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Volvo MD2- Strong Engine, Slipping Gear

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nlmartin
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Username: nlmartin

Post Number: 1
Registered: 10-2014
Posted on Tuesday, October 14, 2014 - 09:12 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only)

First off, I want to say thanks to everyone on this forum. The information contained here has been invaluable during my restoration (and is very interesting to read).

I have an early 1960s Volvo MD2, which powers my 1950s Dyer Glamour Girl. The boat belonged to my grandfather and sat behind his barn since 1992. Itís been a two year complete restoration, but I got the boat in the water this August. She turns heads everywhere she goes.

The motor needed the least amount of work on the boat. It spun freely so I left the motor for last, after restoring the rest of the boat. I cleaned and repainted the engine, had the starter and the alternator rebuilt, new wiring and gauges, new oil and filters, etc. The motor now starts up immediately, runs with very little smoke, no knock, idles very well, holds good temperature/oil pressure and has great power. My question is concerning the gear box.

Astern engages cleanly and works very well. Ahead however is problematic. When first engaged it seems like only 1/3rd of engine power is being transmitted to the prop. After some period of time (maybe 20-30 seconds) it engages with full power. It does this whether the engine/gear box is hot or cold, though it does seem like it takes less time when hot (though could be my imagination). I took her out 15-20 times since August and it hasnít left me stranded, but that could of course change at any time.

At first I thought the cone clutch was slipping and then ďgrabbedĒ, but with the boat out of the water there is almost zero play in the prop shaft. I can even spin the motor by turning the prop (though Iím sure Iím not supposed to do that). I still have the manual and the reverse gear section indicates that the pressure exerted by the prop helps keep the cone clutch engaged/aligned. So perhaps there is not enough play in the shaft?

Or the clutch could be worn out. Though I tend not to think so since reverse works well, the connection seems extremely solid and it does engage after a short wait. It makes me think itís just out of adjustment somehow.

I havenít taken it apart yet- I wanted to have a strategy before I did that. The manual says the clutch is not relineable, but as Iíve learned parts for these motors are very expensive and very hard to come by. Iíd appreciate anyoneís thoughts or recommendations.
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matt_morehouse
Senior Member
Username: matt_morehouse

Post Number: 140
Registered: 12-2009
Posted on Tuesday, October 14, 2014 - 10:08 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only)

Is it an RB gearbox?
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nlmartin
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Username: nlmartin

Post Number: 2
Registered: 10-2014
Posted on Tuesday, October 14, 2014 - 10:11 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only)

Sorry, not sure what an RB gearbox is?
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matt_morehouse
Senior Member
Username: matt_morehouse

Post Number: 141
Registered: 12-2009
Posted on Tuesday, October 14, 2014 - 10:23 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only)

The back end is bell shaped.
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nlmartin
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Username: nlmartin

Post Number: 3
Registered: 10-2014
Posted on Tuesday, October 14, 2014 - 10:43 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only)

Yes it is. It's the same as shown in this post:

http://www.oldmarineengine.com/discus/messages/3/7310.html
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nlmartin
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Username: nlmartin

Post Number: 4
Registered: 10-2014
Posted on Wednesday, October 15, 2014 - 09:08 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only)

I confirmed its an RB gear 1.87:1 as per the manual. Here is a pic. Any theories?Picture
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matt_morehouse
Senior Member
Username: matt_morehouse

Post Number: 143
Registered: 12-2009
Posted on Thursday, October 16, 2014 - 12:25 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only)

That tranny has friction discs which are probably worn. Take it apart and inspect.

Looks like someone might have been in there before as that is not the original color.
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nlmartin
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Username: nlmartin

Post Number: 5
Registered: 10-2014
Posted on Thursday, October 16, 2014 - 09:58 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only)

Any suggestion on where to get replacement friction discs? Marine Parts Europe and Marine Parts express don't seem to have it. I was hoping it wasn't the clutch based on the symptoms but you may be right.

(The engine was painted red when I got it, so I stuck with that and repainted it red again)
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matt_morehouse
Senior Member
Username: matt_morehouse

Post Number: 144
Registered: 12-2009
Posted on Thursday, October 16, 2014 - 10:10 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only)

I don't know where you could get replacements.

They may have enough material left to clean and rough up or you may be able to have new material bonded on.

First step is to disassemble and take a look.
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oslin04
Senior Member
Username: oslin04

Post Number: 77
Registered: 10-2006
Posted on Thursday, October 16, 2014 - 12:10 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only)

you might try Coastal Rides in Kent or Volspec in Essex.
Keith
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oslin04
Senior Member
Username: oslin04

Post Number: 78
Registered: 10-2006
Posted on Thursday, October 16, 2014 - 12:12 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only)

You might try Coastal Rides in Kent or Volspec in Essex
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nlmartin
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Username: nlmartin

Post Number: 6
Registered: 10-2014
Posted on Sunday, October 26, 2014 - 06:40 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only)

Just spent most of the day disassembling the transmission. I took my time, stripped off all the paint and was very careful as I didn't want to break any bolts. A few looked terrible but came out without too much fuss. Inside it looked brand new, no signs of wear or play. The clutch facing also looked great, as did the cone. The clutch stack measured exactly 85mm, which is per volvo spec. So it looks like I ruled out a slipping clutch. Anyone have any other ideas? Maybe it's not enough prop back pressure like I thought at first? I was skeptical but I don't know what else it could be.
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matt_morehouse
Senior Member
Username: matt_morehouse

Post Number: 145
Registered: 12-2009
Posted on Monday, October 27, 2014 - 09:52 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only)

I know this sounds stupid but I have found sometimes when I tear into something and find nothing wrong when I put it back together it works perfectly.

Try that. You have nothing to lose and think of all you learned about RB transmissions.

If you still have the problem change the prop.
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matt_morehouse
Senior Member
Username: matt_morehouse

Post Number: 146
Registered: 12-2009
Posted on Monday, October 27, 2014 - 09:54 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only)

Another thought; could it be the linkage?
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nlmartin
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Username: nlmartin

Post Number: 7
Registered: 10-2014
Posted on Monday, October 27, 2014 - 11:33 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only)

The linkage is solid. I was hoping I sheared a key in the shaft flange but no such luck. I'll put it back together and see what happens. You're right- it was fun taking it apart. It's an impressive piece of machinery.

Once I get it back together I'm going to do a calculation on what type of prop should be on there. The boat is from the 50s and the motor is from the 60s (this probably had an atomic 4 originally). I have reason to believe my grandfather may have installed this motor in the 90s. The prop is made by michigan wheel and is date stamped 1992. He may have just replace it with the same one what was on there before, or whatever he could find.

I'm not positive, but I think i read somewhere that Atomic 4s had a gear ratio closer to 1:1 whereas this has a 1.87:1. So it could be that the size or pitch of the prop i have is not pushing enough water for the gearing of this motor- enough water to keep enough pressure on the clutch. It's a cone, so if there isnt enough pressure pushing the small cone into the big cone then it will slip. This also explains why it works so well astern- the prop pitch is reversed and there is a ton of pressure on the cone and no slippage. I think this is also supported by the physics of this sailboat motor in a 16 foot motor launch. Less displacement and ideally greater speed and prop speed. I think i need a prop with more pitch to make up for the slower shaft rotation.
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nlmartin
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Username: nlmartin

Post Number: 8
Registered: 10-2014
Posted on Tuesday, October 28, 2014 - 06:19 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only)

I just finished putting the gear back together and back on the motor. While lubricating the parts with some left over oil, I noticed that i had used 30W Shell Rotella when i changed the oil before launching this summer. I checked the manual and Volvo recommends SAE 10W between -10C and 20C (15F and 70F) and SAE 20 above that.

After all this could it be something as dumb as using the wrong oil? Since the gear uses the same lubrication system as the engine? Could the higher weight oil have "stuck" to the clutch more than it should have, causing it to slip? Maybe i way over thought this problem!
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nlmartin
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Username: nlmartin

Post Number: 9
Registered: 10-2014
Posted on Thursday, November 06, 2014 - 02:47 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only)

I spoke with a few local folks (local marina mechanics and the US East Coast Penta distributor) and the consensus was 1)a clutch that takes 30-40 seconds to catch in a 54 year old motor inst too bad! and 2)the most likely remaining culprit is the oil.

As far as anyone can tell, SAE 20 isnt made anymore other than for lawnmowers. So the only other option is a multi-viscosity. The opinions were mixed as to whether that would harm the engine. Matt, Oslin or anyone else, what's your take on this? Thanks again for your help on this issue!
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oslin04
Senior Member
Username: oslin04

Post Number: 79
Registered: 10-2006
Posted on Friday, November 07, 2014 - 04:53 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only)

Hi Nimartin, well first of all 30 to 40 seconds to catch or engage is not acceptable, having had this engine and gearbox plus the later one in the past I can tell you the catch should be almost instant, something is not right there,
re the oil, the later engine gearbox uses TQF or automatic transmission oil in its own sump and the early one used engine oil fed from the engine but you have to remember oils have gone a long way since then and you could possibly use something like 5/15 or 10/20 multi grade,

I can not recall if the gearbox has an oil pressure pump for the clutch or is fed from the engine or not, but if it has I feel you should have a look at the pump and check the oil pressure output, and check the engine oil pressure is correct as well if the gearbox is fed from the engine.
Keith.
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nlmartin
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Username: nlmartin

Post Number: 10
Registered: 10-2014
Posted on Friday, November 07, 2014 - 08:39 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only)

Yea, I think they were teasing me a little saying the delay was ok, like it was part of the character of an old machine.

The is no transmission oil pump, just the main oil pump and three weep holes which conect to the crankcase. Overall oil pressure is very good actually. I think multigrade is the best option. I can't imagine that the new detergents, viscosity modifiers or anti foamers in new oil would harm the engine.
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matt_morehouse
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Username: matt_morehouse

Post Number: 147
Registered: 12-2009
Posted on Friday, November 07, 2014 - 10:23 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only)

What is your oil pressure?
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oslin04
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Username: oslin04

Post Number: 80
Registered: 10-2006
Posted on Friday, November 07, 2014 - 10:44 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only)

Hi Nimartin,
It has been years since I stripped one of those gearboxes but it would appear the gear select is manual and not hydraulic,
therefore when the gear is selected it should be positive so either the clutches are worn or they are not moving enough to engage correctly or there movement is being held up on the shaft or spline,
are the gear selectors moving to there full extent ?
Keith
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nlmartin
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Username: nlmartin

Post Number: 11
Registered: 10-2014
Posted on Friday, November 07, 2014 - 11:38 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only)

Oil pressure is 30-35 which is per volvo spec. I had an issue with oil suction at first due to a leak in the dip tube gasket but pressure is good now.

Yes gear select is manual. I disassembled as outlined above and the clutch face looks good and the thickness of the clutch stack is per volvo spec. The shift lever moves fully and when engaged the lock appears very strong. I can turn over the engine by spinning the prop even with the compression release down. So my only theory was the oil being too heavy at low temps, as it engages a little faster when hot ( but still not instantaneous). Or the propeller pitch theory.

Or maybe as Matt suggested above, it's a mystery and may spontaneously work again after taking it apart and reassembling!
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oslin04
Senior Member
Username: oslin04

Post Number: 81
Registered: 10-2006
Posted on Saturday, November 08, 2014 - 05:02 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only)

This might sound a bit daft nimartin but as everything else checks out you will need to look elsewhere have you got a keyway worn and slipping ? for example shaft to coupling keyway/pin, gearbox keyway/spline?, you will need to look at eveything now,
Yes thicker oil will slow it down but not that much, and re the prop pitch that will make no difference to the engine gear selection,
another thought some gearbox cone clutches have groves cut in to the friction side and also sometimes in to the femail side of the cone clutch to displace oil when engageing, I can not remember if Volvo clutches had this of not, might be worth a check in case the volvo clutches had and they have worn down ???
Keith
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nlmartin
Member
Username: nlmartin

Post Number: 12
Registered: 10-2014
Posted on Saturday, November 08, 2014 - 07:32 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only)

The propeller pitch theory was based on a comment in the volvo workshop manual that propeller pressure helps keep the cones engaged, but for some reason I doubt that's the culprit. The drivetrain is very solid. Very little play up and down in the cutlass bearing and no play forward and back on the prop. Pushing in and pulling out the prop doesn't seem to impact my ability to turn the engine. And yes the shaft key and set screws are all intact. I was hoping it was that. I didn't see any grooves on the clutch face, but the clutch stack height was at the high end of the wear range, so I dont think grooves wore off.

At this point, I have to think if it's not the oil, something was stuck or binding inside the gear and the cleaning I gave it will resolve the issue.
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oslin04
Senior Member
Username: oslin04

Post Number: 82
Registered: 10-2006
Posted on Saturday, November 08, 2014 - 08:56 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only)

Sorry to tell you how to suck eggs nimartin, but as a retired Marine Engineer I thought I should mention it,
lets hope you are right and all is well when the box goes back in service but I still thing it is more than a bit odd, but odd things do happen of course and if you are happy with everything you have inspected then it should work correctly.
p.s. do not worry about modern oils they will be much better than the old recommendations which would not apply today anyway.
Keith.
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nlmartin
Member
Username: nlmartin

Post Number: 13
Registered: 10-2014
Posted on Saturday, November 08, 2014 - 05:58 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only)

I do appreciate all the help. I'm just a tinkerer. My theories pan out sometimes, other times I'm way off! I probably won't have an answer until I put the boat back in the water in the spring, so we'll see. Thanks again for all the help.
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matt_morehouse
Senior Member
Username: matt_morehouse

Post Number: 148
Registered: 12-2009
Posted on Saturday, November 08, 2014 - 09:01 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only)

I'm thinking by tearing it down, cleaning it and putting it all back together you have exorcised the demons and it will obey your every command.

However, just to make sure; repaint it to Volvo green. Now that I think on it that red paint may have been the problem.

Don't laugh. Machines have a soul.
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nlmartin
Member
Username: nlmartin

Post Number: 15
Registered: 10-2014
Posted on Monday, June 15, 2015 - 09:56 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only)

Thought I would post an update now that i have the boat back in the water for the season. The transmission is now working as designed and the boat is much quicker.

I think it was mostly just a dirty and sticking shifting mechanism, but i also discovered that the stuffing box was way too tight. I'm sure that didn't help the shaft movement forward to engage the clutch.

Thanks again for all the help!
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ezimmermandptgmailcom
New member
Username: ezimmermandptgmailcom

Post Number: 1
Registered: 07-2018
Posted on Wednesday, July 11, 2018 - 09:44 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only)

Hi nlmartin, I have the same exact engine and the same exact gear slipping you described earlier. I have looked at the service manuals, but failed to see how and where to lubricate same.
Will attempt loosening the stuffing box, but would appreciate any further suggestions for this old MD1.
Thank you.

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