OX-5 Update - January 1, 2016

Happy New Year everyone!

I've been working on the firewall, it is just about done.  The next post will include details.  Mostly, though, I've been working on the OX-5.  It's been slow-going and taking a lot longer than most engines I've done, but extra care will be worth it in the end.

Installed lower crankcase half

Engine builders?? initials engraved into baffles

 One of the first things I did was finish up the lower end.  This involves installing the screen, oil pump, internal baffles and oil level indicators.














Here's a shot of the baffles.  These are original, made from galvanized steel with an interesting galvanizing pattern. If you look closely at the upper part of the baffle, you will see some initials engraved in the metal.  Maybe the original engine builder??

Oil level float components

New float modified with brass bushing

Completed float assembly

 The OX-5 uses a cork float to indicate the oil level in the engine, in other words - no dip stick.  The original cork float was broke, so I made a new one.  I modified it to hopefully make it last longer by adding a brass bushing  where it rides on the arm.

Float level indicator (left) and oil level fill plug (right)

New oil sump gaskets

And of course, like everything else, new gaskets had to be made.  A little bit of care here, though.  Too thick or too thin and the front thrust bearing will not be captured properly and the front plate will not bolt on.  .032" gasket paper was the proper thickness.

New intake gaskets

The intake manifolds were then permanently installed.  I had a new set of copper crush gaskets that you can see here in this picture.

Intake manifolds installed

Next will be installing the valve train, so I spent quite a bit of time getting the components ready like making sure push rods were straight, etc.  Also, modifying the intake pull rod hold down straps.  The intake valves are pulled open on the OX-5 by a tube that covers a conventional looking push rod that pushes open the exhaust valve.  One of the interesting oddities of the OX-5.  The modification involves making sure the pull down tube remains lubricated where it slides thru the hold down strap.  The importance of this is mentioned in old manuals like the Miller Rev's for OX's, where it talks about "lots of rev's are lost here from friction".

The metal-to-metal joint itself can simply be lubricated, but won't last long.  I've seen where felt has been safety-wired around the pull down tube then soaked with oil which seems to work pretty good.  I wanted something a little more "factory" looking without doing a whole lot of fabrication, so here's what I came up with...

This picture shows the intake pull down tube in the strap with felt washers installed that can be periodically oiled to keep the area lubricated.

Components used to make the "lubricator"

Holes drilled on top of strap

Brass cotter keys bent over to avoid interference with spring

 The components are inexpensive and can be purchased from numerous sources:  3/4" felt washers and a plastic washer as a backup.  1/16" brass cotter keys hold the parts in place.

Completed assemblies

I started by drilling 2 small holes on the top of the strap.

The plastic washer followed by the felt washers are slid down, and the 2 cotter keys slid thru the washers and into the holes in the strap.  It's important that the cotter keys are bent over flat and out toward the edges of the strap so they don't interfere with the intake pull down springs that go in the straps.

Here they are all ready.  The brass wire wrapped around the top is just to keep the felt washer against the tube so the lubrication works.  

We'll see how they work...

Also added the "crown jewel", the data tag.  Now it looks like a real Curtiss!

So now I can install the rest of the valve train.  It will take some time as there is a lot that has to come all together.  Plus, I need to make new rollers and shafts for the Miller roller rockers.  I'll also keep plugging away at airframe items too.  Check back soon!