lifting a gearbox

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kashurst

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plan next week to take of the gearbox/V drive to investigate the knocking sound in my engine. On top of the gearbox there are two threaded holes, one on each of the large body castings, pretty much next to each other. I think these are for a lifting eye. I measured the thread size whilst in Spain but didn't write it down and its not marked in the user manual or web drawings. It's a Twin Disc gearbox - I don't suppose anyone happens to know what the thread size is???
 
If the engine mounts are connected to the vdrive we don't normally lift the drive. Just pack under engine with blocks, undo bolts and slide the drive away. That is the normal way we change the drive rubbers.
 
I wish it were that simple. There is enough room to slide the gearbox back to clear the bell housing leaving a gap of @ 1 inch. Need to lift it clear as I want to take bell housing/timing gear cover off. The engine has a fibreglass liner underneath it and I'm not sure how much weight it could stand so I am going to hang the engine from a beam above it. The engine has a composite sump - I think Im going to take the plastic sump off and put a lifting strop under the block (obviously protecting any bits that stick below the block)- unless anyone has a better idea???
 
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Bit more info from out tel converts last Thursday.

I'd be taking the valve cover off before your strip that lot off as there has in the past been roller failure on some D9s , the rollers operate the fingers to the valves and unit injectors , one not working will cause the engine to run rough , you will also get the noise you are talking about. Easier to take the cover off first you never know what you might find.
Yes I remember when I was there two years ago it won't come off upwards so take the header tank off and slide it past. Git to be worth a look because if there is a gear issue you will need it off anyway.
 
The cam cover is already off. Cams and rollers all look good. The inlet manifold is off, exhaust, camshaft inertial damper, top part of timing cover, raw water pump, fuel pump, several million pipe clips and half a mile of pipes and tubes. - noise is definitely from the timing area. When we find it I will take pics. Chris at RK marine wants to know what's wrong too. (very helpful by the way)
 
We've had very similar symptoms to what you describe with injector failures on D9s and D12s shutting off individual injectors made no differance. But we did have lots of smoke and fuel on the surface of the water.
 
No smoke or fuel - engine runs pretty well. I've been listing for the rattles and clangs by spinning the engine on the starter with the electronic bits disconnected from power.
 
What are the chances of leaving the vdrive where it is, making some brackets to support the back of the engine on the engine beds and sliding the engine away from the vdrive?
 
thats how it was done back in march when we thought all we had was a busted drive coupling. From experience on this engine in this engine bay, easier to move 150Kg gearbox up and sideways (three wheatabix today!) than put 1100kg engine on rollers and pull it forwards. The engine beds have a slope on them - the engine wants to roll towards the front of the boat and its hard to control. Also the rear engine supports are on the timing gear cover which has to come off - hence the lifting strop under the block.
 
kashurst said:
plan next week to take of the gearbox/V drive to investigate the knocking sound in my engine. On top of the gearbox there are two threaded holes, one on each of the large body castings, pretty much next to each other. I think these are for a lifting eye. I measured the thread size whilst in Spain but didn't write it down and its not marked in the user manual or web drawings. It's a Twin Disc gearbox - I don't suppose anyone happens to know what the thread size is???
Click to expand...

Twin Disc transmissions I have come across generally tapped 3/8-16 UNC about 11/4 deep to take eye standard eye bolts.
 
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