Bog's Paddleduck Engine

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kvom:
With all the working pieces fabricated, I wanted to put it all together for a trial fit. Here's the result:

It's not quite ready to run yet, as it's still too stiff to turn by hand. The main culprit is the right hand piston rod, which binds in the gland. I think I will progressively test each eccentric and each piston separately to try to get them loose enough so that the tuning process can be done. The bottom end (crankshaft) does turn by hand fairly easily, and the valves and one piston slide freely when not connected, so hopefully I can get it to run quite soon.

Darren:
That is looking real good there, every time you post I think I should do something with mine....

So much to do and not enough time

Like I said, your build is quite something to follow.... :clap:

CrewCab:
Kvom :bow: .......... well done wit the fix .......... nicely done :thumbup:

The rest of the build ain't too shabby either :beer:

Cracking work mate :clap:

Dave

kvom:
Thanks for the encouragement. :wave:

I just spent the past hour fiddling with it. The 2nd piston/rod combo is definitely not straight, so I will likely make it once again (#5 if I'm counting correctly). The one piece design seems more likely to come out; since I now have some steel that's over .5" in diameter I think I'll try that again.

With everything connected except that piston&rod, I can turn the shaft assembly by hand, although not easily. I had to quit when my fingers sharter to get sore from pushing on the cranks and crossheads to move them. I suppose I can hook up the electric drill, but since I heard John bad-mouthing that process I decided to wait for advice.

bogstandard:
Nice one Kirk.

That is sure one big engine, comparing it to the size of the can.

I think you have now found out, thinking about doing a rescue can be a lot more gut wrenching than actually doing the job. In fact it can be a massive anti climax when you find out just how easy it is.
Now you have done it the once, all that worry shouldn't be there when you do the next one. You will be plugging holes and redrilling every chance you get.

You are quite right that I don't believe in solving problems by mechanically turning over an engine. Most of my repair work is caused by such actions, you only have to look at my latest repair job. So many worn out parts, before the engine is even running.

I am not saying you shouldn't do it in all cases, as I do it sometimes. Mechanical turning over should only be done on an engine that already turns over fairly easily by hand. I do it to align say crank bearings. Gently have it turning and then slacken the bearing and retighten, allowing the components to find their own perfect running positions. This usually realigns it much better than you can do it by feel.

Are you sure it is not the crosshead guide bars that are causing your problems? With the con rod disconnected, you should be able to push the piston up and down fairly easily. If it tightens up after putting the con rod back, it points to your two cross holes in the con rod not being perfectly parallel. In which case, if they are not far out, you can realign things to run by slackening off the two crosshead guide bars and allow them to find their own position, as the engine is turned over slowly, then a slow and gentle retighten until tight again.

It might not be this, I am just trying to help you fault find before you start to make new parts, that might not be necessary.

Best of luck and well done so far.

John

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