Volvo Penta engine coupler runout … aka wobble

[highpowerdad]

I picked up a VP 2006 5.7 GI motor with the intention of putting it in a project boat…it is in great shape, however… the engine coupler is “wobbling”. When I measure the runout of the coupler HOUSING (not the spline, but the outer metal housing, on the diameter, at the aft most edge, measured to a common reference point as I rotated the engine), I get .040” of radial movement, so .020” from “concentric” IF I take angle measurements, I get a change of about 0.3 degrees on the aft face of the coupler as I rotate the crank, so, again, an error of about 0.15 degrees from the normal, which, doing the trig, is the same .020” change, so it is a “Wobble”.

This doesn’t seem right, but I have no reference point as to what is good and bad…

SO, is this, ok? Will it cause vibrations, damage bearings? Is this possibly a bad coupler or, worse, a bent engine crankshaft? This engine was pulled from a boat that was in a road accident. The boat was not hit but came off of its trailer when the trailer went off the road into a ditch, the gimbal ring was broken from transom at the top pivot, I assume from the inertia. I had also assumed that with the U-joints and the rubber coupler in line, the engine crankshaft was protected, now I am not so sure. Any insight is appreciated.

Thanks
Scott R.

 

[Scott Danforth]

first, make sure the coupler is mounted properly.

then make sure you are looking at the hub

you dont have a bent crankshaft. forces required to bend the crankshaft would have broken the block

 

[Lou C]

Maybe remove the coupler and make sure nothing of off with the mounting also you might be able to check the run out of the flywheel where the coupler mounts…

 

[highpowerdad]

first, make sure the coupler is mounted properly.

then make sure you are looking at the hub

you dont have a bent crankshaft. forces required to bend the crankshaft would have broken the block

Scott D, Thanks for your insight, So, I am pretty sure this would be the original coupler, as it doesn't look like the bell housing has ever been removed, I guess the best thing to do is remove the bell housing so I can really see what is going on and spin the motor. Any tricks to removing the bell (assuming that is what it is called on a boat?). Also, since you didn't say "that is normal" I guess I am looking for what is bent or not aligned. I can't really get a good measurement off of the hub itself, but if the metal housing of the coupler is wobbling, I would assume the center hub is wobbling also.
Scott R.

 

[alldodge]

Support the rear of the motor and than remove the bolts holding the bell housing

 

[Scott Danforth]

Pull drive
Disconnect the motor
Then pull the motor
Then remove the bellhousing

 

[bruceb58]

If it were my boat, I would be putting in a new coupler.

 

[highpowerdad]

All, sorry if I wasn’t clear in the original post, the motor is NOT in the boat, so I have full access to work on it. I was wondering if anyone had seen this wobble of the coupler on their past experiences, and what was “normal”. Since the engine was from a boat that was involved in a road incident, I was concerned that maybe the crank was bent. So, now that I know I need to figure out what is going on, first thing is to remove the bell housing, anything special about doing that? Support back of motor, from lift ring or can I have a block under the oil pan? Remove starter first, or it can stay? Is the a gasket around the top of the bell that needs to be replaced? I assume the front close out piece needs to come off so I can clear the flywheel. Looking for guidance so I don’t reinvent the wheel…I know some of you have done this several times, this is my first rodeo. I do have a shop manual, I will need to take a look at that also.
I’m gathering the information before dive in, thank you for sharing any experience you have.

 

[Bondo]

All, sorry if I wasn’t clear in the original post, the motor is NOT in the boat, so I have full access to work on it. I was wondering if anyone had seen this wobble of the coupler on their past experiences, and what was “normal”. Since the engine was from a boat that was involved in a road incident, I was concerned that maybe the crank was bent. So, now that I know I need to figure out what is going on, first thing is to remove the bell housing, anything special about doing that? Support back of motor, from lift ring or can I have a block under the oil pan? Remove starter first, or it can stay? Is the a gasket around the top of the bell that needs to be replaced? I assume the front close out piece needs to come off so I can clear the flywheel. Looking for guidance so I don’t reinvent the wheel…I know some of you have done this several times, this is my first rodeo. I do have a shop manual, I will need to take a look at that also.
I’m gathering the information before dive in, thank you for sharing any experience you have.

Ayuh, a block of wood under the pan will work, 'n the starter can stay put,....
pull the little cover off the bottom of the flywheel cover, then the bolts holding the flywheel cover to the block,....
At that point, the flywheel cover can be removed,...
No gaskets involved, atleast on a Merc,.... not sure on a Volvo, but I doubt it,....

 

[highpowerdad]

Ayuh, a block of wood under the pan will work, 'n the starter can stay put,....
pull the little cover off the bottom of the flywheel cover, then the bolts holding the flywheel cover to the block,....
At that point, the flywheel cover can be removed,...
No gaskets involved, atleast on a Merc,.... not sure on a Volvo, but I doubt it,....

Thank you, going to take it apart hopefully this week.

 

[highpowerdad]

I took a slow-motion video of wobble, will not get a chance to work on this until sometime in the new year...

 

[alldodge]

I wouldn't pay much attention to what's happening on the outer piece, need to check the inner

Use a 1 inch bar or other and get a dial indicator reading on runout

 

[Scott06]

I would think .040" runout is not an issue on this, but given the age of the boat I would also consider it prudent to replace the coupler while out. Of course this depends on what your plans are for the boat and how much of an issue it is if you have to jank the engine again.

How was the alignment prior to engine removal ?

When i bought a handymands special back in 2015 the boat only had 37 hrs and alignment was pretty good so I left the existing coupler in place . 10 years and 400 hrs later no issue

 

[highpowerdad]

I wouldn't pay much attention to what's happening on the outer piece, need to check the inner

Use a 1 inch bar or other and get a dial indicator reading on runout

Yea, Scott D said the same thing, unfortunately, the center is moving just like the outside rim, and I can see that in the video also. I am surprised though, with my alignment bar, that I can move the coupler hub about 2 inches at the end of the bar with about 10-20 lbs force, that equates to over 5 deg each way (outside rim doesn't move), I would have expected the rubber to be very hard. Right now, just "hoping" that Scott D is right and the Crank is stronger than the coupler since I had planned on replacing the coupler anyway. Looking at the cranks online, they do look very stout, even the flange where the flywheel mounts to is massive. Hope is the only thing I can do until I can get it apart. I am just bummed that it is something else that needs to be worked on...

 

[highpowerdad]

I would think .040" runout is not an issue on this, but given the age of the boat I would also consider it prudent to replace the coupler while out. Of course this depends on what your plans are for the boat and how much of an issue it is if you have to jank the engine again.

How was the alignment prior to engine removal ?

When i bought a handymands special back in 2015 the boat only had 37 hrs and alignment was pretty good so I left the existing coupler in place . 10 years and 400 hrs later no issue

Unfortunately, I don't have any history on the boat this came from, it was pulled from a boat that was in a road accident, trailer went off the road and into a ditch, boat came off of trailer, the outdrive separated from the transom at the top pivot, I assume from the inertia of being thrown around. the side and top of boat was damaged, so I assume it was upside down at some point.

 

[Lou C]

When the outdrive separated from the transom mount did the driveshaft pull out of the coupler or was it broken off and one end stayed in the coupler?
if you are seeing the same run out of the center section then I'd get a new coupler. Something was wrong either from the start (defective) or from the road accident.
When you remove the old coupler, it will be interesting to see what kind of shape the mounting bolts and the surface of the flywheel are in.

 

[highpowerdad]

When the outdrive separated from the transom mount did the driveshaft pull out of the coupler or was it broken off and one end stayed in the coupler?
if you are seeing the same run out of the center section then I'd get a new coupler. Something was wrong either from the start (defective) or from the road accident.
When you remove the old coupler, it will be interesting to see what kind of shape the mounting bolts and the surface of the flywheel are in.

The drive shaft pulled out, and from what i was told, the outdrive was undamaged, just the transom attachment, so the shaft wasn't bent, I do have a photo of that, and the outdrive. I have no idea what condition the gimbal bearing or surrounding structure was in.

 

[Scott Danforth]

again, any force strong enough to bend the crank would have busted the block.

pull the flywheel housing. then unbolt the coupler, inspect it. however as stated above, spend a few on a new coupler.

 

[alldodge]

I can move the coupler hub about 2 inches at the end of the bar with about 10-20 lbs force, that equates to over 5 deg each way (outside rim doesn't move), I would have expected the rubber to be very hard.

It should be solid and hard, being able to move it than the coupler is toast and needs replaced, crank is fine like Scott said

 

[Scott06]

Unfortunately, I don't have any history on the boat this came from, it was pulled from a boat that was in a road accident, trailer went off the road and into a ditch, boat came off of trailer, the outdrive separated from the transom at the top pivot, I assume from the inertia of being thrown around. the side and top of boat was damaged, so I assume it was upside down at some point.

I would just replace the coupler based off that history, unless its supper easy to jank the engine. Some boats are more work than others.