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Jowitt Major Completion

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Jasonb:
I was originally asked about machining the flywheels  (did not fit owners lathe) and tidying up the rough casting pretending to be the cylinder. I won't go into details but I have ended up taking the engine right through to completion and although I did not take that many photos will describe some of what was done here.

From the original ebay listing it looks as though the partially machined set of castings and materials have been maturing for some time. Along the way a few bits have been lost, the main one being the cast engine bed along with a couple of governor parts. The plastic box of steel stock did not make it to me either, not a bad thing incase that rust bug is catching!




The cylinder casting was quite rough with a lot of shrinkage at the sides and it looked like a previous owner had milled some flats to enable it to be held while boring. The bore wa snot bad but there were a lot of pits either from porosity or maybe there was not enough machining allowance to get a clean bore but as it was going to be run for display I left the bore alone.



As I got further into the build I found that the long 3/16" holes for the two piston rods had wandered all over the place, the counterbores for the valve seats were not concentric to the valve holes, tapered, oversize and the wrong depth. The supplied oil pots did not fit the tapped holes and the stud holes to hold the cylinder to the bed were again all over the place.

Having established that the bottom of the casting was reasonably parallel to the bore I set it up and took a skim off the top of the cylinder so that I could accurately hold it upside down for further work. I don't often use the 100mm ARC vice as it is too big mounted conventionally but was ideal for this when mounted along the mill table.



The width of the bottom could then be brought to final size and the undersides of the two wings tidied up



I then treated the casting much like the solid blocks that I used to make my smaller versions out of and shaped the outside with a series of cuts. I ended up taking 2.5mm depth of at the ends but still had to resort to using some JB Weld to fill the very low areas.



The facets were then blended with a file to get a nice series of flowing curves. I also added some shallow counterbores so that bosses could be bonded in around the oiler positions.

The endcaps were very tarnished and hard to tell they were gun metal and not rusty iron. The builder had also used the tip of a pointed tool to mark the position of the bolt PCDs rather deeply so a skim cut over all those parts brightened things up. I also turned the spring retainers and cams.






The turning of the flywheels was quite straight forward after a quick bit of fettling with files. I like to get the hand work out the way first as there is less risk of marking the freshly machined surfaces. The spare corner of a CCGT 060202 insert and about 300rpm soon had the turning done.

http://www.youtube.com/watch?v=YlOuUmVWBFI

As you can see in the ebay listing photo the flywheels were the stuart ones with the "lumps" where the spokes joint the rim which I personally do not like so these were milled away on the rotary table followed by some Dremel work to blend the machined surfaces into the cast ones.



Well that covers what I was originally supposed to be doing, the next few posts will cover the rest.

Dave Otto:
I always amazes me how much damage people can do to an engine kit before they get frustrated, quit and stash it away out of sight. Probably more work fixing all the problems than just starting from scratch.
Nice work patching it all up.

Dave

Chipswitheverything:
Whoever decided that a silk purse cannot be made from a Sow's ear was obviously not any active member of this Forum, where these miracles seem to happen with a fair amount of regularity!  Will be interesting to see this build log, or account, as it progresses.

Sanjay F:
Amazing transformation and I narrowly avoided this one as I saw it on eBay and well beyond my restorative capabilities!

It’s a big old engine compared to the smaller version, watching along  :NotWorthy: :popcorn:  :ThumbsUp:

Jasonb:
Dave, as you say starting with a block of Iron may have been the better option given the number of "features" that were hidden within.

Chips, it has turned out to be quite a nice purse

Sanjay, I think you could have done it with some forum guidance. Even if you did not at the price it went for it was not a bad buy. Less than the cost of two new Flywheel castings from Stuart and there was the best part of a whole untouched governor kit in there too.

Yes it's quite a size, you will have to wait for the full trilogy to be revealed ;)


I snipped this image which shows the amount of filler I still had to use on the other side of the casting which was a lot worse than can be seen in my earlier photos.

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