Rebuilding a 1968 Sabb model GG

[RichardS]

I've not read the whole thread again but the usual explanation for seawater in the combustion chamber is that the engine has been turned over too many times without actually firing. This will gradually fill the exhaust water trap and exhaust system until the water is high enough to flow into the exhaust manifold and through the exhaust valve and into the cylinder.

Hopefully it will not have done any damage to the engine but some of the water might well have found its way into the sump so check or change the oil.

Richard

 

[schmidp]

I've not read the whole thread again but the usual explanation for seawater in the combustion chamber is that the engine has been turned over too many times without actually firing. This will gradually fill the exhaust water trap and exhaust system until the water is high enough to flow into the exhaust manifold and through the exhaust valve and into the cylinder.

Hopefully it will not have done any damage to the engine but some of the water might well have found its way into the sump so check or change the oil.

Richard

Thanks Richard! I was more careful this time to not turn the engine over too much without it firing.
Actually after reassembling and making sure the push rods are correctly setup, the engine now starts immediately and repeatedly so far. It's a joy

So far I had the engine running only for a few minutes a time, because I'm afraid it might overheat as I have no experience how hot the cylinder head should get and the engine itself does not have a thermometer.



If I touch the cylinder head where I marked it red, the head feels very hot, plate hot. A few cm further up it is noticeably colder. Is that normal or is it getting too hot?

Any suggestions what I should do in the long term so I can feel confident about the engine temperature?

 

[RichardS]

Thanks Richard! I was more careful this time to not turn the engine over too much without it firing.
Actually after reassembling and making sure the push rods are correctly setup, the engine now starts immediately and repeatedly so far. It's a joy

So far I had the engine running only for a few minutes a time, because I'm afraid it might overheat as I have no experience how hot the cylinder head should get and the engine itself does not have a thermometer.

View attachment 107627

If I touch the cylinder head where I marked it red, the head feels very hot, plate hot. A few cm further up it is noticeably colder. Is that normal or is it getting too hot?

Any suggestions what I should do in the long term so I can feel confident about the engine temperature?

I don't know what cooling system the Sabb employs but as long as the thermostat is working correctly (you can check that easily) and there is a good flow of water out of the exhaust then you should not have any problems. You could use a cheap IR/laser thermometer on the block to check that the temperatures are all around the thermostat temperature, 80 - 90 degrees.

Richard

 

[Tamar]

Thanks Richard! I was more careful this time to not turn the engine over too much without it firing.
Actually after reassembling and making sure the push rods are correctly setup, the engine now starts immediately and repeatedly so far. It's a joy

So far I had the engine running only for a few minutes a time, because I'm afraid it might overheat as I have no experience how hot the cylinder head should get and the engine itself does not have a thermometer.

View attachment 107627

If I touch the cylinder head where I marked it red, the head feels very hot, plate hot. A few cm further up it is noticeably colder. Is that normal or is it getting too hot?

Any suggestions what I should do in the long term so I can feel confident about the engine temperature?

I had the same concerns with my sabb, I was constantly touching the head when it was running, almost too hot to touch, then a few inches away, cold. I never did find out if it was normal, but I ran the engine one day for 12 hours motoring home in a calm with no Ill effects. I think it's something to do with the swirl chamber. They are great engines.

 

[schmidp]

Ok, I had it running for about three hours today and although the area close to the swirl chamber gets hot, the temperature seems stable.

@RichardS to me it looks like the engine does not have a thermostat. Is that possible? I believe the sea water is just pumped through and not temperature dependant.

 

[schmidp]

The boat apparently had a different engine before as there is an oil pressure indicator installed and oil pressure line was just dangling around in the engine bay. Not having much idea about engines I would a assume a splash lubrication engine like the SABB would not really have any oil pressure right?

So since there is now a useless oil pressure dial installed that could make way for a temperature dial instead I was reading the GG manual and found the following wiring diagram:



So apparently it makes sense to install a temperature sensor/plug somewhere in the engine and have that shown on a dial, but the manual does not seem to talk about where to put the sensor...

Could it be this unused socket at the cylinder head marked in red (ignore the finger):



I love that little engine. I would have never thought that I can do work on a diesel engine or even repair it on my own!

 

[RichardS]

Ok, I had it running for about three hours today and although the area close to the swirl chamber gets hot, the temperature seems stable.

@RichardS to me it looks like the engine does not have a thermostat. Is that possible? I believe the sea water is just pumpt through and not temperature dependant.

That is possible, I guess. I believe that directly cooled engines usually have a thermostat circuit and a bypass but perhaps not all.

Richard

 

[schmidp]

I am finally back on the boat and the engine started up immediately, so far for the good news!

The bad news is: my reverse clutch is slipping and I still can take her out to the sea.
I believe the previous owner had the engine not properly aligned and I fear some parts might have worn. I have started to dismantle the gearbox to see if I can find a problem.

The engine was screwed directly to the steel frame instead on a wooden spacer or 3mm hard rubber, so I am trying to so source 3mm hard rubber and steel plates as shims for a better alignment.
In addition, I want to get a Vetus Bullflex 1 flexible coupling instead of the steel adapter that is currently between the shaft and motor flanges.
Since I assume I won't be able to get the alignment absolutely perfectly right with just moving and pushing the engine, I hope that the flexible coupling will take care of any slight remaining miss-alignments.


So far I have removed the gear lever, chain and intermediary gear as well as the gear housing itself from the engine. I am now trying to get the shaft out of the gearbox. In the manual it just says "press out from the rear", does that mean I need to find a ship with a press with enough force or should I be able todo this on my own? For example by hammering it out?

So what are my current ideas of why the clutch is slipping:

1) The engine is not properly aligned: the flange that goes on the shaft is held in place by the two screws you can see in the first picture. Now the inner diameter of the flange is slightly larger than the shaft, so when the screws are in, the center of the flange is off by 2-3mm. This, I cannot fix without switching to a different coupling and is another reason why I want to go for the flexible coupling.

2) The way of the lever is much more for reverse than for forward, but the manual says it should be approximately the same (10cm). What also seems strange to me is that the lever has some play. For example if you move it astern the clutch will move, but then you can move the lever further without the clutch moving anymore. The lever has a little dowel at the end that goes into the gearbox and moves the shaft/clutch ahead and astern to engage the forward or reverse clutch.
But if reverse has so much more way and there is some play I guess the clutch will not stay engaged?
On the other hand, the pulling force of the prop should keep the clutch engaged, should it not?




3) Clutch linings are worn: I don't know how many mm of linings there should be, but they do seem fine from the pictures don't they?
Is it possible to tell from the pictures if they are worn or not?



4) Bearings worn: So I can move the shaft up and down a little bit if the clutch is not engaged. If I move the shaft up and down it makes a mechanical clank noise and I can see the clutch itself going up or down. I assume because the engine was not properly aligned that the bearing of the shaft that comes out of the engine might worn?

Any ideas experiences with that gearbox? How could I identify the actual problem or problems?
Does it make sense to get a flexible coupling like the Vetus Bullflex?
Any other hints that could help me with my slipping reverse clutch.

I will try to also make a video tomorrow. I actually did do some videos but apparently, I did not always point the camera in the direction my eyes were looking so you cant see the lever play.

 

[schmidp]

Another thing that just dawned on me. I was using the following oil in the engine and gearbox: Marine 4T Motor Oil 15W-40 / 5 L buy now | SVB

Is that a correct oil for the SABB? It was recommended to me but now I am questioning if maybe the oil is also contributing to the slipping clutch?

 

[Tranona]

Not sure a Bullflex is the right way to go. Is the propshaft fixed - that is does it have a bearing at both ends of the tube? If that is the case and your engine is solidly mounted - that is not on modern flexible rubber mounts then it is essential to get the engine lined up perfectly to the shaft. That is what I had on my old boat with the original Stuart Turner, mounted directly on a steel frame. It was aligned by using a collection of U shaped steel shims which were slid between the frame and the mounts on the engine until there was no misalignment. The 3mm rubber pads you mention would not affect this alignment method but might dampen some of the vibration.

When I fitted a modern engine with flexible mounts I kept the fixed prop shaft and used a Bullflex coupling. however this is not a substitute for poor alignment. Given that the shaft is fixed, I adjusted the mounts so that the engine would slide perfectly onto the propshaft flange. The purpose of the Bullflex was to allow the engine (a bouncy Yanmar 1GM) to move around without trying to move the fixed shaft. Worked very well.

Can't help with the gearbox as have no experience of that design.

 

[Tranona]

Another thing that just dawned on me. I was using the following oil in the engine and gearbox: Marine 4T Motor Oil 15W-40 / 5 L buy now | SVB

Is that a correct oil for the SABB? It was recommended to me but now I am questioning if maybe the oil is also contributing to the slipping clutch?

That should be OK See the Instruction manual. I can't upload it because the file is too big, but if you PM me with an email address I will try and send it to you as a PDF

 

[K-ron]

Hi Schmid,
Glad to see you are having some fun with your sabb!!
I have found the pdf with additional notes.
Please PM with your email and I will forward.

The plug you have circled in red is exactly where my thermometer sensor goes. In the notes I think there is a reference to the water pump capacity Lt or gallons per minute. Measure your flow with a bucket under the exhaust then if it is correct install your temperature gauge. Providing you don’t have any blockage around the water jacket and a water temperature around 35 - 40 degrees you should be good.
As for the engine alignment, as previously mentioned, I would not use the flexible coupler, you need to get yourself a pile of different thickness shims and get the alignment spot on. I won’t lie it is a horrible job on my boat. But don’t settle for not perfect. Take a break have a cup of tea then do it again!!!
The excessive play in the gear lever and slipping in reverse sounds like the shims need adjusting. I would also change the bearings whilst you are in there.

Good luck

Kieran

 

[schmidp]

Not sure a Bullflex is the right way to go. Is the propshaft fixed - that is does it have a bearing at both ends of the tube? If that is the case and your engine is solidly mounted - that is not on modern flexible rubber mounts then it is essential to get the engine lined up perfectly to the shaft. That is what I had on my old boat with the original Stuart Turner, mounted directly on a steel frame. It was aligned by using a collection of U shaped steel shims which were slid between the frame and the mounts on the engine until there was no misalignment. The 3mm rubber pads you mention would not affect this alignment method but might dampen some of the vibration.

When I fitted a modern engine with flexible mounts I kept the fixed prop shaft and used a Bullflex coupling. however this is not a substitute for poor alignment. Given that the shaft is fixed, I adjusted the mounts so that the engine would slide perfectly onto the propshaft flange. The purpose of the Bullflex was to allow the engine (a bouncy Yanmar 1GM) to move around without trying to move the fixed shaft. Worked very well.

Can't help with the gearbox as have no experience of that design.

Damn, I thought I had a workable solution with the bullflex. Yes I am pretty sure it's a fixed propshaft, there is no movement at all if I apply some force on the shaft by hand.
Also from the manual I believe it is this system you can see in the diagram below (except that the shaft seems to go through propeller as I posted in this thread: Shaft goes through prop).

So my current shaft flange looks pretty worn and there is some play. If I screw it onto the propshaft, the screws are pushing the flange out of alignment (the shaft gets harder to turn when the flange is fixed to the shaft). The whole flange is in pretty bad condition as well as you can see from the pictures.

My train of thought was that if I need to get a new coupling anyway, a flexible coupling does not hurt but would compensate for some misalignment or other wired things going on with the boat. In the vetus manual I posted below it seems like they say it is also fine for fixed propshafts and allows to act as a flexible balljoint allowing misalignments of up to 2degrees.

So what I wonder, are you saying the bullflex is overkill and I should just get another flange or that the bullflex could hurt the gearbox/engine/shaft? (I'm still hanging on the the bullflex idea.... my light in the dark ? )

Regarding the motor mounts my plan was to get some shims as you proposed and 3mm rubber as in the manual as a vibration damper.
I will drive to Zadar today and see if they have some shims for me.

 

[schmidp]

The plug you have circled in red is exactly where my thermometer sensor goes. In the notes I think there is a reference to the water pump capacity Lt or gallons per minute. Measure your flow with a bucket under the exhaust then if it is correct install your temperature gauge. Providing you don’t have any blockage around the water jacket and a water temperature around 35 - 40 degrees you should be good.

Cool so I will get my self one, so I can use my infra-red for checking the water temperature for swimming instead

As for the engine alignment, as previously mentioned, I would not use the flexible coupler, you need to get yourself a pile of different thickness shims and get the alignment spot on. I won’t lie it is a horrible job on my boat. But don’t settle for not perfect. Take a break have a cup of tea then do it again!!!
The excessive play in the gear lever and slipping in reverse sounds like the shims need adjusting. I would also change the bearings whilst you are in there.

I still can't warp my head around how the lever play should go away by removing shims (as indicated in the manual for reverse) but I will understand more when I got the shaft out of the gearbox. Do you remember if you were able to push it out by yourself? In the manual it says something about pressing which I assumed means I need professional help?
I could try to put the locker nut back on and use the hammer to push it out, but so far I was afraid of breaking something.

 

[schmidp]

Now that I thought more about it, since the propeller needs to pull the shaft for the gearbox to stay engaged, the rubber of a flexible coupling would probably actually increase the chance of the reverse slipping right?

 

[RichardS]

I can't help with the gearbox or alignment issues as I'm not familiar with those but can advise that "clonking" play in shafts or bearings usually suggests that something needs to be changed or adjusted. Shafts often have end-play or float along the line of the shaft and that is usually permitted but that is obviously not the same as side-to-side play.

If the manual says "press" it almost certainly means mechanical/hydraulic press. It is sometimes possible to use a hammer and a block of wood, or similar, if access permits but you do risk damage when removing and refitting and it might be impossible. The best way to avoid damage if you wish to give it a try is to use a lot of heat when dismantling and heat/freezing when re-assembling.

Richard

 

[179580]

Have posted on your other question regarding the prop, You have a Sabb CP prop. Few informative views on you tube. Looks like previous owners have been replacing engines without changing stern gear.

 

[K-ron]

Philip, I’m struggling to remember exactly how I got the gearbox apart, the biggest problem was removing the large nut after removing the gearbox it was so so hard to hold the gear box whilst torquing the nut. The rest of it I certainly did with no professional help. I had a 12 mm diameter brass drift and not a lot else.. if you can send some more detailed pictures it may jog my memory.

 

[Saffron]

Philip, I’m struggling to remember exactly how I got the gearbox apart, the biggest problem was removing the large nut after removing the gearbox it was so so hard to hold the gear box whilst torquing the nut. The rest of it I certainly did with no professional help. I had a 12 mm diameter brass drift and not a lot else.. if you can send some more detailed pictures it may jog my memory.

Hi Kieron… what a fab job you did rebuilding your sabb..

How is it running? And do you still have it??

I’m just sorting mine
Pictures to follow

Jamie

 

[Saffron]

Hi Kieron… what a fab job you did rebuilding your sabb..

How is it running? And do you still have it??

I’m just sorting mine
Pictures to follow

Jamie