Demon is like an 850 cfm Holley, except it still snaps like a 750 cfm carb will! Demons like LOTS of Initial Timing! 14 to 16 degrees of initial! The stock setup for that distributor is a bit conservative. Depending on your cam. a good starting point will be 15 intial (idle) then max advance 32 degrees. all in by 3000 RPM. Remember a boat is always under load! Unlike cars, boats dont coast! Do yourself a favor. document your settings now. timing & advance curve, Idle speed. GPS top speed, max rpm, if possible ET from 1500 rpm start to max RPM. this will give you and us the information, to help you make improvements as you go! engine build details is always a plus also! LOL!

78_Tahiti
07-21-2012, 04:54 AM
Questions... When you sharpen the impeller blades up front, how do you do it? I don't just mean what tools you use... but also whether you shave the top (or front) of the blade face, or underneath, or both? Put another way, do they come to a point like a needle ideally or is it beveled like most razor blades? Does it matter?

I have some small dings on the face of the blades on mine...
Yes! it matters! keep the leading edge straight, you want the leading edge sharp on these impellers, the front edge (or top if its setting on bench) should be filed at almost the same angle as the blade drops. better yet heres a picture.