Silver Century chop?

[Mutineer]

I know this may sound blasphemous
But how possible is it to chop a longshaft silver century down to regular shaft size?
I'm normally not too keen on the idea of altering otherwise fine units but there's one available and it's a longshaft...much too long for my boat which works well with a 40 plus size

[charlesp]

Certainly it's possible.

In fact the factory used to sell conversion kits, complete with gearbox gasket, new fasteners, water pipe, drive shaft casing, exhaust, and a set of instructions stressing the importance of changing the serial to reflect the new status of the motor. I have a couple of sets of instructions here.

[Mutineer]

THanks Charles
That's good to know
I have the shop manual but I don't believe I saw it covered in that
How much are the instuctions? do you sell them?
Maybe I'll pick up this Silver century too..what fun!

[Horsley-Anarak]

I have cut down a couple, just take the same length off exhaust, drive tube and water pipe.

Some of the century engines have a stepped drive tube. so if yours is like that then you will need to turn down the bottom end so it will fit the waterpump housing again.

I would only cut it down to standard length. You might want to sell it one day.

If it is a clutched engine the thread on the end of the clutch rod is 1/4" BSF.

H-A

[charlesp]

To be honest it would take days to find them, and they wouldn't help you much. The kit didn't assume hacksaws would come into play at all!

Better idea than chopping would be to get hold of the right bits second hand - John will, I'm sure, be happy to oblige.

[Horsley-Anarak]

All you need is a thin metal cutting blade in a small angle grinder.

The whole process takes about half an hour.

H-A

[Mutineer]

Excellent
I have have access to an angle grinder and thin metal cutting blade..and a measuring tape (haha)
Thanks

[Francis]

I too am in the process of chopping my Silver Century. I am shortening it a total of 7 inches, the drive tube is at a machine shop awaiting the step to be cut. As far as the clutch rod goes, I am forgoing the cutting of threads and will shorten the other end. I do not have the Witworth dies to cut new threads and I am sure a torch, vice and hammer will make the 90 degree bend at the top of the rod to connect to the shift lever. I have miter type chop saw that I can remove the wood cutting blade and replace with a thin metal cutting blade to cut the rest. I expect the edges will then be true at 90 degrees. I will never sell this motor so I expect my Grandkids will be scratching their heads when they inherit the whole mess...

[Mutineer]

Such excellent information
THis forum really is a dandy thing
i have another question if i may
I remembered seeing something regarding the drive tube? on certain silver centuries, perhaps it was the plus models
one of them was stepped down on the ends to fit into the appropriate housings and this would require remachining if it was to be cut down
Sorry for the vagueness, I can't find the original post regarding it though I searched
i think Francis is referencing the same thing in his post
Does anyone know which models in particular have this peculiarity?
By the by mine is a direct drive version long shaft silver century
Not sure if it's a plus model as i'm picking it up tomorrow (will know then obviously)
Thanks again all
I believe forums like these to be one of the real advantages of the internet..that and research...and long distance communication...and naughty pictures of course

[Mutineer]

oh
I think I found it again
Apparently it's the plus models that have the thicker casings with the turned down ends?

[Francis]

The is the end of my Silver Century that I had cut 7".

The end was turned on a lathe to fit...

[Horsley-Anarak]

One tip for cutting the exhaust square.

Wrap a sheet of A4 paper round the exhaust at the cut point.

Line up the edge of the paper and tape it in place, this will give you a perfect square line to work to.

H-A

[Francis]

Note the shift rod of a Silver Century Plus has a dog leg bend as shown. You will need to cut the top of the rod and bend it rather than cut the bottom and rethread. Those bends need to stay where they were put originally to clear the exhaust tube.

[Mutineer]

Finally picked up my long shaft silver century and a 40 plus and a 40 plus parts motor that someone chopped down to 40 minus length..
WSL 366 FF4
SJP 25135
SJP 242E4
The first 2 run fine
the third needs a float bowl, float, Prop, fastener for the throttle control..might need more too
All need a good cleaning
I think the long shaft silver century might be the easy to convert type, not a plus, nor a clutched model
Spent 4300 for the lot, pretty good i think
now i have 5 ..ulp had 4 sold 2..now 5 hmmmm, yup I'm a gonner!

[40TPI]

All you need is a thin metal cutting blade in a small angle grinder.

The whole process takes about half an hour.

cut down.jpg

H-A

And another recycled pic and post. Use of a joiner's mitre saw makes it an abs doddle to keep the end of the sawn tube square...

http://www.saving-old-seagulls.co.uk/fo ... =saw#p8000



Peter