A Simple Uniflow Engine

[gary.a.ayres]

Many thanks, guys.
 

[gary.a.ayres]

Slow progress...

Not getting as much shop time as I'd like, so still working away at tidying up the bottom corners of the frame.

I took the cross-braces out and bolted the frame sides and support bars together so that I could work on them all as one so that they will match each other.

Filing, drawfiling, needle files, drum sanders, cheap Dremel clone, flap wheels... changing tools frequently as much to alleviate the tedium as anything else!

Heading in the right direction, but still quite a way to go:





Gonna get the hacksaw on to these square corners tomorrow to speed the process along a little.

[propforward]

I admire your craftsmanship. It's very stylish - beyond my patience to be honest, but it's going to be a very unique and interesting engine for sure.

[gary.a.ayres]

Very kind of you Stuart - thank you.

It's certainly testing my patience - give me cast iron or even steel any day over aluminium to work with files!

[gary.a.ayres]

Well, all that filing got me to a place I'm reasonably happy with. The bottom corners of the frame are looking ok, bar some final cleanup:





I'll also cut the base plate to length at each end for a tidier look.

The next step was the installation of drip feed oilers on the main bearings. I had two of these, bought from PM Research for another project:



Will have to order new ones for the other project but that's ok.

In order to keep the oilers parallel to each other, I decided to drill the holes for them in the bearings in situ, with the frame set up in the mill:



It's a small mill and a fairly large engine so it was a bit of a squeeze. Even with the drill bit held in the ER-32 collet chuck instead of a drill chuck I only just managed to get everything in.

I drilled with the tapping drill through the outer sleeve of each bearing (which sits on the inside of the frame) and into the inner parts of the bearings. The inner parts of the bearings were just spotted with the end of the drill. These holes were then finished with a much smaller bit. The oilers are adjustable, but if not enough oil finds its way through to the crankshaft, these smaller holes can always be opened up a bit:



The finished bearing assembly (one of two) with the oiler in situ...



... and the finished assemblies in situ on the frame:



In the interests of transparency I will confess: The two oilers are not in perfect alignment with each other. Don't know how it happened, but I have various theories, all of which boil down to carelessness or impatience (mainly the latter). The runout is not horrendous, but it's definitely noticeable. My sense is that when the crankshaft, big end, flywheel and pulleys are all installed, no-one will ever notice. No-one except me, that is. You know how it goes...

After that, it was back to cylinder duty. I opened up the two exhaust ports to partial depth and tapped them:



The inner parts of these ports remains narrow as before, but they can always be widened later if needs be.

Elbows were then installed so that piping can be added later when the engine is set up with a boiler:



The elbows came with black paint on the cast part but I removed this with acetone.

Next, a gasket was made from some orange coloured gasket paper. Amidst the clutter of this picture you can see the various items that were used in the process:



The gasket, partially done...



... and the cylinder complete with gasket and exhaust connectors:



Not long to go now...

[crueby]

           
 

[gary.a.ayres]

Today, the ends of the base plate were cut with a hacksaw and milled square and to length:



This completes the four bottom corners of the frame, bar some final cleanup. I'm quite pleased with the result:





I then gave the parts a rough cleanup with acetone to remove most of the layout dye, then reassembled the engine. There are only a few jobs left to do, and the photos below give a good idea of what the finished engine will look like:





I confess I am happy with the look...

[MJM460]

Hi. Gary, looking great.  A very interesting design of the frame to match the interesting operating principle of the engine.

Looks like it could be the basis for a modular design which could accomodate different cylinders.

MJM460

[propforward]

Love it Gary, great looking engine - I always like following your progress.

I've been wondering where my marking blue went...................................

[gary.a.ayres]

Thank you both, gentlemen. 

@ MJM - yes, I guess a cylinder with a slide valve or a piston valve could be slotted in there as an alternative with not too much overall modification.

@ Stuart - I'm sorry, ok? I have a thing for marking blue and I just couldn't resist raiding your stash. I'll pay you back as soon as I can... I'm expecting a cheque next week... honest!
You may have noticed I'm crazy for the red version too (less covering power, but man! The colour...).

Listen - if you ever get a chance to score some other colour - green, for example, I'll definitely be interested.

[propforward]

 

[Admiral_dk]

I confess I am happy with the look...

Well that is the most important critic you're satisfying 

Congratulations are in order 

[gary.a.ayres]

Per - you have a point!

 

[gary.a.ayres]

It seemed to me that the big end needed an oil hole for lubrication of the bearing. I hadn't sufficiently taken this into account at the design stage so I was left with very few options for an oil hole that wouldn't foul either the threaded holes for the screws that hold the bearing cap in place or the probably over-deep hole into which the connecting rod is threaded:



My solution was to drill the oil hole at an angle from a point very close to the bearing cap screw hole through into the bearing. Here I am just about to make a start with a centre drill before swapping to a twist drill:



After centre drilling I started with a reasonably wide drill to create a small oil reservoir at the top end of the hole, then I changed to a much smaller drill and drilled though to the bearing surface. In practical terms this appears to have worked ok, but I am not happy with the way that the oil hole clashes with the cap screw hole:



It's not a great look but as I say I was limited for choice. The oil hole emerges quite pleasingly on the inside of the bearing, though:



Initial testing would suggest that the flow of oil into the bearing is not too fast. If in practice it turns out to be too slow, the hole can easily be opened up a little.

Note the weeds growing back between the slabs of my back yard after a recent weeding. Building engines is a more attractive pastime to me than weeding is.

That done, it was time to mill flats on the crankshaft to seat the flat-nosed grub screws which secure the flywheel and pulleys. I had already done similar before I changed the overall layout of the engine so there are now some redundant flats on the shaft as well as those which are in use. I don't think that's an issue, though. Marking out the positions of the flats with the shaft in situ:



Milling the flats (I find 0.5mm depth to be about right on this 12mm shaft):



These jobs done, I completely dismantled the whole engine:



On reassembly, each part was cleaned as I added it. For the aluminium, I was not seeking a mirror finish, but more of a satin look, so I used steel wool then wiped with French 'alcool à bruler' (basically methylated spirits). There are still some marks on the larger areas - a scratch here and there, even a couple of scribe lines. These do not bother me:



I also deburred the decorative holes in the frame where required.

The cast iron parts and the steel flywheel were also given the steel wool treatment, but the bronze collars and bearings and the brass pulley were spruced up with 'Autosol' metal polish:



Screws and other small parts were given a soak in the alcool à bruler and brushed clean.

The newly cleaned-up engine was reassembled yet again, and this build is nearing its end. I shall post a couple of pictures of it sometime over the next day or two, along with some details of overall weight and dimensions.

All that remains now is to finish the oak base and mount the engine on it.

[crueby]

Great journey so far, getting close!!