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8 Cylinder Torpedo Engine - Restoration


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A very interesting engine.  I wonder who made it?   I had some dealings with Commonwealth service torpedoes pre 1990, but have never seen an 8 cylinder engine like Simon's. If it was made in the UK, I

A big thank you not just to John, but to you too Simon for what you are doing. To we observers it is a revelation and an absolute treat to see what can be done  with the right attitude and a lot of sk

Simon, I have made the tool and posted it to you.  It should arrive tomorrow (hopefully).  Pics of tool are below. The reduced size on the end of the lever handle is to accommodate a 3/4 drive ex

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Simon,

 

Good news about the die.  Is the bore machined?  If it is, it might be possible to make a special die holder that picks up on the machined bore.  In my experience, it is very difficult to start a die in such circumstances without it going off course and cutting a new thread..

John

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3 hours ago, attleej said:

Good news about the die.  Is the bore machined?  If it is, it might be possible to make a special die holder that picks up on the machined bore.  In my experience, it is very difficult to start a die in such circumstances without it going off course and cutting a new thread..

 

I will have to check - as of now I am probably one of the few who a) work at home a lot so nothing much changes and b) engaged in something that is seen as important enough to keep going, for now at least and c) I'm looking ahead & planning for a time when I too have more time on my hands.

But its a good point. Some of the threads need more TLC than others. The other factor is how these were originally made - the threads were cut prior to assembly/welding onto the barrel...so there is limited room and there is no way a standard die wrench will work...like everything else, the torpedo engine is unique in that respect and never intended for overhaul. 

Edited by SimonBrown
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Posted (edited)
3 hours ago, attleej said:

Good news about the die.  Is the bore machined?  If it is, it might be possible to make a special die holder that picks up on the machined bore.  In my experience, it is very difficult to start a die in such circumstances without it going off course and cutting a new thread..

 

Duplicate post...

Edited by SimonBrown
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Hi Simon I had a look, the largest I have is about 1' 1/4 whitworth. Sorry about that. As for using a die I would use a die nut as you don't need a die wrench that would get in the way of the rest of the engine. I have in the past used grinding paste to work a thread on freely. One thing you won't be able to do is restore the missing thread's when retapping. The worst you can do is cross thread especially this size.

 

 

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I agree that The worst you can do is cross thread especially this size.  That is why I think that what is needed is a special die holder that is machined to 'pick up' on what I hope is the machined bore.  Thus the die would be held perfectly square and would be much less ;likely to go cross threaded. There would also be no question of handles.  It would have a square or hex drive.

 

John

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14 hours ago, BC312 said:

Hi Simon I had a look, the largest I have is about 1' 1/4 whitworth. Sorry about that.

No problem - thanks for looking. I agree; a die nut would be best, for many reasons.

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I agree that The worst you can do is cross thread especially this size.  That is why I think that what is needed is a special die holder that is machined to 'pick up' on what I hope is the machined bore. 

This is just one reason - the opportunity for cockup being extremely high - I have put the project down. Time to think about how to solve it rather than rush...

I think the idea of a spigot to follow the bore might be sound...I need to have a look at them. Square or hex drive would be required too.

I will post up some more photos.

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It might be worth getting a engineer machinist to have a look and give an opinion. I have a mate who may be able to help out. I will send him the picture and see the best way.

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Finally I got a little spare time to start thinking and tinkering with the torpedo engine.

The barrels will be going for some light soda blasting at some point, mainly to remove a little surface corrosion.

One nagging thought; the bolts that hold the barrels onto the crank case are (like most things) somewhat unusual. Normally I would expect to see studs, but not here. 

What we have are pan head bolts with a tiny pip on the underside of the pan head. As far as I can tell the pip is intended to stop the screw rotating on assembly...the slot is a nightmare to get to when reassembling and to be quite frank the pip is too small to be really effective.

SBrown-20200621-0004.thumb.jpg.456c72b0810dfd1b4deee0a257dbb988.jpg

It all serves as a reminder this engine is most likely a prototype and a proof of concept. No one in their right mind would want to put this thing into series production.

Anyway, I am contemplating using a modern Loctite to secure the pan heads in place. This goes against the grain a little, but it will make it easier to reassemble. There does appear to be some black adhesive of some form in the holes, but quite what it might be is beyond me.

So...What are the collective thoughts of the forum on this idea? I am open to struggling, or taking a short cut. Should I be that precious or make life easy? Is modern Loctite an act of heresy? Or just common sense?

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Simon,

I would not hesitate to use loctite.  For instance, why risk having a stud unscrew rather than the nut with all the attendant difficulties when a dab of loctite will solve the problem.  Easy to get undone with heat if nec.

It is difficult enough to work on old equipment without turning down some modern technology.

 

John

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On 6/21/2020 at 3:03 PM, SimonBrown said:

Finally I got a little spare time to start thinking and tinkering with the torpedo engine.

The barrels will be going for some light soda blasting at some point, mainly to remove a little surface corrosion.

One nagging thought; the bolts that hold the barrels onto the crank case are (like most things) somewhat unusual. Normally I would expect to see studs, but not here. 

What we have are pan head bolts with a tiny pip on the underside of the pan head. As far as I can tell the pip is intended to stop the screw rotating on assembly...the slot is a nightmare to get to when reassembling and to be quite frank the pip is too small to be really effective.

SBrown-20200621-0004.thumb.jpg.456c72b0810dfd1b4deee0a257dbb988.jpg

It all serves as a reminder this engine is most likely a prototype and a proof of concept. No one in their right mind would want to put this thing into series production.

Anyway, I am contemplating using a modern Loctite to secure the pan heads in place. This goes against the grain a little, but it will make it easier to reassemble. There does appear to be some black adhesive of some form in the holes, but quite what it might be is beyond me.

So...What are the collective thoughts of the forum on this idea? I am open to struggling, or taking a short cut. Should I be that precious or make life easy? Is modern Loctite an act of heresy? Or just common sense?

We had a similar situation but much larger.

The Pivot pins on our Railway ballast hopper has 65mm dia pins as a pivot point on the hopper doors.

We found out the hard way thaat small 5mm stubs located in the pin housing and to undo or make up you needed to hold the shaft from turning and keep the stud end located firmly in the socket otherise the stud would shear off.

Hopper pin stud.jpg

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