"CS" wrote in message
ups.com...
I fitted a Centaflex AGM coupling - 2 rubber couplings and a 2.4mtr 5
inch diameter hollow shaft in between and it was considerably cheaper
than Aquadrive - but not sure about Python drive. Are not Aqua and
Python the same thing but Python is the US version??


I considered the Centaflex but I would like to fit really soft engine mounts
so preferred a double CV coupling.

It appears to me that both the PythonDrive and the AquaDrive both utilize
double CV joints. AquaDrive has been around longer and is therefore well
known. Maybe this is the only reason it's more expensive.

Adrian Smith

I considered the Centaflex but I would like to fit really soft engine mounts
so preferred a double CV coupling.

Centaflex AGM is a double coupling - one at the gearbox flange and one
at the thrust bearing. CV joints in Aqua and Python are still metal to
metal - and transmit noise. "Really soft engine mounts" - mounts
should be calculated to the weight they have to support. My engine has
6 mounts and each were calculated to take account of the static weight
plus the dynamic weight increase and or decrease caused by the torque
of the engine. The rubber is still quite stiff. Really soft mounts
may not be designed for the weight and will just collapse/bottom out
and you will have a very healthy noise short from engine to bearer..

"CS" wrote in message
oups.com...

I considered the Centaflex but I would like to fit really soft engine
mounts
so preferred a double CV coupling.

Centaflex AGM is a double coupling - one at the gearbox flange and one
at the thrust bearing. CV joints in Aqua and Python are still metal to
metal - and transmit noise. "Really soft engine mounts" - mounts
should be calculated to the weight they have to support. My engine has
6 mounts and each were calculated to take account of the static weight
plus the dynamic weight increase and or decrease caused by the torque
of the engine. The rubber is still quite stiff. Really soft mounts
may not be designed for the weight and will just collapse/bottom out
and you will have a very healthy noise short from engine to bearer..


By 'really soft', I mean mounts that are obviously suitable for the engine
but allow more movement than can realistically be accommodated for by the
typical coupling to the propshaft via a R&D coupling.

What kind of coupling joint does the Centaflex use?

Adrian Smith

On Mon, 11 Sep 2006 18:46:45 GMT, "Adrian Smith" wrote:


"CS" wrote in message
roups.com...

I considered the Centaflex but I would like to fit really soft engine
mounts
so preferred a double CV coupling.

Centaflex AGM is a double coupling - one at the gearbox flange and one
at the thrust bearing. CV joints in Aqua and Python are still metal to
metal - and transmit noise. "Really soft engine mounts" - mounts
should be calculated to the weight they have to support. My engine has
6 mounts and each were calculated to take account of the static weight
plus the dynamic weight increase and or decrease caused by the torque
of the engine. The rubber is still quite stiff. Really soft mounts
may not be designed for the weight and will just collapse/bottom out
and you will have a very healthy noise short from engine to bearer..


By 'really soft', I mean mounts that are obviously suitable for the engine
but allow more movement than can realistically be accommodated for by the
typical coupling to the propshaft via a R&D coupling.

What kind of coupling joint does the Centaflex use?

Adrian Smith

See note from Colin Stone (CS) who wrote
I fitted a Centaflex AGM coupling - 2 rubber couplings and a 2.4mtr 5
inch diameter hollow shaft in between and it was considerably cheaper
than Aquadrive - but not sure about Python drive. Are not Aqua and
Python the same thing but Python is the US version??

His installation is a little different to yours in that he has the
"doughnuts" 2.4m apart.
I fitted an AGM on my Narrowboat because
1 It was shorter than the Aquadrive or Python
2 No metal to metal and lubrication issues
3 Even though shorter the allowable angular misalignment appeared
greater
4 I got it cheap!

I had to move the engine forward 4 inches but fabricated some solid
mounts for the thrust bearing and I have been very pleased with it.
Very little to go wrong and thrust bearing (if it ever goes pop) is an
off the shelf item at most good bearing suppliers.

Richard

Nb "Pound Eater" Parkend G+S

"Adrian Smith" wrote in message
news
"Lew Hodgett" wrote in message
link.net...
Adrian Smith wrote:

Why did you choose the Aquadrive over the cheaper PythonDrive?

Did you notice a big before/ after difference in both noise and
vibration?

Just noticed that you are probably in UK which may impact pricing.

Here in US, a complete AquaDrive package, including engine mounts
and
adapters is probably less than $1,500 USD for most sail boat
engines.

Lew


Don't suppose you can remember what model/size AquaDrive you have?

PythonDrive for my engine (2.25litre 48BHP@2800) is approx 600USD
(converted
from GBP) Probably get one cheaper over there. For complete unit/
adapters
but not engine mounts.

From what I can see in the specs there is not much difference
between an
AquaDrive and a PythonDrive.

Adrian Smith

Adrian
Everybody has been giving their own personal recommendations before
you said what engine you have in your boat and what sort of boat it
is.
Also, do you really want to mount the engine on flexible mounts rather
than solid mountings?
From your latest post, am I correct in assuming that you have a 4 cyl
diesel? Japanese based unit or BMC etc?

Are you more concerned about alignment problems or
vibration/noise transmission?

Phil

Adrian Smith wrote:


Don't suppose you can remember what model/size AquaDrive you have?

From memory, up to about 30HP, they only have one unit.

The mounts are selected based on weight of engine/tranny.

They are soft enough to go into resonance at a low enough frequency to
isolate the engine vibration which is exactly why the system works so
well.

Lew

Subject

Just for funzies, did a Google for "python drive".

Came up with several hits for web sites; however, many of them came up
empty.

I wonder why?

Lew

"Phil R" wrote in message
...

"Adrian Smith" wrote in message
news
"Lew Hodgett" wrote in message
link.net...
Adrian Smith wrote:

Why did you choose the Aquadrive over the cheaper PythonDrive?

Did you notice a big before/ after difference in both noise and
vibration?

Just noticed that you are probably in UK which may impact pricing.

Here in US, a complete AquaDrive package, including engine mounts
and
adapters is probably less than $1,500 USD for most sail boat
engines.

Lew


Don't suppose you can remember what model/size AquaDrive you have?

PythonDrive for my engine (2.25litre 48BHP@2800) is approx 600USD
(converted
from GBP) Probably get one cheaper over there. For complete unit/
adapters
but not engine mounts.

From what I can see in the specs there is not much difference
between an
AquaDrive and a PythonDrive.

Adrian Smith

Adrian
Everybody has been giving their own personal recommendations before
you said what engine you have in your boat and what sort of boat it
is.
Also, do you really want to mount the engine on flexible mounts rather
than solid mountings?
From your latest post, am I correct in assuming that you have a 4 cyl
diesel? Japanese based unit or BMC etc?

Are you more concerned about alignment problems or
vibration/noise transmission?

Phil



The engine is an Izuzu marine engine. (4 cyl)

I want to reduce all noise and vibration to an absolute minimum and that is
not possible on solid mounts. Some guys have solid mounts but they generally
have older, heavier low reving engines.

Adrian Smith

"Lew Hodgett" wrote in message
news
Subject

Just for funzies, did a Google for "python drive".

Came up with several hits for web sites; however, many of them came up
empty.

I wonder why?

Lew

I have done the same and was surprised to only find one account of fitting a
PythonDrive. The author gave the thumbs up for the drive.

Adrian Smith

"Adrian Smith" wrote in message
. uk...
I posted this to a number of groups as I'm sure it's of interest to all.

I'm looking to purchase a CV coupling to go between the engine and the
prop shaft.

The two contenders seem to be either an Aquadrive or a PythonDrive. The
PythonDrive is cheaper. Has anyone any experience with the PythonDrive.

Will it handle movement from a soft mounted engine in up/ down, side/ side
and fore/ aft directions.

My engine is currently coupled to the prop shaft with a R&D flexible shaft
coupling, this is basically a plastic plate that can flex slightly.
Although the setup works, it's a bit primitive. At certain throttle
settings the engine bounces about a bit and vibrations can be felt.

Any info will be appreciated.

Adrian Smith



Guys, thanks for all your help.

I'll post here with what I decide to do and the results for others to
benefit from.

Adrian Smith