bport
New Member
Newbie question (new to V-drives, that is). How do they align the shafts? What is adjusted?
Checking Shaft Alignment as Maintenance???
- Thread starter Liquid Pleasure II
- Start date
capecodcruiser
Active Member
Your signature says you have Bravo's, you also say you are new to Vdrives. V's are not the same as Bravo's. We will explain if you are in need of clarification.
David
bport
New Member
Right...new boat with V-drives. I will update the signature when I can get a picture...
But being new to v-drives, I would like to understand how this is adjusted.
But being new to v-drives, I would like to understand how this is adjusted.
- Oct 6, 2006
- 12,155
- Boat Info
- 1996 450DA
- Engines
- 3116 Caterpillars
However, before you go jacking around on the motor mount nuts, a little goes a real far peace.
Scottzzzy
New Member
- Jun 15, 2008
- 865
- Boat Info
- 2002 Sundancer 340
- Engines
- Twin V 8.1's CWC
Westerbeke Genset
Ok Frank, here's another newbie question regarding this topic to get your BP up. I notice some vibration from my 8.1's which initially I attributed to the size of the engines and my inexperience, but I do notice that approx. 3000+ rpm I can feel what i would describe as a pulsing vibration in the helm. At lower rpms I do not feel it, nor at higher rpms up to WOT on the sea trial.
My surveyor attributed some of this vibration to this type and brand of boat, and upon questioning compared getting all the vibration out to "finding the perfect golf swing" that "there are many many points that can attribute to a slight vibration and the are often hard to nail down". Even by the best tech.
Sound like excuses on his part, or lack of experience on mine?
I am wanting to be very proactive with my service regimen so any input is appreciated!:thumbsup::thumbsup:
My surveyor attributed some of this vibration to this type and brand of boat, and upon questioning compared getting all the vibration out to "finding the perfect golf swing" that "there are many many points that can attribute to a slight vibration and the are often hard to nail down". Even by the best tech.
Sound like excuses on his part, or lack of experience on mine?
I am wanting to be very proactive with my service regimen so any input is appreciated!:thumbsup::thumbsup:
skolbe
Well-Known Member
- Oct 3, 2006
- 3,549
- Boat Info
- 320 Sundancer, Zodiac 290 Wave Inflatable Tohatsu 6HP, Boston Whaler 130 Sport
- Engines
- 350 Mag V-Drive - Kohler 5ecd
Sounds like an excuse - My new 320 had a little vibration - then I had the props redone - it was really smooth and both motors hit the same RPM's at WOT.
- Oct 6, 2006
- 12,155
- Boat Info
- 1996 450DA
- Engines
- 3116 Caterpillars
A boat is a mechanical beast........it doesn't have feelings nor is vibration due to boat type. Generally, round things rotate and if everything is symmetrical and balanced and there is nothing growing on the rotating mass then there is no vibration. However, when you put 2 engines and rotating masses of round things together, harmonics begins to play a roll in the relative smoothness. Get the engines slightly out of sync by running them at slightly different rpms........no, the sync gauge isn't precise and neither are the tachs.......and you might feel some drumming or pulsing.
If there is a bent prop or shaft, you will feel a vibration and that vibration will gradually get worse as the rpms increases, but it won't go away. If your pulsing goes and comes then goes away at higher rpms, I'm betting on harmonics and not something bent.
You should be aware that some owners feel that the 8.1's in a 340DA have a natural pulsation at some rpms...perhaps someone who owns one can offer an opinion on that.
If there is a bent prop or shaft, you will feel a vibration and that vibration will gradually get worse as the rpms increases, but it won't go away. If your pulsing goes and comes then goes away at higher rpms, I'm betting on harmonics and not something bent.
You should be aware that some owners feel that the 8.1's in a 340DA have a natural pulsation at some rpms...perhaps someone who owns one can offer an opinion on that.
Excellent thread and very timely for an issue I'd like Frank's (and others) feedback on.
But first, I can confirm the 8.1s have a sort of audial pulsing at cruise speed, I hear it usually when the engines are in sync and the water's smooth - it's a sign all is well to me
For the past month or so, I've been having a Port side vibration while getting on plane, that quickly goes away. It sounds distinct and significant, almost like a metal banging every fraction of a second - but again only lasts for about 10 seconds between 2000 and ~3300 RPM or just as you're backing off the throttles a bit as you're coming up on plane.
Once on plane I can vary speed from 3000 to WOT with no further vibration, consistent RPMs and great performance. I've run for half an hour at least like this with it not returning.
I initially thought I had something wrapped in the line and asked my diver to check things out. I was surprised to hear he reported all clear - no lines, obstructions or even minor prop damage (visually at least).
Diver did have a theory though, he thought the prop nut might be loosening a bit though and said he was able to tighten it one full turn. He suggested that the prop itself may be slightly wobbling/vibrating coming up on plane until it settled into place, then when you come off plane that it moves again. Sort of makes sense in relation to what I'm hearing. But, on first power up after the tightening, it did exactly the same thing.
And as I've listened closer and observed it more, I've noticed that the faster I power up the more/longer it occurs and if I do a very slow power to plane I can almost eliminate the effect.
So, I'm thinking alignment, or cutlass bearing or prop reconditioning - but can't figure why any of these would only have an impact in a certain RPM/operating range.
I'd also considered some sort of tranny/engine issue that maybe had nothing to do with the running gear. Checked tranny fluid/general inspection and all is normal. Engine running fine in all other conditions.
Thoughts and clues?
Thanks gang (and Frank!), this site is always so helpful.
Kevin
But first, I can confirm the 8.1s have a sort of audial pulsing at cruise speed, I hear it usually when the engines are in sync and the water's smooth - it's a sign all is well to me
For the past month or so, I've been having a Port side vibration while getting on plane, that quickly goes away. It sounds distinct and significant, almost like a metal banging every fraction of a second - but again only lasts for about 10 seconds between 2000 and ~3300 RPM or just as you're backing off the throttles a bit as you're coming up on plane.
Once on plane I can vary speed from 3000 to WOT with no further vibration, consistent RPMs and great performance. I've run for half an hour at least like this with it not returning.
I initially thought I had something wrapped in the line and asked my diver to check things out. I was surprised to hear he reported all clear - no lines, obstructions or even minor prop damage (visually at least).
Diver did have a theory though, he thought the prop nut might be loosening a bit though and said he was able to tighten it one full turn. He suggested that the prop itself may be slightly wobbling/vibrating coming up on plane until it settled into place, then when you come off plane that it moves again. Sort of makes sense in relation to what I'm hearing. But, on first power up after the tightening, it did exactly the same thing.
And as I've listened closer and observed it more, I've noticed that the faster I power up the more/longer it occurs and if I do a very slow power to plane I can almost eliminate the effect.
So, I'm thinking alignment, or cutlass bearing or prop reconditioning - but can't figure why any of these would only have an impact in a certain RPM/operating range.
I'd also considered some sort of tranny/engine issue that maybe had nothing to do with the running gear. Checked tranny fluid/general inspection and all is normal. Engine running fine in all other conditions.
Thoughts and clues?
Thanks gang (and Frank!), this site is always so helpful.
Kevin
Last edited:
stuckinforward
New Member
an unbalanced tire doesnt vibrate all the time, only at certain speeds, upon inspection did your diver note the condition of the strut bearing? at times harmonics will come and go with RPM's. have you done an alignment check?
I assume you have 630's in there and the alignment could easily be checked, one thing though when doing the alignment is, when you are using your feeler gauges and you have a gap on one side lets say its at .008 and 180 across on the other side the coupling is touching, if you rotate the shaft 1/2 turn and the .008 gap ends up on the other side then you have a bend in the shaft, if after spinning and the gap stays in the same spot, its alignment...its often mistaken as an alignment problem and adjusted that way, this is a pretty precise way to check for bends and alignment.
at times the shaft will bend at the taper also and its hard to recognize in the alignment procedure, instead of a bow easily picked out by alignment its a sharper bend which can only be picked out by a dial indicater at the prop. even if you scuff a sand bar it may throw the prop out, Always when i get up on a boat, I will sit in the engine room and watch the stuffing box or dripless and have the owner tie the boat off tight and put it in forward, if its moving at all there's a problem.....unless its the prop or a bend at the taper. when i say bend, i mean a bend only recognizible by a dial indicator not the human eye...well if you can see a bend by eye, then you know its bent lol
I assume you have 630's in there and the alignment could easily be checked, one thing though when doing the alignment is, when you are using your feeler gauges and you have a gap on one side lets say its at .008 and 180 across on the other side the coupling is touching, if you rotate the shaft 1/2 turn and the .008 gap ends up on the other side then you have a bend in the shaft, if after spinning and the gap stays in the same spot, its alignment...its often mistaken as an alignment problem and adjusted that way, this is a pretty precise way to check for bends and alignment.
at times the shaft will bend at the taper also and its hard to recognize in the alignment procedure, instead of a bow easily picked out by alignment its a sharper bend which can only be picked out by a dial indicater at the prop. even if you scuff a sand bar it may throw the prop out, Always when i get up on a boat, I will sit in the engine room and watch the stuffing box or dripless and have the owner tie the boat off tight and put it in forward, if its moving at all there's a problem.....unless its the prop or a bend at the taper. when i say bend, i mean a bend only recognizible by a dial indicator not the human eye...well if you can see a bend by eye, then you know its bent lol
- Oct 6, 2006
- 12,155
- Boat Info
- 1996 450DA
- Engines
- 3116 Caterpillars
Kevin,
In reading your PM’s and the your post on this thread, this looks like where you are:
1. You have 8.1’s and are experiencing a pulsing with the engines synchronized.
2. You have recently developed a vibration on the port side when under load, for a short duration, between 2000-3300 rpm.
3. The vibration stops when you retard the throttles to cruise setting.
4. The boat performs normally once on plane and the vibration does not return at any speed above 3000 rpm.
5. Your diver examined the running gear and reported that he saw no damage and everything looked normal.
6. The diver discovered the port side prop to be loose on the shaft.
7. The vibration appears to be more significant the faster you accelerate.
8. Your transmission appears to operate normally and shows no fluid leakage.
You asked for thoughts and clues………….
It has been a while since I’ve owned gas engines, but I do run 320DA and 340DA’s fairly often and have been around inboard Sea Rays for 20+ years, so here are some theories and guesses:
1. There is a known issue with 8.1’s having a harmonic vibration in 34DA’s. For most owners it is more of an annoyance than a problem; however, when coupled with other real vibration from other sources, it becomes a problem.
2. (also 4.) Typically a bent shaft or a bent blade on a prop gets worse as rpm’s increase. At 2000 rpm you may not notice it; at 3000 rpm you begin to feel it and see the rails and stanchion begin to vibrate; at 4000 rpm, the rails may shake, you may feel it under your feet in the deck, the bimini supports may rattle and the cups and dished may rattle and move about, but bent running gear almost never decreases in intensity as rpm increases.
3. (also 4.) I believe, but am not sure, that Mercruiser delivered the 8.1 with 2 different damper plates (couplers). One was a 2-part assembly that is bolted together with springs much like an auto clutch disc, the other has the coupler vulcanized to the damper plate. The 2 piece damper has been known to rattle at some rpm ranges.
3. (also) Engine alignment can cause the vibrations you are experiencing. When the shaft is deflected to bolt up to a misaligned coupler, it can cause the other end of the shaft to whip in the cutlass bearing. The whipping can change with rpms and harmonics from the other engine and shaft.
5. Divers serve a valuable purpose, but there is very little a diver can do to check for out of balance running gear, bent struts, bent shafts or damaged props, unless he sees visible signs of physical damage. Holding a screwdriver against a strut to check for bent blades on a prop just won’t work.
To accurately check a shaft for straightness requires a dial indicator; to straighten a shaft requires that it be removed from the boat and taken to a machine shop with a lathe and press.
Props are similar. A prop can be out of balance and one or more blades can be deformed by hitting something or a grounding. Only a qualified prop shop can check a prop’s pitch, cup and balance.
6. The loose prop is a problem. While it is possible that your vibration and rattle is coming from it, I doubt it. Your shafts are 1-1/2” in diameter and the prop end has 1-1/8” X 7 tpi threads. If the prop nut were 1 revolution loose, the prop could have been moving back down the taper about .150”. When in forward gear, the prop would move forward on the taper where it becomes tight as the prop pushes the boat forward. In reverse, there should have been a clunk or bang (almost a ringing sound) as the prop slid aft and hit the prop nut. You may have had some rattle and vibration in reverse because the prop would have moved aft where the taper is a smaller diameter. Much running in reverse and the keyway in the prop may have worn, but in forward, I think the boat would have operated normally because the thrust of an 8.1 would have been holding the prop tight on the taper.
8.Bad bearings or worn shafts in a transmission can make noise, but typically, once you get enough wear to make a noise, it is usually obvious because transmission will rumble when it is put in gear and the noise will get louder as rpms increase but never go way at high rpms. A missing tooth will cause a click every time the missing tooth passes the gear it mates to and the clicking won’t go away at any speed. You will get an early warning since this kind of wear is obvious by the ferrous metal filings in your waste transmission fluid and filter wash solvent when you service the transmission. Transmission problems may be possible, but not at all likely with the symptoms you describe.
The running gear is a 340DA is probably a little more subject to vibration and harmonic issues with the running gear than other boats because of the combination of shaft diameter and length. Remember the aft end of your 68” shaft is supported by the strut which has rubber sleeve or bearing in it. My suggestion would be to approach this one step at a time and eliminate/improve each component in the process, doing the cheapest and easiest first.
1. Get in touch with the service manager at your Sea Ray dealer and discuss the 340DA harmonic vibration. Ask about the 2 piece damper plate………my bet is that this isn’t the first time he’s heard about either one. Perhaps there is an easy fix or this is something Mercruiser has done one of their “Double Secret Probation” type of recalls or technical service bulletins on.
2. Get in the engine compartment while somebody else runs the boat and look at the shaft where it comes out of the shaft tube and Tides seal. There should be no or almost no run-out or movement in the shaft as it rotates. Run-out usually means a bent shaft. This one doesn’t cost anything.
3. Do an engine alignment …in the water. If you haven’t ever done this, you probably need to anyway. Be careful trying to check for a bent shaft at the coupler. Due to the weight of the shaft being supported only by the rubber cutlass bearing, with the coupler loose, the shaft has a tendency to drop. You can check the 3 o’clock and 9 o’clock positions, but not the 12 and 6 positions. But, not all shaft damage can be determined at the coupler……see # 5 below.
4. Have a decent prop shop check your props checked, trued, balanced and brought back to the pitch and cup you are running. This is a good idea anyway since most owners can usually tell a difference in smoothness and performance with true-ed props.
5. The next time the boat is out of the water….or go spend $50 on a forklift haulout…have the shafts checked for straightness with a dial indicator. Remember that when the shaft is bent on most of these boats, the bend is aft of or right at the cutlass bearing. Perhaps this comment is a local one since we are in shallow sandy areas and most damage comes from someone letting an anchored boat bounce on the bottom as the tide runs out.
Also check your cutlass bearings for wear or abnormal wear patterns. A worn strut bearing can cause the shaft to wobble or move about. It usually makes a rumble under the boat, but a worn bearing can let the shaft move enough to vibrate if there are other things that set the shaft in motion like misalignment, harmonic vibration, bent prop, etc.
A cutlass bearing with a side-to-side wear pattern may indicate a bent strut. It isn’t likely unless the boat hit something pretty hard, but a bent strut can cause the shaft to whip since the engine end will be deflected. The symptoms will be the same as those of a misalignment.
Solving this one is going to be a process of elimination as you remove possible causes and insure that the running gear is straight and true. With 340DA’s the closer each part of the rotating assembly is to right, the less you will be bothered by the harmonic and other smoothness issues. You’ll never eliminate them, but you can make them tolerable.
Good luck with it……….
In reading your PM’s and the your post on this thread, this looks like where you are:
1. You have 8.1’s and are experiencing a pulsing with the engines synchronized.
2. You have recently developed a vibration on the port side when under load, for a short duration, between 2000-3300 rpm.
3. The vibration stops when you retard the throttles to cruise setting.
4. The boat performs normally once on plane and the vibration does not return at any speed above 3000 rpm.
5. Your diver examined the running gear and reported that he saw no damage and everything looked normal.
6. The diver discovered the port side prop to be loose on the shaft.
7. The vibration appears to be more significant the faster you accelerate.
8. Your transmission appears to operate normally and shows no fluid leakage.
You asked for thoughts and clues………….
It has been a while since I’ve owned gas engines, but I do run 320DA and 340DA’s fairly often and have been around inboard Sea Rays for 20+ years, so here are some theories and guesses:
1. There is a known issue with 8.1’s having a harmonic vibration in 34DA’s. For most owners it is more of an annoyance than a problem; however, when coupled with other real vibration from other sources, it becomes a problem.
2. (also 4.) Typically a bent shaft or a bent blade on a prop gets worse as rpm’s increase. At 2000 rpm you may not notice it; at 3000 rpm you begin to feel it and see the rails and stanchion begin to vibrate; at 4000 rpm, the rails may shake, you may feel it under your feet in the deck, the bimini supports may rattle and the cups and dished may rattle and move about, but bent running gear almost never decreases in intensity as rpm increases.
3. (also 4.) I believe, but am not sure, that Mercruiser delivered the 8.1 with 2 different damper plates (couplers). One was a 2-part assembly that is bolted together with springs much like an auto clutch disc, the other has the coupler vulcanized to the damper plate. The 2 piece damper has been known to rattle at some rpm ranges.
3. (also) Engine alignment can cause the vibrations you are experiencing. When the shaft is deflected to bolt up to a misaligned coupler, it can cause the other end of the shaft to whip in the cutlass bearing. The whipping can change with rpms and harmonics from the other engine and shaft.
5. Divers serve a valuable purpose, but there is very little a diver can do to check for out of balance running gear, bent struts, bent shafts or damaged props, unless he sees visible signs of physical damage. Holding a screwdriver against a strut to check for bent blades on a prop just won’t work.
To accurately check a shaft for straightness requires a dial indicator; to straighten a shaft requires that it be removed from the boat and taken to a machine shop with a lathe and press.
Props are similar. A prop can be out of balance and one or more blades can be deformed by hitting something or a grounding. Only a qualified prop shop can check a prop’s pitch, cup and balance.
6. The loose prop is a problem. While it is possible that your vibration and rattle is coming from it, I doubt it. Your shafts are 1-1/2” in diameter and the prop end has 1-1/8” X 7 tpi threads. If the prop nut were 1 revolution loose, the prop could have been moving back down the taper about .150”. When in forward gear, the prop would move forward on the taper where it becomes tight as the prop pushes the boat forward. In reverse, there should have been a clunk or bang (almost a ringing sound) as the prop slid aft and hit the prop nut. You may have had some rattle and vibration in reverse because the prop would have moved aft where the taper is a smaller diameter. Much running in reverse and the keyway in the prop may have worn, but in forward, I think the boat would have operated normally because the thrust of an 8.1 would have been holding the prop tight on the taper.
8.Bad bearings or worn shafts in a transmission can make noise, but typically, once you get enough wear to make a noise, it is usually obvious because transmission will rumble when it is put in gear and the noise will get louder as rpms increase but never go way at high rpms. A missing tooth will cause a click every time the missing tooth passes the gear it mates to and the clicking won’t go away at any speed. You will get an early warning since this kind of wear is obvious by the ferrous metal filings in your waste transmission fluid and filter wash solvent when you service the transmission. Transmission problems may be possible, but not at all likely with the symptoms you describe.
The running gear is a 340DA is probably a little more subject to vibration and harmonic issues with the running gear than other boats because of the combination of shaft diameter and length. Remember the aft end of your 68” shaft is supported by the strut which has rubber sleeve or bearing in it. My suggestion would be to approach this one step at a time and eliminate/improve each component in the process, doing the cheapest and easiest first.
1. Get in touch with the service manager at your Sea Ray dealer and discuss the 340DA harmonic vibration. Ask about the 2 piece damper plate………my bet is that this isn’t the first time he’s heard about either one. Perhaps there is an easy fix or this is something Mercruiser has done one of their “Double Secret Probation” type of recalls or technical service bulletins on.
2. Get in the engine compartment while somebody else runs the boat and look at the shaft where it comes out of the shaft tube and Tides seal. There should be no or almost no run-out or movement in the shaft as it rotates. Run-out usually means a bent shaft. This one doesn’t cost anything.
3. Do an engine alignment …in the water. If you haven’t ever done this, you probably need to anyway. Be careful trying to check for a bent shaft at the coupler. Due to the weight of the shaft being supported only by the rubber cutlass bearing, with the coupler loose, the shaft has a tendency to drop. You can check the 3 o’clock and 9 o’clock positions, but not the 12 and 6 positions. But, not all shaft damage can be determined at the coupler……see # 5 below.
4. Have a decent prop shop check your props checked, trued, balanced and brought back to the pitch and cup you are running. This is a good idea anyway since most owners can usually tell a difference in smoothness and performance with true-ed props.
5. The next time the boat is out of the water….or go spend $50 on a forklift haulout…have the shafts checked for straightness with a dial indicator. Remember that when the shaft is bent on most of these boats, the bend is aft of or right at the cutlass bearing. Perhaps this comment is a local one since we are in shallow sandy areas and most damage comes from someone letting an anchored boat bounce on the bottom as the tide runs out.
Also check your cutlass bearings for wear or abnormal wear patterns. A worn strut bearing can cause the shaft to wobble or move about. It usually makes a rumble under the boat, but a worn bearing can let the shaft move enough to vibrate if there are other things that set the shaft in motion like misalignment, harmonic vibration, bent prop, etc.
A cutlass bearing with a side-to-side wear pattern may indicate a bent strut. It isn’t likely unless the boat hit something pretty hard, but a bent strut can cause the shaft to whip since the engine end will be deflected. The symptoms will be the same as those of a misalignment.
Solving this one is going to be a process of elimination as you remove possible causes and insure that the running gear is straight and true. With 340DA’s the closer each part of the rotating assembly is to right, the less you will be bothered by the harmonic and other smoothness issues. You’ll never eliminate them, but you can make them tolerable.
Good luck with it……….
