Gearbox coupling for a John Deere JD3

[Augustamay60]

Hi All, I have recently fitted a John Deere JD3 engine to my boat. Problem is it came with no gearbox or bell housing. I have managed to get a drive plate worked out. I just need a way of coupling the gearbox to the engine or maybe putting the gearbox on its own mounting then a sort of drive shaft between the 2. There is plenty of room in the engine room. Any suggestions would be greatly appreciated. 

[MtB]

Have you tried asking Beta Marine if they can supply a bellhousing? 

 

 

[Augustamay60]

I asked and They weren’t too helpful about it as the engine is not one they made. It’s also slightly different to the beta tug engine. It was purchased straight from John Deere. 

[Bee]

for, John Deere 6100,6200 Engine Rear Bell Housing in Good Condition | eBay, This may be useful (?) there are others on E bay. Then maybe an adaptor plate to fit your potential gearbox , ASAP and no doubt others (Lancing marine in Shoreham do all sorts of stuff)  Somewhere there will be a combination of parts that works but it might take a while to find them

Edited March 5 by Bee

[David Mack]

If the engine is designed with a standard SAE gearbox mounting, you could probably find a bellhousing intended for another engine with the same SAE mounting. Try other engine marinisers.

[BEngo]

First stop is John Deere for details of the back of the  engine.  There will be a drawing showing the mounting holes that are available and the holes in the flywheel provided for  drive plate ( aka clutch housing) fastenings. They may also have a variety of bell housings available.

 

Next stop is your chosen gearbox supplier for details of the front of the gearbox you fancy.   PRM 260?? Again there will be  a drawing showing the mounting holes and the available drive options- flange, splined shaft etc.

 

  You may need to research some of the options to get the detail needed as they may be defined as, for example,  SAE standard items.

 

Try to get the drawings as electronic versions in .dwg format.

 

Then you need a CAD technician to draw up a 3D CAD model of the engine/box junction, particularly the bell housing and gearbox adaptor  plate.  S/He will be really happy if you can provide 3D drawings of the engine eear and the gearbox front.

 

 Once armed with  drawings  look for a 3D printer to make the housing and a machine  shop like Paul Redshaw at Braunston to make the adaptor plate.

 

Most of the drive plate vendors can do a special to connect the gearbox input to the engine drive end. Buy a spare!

 

  Using an intermediate shaft can also be done, using a similar process.  Don't forget to include proper guards.

 

N

 

 

[john.k]

It will be very costly to buy new housings to suit a gearbox .....and even more costly to involve an engineering shop..............we used to buy new JD engines to suit cranes ,and I have a stack of new flywheels and backplates the engines came with,but didnt match the crane transmissions................If the engine is actually fitted to the boat,then Id think it would need to be removed to work on .

[dmr]

We need some photos.

I think there is a shallow and a deeper bell-housing (though they are straight rather than bell). The deeper one fully encloses the flywheel. The one in the post above does not look like the one that Beta use. If you can get the deeper one (from a  Deere agent) then you still need the gearbox plate.

John Deere have a comprehensive on-line parts catalog.

What driveplate have you got?

Do you intend to run the engine as Deere intended (850-2400rpm) or derate it as Beta do (450-1200rpm)? If you go the Beta route then you will need a suitable "special" drive plate to cope with the torsional movement, and maybe a water pump pulley adaptor etc. 

If you plan a remote gearbox then it needs a shaft that mates with the driveplate spline, but if you have the very flexible Beta style driveplate it will certainly need a bearing/support, in fact any flexible driveplate will likely not be happy supporting a shaft directly..

Which variant of the 3029 have you got?

[john.k]

What gearbox do you have ?.....if you intend to buy one,then a BW Velvet- drive is as good as any ,and lots of them about ,they are easily rebuilt and new parts are plentuiful and cheap............If you buy a used gearbox,find one from the same motor as yours preferably,and be sure to get all the bits .......dont buy a bare transmission (unless its a super bargain)

[Augustamay60]

Hello, thanks for all the suggestions. I will attach some pictures of the engine, it runs at 450 - 1250 rpm just like the beta tug engine.  The engine is a CD3029D. When I purchased the engine it came with a Borg Warner gearbox attached but I have removed this because I need the gearbox to drop the output for alignment reasons. Hence choosing a PRM. 

The drive plate is the same as the one used by beta on the tug engine. It’s made by R&D. 

[Tony Brooks]

10 minutes ago, Augustamay60 said:

I purchased the engine it came with a Borg Warner gearbox attached

 

So was it a total bodge up, or was it on a flywheel housing? If the latter than was there an SAE standard adapter late bolted to the back of the housing to accept the Velvetdrive. If the gearbox bolted straight onto the flywheel housing, then you can probably get more holes drilled, if needed, to fit the PRM and use longer bolts and a distance piece if needed. If there is an SAE adapter plate, then I think PRM or someone like ASAP supplies will sell you the correct one for a PRM.

[Augustamay60]

It was a very strange armament before with a steel ring, plate and some spacers. I believe it works but re creating it for a prm is proving tricky. I have tried a SAE 4 and 5 end plate but neither will long up to the engine. 

[dmr]

Is this the engine that RCR were selling? Its odd as they advertised it as a Beta but it looks nothing like the Beta marinisation. Also I hope you negotiated the price down significantly.

 

I am not at all sure that the driveplate that you have is adequate, there will be some significant torsional displacements at lower speeds, Beta used a plate that was very soft to cope with these. It might be easiest just to copy what Beta did. The deeper Bellhousing will be on the John Deere parts site, if you nominate a dealer then it will show prices. I don't know where the adapter plate comes from but it does not say Beta so might be an off the shelf item rather than a Beta casting.

 

Crossed posts, that does look like the RCR engine, a strange thing.

 

Is the front end all ok? Beta fit a much bigger crank pulley to get a decent alternator speed, then a pulley adaptor on the water pump to compensate.

The breather will need plumbing into the intake.

[David Mack]

21 minutes ago, Augustamay60 said:

It was a very strange armament before with a steel ring, plate and some spacers. I believe it works but re creating it for a prm is proving tricky. I have tried a SAE 4 and 5 end plate but neither will long up to the engine. 

That looks very much like a bespoke adaptor fabricated for the purpose rather than an off the shelf part. Can you not adapt it to suit your purpose?

[dmr]

I was thinking the same, if you want to save expense then re-use that DIY scheme and make an "adaptor plate for the adaptor plate". You could maybe get any plate for the PRM and modify it to suit. The length of the splined shaft from the gearbox might be an issue.

The correct driveplate only costs a couple of hundred of quid (from memory) and you can get it direct from the supplier, you do not have to go via Beta.

I should be able to give details if you go that route.

[Augustamay60]

Yes it was the engine that RCR was selling. I was looking for a beta tug engine but as they no longer make them and are quite a rare beast this engine was my best option. I know about the drive plate that beta use, it’s a sort of star shaped plate. I sent R&D all the torque specs and this is the plate they came up with. I will get in touch with John Deere see if they have the bell housing then an adapter plate can be made. Why does the vent need connecting to the intake? It’s not a tricky job I just wonder why? 

[john.k]

There will be a #3 SAE housing for the JD motor ,and any marine gearbox should also have a #3 housing to match .............the only time ive seen a housing made of pillars,it was for a Deutz or a Lister ,so that air for the engine could pass thru ..........a monumental bodge as they say in the boating industry........A big however is that a flywheel housing ,and a flywheel (if needed) will be very costly new ....I have all the John Deere manuals for industrial motors ,including the 3/2.9 ..............incidentally ,all the blocks are drilled the same 3,4 and 6 cylinder ,so parts from one fit another.

Edited March 6 by john.k

[magnetman]

What is the height difference between existing gearbox output and the tail shaft? 

 

It seems to me if there is 'plenty of room' you could consider using a cardan shaft custom made to your requirements. Weld up a bracket and put a plummer block on near the end of the tailshaft to protect the stern tube. 

3 hours ago, Augustamay60 said:

. When I purchased the engine it came with a Borg Warner gearbox attached but I have removed this because I need the gearbox to drop the output for alignment reasons. 

 

[Augustamay60]

That’s good news about parts being interchangeable, I will try John Deere see if they can supply me one. There is probably about 1 inch between the two my plan was to have a shaft with x2 universal joins. There is a block bearing fitted at the stern tube end as support. I have found a company who can manufacture a short shaft. 

[Tracy D'arth]

3 minutes ago, Augustamay60 said:

That’s good news about parts being interchangeable, I will try John Deere see if they can supply me one. There is probably about 1 inch between the two my plan was to have a shaft with x2 universal joins. There is a block bearing fitted at the stern tube end as support. I have found a company who can manufacture a short shaft. 

Will an Aquadrive or Python do it?

[Augustamay60]

Yes most likely 

 

[dmr]

55 minutes ago, Augustamay60 said:

Yes it was the engine that RCR was selling. I was looking for a beta tug engine but as they no longer make them and are quite a rare beast this engine was my best option. I know about the drive plate that beta use, it’s a sort of star shaped plate. I sent R&D all the torque specs and this is the plate they came up with. I will get in touch with John Deere see if they have the bell housing then an adapter plate can be made. Why does the vent need connecting to the intake? It’s not a tricky job I just wonder why? 

 

I think the pipe you have is just open at the bottom?. All engines "breathe" a bit, especially as they get older, a bit of exhaust gas "blowby" and some oil mist , Its ok for a tractor to drop this on the ground but is not ideal in a closed space in a boat.      

Some JD3's did have an issue with producing a lot of blowby oil mist but there might be something in your rocker cover to reduce this.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   

11 minutes ago, Augustamay60 said:

That’s good news about parts being interchangeable, I will try John Deere see if they can supply me one. There is probably about 1 inch between the two my plan was to have a shaft with x2 universal joins. There is a block bearing fitted at the stern tube end as support. I have found a company who can manufacture a short shaft. 

 

A shaft with a pair of Hookes joints can work fine, ours has done 20,000+ hours but is a much longer shaft than yours. If you use simple UJ's then a bit of missalignment is desirable, if things are almost in line there can be issues with stiction effects. With your "short" installation a Python drive might be better but I have no experience of these.