PDA

View Full Version : how to balance a 2 blade prop



JET BUG
09-18-2001, 08:24 AM
hello i need some advice my oldman has a
v drive (early casale no in out box)with a 2
blade stellings prop it has a inch and a quater shaft turning 6700 rpm is the shaft to thick also it has a split coupouling
with a whip strut.what is the correct
procedure for balancing this set up
the boat is a 70s ski racing boat designed in south africa and was powerd by a tunnel
port holman moody 427 side oiler ford
the prop is 12x16 pitch
all help is appreciated
cheers
J.B

HAVASANGER
09-18-2001, 06:54 PM
INCH AND A QUARTER IS NOT TOO THICK. THE SHAFT MUST BE STRAIGHT. CHECK IT OUT OF THE BOAT WITH A DIAL INDICATOR. THE STRUT MUST LINE UP THE SHAFT WITH THE V-DRIVE WITHOUT PUTTING A FLEX ON IT. THE PROP SHOULD BE CHECKED FOR STRAIGHTNESS AND PITCH UNIFORMITY AT A PROP SHOP.

superdave013
09-18-2001, 08:34 PM
1 1/4"! Man that's beefy and that's a good thing. My old ski racer has a 1 1/8" shaft. Yours is rare so be careful with that prop as you will have a very hard time finding a used one and new ones are super spendy. Like HAVASANGER said, check the prop shaft out of the boat. But before you pull it out see if there is allot of slop in the strut bushings. Some is OK. I would not try to balance your prop your self. I also would not send it to just any shop. Most shops don't do v-drive stuff and will treat your race prop like the ones that are on inboard ski boats! Send it back to Stellings, Menkins, Chad Hill, or Hill propellers. Sounds like your dad has one hell of a piece there. Can you post a pic of it or send me one?

JET BUG
09-18-2001, 10:29 PM
hello superdave013 and havasanger
thanks for the info i have a digital camera
and will take some pics the motor is out at the moment the 427 block needs a re-sleve but we built up a 390 using a lot of the 427 stuff the shaft is straight but it seems to have a lot of whip when we try to balance it
i dont think that it is possible to use the
same method as cars propshaft as this method secures the shaft at both ends i assume for the boat that you only secure one end and then try to balance it with the support struts in the right positions and this is where we are picking up problems the way we came upon it is we have a vibration while under way
cheers
J.B

superdave013
09-19-2001, 08:44 AM
If it's straight then run it. I have never seen or heard of balancing a propshaft. All v-drive boats have vibrations. Way more that any other types of boats. With your strut and the whip strut you will be fine. Also never run your boat in gear with it out of the water. The water lubs and cools the strut bushings. It will make a horriable sound it you turn it dry.

HAVASANGER
09-19-2001, 06:58 PM
JET BUG--NOT SURE WHAT YOU'RE TALKING ABOUT WITH THE BALANCING. LAY THE BARE PROP SHAFT IN A PAIR OF V-BLOCKS, AND ROTATE IT. LOOK FOR ANY RUN-OUT. IT CAN BE STRAIGHTENED IF IT'S TWEAKED. ALSO CHECK YOUR DRIVESHAFT FROM THR MOTOR TO THE V-DRIVE FOR BAD U-JOINTS OR LOOSE BOLTS. GOOD LUCK.

spectras only
09-19-2001, 08:45 PM
Jetbug, if a two blade prop doesn't vibrate over 3000 RPM,don't worry about balancing.Sold a lot of menkens etc, in the seventies and eighties and they all have a little bit of roughness at idle or low speed.As superdave said ,you don't balance the shafts,but check them for straightness.If it's properly aligned with the V-drive and the strut,you should be able to turn the shaft by hand easily.A little play in the bearing is not detrimental,but as soon you have vibration that disappears at alternating speeds,it's time to replace the fibre bushing.I've seen this happening ,when the clearence grown to almost 1/16th .As superdave mentioned ,don't spin the shaft with the engine without submerged in water.

JET BUG
09-20-2001, 12:08 AM
hey guys
thanks for all the advice i also wanted to ask, we have a casale toploader with a 1:17 ratio serial no 51538b64 we want to retro fit this drive to the boat where can i find info on this make and model how to overhaul etc,does this drive have some sort of thrust bearing in it or is it just straight bearings that are used we are concerned about the pressure placed on the bearings or doesent this matter help please
cheers J.B

spectras only
09-20-2001, 11:21 AM
Jet bug ,I think all the Casale units have thrust bearings,but if you anxious to find out ,why not call Andy Casale himself? BTW,do you still have that 427 sideoiler ,or it is found it's way into a hot Mustang?

superdave013
09-20-2001, 11:27 AM
JET BUG, I have the info you need on that top loader. When I get home from work I'll send it to ya!