Liney RV-2 Rescue

[JasonBModerator @jasonb]

I got an email a few weeks ago from an internet friend asking if I wanted a part built engine that he had going spare. Now I use the word “Friend” in the broadest terms, as I don’t think a real friend would have dared to give me an engine with so many interesting additional machining features that the original builder had included, but it certainly turned out to be the gift that kept on giving in that respect.😂

His email included a couple of images of the drawings which did not have the engine name or who designed it as well as some images of what he had. The story is that a friend of his bought them from a guy in America who had started to build ten engines and as they were cheap he got two for my friend, I subsequently found out why they were so cheap – almost expensive scrap.

The style of engine reminded me of the Liney “Halo” and after some googling and asking on an American forum it was confirmed that the engine was the Liney RV-2. A flat four boxer air (or steam) engine of 3/8″ bore and 1/2″ stroke. As soon as the drawings arrived, I redrew them in Alibre to see if all was OK, I just made one change to the pipe positions that come out the central manifold so that they were not offset from the cylinder ctr lines. Apart from that it all looked like it should work. Although imperial the drawings were in decimals and not fractions with many sizes being in multiples of 25, 50 and 100 thou which I have seen a couple of times on other American drawings and quite easy to work with.

The voyage of discovery started when I took the engine parts down to the workshop. Starting with the cylinders which looked quite nicely machined on the outside it soon turned out that their spigots to locate them in teh crankcase were a bit small and varied bt I can take care of that on final assembly. A bigger problem was the bores which again varied by a thou or two but worse was that they were all tapered and a piece of 3/8″ silever steel would only enter so far into each but by different amounts. Luckily I had an expanding reamer to suit that range of sizes so worked my way through all 4 cylinders, slowly increasing the bore until all four were cutting full length. The bore ended up approx 9.75mm.

The drawings spec UNC threads throughout the engine mostly #2-56 and #0-80 but I prefer metrix so thought I would be able to rethread the holes for the cylinder head screws M2.5, it was only when I tried a screw in teh existing threads that I discovered many were crooked.

To cure that I decided to drill and tap new holes placed between the old ones and take the opportunity to go down a size to M2

Offering up the sump plate to the crankcase I first thought that the sump was too narrow but after  a qick going over with the digi callipers it turned out that the crankcase was 2 1/16″ wide not the 2″ called for on the drawings. So after re-tapping all the sump screw holes to metric, it was screwed to the crankcase and the case taken down to width, just skimming the sump at the same time. I then did all the other external faces as the previous builder had polished it up with a buffing wheel, judging by the muck still in the case and it was all a bit rounded over for my liking as well as being too shiny.

I also got rid of the foot mounting lugs on the sump as I wanted to use the optional rear mount shown in the drawings

I thought I was done with the crankcase but there were some more surprises to come!

 

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