prop moves on shaft-should it be tight? |
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91SN
Newbie Joined: August-24-2008 Location: United Kingdom Status: Offline Points: 38 |
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Posted: September-21-2008 at 7:44pm |
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my prop seems to have a bit of play in it, its not dead tight on the shaft. I can move it a tiny bit back and forth on the shaft before the shaft rotates.
im guessing this isnt normal - is it just a case of tightening the castle nut on the shaft to tighten it up? cheers |
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8122pbrainard
Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41040 |
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Andrew, It may not be just tightening up the castle nut. I'd pull the prop and check to see if the props taper matches the shaft taper. The proper way to do this is to use "high spot" blue. It's typically used to check the contact area of the teeth of two gears such as the ring and pinion in the rear end of a car.
The tapers should match within about .002" front to back. If the taper is bad, then valve grinding compound is used to lap in the taper. How long has it been this way? It could also be that the prop was never installed properly ether. It's the taper that transmits 80% of the HP and torque to the prop so do check the key too. Never oil a taper. the taper fit is why we need a puller to remove the prop! |
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jbear
Grand Poobah Joined: January-21-2005 Location: Lake Wales FL. Status: Offline Points: 8193 |
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Sure do enjoy your posts and knowledge Pete.
john |
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"Loud pipes save lives"
AdamT sez "I'm Canadian and a beaver lover myself"... |
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OM45GE
Senior Member Joined: September-07-2007 Location: United States Status: Offline Points: 109 |
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He really is a fountain of knowledge. I can't tell you how many times I learn something new from Pete's posts - even after almost 50 years of messing around with boats. |
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1989 SN 2001
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eric lavine
Grand Poobah Joined: August-13-2006 Location: United States Status: Offline Points: 13413 |
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He helped build Noahs Ark
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"the things you own will start to own you"
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8122pbrainard
Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41040 |
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Guys thanks for the compliment. It's really appreciated but trust me that there are many times when I need help too and that will never end. We all help each other. |
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adamt
Gold Member Joined: July-18-2007 Location: Orlando, FL Status: Offline Points: 927 |
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Pete B for President!!! |
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-Adam
1973 Skier |
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91SN
Newbie Joined: August-24-2008 Location: United Kingdom Status: Offline Points: 38 |
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thanks for that. not sure how long to be honest, only just noticed it. dont remember it being like that last time I looked as couple of months back. there always seems to be something which needs looking at! |
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randall
Senior Member Joined: July-30-2004 Location: United States Status: Offline Points: 123 |
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I am trying to get my acme 540 to seat happily again on my shaft.
How long do you twist the prop on the shaft using the valve lapping compound. (5 revolutions, 5 minutes, etc)?? And, I assume you should clean the lapping compound off the shaft and prop VERY well before final install? Thanks. |
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1973 CC Mustang
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79nautique
Grand Poobah Joined: January-27-2004 Location: United States Status: Offline Points: 7872 |
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you don't have to lap it in unless it's really out of wack. Just remove the keyway slide the prop on as far as it will go onto the shaft then mark the shaft on the back side of the prop, then remove it, install the key way, install the prop tighten it down then verify that the mark is even or gone once you tighten the castel nut.
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8122pbrainard
Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41040 |
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"happily"? Sounds like you feel there's a problem. What did you do to check the fit? |
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randall
Senior Member Joined: July-30-2004 Location: United States Status: Offline Points: 123 |
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The store was out of High Spot Blue or equivelant. I didn't check with that. I put on lapping compound and made revolutions for a couple of minutes, cleaned up, and reinstalled.
I bent my beloved 540 in Aug. (I ran it 3+ years) I hit a piece of firewood floating. I sent to ACME and decided to also have them take off .5 inch diameter to help with clearance. "Ain't" got it right since... My old Fed 12x14 runs fine...makes me think shaft OK. I am still getting a lot of vibration in my ski mirror between 15-25mph with the 540. I have been working with Jim Thelen at ACME. They have been great. They checked the prop a second time and sent it back. He is questioning the install and recommended using the lapping. He said sometimes you just don't get a good join of prop and shaft. I hope we didn't create "frankenstien" with cutting the diameter down. I think there is documentation on this forum that people have tested the 540 on older Tiques and Mustangs and had uncorrectable minor vibration. So now, I don't know which way to throw money... (advice appreciated) A. $90hr to have the dealer mechanics check everything out. (shaft, alignment, prop install, strut and bushing) B. Try to work out something with ACME on trying a 1210 or another prop. C. Give up on the 540 and buy a less aggressive OJ (~$300). D. Give up and stay with the old Fed 12x14 (naa..not after feeling the 540 holeshot) I would hate to give up on it. The performance is just too good. Thanks all. |
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1973 CC Mustang
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8122pbrainard
Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41040 |
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Randall,
Even without the high spot, you should be able to look at the contact area of the taper and see if the lapping compound is only working on certain spots. A good taper doesn't take much force to stick it. Without the key and the taper wiped clean, put the prop on by hand. Get the prop and shaft keyways close to being lined up and then slightly twist and push. Does it stick? I've had them stick to the point that I will need to put the puller on to pull the prop - that's a good taper fit! Since you sent the prop to Acme twice, hopefully they checked the taper. I don't feel that cutting down the dia. created a problem. I know you have mentioned you have been running the 540 for some time and weren't getting the vibration some of us have had (like me!!) Is the vibration new to the 540? Did you get any before the dia. change? With the new dia., the vibration just may be at a different RPM range. Mark the forward position of the hub during a dry fit as recommened and try it again to make sure your not binding on the key. |
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randall
Senior Member Joined: July-30-2004 Location: United States Status: Offline Points: 123 |
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The ground paste did look even when I looked at the shaft and prop. The only place it wasn't touching the prop taper was at the tail end close to the nut where the diameter is smallest. I did notice a straight line the full length of the taper that might be high or low. I will check again.
I ran the 540 (13'') out of the box for 3+ years without vibration. So far, the diameter trim seems like a mistake. I will check again for the key/no key placement on the shaft. In the back of my mind, I am thinking by the time I pull it 80+ miles both ways and pay 90hr, I could just as easy get in a shiney new OJ 12x13. I want to get the mechanics to check everyhing...but I also know the 90hr labor doesn't always buy you superior service. Thanks! |
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1973 CC Mustang
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h20loo
Senior Member Joined: August-30-2008 Location: Canada Status: Offline Points: 225 |
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Maybe not build it but DEFINITELY HELPED RESTORE TO ORIGINAL!!! |
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70 Mustang project
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randall
Senior Member Joined: July-30-2004 Location: United States Status: Offline Points: 123 |
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Here are some pictures of the mark down the middle. Notice the rest of the surface shows smooth contact (lightly sanded look). I can't tell if this is a high or low point.
Do you think this is enough to cause problems? Also, notice the area closest to the nut does't make contact... The prop was on there good. It was tight. I will try the key test next. Thanks all. |
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1973 CC Mustang
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79nautique
Grand Poobah Joined: January-27-2004 Location: United States Status: Offline Points: 7872 |
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I would say that is just the compound being moved as the prop is being removed from the shaft and riding against the top of the shaft as the weight of the prop while cause it to make contact will removing it.
in others words your ok nothing to get excited about, to uniform not to be a drag mark during removal. |
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jbear
Grand Poobah Joined: January-21-2005 Location: Lake Wales FL. Status: Offline Points: 8193 |
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Pete is also a very flashy dresser...know he could also give out some tips on how we could all look our best. john |
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"Loud pipes save lives"
AdamT sez "I'm Canadian and a beaver lover myself"... |
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8122pbrainard
Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41040 |
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Randall's pictures of the prop bore are a perfect example of what I have mentioned before. In another thread, I stated that the prop OEM's (especially Acme) are recommending lapping and I felt it was due to the RMS finish of the bore. We are not seeing the reamed or ground finishes we saw in the past. With the advent of the CNC machined prop, they are skipping the steps needed to produce the better RMS finishes. These pictures are after he lapped the bore and you can still see how rough it is. I think it was in one of the lapping instructions that I saw the min. contact area they wanted after lapping is 70%. Now that's a tough one because our eyes are not optical comparators!!
New out of the box props need to be checked for fit. Take the time to use the high spot blue. Keep in mind the front to back difference is the most important and shouldn't be over .002" - that will show up as the high spot showing more on one end of the taper. Randall, I don't know what that mark is! Lap it some more and see if it starts to go away. John, Just so you know, I've never need to worry about having my shirts stolen. I don't thick there are many thieves out there with PWB initials!! |
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8122pbrainard
Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41040 |
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Randall,
Out of curiosity, I printed out your pictures and brought them in this morning to show one of out tool makers the bore finish. The first think he said, was that it sure looks like they had their feeds and speeds wrong when they machined that taper! The RMS should be better than that on a CNC. He continued on to say that the finish needed to produce a decent taper fit should include a secondary grinding or reaming. Without that, it's defiantly the reason for the lapping recommendation. Without the high spot and just looking at the pictures, he said the closest guess to a contact area is 60%. I have to agree with the % figure. Lap it in some more like I said and try it out. I however don't feel it will cure your vibration issue. What's the prop shaft look like? |
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randall
Senior Member Joined: July-30-2004 Location: United States Status: Offline Points: 123 |
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Thanks 8122pbrainard!
The shaft is 7 years old (updated). After the lapping compound, it has the same dull lightly sanded look where there was contact. I ran this prop and shaft combination for 3.5 years without problems. Can shafts be this fragile?? This could be two bent shafts in two hits in 7 years. I am hoping the shaft isn't bent. It runs the fed 12x14 just fine. But, I guess that is like comparing apples to oranges. I noticed my rudder has about 1/4 inch of horizontal play in it. I will check that tonight. Could that cause vibration on one prop vs the other?? |
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1973 CC Mustang
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8122pbrainard
Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41040 |
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Randall, Probably wouldn't hurt to check the shaft for straightness. I have a feeling that's not what is causing the vibration especially since the Federal prop runs good. It just may be the harmonics with the Acme which has changed since it was cut down. I don't feel it's your rudder ether.
When I asked about the shaft, I was asking about the taper on it. |
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randall
Senior Member Joined: July-30-2004 Location: United States Status: Offline Points: 123 |
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Here are two shots of the prop after two good "lappings". The line on the prop is less visible now.
From testing, no doubt the old fed 12x14 runs smooth at the same mph range (tach is broke). I am going to do one more lake test and then swap something with Jim at ACME. Thanks for the feedback. |
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1973 CC Mustang
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