velvet drive terrible noise only in gear

[sdowney717]

My slipmate's 1984 Tiara has twin 350 , 260 HP engines. One of the velvet drives is making a racket in gear only.
I found a video of another velvet drive and it sounds exactly like this one.
Video guy say 'clutches', but I am sure more than that went bad,
I have rebuilt these before on my boat replacing clutches, but what do you think is really wrong.
We disconnected prop hub and gear reduction turns smoothly.

And I told him I would help him take it out of boat.. Weight is 150 lbs. We could slide rear of boat under the dock, do you think two 60 year old guys can lift it up off the boat deck onto the dock?
Other option was unbolt the gear reduction, take it apart in boat to make it lighter.

This combo has the rear mounts on the side of the trans, do they have to be unbolted to loosen the velvet drive bolts to the bell housing?

What is the chance the damper plate has failed, would it only make noise in gear though, or all the time then?
I checked his gear oil and it was clear red but was down half a quart low. Filling it made no difference to the racket.

 

[rslifkin]

Definitely could be a damper plate. What's the idle speed of the engine both in gear and in neutral? Too low an idle can cause a damper plate rattle. Does the noise go away if you increase RPM a little?

If weight is an issue to pull it, you might be able to save 40 lbs by taking the reduction unit off first, then pulling the rest of the trans out.

 

[sdowney717]

500 rpm or so for idling. The other motor at same speed has no noise.
We increased the rpm, and it lessened, but it was still there, just more subdued.
Our noise was noticed with prop shaft hub connected. I told him today to try running with it disconnected to see if the noise is still there.

Regarding the youtube comment about it being clutches. I dont understand how worn out clutches could make that noise? I could understand slipping, but the trans does not slip.

about a bad damper plate, I could understand with trans loaded, more noise. Only way to know is take it off and look. But the trans input shaft spins in or out of gear along with the damper plate. So you would think noise all the time. And in neutral it has no noise.

 

[rslifkin]

500 rpm in gear is way too low. With Velvet Drives, spec is typically 650 - 700 in forward gear (not in neutral). I personally treat that as "in forward gear, tied to the dock", so they idle a bit higher when moving (and usually 850 - 900 in neutral when warm). Gives better idle thrust that way, keeps things quiet, and also means no stalling concerns when shifting before the engines are fully warm (especially when going for reverse while moving forward).

 

[sdowney717]

500 rpm in gear is way too low. With Velvet Drives, spec is typically 650 - 700 in forward gear (not in neutral). I personally treat that as "in forward gear, tied to the dock", so they idle a bit higher when moving (and usually 850 - 900 in neutral when warm). Gives better idle thrust that way, keeps things quiet, and also means no stalling concerns when shifting before the engines are fully warm (especially when going for reverse while moving forward).

yes, well when we checked this, engines were cold and we are tied to the dock. Dont want to force it to much like that.
Regardless, other engine at same rpm does not have the loud racket. The sound was worse the slower the engine.

 

[rslifkin]

The point where a damper plate rattle starts does vary, so they may not both rattle at the same rpm. And with cold engines 500 rpm in gear may be ok, idle will be higher when fully warm in most cases. But you mentioned raising the RPM didn't eliminate the noise, so chances are, the trans is going to need to come out.

 

[sdowney717]

When I rebuilt my engines, my damper plates were still good. And they are from 1970. They are round and not very wide, closest thig they look like is a clutch disc and pics look like some used in a DD app.

His maybe the triangular shape.
I oiled my plates with heavy gear oil, you know there are moving parts, the springs and the center hub.

 

[koliver]

My slipmate's 1984 Tiara has twin 350 , 260 HP engines. One of the velvet drives is making a racket in gear only.
I found a video of another velvet drive and it sounds exactly like this one.
Video guy say 'clutches', but I am sure more than that went bad,
I have rebuilt these before on my boat replacing clutches, but what do you think is really wrong.
We disconnected prop hub and gear reduction turns smoothly.

And I told him I would help him take it out of boat.. Weight is 150 lbs. We could slide rear of boat under the dock, do you think two 60 year old guys can lift it up off the boat deck onto the dock?
Other option was unbolt the gear reduction, take it apart in boat to make it lighter.

This combo has the rear mounts on the side of the trans, do they have to be unbolted to loosen the velvet drive bolts to the bell housing?

What is the chance the damper plate has failed, would it only make noise in gear though, or all the time then?
I checked his gear oil and it was clear red but was down half a quart low. Filling it made no difference to the racket.

You don't say how both 60 yr olds get in position to lift the trans in that Tiara.
When I did my engine swap, I needed to remove the velvet drive trans from the engine nearest the door, before the lift out of the hole, as the crane needed more swinging room than was available on that side. An old guy on a nearby boat had offered help, so I asked him to help on that part of the job. He went down into the hole, I went for some wood blocks. When I returned with the wood blocks, the trans was up on the saloon floor, so I didn't see how that old guy had done it, by himself. I put the trans back on, by myself, and it was hard to find room for only two arms, but the weight could be managed with lots of wood blocks.

 

[RT Firefly]

Greetings,
Mr. sd. "...do you think two 60 year old guys can lift it up...". Hire a couple of yard apes for a few $$...OR...

You will note there are no obnoxious springs or pads.

 

[sdowney717]

You don't say how both 60 yr olds get in position to lift the trans in that Tiara.
When I did my engine swap, I needed to remove the velvet drive trans from the engine nearest the door, before the lift out of the hole, as the crane needed more swinging room than was available on that side. An old guy on a nearby boat had offered help, so I asked him to help on that part of the job. He went down into the hole, I went for some wood blocks. When I returned with the wood blocks, the trans was up on the saloon floor, so I didn't see how that old guy had done it, by himself. I put the trans back on, by myself, and it was hard to find room for only two arms, but the weight could be managed with lots of wood blocks.

Getting trans out first involves the engine hook on the intake manifold.
He is constructing a stacked 2x4 bridge screwed together to form a beam. like 4 of them.

That will sit on stacked wood blocks on the ends. I have chain and a come along, plan to winch up rear of engine to clear the prop shaft. Then will maybe block engine in place and move bridge further back for trans lift. was thing engine could be propped on exhaust manifold to stringer with 2x4

I have a pull sling, can wrap around trans and use come along to lift it out of the hole. then lay hatch down and drop trans. the lift point needs high enough to clear trans from floor. (sole)

When I rebuilt both my v8's, i took off heads and exhaust and trans and used a stepladder, 2 cedar 4x6's and a 4x4 on top as a beam and other end on the window sill built a strong X shape with a center and it sat on the outside deck with beam thru the open window and lifted out the engines which was not more than 600 pounds doing something similar.

 

[sdowney717]

Greetings,
Mr. sd. "...do you think two 60 year old guys can lift it up...". Hire a couple of yard apes for a few $$...OR...

You will note there are no obnoxious springs or pads.

yeah, more worried about lifting it up onto the dock. We can slip the boat under that dock, stand there and heave it up, maybe together, definitely if take off the gear reduction. From boat deck to dock deck, depending on tides, would be up to 5 feet or so.

I figure if damper plate is obviously bad, trans is good so wont have to lift it out.

 

[Max Simmons]

When I removed mine, I managed to bolt some chain to it to make a handle. Made it a heckuva lot easier to get out of the ER

 

[Ski in NC]

No gear reduction on that unit. It is 1:1. Probably more like 100lbs.

Do check for a misfire in that engine. If engine is missing or stumbling it will set up a mean gear rattle. Even with a good drive plate and good trans.

But agree with others that it sounds like more than that. I'd check engine first, but before I went out on that boat I would want to know that the drive plate was good.

When pulling prop shaft back, check that the big central nut in the tranny flange has not come loose.

 

[rslifkin]

No gear reduction on that unit. It is 1:1. Probably more like 100lbs.

Do check for a misfire in that engine. If engine is missing or stumbling it will set up a mean gear rattle. Even with a good drive plate and good trans.

But agree with others that it sounds like more than that. I'd check engine first, but before I went out on that boat I would want to know that the drive plate was good.

When pulling prop shaft back, check that the big central nut in the tranny flange has not come loose.

Good catch, I didn't even notice the lack of reduction unit on there. Should be 100 - 110 lbs in that case, I think.

 

[SoWhat]

Bad damper plate would create constant noise while running so that is unlikely cause but I would replace it while transmission is out.

Diagnosing the cause is somewhat moot. The transmission needs a rebuild. New clutch plates will be part of that rebuild. Cost is typically ~$750. If bearings are shot price goes up. If gears are shot then price goes way up.

I used 1X10 ramps to walk transmission up and down heights but for 5' I would be tempted to build an A frame. Tie a safety rope to the transmission in case it goes over. Alignment for reinstallation is harder than removal so install 2 studs in place of 2 mounting bolts. Makes job a lot easier.

 

[SoWhat]

No gear reduction on that unit. It is 1:1. Probably more like 100lbs.

No reduction gear on the video. But OP has some high hp engines and more likely than not has 2:1 reduction gears. Removing it reduces the weight a little but most of the weight is in the transmission and is in hernia zone.

 

[sdowney717]

His Tiara does have a gear reduction, likely 2 to 1 makes sense.
The linked video is someone else boat that has the exact same noise

New info now, was out there today and we started engine, and with prop shaft disconnected and forced back, no noise idling in gear forward and back with extremely slight noise occasionally. That leads me to think the damper plates is breaking apart.

For in gear the below is observed
With prop connected and idling under load lots of terrible constant noise
With prop disconnect , so under zero load, no noise with occasional extremely tiny noise.

 

[sdowney717]

To get off the damper plate, move trans out of the way. Then does the bell housing have to come off back of motor? It seems it would if it is the triangular looking version.

Next few days, he is removing all the exhaust pipes, starter (sits on top right rear of engine), shift linkage, hoses, to make it easier on me.

The trans has the rear engine mounts bolted onto side wings attached to velvet drive was wondering if they have to also come off. Looks like the top locking nut for mounts have to come off to lift it enough to get off those support side wings. May also be easier to unbolt the motor mounts from stringer to get access to those side wing bolts.

I think the side support wings interfere with removing the 6 velvet drive attachment bolts into the bell housing.

 

[sdowney717]

Also does the new damper plate need an alignment tool to aid in then sliding the velvet drive shaft in? Like is done with an auto clutch and pressure plate?

 

[jleonard]

Also does the new damper plate need an alignment tool to aid in then sliding the velvet drive shaft in? Like is done with an auto clutch and pressure plate?

If you buy some threaded rod (same thread as the bolts) and put 2 lengths into the bolt holes on opposite sides they will act as a guide to help get the shaft into the hole. It will support most of the weight.
I don't recall the thread size or the length but that's the easy part.

 

[sdowney717]

If you buy some threaded rod (same thread as the bolts) and put 2 lengths into the bolt holes on opposite sides they will act as a guide to help get the shaft into the hole. It will support most of the weight.
I don't recall the thread size or the length but that's the easy part.

That sounds a good idea. It is 3/8 bolt standard thread.

 

[SoWhat]

Also does the new damper plate need an alignment tool to aid in then sliding the velvet drive shaft in? Like is done with an auto clutch and pressure plate?

Belll housing must be removed.

No alignment tool needed, but splined input shaft has to be centered in damper plate when installing. Possible to ruin damper plate if you try to force a misaligned shaft in. Thus the 2 studs in mounting bolt holes.

Note that triangle shaped damper plate is only rated to 360 Cu In. Install the HD round ones. They are universal fits and about the same price.

All the work is getting transmission out. I would replace the clutch plates and seals while it is out.

 

[sdowney717]

Belll housing must be removed.

No alignment tool needed, but splined input shaft has to be centered in damper plate when installing. Possible to ruin damper plate if you try to force a misaligned shaft in. Thus the 2 studs in mounting bolt holes.

Note that triangle shaped damper plate is only rated to 360 Cu In. Install the HD round ones. They are universal fits and about the same price.

All the work is getting transmission out. I would replace the clutch plates and seals while it is out.

That is good info. Now your saying the round dampers are universal. So the spline counts on the input shaft are the same? Do you happen to have a link example to a round one that will work? It is his boat, and if the damper is what is wrong, that is all he will want done.

Here are a variety of dampers, can you look at them and tell me which would be good ones?

https://bpi.ebasicpower.com/search_...er Part # &,Velvet Drive ... 10 more rows

ALTDA-107 seems like it would be the right one

 

[SoWhat]

That is good info. Now your saying the round dampers are universal. So the spline counts on the input shaft are the same? Do you happen to have a link example to a round one that will work? It is his boat, and if the damper is what is wrong, that is all he will want done.

Here are a variety of dampers, can you look at them and tell me which would be good ones?

ALTDA-107 seems like it would be the right one

Velvet drives typically have 26 tooth splines. Very generic.

I purchased the ALTDA-107 for my Ford Lehman's before I removed the transmission. The mounting hole pattern should match just about everything. But his engine may require a different bolt pattern so I can't say with any certainty that the ALTDA-107 is the correct one.

 

[sdowney717]

Velvet drives typically have 26 tooth splines. Very generic.

I purchased the ALTDA-107 for my Ford Lehman's before I removed the transmission. The mounting hole pattern should match just about everything. But his engine may require a different bolt pattern so I can't say with any certainty that the ALTDA-107 is the correct one.

If he has a triangular damper, will the round one use more bolts to hold it to the flywheel? How many bolts are typically used for this?

I am certain though he will have whatever Mercruiser used in 1984

 

[SoWhat]

If he has a triangular damper, will the round one use more bolts to hold it to the flywheel? How many bolts are typically used for this?

I am certain though he will have whatever Mercruiser used in 1984

I did not have triangular type. Mine used 6. Seriously doubt it would be triangular. Not rated for that hp. Damage will be obvious. Bit's of broken springs in bottom of bell housing or very loose springs.

 

[psneeld]

Bad dampner plates can make some sounds off and on, hard to tell it them, then go silent until major failure down the road.


Mine screeched for a bit in North Carolina, then went silent for hours.


The advice given to me was try for home (Jersey) and change it there...well it di fine with no noise/symptoms till 13 miles from home marina when it choked the engine to stoppage as spring bits jammed the flywheel.

 

[PM]

No matter what or where the noise is coming from the transmission needs to be separated from the engine. The first part you will encounter is the damper plate. It will be obvious to you if it is good or bad.

If it is bad replace it. If it looks good, keep digging, you will be replacing the damper plate anyway.

Two 60 or 70 year old guys can easily get the tranny out of the bilge, without even breaking a sweat. You each bring a 20 year old grandson, nephew or hired hand along for the final lift. Before they arrive, you guys do all the brain work like supporting the rear of the engine, getting the shaft loose and backed off, disconnecting the cooling and control lines, etc. Then call in the young muscle.

pete

 

[Choices]

The dampner plate can be changed in just a couple hours.

Mine sounded like lifter racket and went away slightly above 1k rpm.

It is about $150. Crazy not to change it. I think they are good for around 2500 hours, I changed mine at 5k, might have gone 250 more hours.

Dplate keeps input shaft aligned. As it fails it imparts a vibration into the BW.

When I changed mine noise reduction was dramatic. Shifting was much firmer and softer.

 

[OldDan1943]

I did not read every post but, I concluded, after reading about a page and a half.
A. wont know much more without removing it.

I had the trans rebuilt on my N46 MANY years ago...... It was one of those things that could not be ignored or put off. So that make the price almost immaterial. Caught the trouble via the oil sample.

I actually stumbled on a perfect shop to remove, rebuild and reinstall the transmission. They did it all 'in the water'.

I did recommend the shop to another boater (Grand Banks)..... He went and inspected the shop and talked to the personnel before they did the work.

Please let us know the final outcome please.