Engine / shaft alignment

[Jacq]

Could anyone advise, If the only way to fit an engine left the new output shaft from the gearbox 3 cm higher than the existing prop shaft , would a flexible coupling like an Aquadrive be the best way to get the 2 to align ?

[Yoda]

Could anyone advise, If the only way to fit an engine left the new output shaft from the gearbox 3 cm higher than the existing prop shaft , would a flexible coupling like an Aquadrive be the best way to get the 2 to align ?

 

I don't understand. Please be more specific.

 

Re-reading it, and I have to say no. Dont not connect them with that alignment. You must not run shafts that are out of line.

Edited March 20, 2008 by Yoda

[Jacq]

The fly wheel is so large it wont go any lower, so the 2 shafts wont line up. Any ideas if there is a way round it ?

[magnetman]

A Hardy spicer type drive shaft could perhaps be used, you can get them made to order.

[Les Taylor]

Convert to hydraulic drive?

Maybe expensive?

[RLWP]

Could anyone advise, If the only way to fit an engine left the new output shaft from the gearbox 3 cm higher than the existing prop shaft , would a flexible coupling like an Aquadrive be the best way to get the 2 to align ?

 

Hi,

 

Aquadrives are designed for shafts that don't line up, so in theory, yes. However, it will depend on exactly how much difference in alignment (in your case 3cm) and how long the aquadrive will be. It would be best to talk to the supplier about this. I can recommend TW Marine 01663 745757 who were very helpful when our aquadrive seized up on the river Avon.

 

Richard

[Maverick]

3cm is an awful big difference and I would imagine if you could get a joint on the vibration would be awful.

[Malarky]

Make of engine? - diffrent flywheel, or is it just casing, or bearers in the way. Can you move it further back, and add universal joint?

[Timleech]

Could anyone advise, If the only way to fit an engine left the new output shaft from the gearbox 3 cm higher than the existing prop shaft , would a flexible coupling like an Aquadrive be the best way to get the 2 to align ?

 

A lot depends on how long the shafting is between gearbox & stern tube.

If there's enough length, then a shaft with two Universal Joints ('Hardy Spicer') is an easy answer.

If not, maybe look at fitting a different gearbox which drops the output further?

 

Tim

[Tony Brooks]

Could anyone advise, If the only way to fit an engine left the new output shaft from the gearbox 3 cm higher than the existing prop shaft , would a flexible coupling like an Aquadrive be the best way to get the 2 to align ?

 

 

If all else fails to get a long enough shaft can you still get remote V drives and put the engine in facing backwards with the shaft running below it?

 

I hate the things, but with a modern packless sterngalnd it might just work - I think I favour hydraulics though.

 

If you have access to some engineering what about a dropped belt or chain drive?

[Yoda]

I don't understand. Please be more specific.

 

Re-reading it, and I have to say no. Dont not connect them with that alignment. You must not run shafts that are out of line.

 

Thinking about this problem, I would suggest that the whole engine/gearbox unit is moved forwards (bow) a few inches until it is possible to line up the shafts and then fit a flexible drive coupling and only when the swash on the coupling is virtually nil will that be suitable for transmitting power.

[Jacq]

O.K thanks. The shaft is around 7 feet long as it goes under the boatmans cabin. So 2 universal joints may be the answer.

[Timleech]

O.K thanks. The shaft is around 7 feet long as it goes under the boatmans cabin. So 2 universal joints may be the answer.

 

Should be no problem at all with that length - in fact, it might be 'too straight' at least in theory. UJs need to work through a bit of an angle to keep the needle bearings moving and lubricated, otherwise they're likely to fail early. Don't worry too much about that, provided you use big enough joints and keep them well greased.

 

Tim

[RLWP]

O.K thanks. The shaft is around 7 feet long...

 

Wow! What was installed before then? Did you have a single straight shaft from the stern tube to the gearbox? Are you sure the existing shaft hasn't just sagged now that it isn't attached to a gearbox?

 

Just curious,

 

Richard

[Jacq]

At the moment its a Lister HRW3 with Blackstone box, It apears to be a single shaft running under the boatmans cabin.

I havnt removed the engine. This will be a forth coming project.

[Ads]

Hi

 

I Just replaced my Dorman with an HW2 and had a similar problem the dorman had no big flywheel and was narrower. i fitted a Python drive to over come any possible problems like this and to make lining the engine up easier. only thing was i had to weld a bulkhead in to fit the Python drive to.

I got mine from lancing marine.

To me a universal joint is def the way forward and can save a lot of messing about. mine was about £400 so didnt break the bank to much.

Altough saying that i do have a friend with the same engine as yours and his Aquadrive was in the region of £600

 

best of luck

 

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