Inboard Instalation

[warwicksail]

Hello hope evryone has enjoyed the festive break, "Oh well back to the mill" having finally found a replacement Inboard for my 22' westerly warwick sail boat, I now have the task of installation.
I managed to to find a BMW D7 diesel engine in mint condition along with 5' shaft and 3 blade prop, Having never taken on this task before I'm hoping to gather as much infomation and help as possible in the way of peoples experience and articals/publications available.
When the warwick was built it was fitted with a petter mini 6 diesel engine this was removed by the previous owner Completley, along with shaft, tank, pump well evrything and had a outboard bracket fitted.
All help will be greatfully appreciated Thank you very much. Paul

 

[Peterduck]

The installation of an engine and propshaft is a very complex affair and worthy of a fair bit of study before doing anything. The only book which covers this area that I have is Alan Lucas' "Fitting Out Mechanically". Your first task is to find the position of the axis of the propshaft tunnel with a stringline [bricklayer's twine is excellent for this]. You will have to cobble together a frame to hold the string in position at the point where the front of the engine will be. Then you can measure from the string to the engine beds and compare those measurements with the positions of the engine mountings on the D7.
Peter.

 

[oldharry]

Having re-engined several boats, I dont think its all that complex, though you do need to know what you are doing, so the more you read the better.

Peterduck is right in that you have first to get the engine beds lined up correctly. IF the old Petter and the BMW both have their engine mounts in line with the prop shaft, then life will be relatively easy. You can get this information from drawings of the engines. If you have to raise or lower the engine beds to accomodate the new engine, its far simpler if you make up a 'dummy' - a frame which locates precisely the centre of the gearbox output shaft in relation to the engine mounts. Take trouble over this and you will save trouble later.

Get the prop shaft set up first, this makes it much easier to get the alignment right. Last time I did it, I set up holes in the dummy through which the prop shaft could pass, and using an borrowed old over length shaft was able to pass it right up the sterntube and through the dummy, in order to get the precise location of the engine mounts. But before I finalised everything, I removed the shaft, and sighted down the holes from inside the boat. You will see straight away if anything is not in line, like a series of concentric rings. One even slightly out of line sticks out like a sore thumb! If it is - then its back to the drawing board. BUT - dont forget to allow room for the shims which lift the engine into its precise position - I did the first time, and had to lift the engine out again to re-set the engine beds a few mm lower. That took a great deal longer than it takes to write it too.... in fact I had to take everything out and start again /forums/images/graemlins/frown.gif

Measure everything twice, then again, and have a good think about each stage before you do it. and get as much as you can from books.

 

[alan006]

Its hard to answer this as I'm not sure how much you know so I apologise in advance if you know these basics.
As the previous people have said, you need to get the positioning of everything right or you will suffer from vibration and rapid wear of the stern gland and cutlass bearing.
You should have the propellor calculations done first to be sure the prop you have is the right pitch, diameter and hand for the shaft horsepower and shaft revolutions. Make sure there is sufficent clearence around the prop to avoid cavitation. Its normally a good idea to fit a flexible coupling to drive the prop shaft if you have the space.
Make sure the shaft is not unsuported for long distances or you will suffer from shaft whipping.

 

[Aja]

This book covers everything you need to know:
How to Install a New Diesel Engine
by Peter Cumberlidge

Amazon

It really is comprehensive. I read it before installing my first engine.

Regards
Donald

 

[cliffordpope]

It's worth remembering that an old fashioned prop shaft with a pair of hardy spicer joints gives much more flexibility with regard to alignment than a modern one. HS joints can accommodate a maximum angle change of 15 degrees, so if used in pairs that gives a lot of possibilities for angling the engine in relation to the final shaft. Where the gearbox output is angled significantly I have been told that it is desirable to try and equalise the angle at each joint.
With this set up the engine can for example be more horizontal even though the shaft angles downwards, or can be offset slightly from the centre-line if that gives better clearance.
HS joints can safely transmit end-thrust in say 10 hp installations, so you can rely on the thrust bearings inside the engine. In larger applications, especially with a long shaft, you may need a separate thrust bearing near the back.

 

[warwicksail]

Thanks very much for the Infomation. I have ordered copys of the books listed.
Please dont feel ignorant as per my experience, it is very limited, this will be the first time i've done any kind of marine mechanics although have lots of non marine experience.

I have decided to go for a bukh dv10 rather than the BMW d7 although a bigger lump, I have been informed they run quite smooth (for a single) and will a little modification to the engine bay will align Ok.
So the unit will arive on saturday, Time to start reading and recuiting volunteers, Thanks again paul
PS I am inneed of lots of bit for the installation if anyone can help all i have is the engine and gearbox