I have a CD28 with a Universal M3-20 diesel. Normally after starting
the the engine in neutral, the sound is a purring (relatively speaking for a diesel!),
after I put it into gear the noise is more like a roar.
PROBLEM: I push the gear shift forward and the purr continues.
The boat moves forward slowly. After a period of time usually
2 to 10 seconds, the gear 'kicks in', the roar starts and the
boat surges forward.
I examined the cable and seems ok. Moving the shift handle over
its full range moves the lever on the engine about 180 degrees
which seems to be its full range also.
Watching the propellor shaft, the rotation starts immediately
the gear shift is moved but without power.
Any ideas before I hand this over to the yard? Can I do anything
myself?
Mike
tmike@ma.ultranet.com
Transmission Problem
Moderator: Jim Walsh
-
Bill
Re: Transmission Problem
Hello Mike
I am certainly no expert on diesel engines, but it sounds to me that the engine is having to wait for the fuel to catch up or is running too rich.... Maybe bad injectors, bad fuel, air in line, or timing is off. Just my un-informed (regarding diesels) TCW.
And that's assuming that the roar has nothing to do with the problem.
good luck
Bill
Captain Commanding
S/V Rhapsody (the Original)
CD25D #148
Oklahoma Contingent of the NE Fleet, CDSOA, Inc.
Galley Wench S/V Evening Light
<A HREF="http://www.applegatemarina.com">Kerr Lake, OK (Oklahoma's Outlet to the Sea)</A>
cd25d@rhapsodysails.com
I am certainly no expert on diesel engines, but it sounds to me that the engine is having to wait for the fuel to catch up or is running too rich.... Maybe bad injectors, bad fuel, air in line, or timing is off. Just my un-informed (regarding diesels) TCW.
And that's assuming that the roar has nothing to do with the problem.
good luck
Bill
Captain Commanding
S/V Rhapsody (the Original)
CD25D #148
Oklahoma Contingent of the NE Fleet, CDSOA, Inc.
Galley Wench S/V Evening Light
<A HREF="http://www.applegatemarina.com">Kerr Lake, OK (Oklahoma's Outlet to the Sea)</A>
Mike Thompson wrote: I have a CD28 with a Universal M3-20 diesel. Normally after starting
the the engine in neutral, the sound is a purring (relatively speaking for a diesel!),
after I put it into gear the noise is more like a roar.
PROBLEM: I push the gear shift forward and the purr continues.
The boat moves forward slowly. After a period of time usually
2 to 10 seconds, the gear 'kicks in', the roar starts and the
boat surges forward.
I examined the cable and seems ok. Moving the shift handle over
its full range moves the lever on the engine about 180 degrees
which seems to be its full range also.
Watching the propellor shaft, the rotation starts immediately
the gear shift is moved but without power.
Any ideas before I hand this over to the yard? Can I do anything
myself?
Mike
cd25d@rhapsodysails.com
-
Tom
Re: Transmission Problem
It sounds like the friction plates inside the transmission are slipping. This is the most common problem with the Hurth transmissions. The surface of the plates gets slicked over and when you first put it in gear they slide past each other. Then they heat up from the friction and swell up enough to grab. I'm not sure what would cause the roaring. Maybe you're got a bad bearing that doesn't make much noise while the plates are slipping and then when they grab and the bearing gets torqued it starts making noise?
Does it also hesitate in reverse? Usually the forward gear goes out first. Does it make the roar in reverse also? Has it ever hopped out of forward?(that's the sign of the tranny about to go out.) I'm just guessing from a long way away and without seeing it, but I'm guessing it's inside the transmission and there's nothing you can do. Try everything else first and give the yard a shot at it, but if it is the tranny, you have to pull the engine to get it off because the trans is bolted on from inside the bell housing. Rebuilt transmissions run a round $1500 not including installation which is a two day job.
If it turns out to be the trans, don't let them just bolt a new one on without very carefully checking the alignment of the bell housing and trans. I went through three transmissions before I figured out that the factory alignment was bad and that was eating transmissions. At three thousand a pop that got old real fast. If it comes to a new transmission write me directly and I'll dig out the information on that source in Canada. Favorable exchange rate and no tax and a guy who does the rebuild personally will save you a bunch of money if they're still around. It's been ten years since I dealt with them so I'm not sure they're still there.
I hope it's something other than trans plates. Anybody else have any ideas?
TomCambria@mindspring.com
Does it also hesitate in reverse? Usually the forward gear goes out first. Does it make the roar in reverse also? Has it ever hopped out of forward?(that's the sign of the tranny about to go out.) I'm just guessing from a long way away and without seeing it, but I'm guessing it's inside the transmission and there's nothing you can do. Try everything else first and give the yard a shot at it, but if it is the tranny, you have to pull the engine to get it off because the trans is bolted on from inside the bell housing. Rebuilt transmissions run a round $1500 not including installation which is a two day job.
If it turns out to be the trans, don't let them just bolt a new one on without very carefully checking the alignment of the bell housing and trans. I went through three transmissions before I figured out that the factory alignment was bad and that was eating transmissions. At three thousand a pop that got old real fast. If it comes to a new transmission write me directly and I'll dig out the information on that source in Canada. Favorable exchange rate and no tax and a guy who does the rebuild personally will save you a bunch of money if they're still around. It's been ten years since I dealt with them so I'm not sure they're still there.
I hope it's something other than trans plates. Anybody else have any ideas?
Mike Thompson wrote: I have a CD28 with a Universal M3-20 diesel. Normally after starting
the the engine in neutral, the sound is a purring (relatively speaking for a diesel!),
after I put it into gear the noise is more like a roar.
PROBLEM: I push the gear shift forward and the purr continues.
The boat moves forward slowly. After a period of time usually
2 to 10 seconds, the gear 'kicks in', the roar starts and the
boat surges forward.
I examined the cable and seems ok. Moving the shift handle over
its full range moves the lever on the engine about 180 degrees
which seems to be its full range also.
Watching the propellor shaft, the rotation starts immediately
the gear shift is moved but without power.
Any ideas before I hand this over to the yard? Can I do anything
myself?
Mike
TomCambria@mindspring.com
-
Tom
Re: Transmission Problem
Bill is onto something here. When you advance the throttle does the engine speed up but the boat doesn't move (i.e. trans problem) or does the engine not speed up and hesitate for a few seconds? (i.e., engine problem)
TomCambria@mindspring.com
Bill wrote: Hello Mike
I am certainly no expert on diesel engines, but it sounds to me that the engine is having to wait for the fuel to catch up or is running too rich.... Maybe bad injectors, bad fuel, air in line, or timing is off. Just my un-informed (regarding diesels) TCW.
And that's assuming that the roar has nothing to do with the problem.
good luck
Bill
Captain Commanding
S/V Rhapsody (the Original)
CD25D #148
Oklahoma Contingent of the NE Fleet, CDSOA, Inc.
Galley Wench S/V Evening Light
<A HREF="http://www.applegatemarina.com">Kerr Lake, OK (Oklahoma's Outlet to the Sea)</A>
Mike Thompson wrote: I have a CD28 with a Universal M3-20 diesel. Normally after starting
the the engine in neutral, the sound is a purring (relatively speaking for a diesel!),
after I put it into gear the noise is more like a roar.
PROBLEM: I push the gear shift forward and the purr continues.
The boat moves forward slowly. After a period of time usually
2 to 10 seconds, the gear 'kicks in', the roar starts and the
boat surges forward.
I examined the cable and seems ok. Moving the shift handle over
its full range moves the lever on the engine about 180 degrees
which seems to be its full range also.
Watching the propellor shaft, the rotation starts immediately
the gear shift is moved but without power.
Any ideas before I hand this over to the yard? Can I do anything
myself?
Mike
TomCambria@mindspring.com
-
Mike Thompson
Re: Transmission Problem
Thanks Tom and Bill for your replies.
The speed of the engine seems to change immediately when the
throttle is adjusted.
There is no problem at all with reverse.
When going from neutral into forward gear should I have the engine
running as slowly as possible or at crusing revs?
Mike
tmike@ma.ultranet.com
The speed of the engine seems to change immediately when the
throttle is adjusted.
There is no problem at all with reverse.
When going from neutral into forward gear should I have the engine
running as slowly as possible or at crusing revs?
Mike
Mike Thompson wrote: I have a CD28 with a Universal M3-20 diesel. Normally after starting
the the engine in neutral, the sound is a purring (relatively speaking for a diesel!),
after I put it into gear the noise is more like a roar.
PROBLEM: I push the gear shift forward and the purr continues.
The boat moves forward slowly. After a period of time usually
2 to 10 seconds, the gear 'kicks in', the roar starts and the
boat surges forward.
I examined the cable and seems ok. Moving the shift handle over
its full range moves the lever on the engine about 180 degrees
which seems to be its full range also.
Watching the propellor shaft, the rotation starts immediately
the gear shift is moved but without power.
Any ideas before I hand this over to the yard? Can I do anything
myself?
Mike
tmike@ma.ultranet.com
-
Bill
Re: Transmission Problem
Mike
Dont slam it into gear at cruising revs that could really tear something up. Have it at idle and then put it in gear...
And if the engine revs up immediately when throttle is increase, but speed is unaffected for a short duration, then perhaps it is the tranny...Do you have a tachometer (sp)? If so what happens as you increase throttle? Do the RPMs increase "normally" and steadily? OR do they lag and hesitate? That should give you an indication as well.....
Bill
cd25d@rhapsodysails.com
Dont slam it into gear at cruising revs that could really tear something up. Have it at idle and then put it in gear...
And if the engine revs up immediately when throttle is increase, but speed is unaffected for a short duration, then perhaps it is the tranny...Do you have a tachometer (sp)? If so what happens as you increase throttle? Do the RPMs increase "normally" and steadily? OR do they lag and hesitate? That should give you an indication as well.....
Bill
Mike Thompson wrote: Thanks Tom and Bill for your replies.
The speed of the engine seems to change immediately when the
throttle is adjusted.
There is no problem at all with reverse.
When going from neutral into forward gear should I have the engine
running as slowly as possible or at crusing revs?
Mike
Mike Thompson wrote: I have a CD28 with a Universal M3-20 diesel. Normally after starting
the the engine in neutral, the sound is a purring (relatively speaking for a diesel!),
after I put it into gear the noise is more like a roar.
PROBLEM: I push the gear shift forward and the purr continues.
The boat moves forward slowly. After a period of time usually
2 to 10 seconds, the gear 'kicks in', the roar starts and the
boat surges forward.
I examined the cable and seems ok. Moving the shift handle over
its full range moves the lever on the engine about 180 degrees
which seems to be its full range also.
Watching the propellor shaft, the rotation starts immediately
the gear shift is moved but without power.
Any ideas before I hand this over to the yard? Can I do anything
myself?
Mike
cd25d@rhapsodysails.com
-
Tom
Re: Transmission Problem
It sounds like a transmission problem rather than an engine problem. You want to let the engine come to a complete idle before shifting from neutral into gear. What you have in your transmission is about 6 disks. These disks are thim metal -- about the size of a CD that you put in your music player, but they have a sort of cork-looking material like the brake shoes in your car on both sides. Three of these are attached to your engine driveshaft via little metal "fingers". The other three are attached to your prop shaft via other metal fingers. When you are in neutral the three disks attached to the prop shaft are not turning, but the three attached to your engine are. Thus the ones attached to your engine are spinning between the stationary ones attached to your propshaft. When you shift into gear a shifting "fork" forces the disks to slide along the shaft and press against one another. The disks attached to the prop shaft are now pinched between the disks attached to your engine and this forces the prop shaft disks to turn -- thus turning your prop shaft.
Naturally there is a little slippage when these disks first engage, so you want to have the engine turning over as slowly as possible when you shift into gear so that you don't wear off the surface on the disks. You don't want to shift slowly into gear because this causes the disks to slip past each other for awhile causing the surfaces to wear and get slick. (The same reason you don't ride the cluth on your stick shift car, but shift into neutral and take you foot off the clutch pedal rather than hold the clutch pedal to the floor). You want a quick snap into gear at full idle so there will be as little slippage (i.e., wear) as possible. Once you're in gear you don't want to suddenly throttle up to cruising rpms either. Get the boat moving and then slowly advance the throttle as the boat starts making way. I often see people back the boat out of the slip and then suddenly go into forward and floor the throttle to stop the reverse motion and get the boat moving. It's flashy and exciting, but it's also hell on your clutch plates.
For the same reason you don't want to leave the transmission in "forward" when you shut the engine off. The disks attached to the engine stop when the engine is stopped, but the disks attached to the prop shaft will freewheel from the force of the ocean water on the propeller. Having one set of disks turn while the other set doesn't move is what you DON'T want. This will wear out the lining on the disks and hasten the time when you will need a transmission replacement.
I'm not a mechanic but I had a lot of transmission problems before I figured out what was causing them and thus my education was in the school of hard knocks. I've still got my worn disks around somewhere but I haven't seen them in years. I also took some pictures of them which I might be able to find, but there's not much to look at. Some thin metal plates with brake lining on both sides that either wears out or gets glazed on the surfaces from poor shifting technique. It's not something you can replace yourself unless you're a skilled mechanic because the transmission has to come apart and putting it back together requires shims and special tools and tolerances to the thousandth of an inch. Alignment is critical or you'll have the same problem in a few years -- both inside the tranny and also the bell housing that the tranny bolts to. I can give you more details on this if you get to the point you're sure it's the transmission that's the problem. Usually a boatyard doesn't rebuild transmissions, they just take them out and exchange them for a rebuilt one and bolt it in place for you. That's what I was warning you about before. Just bolting a new one in place is a risky business because the bell housing may be out of alignment too and some of the rebuilds aren't done to specs either. You want to have a really competent mechanic/machinist check everything with a micrometer before you just bolt it up. Your average boatyard worker can't do this. Been there and done that as George the First used to say!
Good luck. I hope we missed something and it's not your transmission.
TomCambria@mindspring.com
Naturally there is a little slippage when these disks first engage, so you want to have the engine turning over as slowly as possible when you shift into gear so that you don't wear off the surface on the disks. You don't want to shift slowly into gear because this causes the disks to slip past each other for awhile causing the surfaces to wear and get slick. (The same reason you don't ride the cluth on your stick shift car, but shift into neutral and take you foot off the clutch pedal rather than hold the clutch pedal to the floor). You want a quick snap into gear at full idle so there will be as little slippage (i.e., wear) as possible. Once you're in gear you don't want to suddenly throttle up to cruising rpms either. Get the boat moving and then slowly advance the throttle as the boat starts making way. I often see people back the boat out of the slip and then suddenly go into forward and floor the throttle to stop the reverse motion and get the boat moving. It's flashy and exciting, but it's also hell on your clutch plates.
For the same reason you don't want to leave the transmission in "forward" when you shut the engine off. The disks attached to the engine stop when the engine is stopped, but the disks attached to the prop shaft will freewheel from the force of the ocean water on the propeller. Having one set of disks turn while the other set doesn't move is what you DON'T want. This will wear out the lining on the disks and hasten the time when you will need a transmission replacement.
I'm not a mechanic but I had a lot of transmission problems before I figured out what was causing them and thus my education was in the school of hard knocks. I've still got my worn disks around somewhere but I haven't seen them in years. I also took some pictures of them which I might be able to find, but there's not much to look at. Some thin metal plates with brake lining on both sides that either wears out or gets glazed on the surfaces from poor shifting technique. It's not something you can replace yourself unless you're a skilled mechanic because the transmission has to come apart and putting it back together requires shims and special tools and tolerances to the thousandth of an inch. Alignment is critical or you'll have the same problem in a few years -- both inside the tranny and also the bell housing that the tranny bolts to. I can give you more details on this if you get to the point you're sure it's the transmission that's the problem. Usually a boatyard doesn't rebuild transmissions, they just take them out and exchange them for a rebuilt one and bolt it in place for you. That's what I was warning you about before. Just bolting a new one in place is a risky business because the bell housing may be out of alignment too and some of the rebuilds aren't done to specs either. You want to have a really competent mechanic/machinist check everything with a micrometer before you just bolt it up. Your average boatyard worker can't do this. Been there and done that as George the First used to say!
Good luck. I hope we missed something and it's not your transmission.
Mike Thompson wrote: Thanks Tom and Bill for your replies.
The speed of the engine seems to change immediately when the
throttle is adjusted.
There is no problem at all with reverse.
When going from neutral into forward gear should I have the engine
running as slowly as possible or at crusing revs?
Mike
Mike Thompson wrote: I have a CD28 with a Universal M3-20 diesel. Normally after starting
the the engine in neutral, the sound is a purring (relatively speaking for a diesel!),
after I put it into gear the noise is more like a roar.
PROBLEM: I push the gear shift forward and the purr continues.
The boat moves forward slowly. After a period of time usually
2 to 10 seconds, the gear 'kicks in', the roar starts and the
boat surges forward.
I examined the cable and seems ok. Moving the shift handle over
its full range moves the lever on the engine about 180 degrees
which seems to be its full range also.
Watching the propellor shaft, the rotation starts immediately
the gear shift is moved but without power.
Any ideas before I hand this over to the yard? Can I do anything
myself?
Mike
TomCambria@mindspring.com
-
Chris Scheck
Why are they so delicate ...
Thanks for your description of how the Hurth works. It's what they call a multi-plate clutch (like a motorcycle transmission) rather than a single plate clutch (like a car) Is there oil in it (which a motorcycle has) or is it dry?
The transmission/clutch on our CD33 went bad when the boat was about 10 years old. It was preceded by a few months of horrendous grinding noises when you shifted into gear. Finally, you couldn't shift into forward, but you could still engage reverse.
These clutches really get very little use compared to a car or a motorcycle ... after all, you're not changing gears every few minutes like you do on the street. And they don't have the shock loading that they do in a car, since the coupling of the prop to the water is a shock absorber in itself, compared to tires on asphalt. Finally, most people only use the boat half the year. I would hope that they would last a lot longer ... and not be so damn hard to change.
cscheck@aol.com
The transmission/clutch on our CD33 went bad when the boat was about 10 years old. It was preceded by a few months of horrendous grinding noises when you shifted into gear. Finally, you couldn't shift into forward, but you could still engage reverse.
These clutches really get very little use compared to a car or a motorcycle ... after all, you're not changing gears every few minutes like you do on the street. And they don't have the shock loading that they do in a car, since the coupling of the prop to the water is a shock absorber in itself, compared to tires on asphalt. Finally, most people only use the boat half the year. I would hope that they would last a lot longer ... and not be so damn hard to change.
cscheck@aol.com
-
Tom
My opinion
I don't speak for Hurth, of course, but I'll give you my opinion. I think they are just woefully undersized for what they are trying to do. My 200cc Vespa motorscooter with 12 horsepower and pushing a 250 pound load had more plates and bigger ones than what is trying to push a 10,000 plus lb load in my boat. One reason they can get away with this is because most people don't use the boat much and can go years before they wear them out. Another is that, as you say, there isn't such a shock load due to the fact that you're pushing something in water (the prop) which allows for a little slip in itself and thus cushions the load.
The reason a lot of designers go with the small Hurth HBW 50 transmission is that they are very small. Imagine trying to push a 5 ton boat with a transmission that is about the size of a honeydew melon. Look at the tranny in your car about the size of a typewriter or small microwave oven. I think boat designers try to maximize the living accomodations on a boat because that sells them at the boat show. Then they try to cram an engine and transmission into some tiny hole at the rear with little access. A foot of extra space inside the cabin is more of a selling point than a big, old honking transmission that would never break down. This is just my own theory about why such inadequate transmissions and why they are so hard to get at to work on.
It's a wet clutch just like a motorcycle. You can turn it over and run it upside down if it's more convenient to have the shift controls on the other side, but if you do that you have to change the fill and draim plugs. The fill plug has a vent in it and this one has to be on top or all your transmission oil will run out. Transmission oil also breaks down with age and has to be drained and replaced just like in your car. It is such a fuss to get to, that most people just seem to run the transmission until they break down and then buy new ones.
Yhe Kuboda block is a great engine, but when Universal did the marine conversion they often didn't get the bell housing centered behind the engine, didn't get the surface of the bell housing parallel to the back of the block, and didn't get the transmission shaft directly behind the hole in the flywheel. The tolerance here is supposed to be two thousandths with 5 thousandths being the outside limit of what's acceptable. On my engine the trans was 15 thousandths out, the surface of the bell housing was 10 thousandths out of true with the flywheel, and the shaft was almost 10 thousandths out of center. The whole setup was egg shaped and would eat the torque plate that's bolted to the flywheel and accepts the transmission shaft in a short amount of time. I had to have the surface of the bell housing milled down and then we had to drill out the bolt holes on the bell housing and install some new pins to get it lined up with the engine.
By the way this is not that uncommmon for other engines as well. The machinist told me that many Cummings and Detroit diesels come new from the factory out of spec and he had sent more than one new engine back to the factory as defective and had it replaced. He's a meticulous guy and a machinist as well as a mechanic. Not all mechanics are that careful and when things break down in the middle of the sailing season we're always pushing them to get it back together and going asap, so the easiest thing is just to bolt a replacement on there without trying to figure out what caused the problem.
JMHO
TomCambria@mindspring.com
The reason a lot of designers go with the small Hurth HBW 50 transmission is that they are very small. Imagine trying to push a 5 ton boat with a transmission that is about the size of a honeydew melon. Look at the tranny in your car about the size of a typewriter or small microwave oven. I think boat designers try to maximize the living accomodations on a boat because that sells them at the boat show. Then they try to cram an engine and transmission into some tiny hole at the rear with little access. A foot of extra space inside the cabin is more of a selling point than a big, old honking transmission that would never break down. This is just my own theory about why such inadequate transmissions and why they are so hard to get at to work on.
It's a wet clutch just like a motorcycle. You can turn it over and run it upside down if it's more convenient to have the shift controls on the other side, but if you do that you have to change the fill and draim plugs. The fill plug has a vent in it and this one has to be on top or all your transmission oil will run out. Transmission oil also breaks down with age and has to be drained and replaced just like in your car. It is such a fuss to get to, that most people just seem to run the transmission until they break down and then buy new ones.
Yhe Kuboda block is a great engine, but when Universal did the marine conversion they often didn't get the bell housing centered behind the engine, didn't get the surface of the bell housing parallel to the back of the block, and didn't get the transmission shaft directly behind the hole in the flywheel. The tolerance here is supposed to be two thousandths with 5 thousandths being the outside limit of what's acceptable. On my engine the trans was 15 thousandths out, the surface of the bell housing was 10 thousandths out of true with the flywheel, and the shaft was almost 10 thousandths out of center. The whole setup was egg shaped and would eat the torque plate that's bolted to the flywheel and accepts the transmission shaft in a short amount of time. I had to have the surface of the bell housing milled down and then we had to drill out the bolt holes on the bell housing and install some new pins to get it lined up with the engine.
By the way this is not that uncommmon for other engines as well. The machinist told me that many Cummings and Detroit diesels come new from the factory out of spec and he had sent more than one new engine back to the factory as defective and had it replaced. He's a meticulous guy and a machinist as well as a mechanic. Not all mechanics are that careful and when things break down in the middle of the sailing season we're always pushing them to get it back together and going asap, so the easiest thing is just to bolt a replacement on there without trying to figure out what caused the problem.
JMHO
Chris Scheck wrote: Thanks for your description of how the Hurth works. It's what they call a multi-plate clutch (like a motorcycle transmission) rather than a single plate clutch (like a car) Is there oil in it (which a motorcycle has) or is it dry?
The transmission/clutch on our CD33 went bad when the boat was about 10 years old. It was preceded by a few months of horrendous grinding noises when you shifted into gear. Finally, you couldn't shift into forward, but you could still engage reverse.
These clutches really get very little use compared to a car or a motorcycle ... after all, you're not changing gears every few minutes like you do on the street. And they don't have the shock loading that they do in a car, since the coupling of the prop to the water is a shock absorber in itself, compared to tires on asphalt. Finally, most people only use the boat half the year. I would hope that they would last a lot longer ... and not be so damn hard to change.
TomCambria@mindspring.com