Model Engine Maker

Engines => Your Own Design => Topic started by: cfellows on July 19, 2012, 08:33:31 PM

Title: Compressed Air V8 Engine
Post by: cfellows on July 19, 2012, 08:33:31 PM
This engine started out being modeled after the 4-cylinder Cirrus engine, but I have since learned it more closely resembles the Whittle V8 engine.  These pictures are at the current progress level and I will go back and repost earlier pictures if there is an interest.

(http://i192.photobucket.com/albums/z195/cffellows/e119dd47.jpg)

(http://i192.photobucket.com/albums/z195/cffellows/e65873c5.jpg)

(http://i192.photobucket.com/albums/z195/cffellows/6e8b5c06.jpg)

Next I'll be working on the pistons...

Chuck Fellows
Title: Re: Compressed Air V8 Engine
Post by: DaveH on July 19, 2012, 08:50:12 PM
Hi Chuck,
I would like to see it from the start please  :D
 :)
DaveH
Title: Re: Compressed Air V8 Engine
Post by: lazylathe on July 19, 2012, 09:09:31 PM
Count me in for the ride Chuck!

Some more pics of the machining steps would be great!

Andrew
Title: Re: Compressed Air V8 Engine
Post by: Bogstandard on July 19, 2012, 09:11:40 PM
Our first engine post, and from one of the 'greats' as well.

Chuck, you are most welcome to post any of your builds on here.

John
Title: Re: Compressed Air V8 Engine
Post by: arnoldb on July 19, 2012, 09:30:11 PM
Hi Chuck.

I agree 100% with John in all respects - keep it coming!

Kind regards, Arnold
Title: Re: Compressed Air V8 Engine
Post by: cfellows on July 19, 2012, 11:06:59 PM
Here is the crankshaft...

Here's a picture of the raw stock. I turned a 1" diameter piece of 12L14 down to 13/16" and drilled center holes in each end.

(http://i192.photobucket.com/albums/z195/cffellows/21121a16.jpg)

I had to noodle on it a bit to figure out the best way to do it. I decided in the end to turn it between centers. So the first problem was to drill center holes on each end, at 90 degree intervals 1/4" off center. I needed an identical set of holes on each end, and each corresponding pair of holes have to be exactly opposite each other. Luckily, I have a nice tool makers vice that is ground square and flat on all sides, so I was able to clamp the blank in the vice, then use my height gauge to find the center and scribe lines all the way around and a second set at 90 degrees to the first. I also scribed a center line on the face of Jaw #1 on my four jaw chuck. Using the 4-jaw chuck to offset the the work by .25" I drilled the holes, loosening the work and rotating it 90 degrees between holes, lining up the radial line on the end of the blank with the scribed line on the face of the chuck jaw. I think I got them pretty true.

(http://i192.photobucket.com/albums/z195/cffellows/8304cc25.jpg)

I'm designing this engine as I go, so work may be slow at times. Just hope I can see it through to the end. Tomorrow I start turning the connecting rod journals, saving the mains journals until last.

Chuck


Title: Re: Compressed Air V8 Engine
Post by: cfellows on July 19, 2012, 11:07:58 PM
I milled away the bulk of material around the soon to be connecting rod journals.

(http://i192.photobucket.com/albums/z195/cffellows/4f63ebdb.jpg)

Then I went back to the lathe and turned the journals down to their finish diameter of 7/32". This was done using my 4-jaw chuck, not between centers as originally planned.

(http://i192.photobucket.com/albums/z195/cffellows/b4664a6c.jpg)

I still have to widen the gap which I will do next.
Title: Re: Compressed Air V8 Engine
Post by: cfellows on July 19, 2012, 11:08:49 PM
I finished up the crankshaft. Turned out really nice. Of course, it took me all day to make it. Quite a process!

(http://i192.photobucket.com/albums/z195/cffellows/0cea186f.jpg)

Kind of hard to tell from the photo, but this is a cross-plane crankshaft. That means that the throws are 90 degrees apart as you proceed from one end to the other.

Chuck
Title: Re: Compressed Air V8 Engine
Post by: cfellows on July 19, 2012, 11:09:36 PM
Got some more done on the engine today. I started roughing out the top part of the crankcase.

Here is a picture of the block I'm using. It's magnesium and was cut from a 1" thick piece that I've had laying around for a long time. The overall dimensions of the block is 3" x 1.7" x 1" thick.

(http://i192.photobucket.com/albums/z195/cffellows/84bd2984.jpg)

Here is the block mounted in my milling vise read to surface one of the sloping sides. I'm using a 1.25" indexable face mill to form the 45 deg angled faces.

(http://i192.photobucket.com/albums/z195/cffellows/549f5765.jpg)

This is the block with one of the angled faces finished. This magnesium machines really nicely. I was able to mill away .100" on each pass.

(http://i192.photobucket.com/albums/z195/cffellows/21a04230.jpg)

And here is the piece with both angled faces milled, along with crankshaft for size comparison.

(http://i192.photobucket.com/albums/z195/cffellows/bdd53841.jpg)

I was careful to vacuum up all the magnesium swarf after I finished. It's not likely to catch fire since the kindling point is around 700 degrees, but didn't want to take any chances...

The next step will likely be to hog out the underneath side of the crankcase. Not entirely sure how I will do that, probably with an end mill.

Chuck
Title: Re: Compressed Air V8 Engine
Post by: cfellows on July 19, 2012, 11:09:59 PM
This is iteration #2 of my crankcase, top half. The first one would probably have worked, but I missed a lot of the dimensions, by a lot, so couldn't in good conscience continue with it.

With this iteration, I've mounted the crankcase half in my dividing head. I will use the rotating motion and lower the end mill a bit at a time to achieve a semicircular, concave cutout in the metal. I think this will give me a lot more consistent result. The metal cuts really nicely so I don't think the long overhang will be a problem. I plan to go slow. Could really use a CNC mill at this point, but this will have to do.

(http://i192.photobucket.com/albums/z195/cffellows/2d4f1d24.jpg)

I may shoot a video of part of the process to show how it works. This is work for tomorrow.

Chuck
Title: Re: Compressed Air V8 Engine
Post by: cfellows on July 19, 2012, 11:10:38 PM
I got the crankcase top, 2nd version pretty well finished today and I'm quite happy with the process and the results. I'll be uploading a video showing how I used my dividing head to position the work for hollowing out the inside.

(http://i192.photobucket.com/albums/z195/cffellows/0635b581.jpg)

(http://i192.photobucket.com/albums/z195/cffellows/af300ad3.jpg)

I'm hoping these will have been the most difficult pieces and having them out of the way should make the rest of the project go pretty smoothly (famous last words!).

Chuck
Title: Re: Compressed Air V8 Engine
Post by: cfellows on July 19, 2012, 11:11:05 PM
ere's a couple of videos. The first shows how I formed the semicircular cavity in the underneath side of the top crankcase half.

http://www.youtube.com/watch?v=gqCRwGf8EtI (http://www.youtube.com/watch?v=gqCRwGf8EtI)

The second video shows it finished.

http://www.youtube.com/watch?v=yZNTW789r9g (http://www.youtube.com/watch?v=yZNTW789r9g)

Chuck
Title: Re: Compressed Air V8 Engine
Post by: cfellows on July 19, 2012, 11:11:30 PM
ere's a pile of cylinders in the rough...

(http://i192.photobucket.com/albums/z195/cffellows/ce0dbd6f.jpg)

And here's the first prototype.

(http://i192.photobucket.com/albums/z195/cffellows/cef5cc31.jpg)

I decided to make the head integral with the cylinder. Simpler and easier to make. Sigh, 7 more to go!

Chuck
Title: Re: Compressed Air V8 Engine
Post by: cfellows on July 19, 2012, 11:12:05 PM
ere's a pile of cylinders in the rough...

(http://i192.photobucket.com/albums/z195/cffellows/ce0dbd6f.jpg)

And here's the first prototype.

(http://i192.photobucket.com/albums/z195/cffellows/cef5cc31.jpg)

I decided to make the head integral with the cylinder. Simpler and easier to make. Sigh, 7 more to go!

Chuck
Title: Re: Compressed Air V8 Engine
Post by: chuck foster on July 19, 2012, 11:39:48 PM
this sure is a neat looking project   8)

were do you get all the ideas from chuck, you must think engines all the time  ;D

i am looking forward to getting back to my fairbanks build but work keeps getting in the way. :(

chuck   the northern one
Title: Re: Compressed Air V8 Engine
Post by: DaveH on July 20, 2012, 02:12:38 AM
Chuck,
Wow, some very nice machining   :) :) :)

Just wondering is there a reason to use magnesium for the block?
 :)
DaveH
Title: Re: Compressed Air V8 Engine
Post by: cfellows on July 20, 2012, 05:07:33 AM
Chuck,
Wow, some very nice machining   :) :) :)

Just wondering is there a reason to use magnesium for the block?
 :)
DaveH

Thanks, Dave!  I used magnesium based on available stock.  I didn't have any aluminum the right thickness, only the magnesium, so that's what I used.

Chuck
Title: Re: Compressed Air V8 Engine
Post by: DaveH on July 20, 2012, 09:07:00 AM
Chuck,
Wow, some very nice machining   :) :) :)

Just wondering is there a reason to use magnesium for the block?
 :)
DaveH

Thanks, Dave!  I used magnesium based on available stock.  I didn't have any aluminum the right thickness, only the magnesium, so that's what I used.

Chuck
Chuck,
That's one of the best reasons  :D :D :D
 :)
DaveH
Title: Re: Compressed Air V8 Engine
Post by: spuddevans on July 20, 2012, 11:56:36 AM
Looking good, there is always something fascinating for me with V8's. I'm looking forward to watching this one grow.


Tim
Title: Re: Compressed Air V8 Engine
Post by: metalmad on July 20, 2012, 02:40:23 PM
Hi Chuck
That Crank is lovely Mate
Pete
Title: Re: Compressed Air V8 Engine
Post by: Dean W on July 22, 2012, 04:06:29 AM
Coming along great, Chuck.  I like the way you chose to remove the stock from inside the crankcase. 
Is this engine going to use your special valve setup?  (Forgotten what you call it..)
Title: Re: Compressed Air V8 Engine
Post by: sbwhart on July 22, 2012, 06:59:31 AM
I'm watching along Chuck this will be a superb engine  :)

Stew
Title: Re: Compressed Air V8 Engine
Post by: NickG on July 22, 2012, 08:44:33 AM
It will be, looking forward to watching this. Will never get anything of my own done that this rate   ;)

Nick
Title: Re: Compressed Air V8 Engine
Post by: cfellows on July 23, 2012, 02:38:14 AM
Coming along great, Chuck.  I like the way you chose to remove the stock from inside the crankcase. 
Is this engine going to use your special valve setup?  (Forgotten what you call it..)

Thanks, Dean, yes this engine will use my slave valve arrangement.  Adds as much to the sound as to the operation!

I'm watching along Chuck this will be a superb engine  :)

Stew

Thanks Stew, always a compliment to know your watching...

It will be, looking forward to watching this. Will never get anything of my own done that this rate   ;)

Nick

Thanks, Nick, I've been having a problem of my own this past few days.  The better half has taken over my shop to paint a piece of furniture.  I can't make chips until she has it finished and back in the house.  Hopefully just another day or two!

Chuck
Title: Re: Compressed Air V8 Engine
Post by: cfellows on July 23, 2012, 02:50:14 AM
For those of you who may not have seen my opposed 4 cylinder engine, this V8 will use the same valve set up and will be a 4 stroke.
http://www.youtube.com/watch?v=SYugS_vvPrQ
Chuck
Title: Re: Compressed Air V8 Engine
Post by: Dean W on July 23, 2012, 05:46:36 AM
It ought to be quite something to hear running then, Chuck.  I've seen a few of your other engines that use the slave
valve, and it really makes a realistic sounding pop on the exhaust.
Title: Re: Compressed Air V8 Engine
Post by: cfellows on July 25, 2012, 04:18:38 AM
I messed up one of the connecting rods trying to make them prettier, so I decided to remake all of them.  Tonight I was drilling the pilot holes for the rod cap screws and broke my only 3/64" bit.  Had to order some new ones so the project is on the shelf for a few days.

In the meantime, I'm working on my own design for a model 2-stroke horizontal oil field engine similar to the Bessemer.  Current plan is for a 1.25" bore, 1.75" stroke, 9" flywheels and hot tube ignition.  If I can't get the hot tube ignition to work, I'll fall back on spark ignition.

Chuck
Title: Re: Compressed Air V8 Engine
Post by: Dave G on July 25, 2012, 01:33:35 PM
Really enjoying your build Chuck. I like your designs a lot, Dave
Title: Re: Compressed Air V8 Engine
Post by: vcutajar on July 25, 2012, 06:35:45 PM
Hi Chuck

Very happy that I can continue following your build here.

Vince
Title: Re: Compressed Air V8 Engine
Post by: swilliams on July 26, 2012, 09:02:56 AM
Checking in late, but I'm here for the ride now Chuck

Steve
Title: Re: Compressed Air V8 Engine
Post by: cfellows on July 27, 2012, 12:47:52 AM
Thanks to everyone for the words of encouragement.

I managed to reclaim my shop from the missus who was using it to paint a large piece of furniture.  Here's 8 new connecting rods.  Not perfect but good enough.  I need to leave well enough alone or I'll wind up making a 3rd set! :hellno:

(http://i192.photobucket.com/albums/z195/cffellows/bed92adf.jpg)

Next I think I'll give the pistons a go.  I'm planning on using steel since they will be riding in aluminum cylinders.

Chuck

Title: Re: Compressed Air V8 Engine
Post by: Dean W on July 27, 2012, 03:26:40 AM
Good progress, Chuck.  Especially since you made enough con-rods for a V-16.  ;)
Everything is nice and neat in their trays, too. 
Title: Re: Compressed Air V8 Engine
Post by: cfellows on July 27, 2012, 03:42:02 AM
Thanks, Dean.  I picked that tray up at Harbor Freight for about $6.  It has 7, nice big compartments that keeps the parts from getting lost in the clutter on my workbench. 

Here is a picture of the first piston.  I decided to make them from brass since it's easier to machine than steel.

(http://i192.photobucket.com/albums/z195/cffellows/a85c898b.jpg)

Chuck
Title: Re: Compressed Air V8 Engine
Post by: chuck foster on July 27, 2012, 03:47:01 AM
nice looking build chuck  :ThumbsUp:

only 2 sets of rods eh?  remember i am the king of re-making parts (9 cylinders for a 3 cylinder engine)  :ROFL:

looking forward to you next posting on this build.

chuck
Title: Re: Compressed Air V8 Engine
Post by: KB on July 27, 2012, 03:39:38 PM

Cooking right along there Chuck!

I can't wait to hear what this one sounds like.
Title: Re: Compressed Air V8 Engine
Post by: DavidF on July 27, 2012, 05:26:08 PM
Ok  im hooked on this thread as well, cant wait to see more!!
Title: Re: Compressed Air V8 Engine
Post by: cfellows on July 27, 2012, 11:30:56 PM
Thanks for the encouragement David, Kevin, Chuck.  The folks on this new forum are a lot more engaged than the other forums. 

I got the pistons all made today.  Still need to drill the wrist pin holes, but other than that, they are finished.  I decided to make them out of steel rather than brass, mostly cause I hate using my brass, but also I figured the steel would wear better.  Turns out they weren't all that hard to machine.

I first cut 8 blanks from 3/8" OD drill rod.  The blanks are are about 7/16" long which is 1/16" oversize.  The first lathe operation after skimming the end is to drill a 1/8" center hole that is 5/16" deep.  This will leave a 1/16" thick top on the finished piston.

(http://i192.photobucket.com/albums/z195/cffellows/4e96d972.jpg)

Next I used a 5/16" end mill to bore out the bottom 1/16" deep, forming the skirt.

(http://i192.photobucket.com/albums/z195/cffellows/bda81bc0.jpg)

Here's 7 of the pistons after drilling the bottoms...

(http://i192.photobucket.com/albums/z195/cffellows/d2064249.jpg)

Unfortunately I didn't take any pictures of the slot milling operation.  All I did was chuck each of the pistons in an ER20 collet chuck that allowed me to hold the piston vertically in my milling vise.  Then I made multiple passes with a 1/8" end mill to form the slot.  After milling all the slots, I then trimmed off the tops of the pistons in my lathe to bring the finished length down to 3/8"

Here's the finished pistons along with all the other parts I have todate.

(http://i192.photobucket.com/albums/z195/cffellows/78c6d6bb.jpg)

Next I'll be figuring out the details of the valve and air supply assembly.  This could take a few days...

Chuck
Title: Re: Compressed Air V8 Engine
Post by: Dean W on July 27, 2012, 11:37:49 PM
Pistons look good, Chuck.  I don't blame you for wanting to save your brass.  Gosh, it's gone through the roof, lately!
Title: Re: Compressed Air V8 Engine
Post by: swilliams on July 28, 2012, 03:14:44 AM
Your really churning out the parts there Chuck. Looking good

Steve
Title: Re: Compressed Air V8 Engine
Post by: sbwhart on July 28, 2012, 07:18:23 AM
Looking good Chuck you're certainly knocking the parts out with this one  :ThumbsUp:

Looking forward to the next bit.

Stew
Title: Re: Compressed Air V8 Engine
Post by: ironman123 on July 28, 2012, 01:02:57 PM
Nice going there Chuck.  Enjoying this build.

Ray
Title: Re: Compressed Air V8 Engine
Post by: NickG on July 28, 2012, 03:40:36 PM
That's a lot of little parts! Great work there, enjoying it too.
Title: Re: Compressed Air V8 Engine
Post by: cfellows on July 28, 2012, 11:15:44 PM
Thanks Nick, Ray, Stew, Steve, Dean.  Comments always appreciated!

A bit of an aside today.  Actually, building fixtures and improving the work area, all related to building this engine.

For the air delivery system, I'm using 3/32" brass tubing.  Because of the engine design, I'll be needing a 90 degree bend in each tube that will have to be pretty tight.  I have a nice tube bending set, but it won't achieve the radius I need.  So I set out to make  a special jig.

I needed to turn a 3/32" wide groove with a radiused bottom 3/64" deep.  So, I ground a semicirular (more or less) tip on a 3/32" cutoff blade.

(http://i192.photobucket.com/albums/z195/cffellows/48eea499.jpg)

Then I chucked a 3/8" diameter length of drill rod in the lathe and cut the groove.  Well, I actually cut two grooves because I originally planned to make a two-piece bending jig.  I later decided it didn't need to be that complex.

(http://i192.photobucket.com/albums/z195/cffellows/042172a0.jpg)

Next I milled an axial notch on the center line of the rod and silver soldered a rectangular piece of cold rolled steel into it.

(http://i192.photobucket.com/albums/z195/cffellows/c6a76e67.jpg)

Finally, I drilled a 3/32" hole though the cold rolled steel, positioning the drill bit in the groove in the rod.

(http://i192.photobucket.com/albums/z195/cffellows/74010390.jpg)

To make the bend, I insert the tubing into the hole...

(http://i192.photobucket.com/albums/z195/cffellows/92f1a9b6.jpg)

Clamp the jig into my bench vice and make the bend using my thumb

(http://i192.photobucket.com/albums/z195/cffellows/8f2d6cd0.jpg)

(http://i192.photobucket.com/albums/z195/cffellows/34b2e851.jpg)

Chuck
Title: Re: Compressed Air V8 Engine
Post by: Dean W on July 29, 2012, 12:45:24 AM
That's a handy tool, Chuck.  It makes a nice looking bend, too.  Thanks for showing that!
Title: Re: Compressed Air V8 Engine
Post by: AussieJimG on July 29, 2012, 01:17:39 AM
I just love the way you build jigs and tools to do the job. And the results show the value of your methods. Thank you for showing. :cheers:

Jim
Title: Re: Compressed Air V8 Engine
Post by: RMO on July 29, 2012, 07:02:52 AM
Chuck,

Thanks for sharing. I am getting more and more motivated watching your work.

Mike O
Title: Re: Compressed Air V8 Engine
Post by: cfellows on July 31, 2012, 03:17:31 AM
Thanks Dean, Jim, Mike...

I'm getting into what is arguably the most tedious part of the project.  I've more or less settled on the air valve and delivery system.  This part is hard because I want to keep the engine looking as much as possible like an IC engine which means keeping the air plumbing as inconspicuous as possible.

Here's a picture of where I am so far...

(http://i192.photobucket.com/albums/z195/cffellows/11d532ef.jpg)

First I drilled the 7/32" axial hole along the top of the block.  The brass tube with the air connection on the end will be Loctited into place later.  The rotary valve will be a 3/16" length of drill rod with a 3/32" hole drilled lengthwise most of the way (but not all the way) through from the back.  A flange will be soldered onto the back of the tube.  This tube will then be inserted into the brass tube from the back of the engine.  The flange will fit inside the air connector and will ride on a shoulder inside.  This is the stop that will keep the valve tube from just sliding out the front of the engine when air pressure is applied to the back.  The secondary cam gear will be mounted on the front side of the air tube and turn it at 1/2 the crankshaft speed.

Radial holes will be drilled through the side of the brass tube and the valve rod.  These holes, which can barely be seen just below the ridge of the crankcase will then supply air through 3/32" brass tubes to the top of the cylinders.

The hex pieces are made from 3/16 hex brass.  They will be threaded, cone side up, into the holes along the ridge of the crankcase.  A 1/16 axial hole will be drilled through the center of each one.  The brass tubes will have a flange and threaded caps to hold them onto the brass hex pieces.

OK, so is everyone thoroughly confused now?

Chuck
Title: Re: Compressed Air V8 Engine
Post by: steamer on July 31, 2012, 10:14:19 AM
Looking like a nice build Chuck!   Can't wait to hear her running!

Dave
Title: Re: Compressed Air V8 Engine
Post by: dsquire on July 31, 2012, 03:40:22 PM
Chuck

Your moving right along with this build. If your not careful you could end up with an engine.  :ROFL: :ROFL:

Cheers  :cheers:

Don
Title: Re: Compressed Air V8 Engine
Post by: cfellows on August 01, 2012, 01:19:37 AM
Thanks, Don, Dave.

I think I've got the details of hooking up the air tubes worked out.  I made a prototype today.  It's fiddly work and the prototype doesn't look very professional, but maybe I can do better on the rest.

I think the pictures will tell the story...

(http://i192.photobucket.com/albums/z195/cffellows/87b26145.jpg)

(http://i192.photobucket.com/albums/z195/cffellows/1e4df3c2.jpg)

The end that threads into the crankcase is a 5-40.  The other end is an 8-32.  The through hole is 1/16" and the OD of the brass tube is 3/32", ID is 1/16".  I'll take a picture of the fixture I made to flare the end of the brass tube. 

I'll probably be tearing my hair out by the time I get these air tubes all done.  Gonna be a challenge!

Chuck
Title: Re: Compressed Air V8 Engine
Post by: ironman123 on August 01, 2012, 04:24:03 AM
Slow but sure.  Looking good Chuck.

Ray
Title: Re: Compressed Air V8 Engine
Post by: cfellows on August 01, 2012, 04:27:56 AM
Slow but sure.  Looking good Chuck.

Ray

Thanks, Ray. 

This is the fixture I made for flaring the 3/32" tubing.

Two pieces of 1/4" thick aluminum bar stock, several inches long, are clamped together evenly in my drill press vice.  Then, using a center drill, I drill a small countersink at the exact point where the two pieces come together.

(http://i192.photobucket.com/albums/z195/cffellows/9a582d6b.jpg)

Next, I change to a 3/32" drill bit and finish drilling the hole all the way through the two pieces.

(http://i192.photobucket.com/albums/z195/cffellows/6773ab3b.jpg)

Then, I take the two pieces to the belt sander and sand off a small amount of the two joining surfaces.  This slightly reduces the diameter of the hole which makes it clamp the tubing securely.

(http://i192.photobucket.com/albums/z195/cffellows/034e9603.jpg)

Next, I clamp the two halves back in my drill press vice with the piece of tubing extended just to the top surface.  Using a center punch and a couple of light hammer blows flares the tubing into the countersink opening.

(http://i192.photobucket.com/albums/z195/cffellows/eb438ced.jpg)

That's all there is to it!

Chuck

Title: Re: Compressed Air V8 Engine
Post by: swilliams on August 02, 2012, 11:49:36 AM
That's good info Chuck. Bound to come in handy sooner or later

Steve
Title: Re: Compressed Air V8 Engine
Post by: chuck foster on August 02, 2012, 12:31:56 PM
looking good chuck, and thanks for showing how to flair tubing as i know that idea will come in handy.

chuck
Title: Re: Compressed Air V8 Engine
Post by: RMO on August 02, 2012, 04:05:20 PM
Learned something new....again.

Thanks

Mike O :whoohoo:
Title: Re: Compressed Air V8 Engine
Post by: cfellows on August 02, 2012, 08:14:51 PM
Thanks Mike, Chuck, Steve.  Nice to have you on board!

I thought I'd include a drawing of the plumbing in case anyone is wondering how this thing is going to work.

(http://i192.photobucket.com/albums/z195/cffellows/8d10d6ac.png)

I ordered some 8-40 taps and dies for the flare connection and won't be doing much else on the engine til I get those.

Chuck
Title: Re: Compressed Air V8 Engine
Post by: NickG on August 02, 2012, 08:41:35 PM
Fantastic design and execution Chuck  :ThumbsUp:
Title: Re: Compressed Air V8 Engine
Post by: Dean W on August 02, 2012, 09:34:55 PM
Thanks for the drawing, Chuck.  We get an idea of what we think it will look like, and it's nice to see if we guessed
right.  I like the way you made the flares for the tubing.  That came out just like factory made.  Good work!
Title: Re: Compressed Air V8 Engine
Post by: AussieJimG on August 02, 2012, 09:36:10 PM
I just love that innovative valving arrangement. You certainly come up with some great ideas. Thanks. :whoohoo:

Jim
Title: Re: Compressed Air V8 Engine
Post by: BillTodd on August 03, 2012, 12:38:50 PM
Very neat, Chuck :)

Is there a reason why you chose bearing balls over say a bearing roller (http://simplybearings.co.uk/shop/advanced_search_result.php?sort=2a&search_in_description=0&keywords=loose%20rollers&x=0&y=1853) for the valve? (Just thinking a roller  would give a better seal while still being hard and exact diameter)

Title: Re: Compressed Air V8 Engine
Post by: cfellows on August 03, 2012, 03:59:31 PM
Very neat, Chuck :)

Is there a reason why you chose bearing balls over say a bearing roller (http://simplybearings.co.uk/shop/advanced_search_result.php?sort=2a&search_in_description=0&keywords=loose%20rollers&x=0&y=1853) for the valve? (Just thinking a roller  would give a better seal while still being hard and exact diameter)

Thanks, Bill, I used balls because they are generally more available.

Chuck
Title: Re: Compressed Air V8 Engine
Post by: cfellows on August 06, 2012, 08:15:37 PM
I finished up the flared tubing connectors this morning. 

(http://i192.photobucket.com/albums/z195/cffellows/3c849ea3.jpg)

The female caps and the male part has an 8-40 thread on the flare end and a 5-40 thread on the smaller end which will screw into the crankcase.  There is a 1/16" center hole drilled all the way through

(http://i192.photobucket.com/albums/z195/cffellows/fd46089b.jpg)

Both the female and male parts are made from 3/16" brass hex rod.  Chucking this small stuff in even a 3" 3-jaw chuck is troublesome and can come loose when trying to cut threads.  So, after noodling on it for awhile, I rummaged through my socket drawer and found a nice 3/16" socket with a depth that was suitable for my work pieces.

(http://i192.photobucket.com/albums/z195/cffellows/a516fc3e.jpg)

I used this to hold the male part for both threading operations and for drilling the 1/16" center hole.

(http://i192.photobucket.com/albums/z195/cffellows/51a57115.jpg)

I also used the socket to hold the female caps for chamfering the top end and cutting the bottom end to uniform length.

Chuck
Title: Re: Compressed Air V8 Engine
Post by: Dean W on August 06, 2012, 10:30:29 PM
Chuck, using the socket is such a good idea!  Sometimes we read a thread just for the enjoyment, and sometimes
we come across a little lightning strike, like this one.  I hope I remember it!
Title: Re: Compressed Air V8 Engine
Post by: cfellows on August 07, 2012, 05:03:50 AM
Thanks, Dean, glad you found something you can use!

Here are the brass tubes that will deliver the air to each of the cylinders...

(http://i192.photobucket.com/albums/z195/cffellows/207f95cb.jpg)

The top right tube with the flare cap fitting was the prototype.  I made 8 new tubes using a new tube bending jig I made which gives me a crisper bend.  The cap will be salvaged from the prototype to go on one of the new tubes.

Slow but steady at this point.

Chuck
Title: Re: Compressed Air V8 Engine
Post by: cfellows on August 07, 2012, 06:13:14 AM
I thought I'd post some pictures of the new jig I made for bending the 3/32 brass tubing...

I started with this... it's turned from 3/8" drill rod and has a 3/32" wide, 3/64" deep radiused groove turned in it.  It's screwed to the aluminum block with a 10-24 SHCS.

(http://i192.photobucket.com/albums/z195/cffellows/dcd18141.jpg)

This is clamped in my vise, about 5/16" down from the top of the jaws.

(http://i192.photobucket.com/albums/z195/cffellows/29eadfe4.jpg)

Next I place the brass tube into the groove in the bushing

(http://i192.photobucket.com/albums/z195/cffellows/fb9b1e8c.jpg)

... and hold it there while I slide a stop block between the bushing and the vise jaw.  The stop block has a 3/32" radiused groove in it so the brass tubing won't kink.

(http://i192.photobucket.com/albums/z195/cffellows/5b5b9843.jpg)

Then I take a second block, also with a 3/32" radiused groove in it and use my thumbs pushing on it to force the tubing around the bushing.

(http://i192.photobucket.com/albums/z195/cffellows/4a97e25f.jpg)

As the Brits would say, it works a treat!

Chuck
Title: Re: Compressed Air V8 Engine
Post by: arnoldb on August 07, 2012, 09:11:36 AM
Good going Chuck; I also like the socket idea.

Did you have to anneal the brass tubing at all before bending ?

Kind regards, Arnold
Title: Re: Compressed Air V8 Engine
Post by: swilliams on August 07, 2012, 10:03:43 AM
That was educational Chuck. Nice to learn a little about miniature pipe work.
Steve
Title: Re: Compressed Air V8 Engine
Post by: cfellows on August 07, 2012, 03:27:03 PM
Good going Chuck; I also like the socket idea.

Did you have to anneal the brass tubing at all before bending ?

Kind regards, Arnold

Thanks, Arnold.  I didn't anneal the tubing.  Don't know if it would have made it easier or not.  Turns out, the 3/32" stuff isn't very hard to bend, although my thumbs are a little tender this morning.   :)

Chuck
Title: Re: Compressed Air V8 Engine
Post by: cfellows on August 08, 2012, 09:06:09 PM
Did some more work on the air inlet tubes today.  I made the flanges that will be soldered to each tube. 

I first chucked a length of 7/16" brass rod in the lathe and center drilled a 3/32" hole about an inch deep.  Than I used a parting tool to part off 9 disks, each .080" thick.  I made an extra one since I usually manage to screw up at least one.   :Doh:

(http://i192.photobucket.com/albums/z195/cffellows/b1c78f65.jpg)

After running each face over some 220 grit sandpaper to remove the flashing I clamped each one individually in my milling vice and milled opposing flats, resulting in a piece 1/4" wide and 7/16 long. 

(http://i192.photobucket.com/albums/z195/cffellows/a300924a.jpg)

Got one piece in the picture mocked up with the air tube sitting in the flange.  When soldered, the top end of the tube will extend through the flange by about 3/32" and extend into the head by that amount.

Next I'll drill the holes on either side of the center hole.  These will be used to screw the flange to the cylinder head.

Chuck
Title: Re: Compressed Air V8 Engine
Post by: ironman123 on August 08, 2012, 10:11:22 PM
Good going there Chuck.  Makes my fingers and wrists hurt just looking at those pictures.

It is all looking good.   :ThumbsUp:

Ray
Title: Re: Compressed Air V8 Engine
Post by: zeeprogrammer on August 08, 2012, 11:28:41 PM
Very interesting thread Chuck.

Thanks for the drawing of the plumbing...very helpful.

I also really liked the use of the socket head. That's given me some ideas I think I'll need in the near future.
Title: Re: Compressed Air V8 Engine
Post by: steamer on August 09, 2012, 12:43:15 AM
Nice tubing bender Chuck....I'll need that for the Wallaby build!

Dave
Title: Re: Compressed Air V8 Engine
Post by: cfellows on August 10, 2012, 10:46:28 PM
Thanks Dave, Zee, Ray... That tubing bender does work nice.  You might pay particular attention to the little block that fits between the spool and the vice jaw.  I purposefull made it that size so it would be a firm fit... Didn't want to have to permanently fix it to the jig.

Got some more work done on the engine today.  I had kind of convinced myself not to make an oil pan for the crankcase, that I would just leave it open.  I like looking at the crank and rods and it also makes it easy to oil them periodically.  However, I decided the engine would look better if it had a pan, so today I got to work and made one.

I started off with a piece of 3/4" thick magnesium 3 inches long and 1.7" wide.

(http://i192.photobucket.com/albums/z195/cffellows/a0d5bbee.jpg)

Here I've milled 3/16" of each side to form the bolt flanges for the screws which will attach the pan to the upper crankcase half.

(http://i192.photobucket.com/albums/z195/cffellows/09b9e742.jpg)

Next I milled out the inside of the pan and rounded the inside edges along the sides.

(http://i192.photobucket.com/albums/z195/cffellows/eb0b9eab.jpg)

Finally I rounded over the outside bottom edges.

(http://i192.photobucket.com/albums/z195/cffellows/6f0ffb8a.jpg)

And here's a picture of the two halves placed together.

(http://i192.photobucket.com/albums/z195/cffellows/22d50fdd.jpg)

Chuck
Title: Re: Compressed Air V8 Engine
Post by: arnoldb on August 11, 2012, 05:24:49 PM
 :ThumbsUp: That looks a treat Chuck.

Kind regards, Arnold
Title: Re: Compressed Air V8 Engine
Post by: sbwhart on August 11, 2012, 05:37:22 PM
Looks good Chuck  :ThumbsUp:

Stew
Title: Re: Compressed Air V8 Engine
Post by: steamer on August 11, 2012, 05:43:18 PM
Coming along quick Chuck!

Dave
Title: Re: Compressed Air V8 Engine
Post by: rleete on August 11, 2012, 06:24:27 PM
Chuck, it's looking really nice.  However, if I may make a suggestion to round the vertical corners of the pan as well as the bottom, it would look more realistic.  Feel free to ignore, comply or ridicule as you see fit.

This thread has motivated me to get back to working on the 4 cylinder boxer version you made a while back.  I just love that exhaust note you get with your ball valve system.  Can't wait to hear how this one growls.
Title: Re: Compressed Air V8 Engine
Post by: Dean W on August 11, 2012, 07:33:53 PM
Really coming together now, Chuck.  Your "growth spurts" are very productive.  ;)
Title: Re: Compressed Air V8 Engine
Post by: cfellows on August 13, 2012, 10:29:51 PM
Thanks Arnold, Stew, Dave, rleete, Dean... Had to take the day off yesterday to help the kids get their house ready to sell.  But I'm back in the shop today.

Here's a couple of photos of the engine partially assembled.  I took rleete's advice and rounded the vertical edges of the oil pan and it does look better that way!  Had to use a file since I couldn't figure out any other way to do it...

(http://i192.photobucket.com/albums/z195/cffellows/304fca77.jpg)

(http://i192.photobucket.com/albums/z195/cffellows/19460e85.jpg)

Next I'm laying out the lines and drilling the holes in the head to accept the air supply tubes and the slave valve assemblies.

Chuck
Title: Re: Compressed Air V8 Engine
Post by: zeeprogrammer on August 13, 2012, 11:06:34 PM
It's looking great Chuck!
Title: Re: Compressed Air V8 Engine
Post by: Dean W on August 13, 2012, 11:49:32 PM
It's looking very engine-y, Chuck.  I like it!
Title: Re: Compressed Air V8 Engine
Post by: rleete on August 14, 2012, 12:01:29 AM
I took rleete's advice and rounded the vertical edges of the oil pan and it does look better that way! 

Glad I could contribute.  It's a fine looking beastie. 
Title: Re: Compressed Air V8 Engine
Post by: cfellows on August 14, 2012, 02:54:27 AM
Thanks, guys.  I appreciate the interest and the kind words.

One last picture for the day.  I finished soldering the bolt flanges onto the inlet air tubes this evening. 

(http://i192.photobucket.com/albums/z195/cffellows/e30532ea.jpg)

The flanges are a little bulkier than I'd like, but I'm not inclined to try to slim them down at this point.  Next I'll have to assemble the flange nuts and then put the flange on the bottom end of all the tubes.  I hate it when I get to this part.  One little misstep can flush a lot of work down the drain!

Chuck
Title: Re: Compressed Air V8 Engine
Post by: steamer on August 14, 2012, 09:20:48 AM
I really like it Chuck!   The look of an old aircraft V8 is definitely there!

Dave
Title: Re: Compressed Air V8 Engine
Post by: ozzie46 on August 14, 2012, 12:57:19 PM


  Looking really good Chuck.

  Ron
Title: Re: Compressed Air V8 Engine
Post by: cfellows on August 14, 2012, 05:23:05 PM
Thanks Ron, Dave.

Managed to sneak in a little more shop time this morning.  I got the air inlet tubes all flared with the flare nuts in place.  It was really pesky getting the length on those tubes correct.  There is very little margin for error.  I used a piece of 5/8" thick cold rolled steel plus an .008" feeler gauge blade clamped in the vise as a gauge and filed the tubes to length.  I would have used 3/32" compression fittings if I'd been able to find any, but didn't have the patience to search the internet for them.  I might have gotten by with using a short length of 1/8" tubing as a compression fitting.  Need to try that some day, it would be a simple solution.

(http://i192.photobucket.com/albums/z195/cffellows/7ec7faf7.jpg)

Chuck
Title: Re: Compressed Air V8 Engine
Post by: Dan Rowe on August 14, 2012, 05:34:57 PM
Chuck,
Nice I really like the micro flare fittings. Good thing to remember the nuts, I have scrapped a few jobs by forgetting the nut before a flare.

Dan
Title: Re: Compressed Air V8 Engine
Post by: KB on August 14, 2012, 06:20:56 PM

Looking really good Chuck!

Quote
Good thing to remember the nuts, I have scrapped a few jobs by forgetting the nut before a flare.

How many times I have soldered some wires together with out the shrink tube, strain relief or plug hardware...I would not mind to forget.
Title: Re: Compressed Air V8 Engine
Post by: vcutajar on August 14, 2012, 08:39:45 PM
Chuck

The engine is taking shape nicely.  Keep it up.

Vince
Title: Re: Compressed Air V8 Engine
Post by: steamer on August 14, 2012, 08:46:14 PM
Those fittings look better though Chuck.

 :ThumbsUp:

Dave
Title: Re: Compressed Air V8 Engine
Post by: Dean W on August 14, 2012, 09:34:00 PM
They look good, Chuck.  I like seeing a micro job done well!
Title: Re: Compressed Air V8 Engine
Post by: cfellows on August 16, 2012, 01:21:31 AM
Thanks for the support and the comments.  Keeps me plugging away at times I'd rather be doing something else!   :)

Here's a video of me using my new Arduino dividing head, built and programmed by yours truly, to cut the small timing gear.  Kind of boring for you guys to watch, but I found it very exciting to do!  That electronic dividing head makes gear cutting a breeze.  I also have a video of me cutting the larger timing gear out of brass, but I haven't loaded it yet.

http://www.youtube.com/watch?v=A6CrFMwxbxQ (http://www.youtube.com/watch?v=A6CrFMwxbxQ)

Chuck
Title: Re: Compressed Air V8 Engine
Post by: cfellows on August 16, 2012, 01:28:11 AM
Here's a picture of the gears (so far).

(http://i192.photobucket.com/albums/z195/cffellows/37285f23.jpg)

Chuck
Title: Re: Compressed Air V8 Engine
Post by: steamer on August 16, 2012, 01:36:29 AM
That dividing head seams to work just fine!

Dave
Title: Re: Compressed Air V8 Engine
Post by: zeeprogrammer on August 16, 2012, 02:17:50 AM
Looks good Chuck.

Watched the video. Always good to see parts being made...gives me a sense of feed and speed.

Got a little worried at the end though. Wondered if the siren were because of you.  :Lol:
Title: Re: Compressed Air V8 Engine
Post by: rleete on August 16, 2012, 02:58:36 AM
Looking good.  But...

You'd damn well better post a complete write-up on that slick electronic dividing head setup, or post a link to it!  That was cool.
Title: Re: Compressed Air V8 Engine
Post by: cfellows on August 16, 2012, 03:00:25 AM
Looks good Chuck.

Watched the video. Always good to see parts being made...gives me a sense of feed and speed.

Don't know that I'm an authority on feeds and speed.  I just do what sounds and feels right.  If it hurts the ears it's probably wrong.  if it makes the hair on my neck stand up, it's really wrong!   :zap:

Quote
Got a little worried at the end though. Wondered if the siren were because of you.  :Lol:

How in the heck did you hear that siren?  I didn't even notice it until you mentioned it and went back to watch the video.  I was probably too busy thinking about what I was going to say next.

Chuck
Title: Re: Compressed Air V8 Engine
Post by: cfellows on August 16, 2012, 03:15:58 AM
Looking good.  But...

You'd damn well better post a complete write-up on that slick electronic dividing head setup, or post a link to it!  That was cool.

Thanks, here's a link to the original thread on HMEM.

http://www.homemodelenginemachinist.com/f39/electronic-dividing-head-using-arduino-17896/ (http://www.homemodelenginemachinist.com/f39/electronic-dividing-head-using-arduino-17896/)

It's one of the slickest tools I've ever made.  Just can't say enough good things about it.  It will do any number of divisions from 1 to 1,000 although the accuracy probably drops off pretty rapidly above 100 or so.  The stepper has 200 steps per revolution and it's geared 5:1 to the spindle giving it an overall resolution of 1000 steps per spindle revolution.   I also added a stepper motor to my small rotary table and use the same arduino and program to run it.  I just have to input which tool I'm running when I start it up. 

It was pretty cheap.  The arduino was around $25, the Sainsmart keyboard/display shield was around $20, the Pololu stepper driver was about $15, and the stepper motor was $20.  Programming the Arduino is pretty simple, if you know the C language.  You program it on your PC then just download the program to the Arduino through a USB connection.  I highly recommend it if you want a great sense of satisfaction.

Chuck
Title: Re: Compressed Air V8 Engine
Post by: cfellows on August 16, 2012, 05:42:23 AM
Here's another video, this time I'm cutting the larger, 26 tooth, cam gear in Brass. 

http://www.youtube.com/watch?v=R1Nk4_cjvbw (http://www.youtube.com/watch?v=R1Nk4_cjvbw)

Chuck
Title: Re: Compressed Air V8 Engine
Post by: swilliams on August 16, 2012, 07:40:34 AM
Love your dividing head Chuck. At first glance it seems you have a 48 division stepper motor and a 5:1 reduction. Is that right or have I got it wrong? So when you cut the gear does the program just take you to the closest available step to what's required?

Steve
Title: Re: Compressed Air V8 Engine
Post by: Bogstandard on August 16, 2012, 08:50:53 AM
After a lot of trepidation on my part about when you first started that little dividing head, now you have it going very well indeed, a good addition to your shop tools.
Although I still think it is a little underpowered to use for continuous milling, but great for the use you are using it for now.

Very nicely done and shown :NotWorthy:


John
Title: Re: Compressed Air V8 Engine
Post by: rleete on August 16, 2012, 12:23:08 PM
That is really neat.  I wonder how I missed it the first time around.
Title: Re: Compressed Air V8 Engine
Post by: cfellows on August 16, 2012, 03:18:31 PM
Love your dividing head Chuck. At first glance it seems you have a 48 division stepper motor and a 5:1 reduction. Is that right or have I got it wrong? So when you cut the gear does the program just take you to the closest available step to what's required?

Steve

Thanks, Steve.  I had originally planned to use a 48 division stepper, but it was a NEMA 17 and was grossly under powered.  The NEMA 23 I wound up using  has 200 divisions and is a much stronger motor.

After a lot of trepidation on my part about when you first started that little dividing head, now you have it going very well indeed, a good addition to your shop tools.
Although I still think it is a little underpowered to use for continuous milling, but great for the use you are using it for now.

Very nicely done and shown :NotWorthy:

John

Thanks, John.  I agree that the older style NEMA 23 motor I used is not strong enough for powered milling.  But for drilling and gear cutting, it's more than adequate.  I'm going to rebuild the control box using a smaller, Arduino Nano.  And I'm going to replace the Sainsmart keypad/display with a hand-held infrared remote.

Chuck

Title: Re: Compressed Air V8 Engine
Post by: cfellows on August 18, 2012, 04:18:04 AM
I am so tired of tapping.  So far I count 106 holes drilled and tapped plus the 8 flare connections threaded on each end.  But, I think the worst is done. 

These are 8 pieces of brass turned from 7/16 rod.  They are destined to become exhaust flanges that will hold the slave valve and spring inside the head.

(http://i192.photobucket.com/albums/z195/cffellows/b721d94e.jpg)

I used my square 5C collet block to hold each flange while I milled a flat on opposite sides.

(http://i192.photobucket.com/albums/z195/cffellows/5131324d.jpg)

Here's 9 of them ready to drilled.  I save the exhaust hole in the middle until the very end since it really weakens the piece.

(http://i192.photobucket.com/albums/z195/cffellows/574fde67.jpg)

And here's a few teaser pictures.  Still got a few more things to complete before it's ready to run, but this gives you an idea of what it will look like.

(http://i192.photobucket.com/albums/z195/cffellows/2487c214.jpg)

(http://i192.photobucket.com/albums/z195/cffellows/acabd46c.jpg)

(http://i192.photobucket.com/albums/z195/cffellows/26e88abc.jpg)

(http://i192.photobucket.com/albums/z195/cffellows/5afa1e93.jpg)

Might have this thing running in a few days!

Chuck
Title: Re: Compressed Air V8 Engine
Post by: steamer on August 18, 2012, 07:50:59 AM
It's looking the part Chuck!   Can't wait for the first run!

Dave


Title: Re: Compressed Air V8 Engine
Post by: chuck foster on August 18, 2012, 01:03:32 PM
holy smokes, take a few days off and chucks got a v8 engine almost ready to run  :whoohoo:

as usual this engine is looking first class  :ThumbsUp:

chuck
Title: Re: Compressed Air V8 Engine
Post by: ironman123 on August 18, 2012, 02:21:12 PM
Mean looking engine Chuck.  Look good in a R/C boat.  Your workmanship is superior.  :ThumbsUp: :ThumbsUp:

Ray
Title: Re: Compressed Air V8 Engine
Post by: cfellows on August 18, 2012, 07:00:06 PM
Thanks, guys.  I appreciate the support.

I need 8 springs for the slave exhaust valve assemblies, well maybe 10 if you count the 1 or 2 that will almost certainly get dropped and disappear into another dimension or at least into the neighbors yard which at it's closest point is at least 50 feet from my workbench (they are springs, after all!).

So I found a smokin' deal on ebay for exactly the right sized springs...

(http://i192.photobucket.com/albums/z195/cffellows/dad0bbb9.jpg)

I didn't count, but there are supposed to be 250 springs there.  Guess I'll be building a few more engines...

Chuck
Title: Re: Compressed Air V8 Engine
Post by: Dean W on August 18, 2012, 09:12:10 PM
Wow, it sure looks good, Chuck.  I'll bet you're even more excited to crank her up than I am to hear it!
Just good luck to find all those springs the right size, I guess.  Making them is easy enough, but like
tapping a lot of holes, it can become a chore.
Title: Re: Compressed Air V8 Engine
Post by: zeeprogrammer on August 18, 2012, 11:46:34 PM
Remember that everyone. If you need a spring...you know where to go.
Although I won't be surprised he uses them up with all the great projects he no doubt has planned.
Title: Re: Compressed Air V8 Engine
Post by: swilliams on August 19, 2012, 02:34:27 AM
Looking great Chuck

Steve
Title: Re: Compressed Air V8 Engine
Post by: cfellows on August 19, 2012, 05:03:10 AM
Wow, it sure looks good, Chuck.  I'll bet you're even more excited to crank her up than I am to hear it!
Just good luck to find all those springs the right size, I guess.  Making them is easy enough, but like
tapping a lot of holes, it can become a chore.

Thanks, Dean.  Yeah, I feel like I'm getting close.

Remember that everyone. If you need a spring...you know where to go.
Although I won't be surprised he uses them up with all the great projects he no doubt has planned.

Yep, I got springs.  And so far, I haven't dropped a single one.  However, within a few days I'll put them away, forget where I put them, and, eventually, begin to wonder if I really ever had them...

Looking great Chuck

Steve

Thanks, Steve,

Probably seems kind of insignificant, but today I got the holes drilled in the pistons, made the wrist pins, and attached the pistons to the rods.  I also epoxied the brass valve tube liner into the crankcase and drilled radial holes that will admit compressed air to the tubes leading to each cylinder. 

(http://i192.photobucket.com/albums/z195/cffellows/f8448a69.jpg)

The next hurdle is assembling the rods, pistons, and crankshaft and installing them in the crankcase along with all the cylinders.  I'm guessing it will be a struggle to get everything turning over smoothly.  May have to run it in a bit using my lathe to spin it.  The only other task left is making the rotary valve tube which will be made from steel drill rod and have the large cam gear attached.  It turn inside the brass tube liner.  I'll then have to time the engine by rotating each piston to it's "firing" position then drilling a radial hole through it's respective air tube fitting into the rotary valve tube.  I know all this probably sounds complicated so I'll take as many pictures during this process as I can.

Chuck
Title: Re: Compressed Air V8 Engine
Post by: RMO on August 19, 2012, 06:40:14 AM
I was wondering how you were going to time the engine.  I will be keeping a close eye on the process.  Looks great so far.

Mike O
Title: Re: Compressed Air V8 Engine
Post by: cfellows on August 20, 2012, 01:49:47 AM
Actually beginning to feel like an engine now.  I installed the crankshaft, rods and pistons.  I had to turn it over a few times with the drill, but that was probably just to remove bits of metal and dust.  Turns over with my fingers now with little very little detectable slop anywhere.  I'm sure there is slop, but I guess the misfits are in random and opposing directions making the overall assembly feel pretty snug.

(http://i192.photobucket.com/albums/z195/cffellows/ddd4b0a0.jpg)

Next I guess I'll decide on a flywheel.  I could make another steel propeller, but that is a fair amount of work and I managed to get smacked by them quite a bit on the other two engines I build with propellers.  Maybe a small, thick sectioned steel or brass flywheel, like those found on older marine engines?  I'd gladly entertain any ideas...

Chuck
Title: Re: Compressed Air V8 Engine
Post by: rleete on August 20, 2012, 01:55:59 AM
I'd suggest small (size of the large gear or so) but not too thick.  It's not gonna need a lot of flywheel to keep it going, so the less the better.  Make it steel to have some usable mass.
Title: Re: Compressed Air V8 Engine
Post by: zeeprogrammer on August 20, 2012, 02:04:14 AM
Looking really cool Chuck.
Getting very exciting.
Title: Re: Compressed Air V8 Engine
Post by: Don1966 on August 20, 2012, 02:16:10 AM
Chuck are you going to show us the process of making the rotary valve? I am curious to see how you do it.

Don
Title: Re: Compressed Air V8 Engine
Post by: cfellows on August 20, 2012, 08:38:19 PM
Chuck are you going to show us the process of making the rotary valve? I am curious to see how you do it.

Don

Hope I can do this justice, Don.  By the way, this is the second time I'm typing this in.  I was just about finished and accidently closed the window before I posted it!   :wallbang:

The rotary valve tube actually starts out as a 3/16" length of drill rod.  The first step is to press a small flange onto the back end. 

(http://i192.photobucket.com/albums/z195/cffellows/8c580a50.jpg)

I made the flange from 5/16" drill rod and drilled the center hole with a #2 drill bit which is about .002" smaller than the 3/16" diameter of the valve tube.  I deliberately made the flange over-sized on both the diameter and length so I could turn it to finish dimensions after it was fixed on the valve tube (which is still a solid rod at this point).  Here's how the valve tube will fit in the engine once finished.

(http://i192.photobucket.com/albums/z195/cffellows/f46cf470.jpg)

Next I had to drill a 3.5" deep center hole in the rod.  The only bit I had which was long enough was 1/8" so that's what I used.  I had to back out of the hole, clear the chips, and add oil about every 1/8" to keep the drill on center and to keep the chips from piling up and seizing the bit.

(http://i192.photobucket.com/albums/z195/cffellows/5ce90752.jpg)

Once the center hole was drilled, I inserted the valve tube into the crankcase from the back.  Here's a picture of the valve tube fully inserted after I had drilled the center hole.

(http://i192.photobucket.com/albums/z195/cffellows/4809db69.jpg)

I then attached the larger timing gear to the front part of the valve tube where it extended out of the crankcase.  Notice that the center hole does not go all the way through the valve tube.  Here's what it looks like with the valve tube installed and the two timing gears attached to the valve tube and crankshaft, respectively.  The crankshaft and the valve tube are now geared together and the valve tube will rotate at 1/2 the rate of the crankshaft giving the engine 4 stroke operation.

(http://i192.photobucket.com/albums/z195/cffellows/9910ec94.jpg)

Here I've turned the crankshaft so that the first cylinder in the firing sequence is at top dead center (far right cylinder).

(http://i192.photobucket.com/albums/z195/cffellows/2de1973a.jpg)

Next I attached a disk which has 4 lines scribed 90 degrees apart to the crankshaft.  These lines are used to measure exactly 1/4 turn of the crankshaft.

(http://i192.photobucket.com/albums/z195/cffellows/3a371ffd.jpg)

Here I'm ready to start drilling the holes in the valve tube.  I've already center drilled the holes in the flare fittings so it's just a matter of running the drill bit down until it hits the valve tube and drilling through to the center hole.

(http://i192.photobucket.com/albums/z195/cffellows/bd1adc5c.jpg)

After drilling the first hole, I rotate the crankshaft 1/4 turn and proceed to the next cylinder in the firing sequence where I again drill a 1/16" hole through the side of the valve tube into the center hole using the cylinders flare fitting as a guide.  This operation is repeated until holes have been drilled for all 8 cylinders.  This results in 8 individual holes in the correct position for each cylinder.  Note, however, that after I finish drilling all the holes, I have to retard the valve tube timing.  As drilled, the holes are fully open when the piston would be at top dead center and in fact you want the piston to be half way through it's stroke before it's valve hole is fully open.

I hope this is a little clearer than mud.  Let me know if you have any questions.  I expect to have this engine running by the end of the day.  Or perhaps I should, ready to run by the end of the day.  Whether it actually runs remains to be seen!

Chuck

Title: Re: Compressed Air V8 Engine
Post by: cfellows on August 20, 2012, 10:16:15 PM
It Runs!!!! And does it sound sweet.  I'll get a video up pretty soon...

Chuck
Title: Re: Compressed Air V8 Engine
Post by: Don1966 on August 20, 2012, 11:03:51 PM
Awesome Chuck, thanks for the detail step by step. I really appreicate that. The one question I have is when the drill bit goes through the rotary tube, does't not leave a  upwards bur on the tube, and will the tube come out after drilling? Do you drill slowly to keep this from happen and does this work for removeable of the tube with out problems.
Can not wait to see the video. Please gives plans for the built so some of us can build it too?

Don
Title: Re: Compressed Air V8 Engine
Post by: cfellows on August 21, 2012, 12:09:49 AM
Thanks, Don.  I run the drill bit at the highest speed my drillpress will go which is probably around 3,000 RPM.  I do also go slow.  The only place there's any burrs is on the inside of the steel valve tube.  I just ran the 1/8" bit back up there to clean them out.  I didn't have any problem removing the valve tube after drilling the radial holes in it.  I did mount it in my lathe and smooth it down some with 600 grit wet or dry sand paper but that was it.

I still have some work to do on it.  I'm using a borrowed flywheel for now and plan to make propeller out of steel as a permanent addition.  I also need to make a stand for it and mess with the timing some.  I've got the timing set backward so the engine is running in reverse, but that's easy enough to remedy.

Chuck
Title: Re: Compressed Air V8 Engine
Post by: cfellows on August 21, 2012, 12:28:49 AM
Here's the video...  Couldn't be more pleased with the way it runs.  Do wish it was a little louder on the exhaust note.

http://www.youtube.com/watch?v=f0VIV4CVl-U& (http://www.youtube.com/watch?v=f0VIV4CVl-U&)

Chuck
Title: Re: Compressed Air V8 Engine
Post by: Don1966 on August 21, 2012, 01:06:39 AM
Woooo! Love that sound, that is awesome Chuck. I like......

Don
Title: Re: Compressed Air V8 Engine
Post by: rleete on August 21, 2012, 01:15:20 AM
Surprised it wouldn't run with the smaller flywheel.  I like the look of the one you made.
Title: Re: Compressed Air V8 Engine
Post by: steamer on August 21, 2012, 01:34:17 AM
Sounds Great Chuck!   Love the sound!    I think it sounds like a Jenny....so a 4 blade old time prop sounds great!

Dave
Title: Re: Compressed Air V8 Engine
Post by: Maryak on August 21, 2012, 01:49:32 AM
Beautiful job Chuck, (http://smileys.on-my-web.com/repository/Respect/bravo-009.gif)

Best Regards
Bob
Title: Re: Compressed Air V8 Engine
Post by: swilliams on August 21, 2012, 02:30:00 AM
Excellent Chuck, really well done :NotWorthy:  :pinkelephant: :pinkelephant: :pinkelephant:

Steve
Title: Re: Compressed Air V8 Engine
Post by: zeeprogrammer on August 21, 2012, 02:51:29 AM
Wow! Excellent Chuck.
I've been waiting all evening to see the video.
Love that low idle.
Title: Re: Compressed Air V8 Engine
Post by: rleete on August 21, 2012, 02:53:45 AM
Do wish it was a little louder on the exhaust note.

Any possibility you could open up the exhaust ports a little?  That might make it louder.
Title: Re: Compressed Air V8 Engine
Post by: ColH on August 21, 2012, 03:58:34 AM
Hi Chuck

First thing I have been doing every day is to check to see if you have the engine running.

Today was the day.   :whoohoo:

Congratulation on a great build, looks and sounds great.  :NotWorthy:

Col
Title: Re: Compressed Air V8 Engine
Post by: vcutajar on August 21, 2012, 07:44:56 AM
Congratulationa Chuck for another well running engine  :ThumbsUp: :whoohoo: :whoohoo:

Vince
Title: Re: Compressed Air V8 Engine
Post by: ozzie46 on August 21, 2012, 12:05:58 PM


  Cogratulations Chuck another well done Job. Love the sound.

  Ron
Title: Re: Compressed Air V8 Engine
Post by: sbwhart on August 21, 2012, 02:10:42 PM
 :pinkelephant: :pinkelephant: :pinkelephant: :pinkelephant: :pinkelephant: :pinkelephant: :pinkelephant:

Well done Chuck I realy like that engine.

What a great runner

Stew
Title: Re: Compressed Air V8 Engine
Post by: ironman123 on August 21, 2012, 02:16:42 PM
Good job Chuck. :cheers:  Another feather in your hat. (we have no karma).  Ready for a V8 IC engine yet?

This has been a very good build.  Thanks,

Ray
Title: Re: Compressed Air V8 Engine
Post by: Dan Rowe on August 21, 2012, 02:23:42 PM
Chuck,
Thanks for the well written thread on this engine. A good looking engine and a good runner. :cheers:

Dan
Title: Re: Compressed Air V8 Engine
Post by: tvoght on August 21, 2012, 04:10:26 PM
An impressive build.
--Tim
Title: Re: Compressed Air V8 Engine
Post by: mklotz on August 21, 2012, 04:18:26 PM
You've outdone yourself again, Chuck.  Very creative design and beautiful execution.  Be very, very proud of yourself.
Title: Re: Compressed Air V8 Engine
Post by: NickG on August 21, 2012, 06:46:14 PM
Awesome work Chuck, I wondered how you would drill the ports in the rotary valve ... never thought of simply using the engine as a jig ... ingenious design.  :ThumbsUp:
Title: Re: Compressed Air V8 Engine
Post by: BillTodd on August 21, 2012, 06:59:38 PM
Wonderful Chuck :)

I had not realised how small this engine was until I saw you hand in the shot.

Lovely job  :ThumbsUp:
Title: Re: Compressed Air V8 Engine
Post by: RMO on August 21, 2012, 07:51:40 PM
Well done indeed.  Simple design.  Thanks for sharing.
Title: Re: Compressed Air V8 Engine
Post by: Dean W on August 21, 2012, 10:10:10 PM
Excellent, Chuck!  It's great to see it run, and to hear it, too!  You've done a fine job, again.  I love it!
Does the crank case have oil inside, or do you just oil it up before each run?
Title: Re: Compressed Air V8 Engine
Post by: arnoldb on August 21, 2012, 10:48:44 PM
Very well done indeed Chuck  :NotWorthy:

Definitely an engine for the shorter end of my long list  :)

Kind regards, Arnold
Title: Re: Compressed Air V8 Engine
Post by: cfellows on August 22, 2012, 05:20:44 PM
Wow, what a great group!  Thank you, all of you, for the support and words of high praise.  Makes me want to get right out there are start the next engine.  But, still got some more work to do on this one.

One observation...  I kind of favor the open and intricate design of separate cylinder barrels and exposed piping for the air routing to the cylinder heads.  But this engine would have been way easier to build if I had made it a solid block design, like an automotive engine.  With an engine block and 2 cylinder heads I could have replaced 8 cylinder barrels, 32 pieces of individual brass plumbing parts, and 48 socket head cap screws.  I would also have eliminated 64 tapping operations.

Next up is the 4 bladed steel propeller which I'm nearly finished with.  I want to post some pictures of the process since some may find it interesting.

Chuck
Title: Re: Compressed Air V8 Engine
Post by: b.lindsey on August 22, 2012, 05:34:35 PM
Awesome as always Chuck. What a sweet sounding engine too!!  I am very interested in your process for making the propeller too so will look forward to that now.

Bill
Title: Re: Compressed Air V8 Engine
Post by: Don1966 on August 22, 2012, 11:28:53 PM
Yea Chuck, don't forget us we need pictures of the propeller built.  :pinkelephant:

Don
Title: Re: Compressed Air V8 Engine
Post by: dvbydt on August 23, 2012, 12:14:48 PM
Super job as usual Chuck! It wouldn't look like one of your engines if it was monoblock.
Question - did you intend the crank to be five bearings?

Ian
Title: Re: Compressed Air V8 Engine
Post by: Alan Haisley on August 23, 2012, 08:08:35 PM

Really pretty engine. The whole flywheel thing fooled me; I thought with that many cylinders it wouldn't even need one.

Do wish it was a little louder on the exhaust note.

Any possibility you could open up the exhaust ports a little?  That might make it louder.


Or some kind of tuned pipe or resonator??


Thanks for sharing this with us, Chuck.


Alan
Title: Re: Compressed Air V8 Engine
Post by: gbritnell on August 24, 2012, 12:32:31 PM
Congrats on another great project Chuck. I thought I was fast but it would be hard keeping up with you.
gbritnell
Title: Re: Compressed Air V8 Engine
Post by: cfellows on August 25, 2012, 12:50:57 AM
Super job as usual Chuck! It wouldn't look like one of your engines if it was monoblock.
Question - did you intend the crank to be five bearings?

Ian

Thanks Ian, I had made the crankshaft to accommodate 5 main bearings if I needed them, but I decided 3 was sufficient.

Chuck
Title: Re: Compressed Air V8 Engine
Post by: cfellows on August 25, 2012, 12:53:36 AM
Excellent, Chuck!  It's great to see it run, and to hear it, too!  You've done a fine job, again.  I love it!
Does the crank case have oil inside, or do you just oil it up before each run?

Thanks, Dean, the crankcase holds oil to lub the lower end.  However, there are no seals, so I have add oil now and again.  Might have to add a dipstick to tell if it needs oil...

Chuck
Title: Re: Compressed Air V8 Engine
Post by: rleete on August 25, 2012, 01:07:48 AM
What kind of oil?
Title: Re: Compressed Air V8 Engine
Post by: cfellows on August 25, 2012, 01:21:54 AM
What kind of oil?

Up to now I've been using 3-in-1 oil, but I'm going to switch to something a little thicker.

Chuck
Title: Re: Compressed Air V8 Engine
Post by: cfellows on August 25, 2012, 01:24:55 AM
Here's another vido.  This one is several videos combined, with a small flywheel, no flywheel, a propeller, and one with the oil pan removed to show the rods and crankshaft.

http://www.youtube.com/watch?v=NSFASUx_NkY& (http://www.youtube.com/watch?v=NSFASUx_NkY&)

Notice the sound is amplified by the board it's sitting on.  I'm going to make a sound box to run my engines on.

Chuck
Title: Re: Compressed Air V8 Engine
Post by: rleete on August 25, 2012, 01:53:50 AM
Yeah, that board really makes it sound much larger.

I knew it didn't need much of a flywheel to run!
Title: Re: Compressed Air V8 Engine
Post by: dvbydt on August 28, 2012, 10:06:31 AM
Yes, looks like three mains are be enough for air loads - your video with no sump shows it running on centre main only!
That was a striking difference in sound when you lifted the engine off of the board, more experiments needed?

Ian
Title: Re: Compressed Air V8 Engine
Post by: KB on September 08, 2012, 06:53:41 PM

Awesome work Chuck! and quick too.

I can't wait to see it all "packaged" up.
Title: Re: Compressed Air V8 Engine
Post by: cfellows on October 17, 2012, 02:37:30 AM
Thanks, everyone, for all the kind words.  I've came down with a nasty cold after we got back from vacation and haven't been in the shop for two weeks or so.  However, I do have something to share with the group.

John McClelland had generously volunteered to make up some nice drawings for the engine just for the experience.  So, attached is a teaser, a full 3 dimensional drawing in PDF format for you to look at.  John will be providing a complete set of detailed drawings which we'll make available at no cost.

Chuck

PS... Thanks again, John
Title: Re: Compressed Air V8 Engine
Post by: Don1966 on October 17, 2012, 02:49:16 AM
Oh wow! Chuck you are the greatest, many thanks for the drawing and John too.  :AllHailTheKing: let us know when you get them in the download section. Hope your cold has eased off. Get well soon.

Don
Title: Re: Compressed Air V8 Engine
Post by: Hagar on January 02, 2015, 12:56:07 PM
Hello.

I know it's been a long time this thread "died", but i discovered it a few time ago.

I've seen both videos and i fell in love with this engine incredible sound. Closer to a actual gas V8 than usual air device songs (pssshhhit  :Lol:). Thanks to spring balled head, it seems. Would it be possible to see pictures of these engine head, please ?
I mean, admission holes and parts hidden in...

I saw scheme on page 4. It's been a great help to understand. But i can't figure how spring can fight pressure when low dead point is reached, since there's atmo pressure behind balls and high pressure on the other side. Even if rotative valve is closed, high pressure remains, i think...

I'm on the verge to start studying my own, i must say. first hand drawings are already layed for a flat pattern and a one-piece connecting rod between two opposite cylinders.
Hope Chuck will allow me to use some of his solutions.
Title: Re: Compressed Air V8 Engine
Post by: cfellows on January 02, 2015, 04:56:57 PM
Hagar,  I've attached a 3-page drawing which you may have already seen, but explains in some detail how the slave valve works.

I saw scheme on page 4. It's been a great help to understand. But i can't figure how spring can fight pressure when low dead point is reached, since there's atmo pressure behind balls and high pressure on the other side. Even if rotative valve is closed, high pressure remains, i think...

The ball valve is quite a loose fit in the passage, up to .010" clearance.  When the inlet valve closes, the residual high pressure air in the cylinder quickly escapes around the ball valve allowing the spring to push the ball back to the resting position.  This arrangement makes the strength of the spring important to the running speed of the engine.  A weaker spring is used for good low idle but limits the maximum speed.  A stronger spring increases the maximum speed, but also raises the minimum idle speed.  In general, for smaller engines, a spring with a wire size of around .010" - .015" works the best. 

My air valve design is completely open for anyone to use in their own designs although I always appreciate the mention of my name in published work.

Chuck
Title: Re: Compressed Air V8 Engine
Post by: sco on January 02, 2015, 05:23:05 PM
That's interesting - wonder if I made my balls a bit too tight a fit in their passages as my engine never ran as well as Chucks.

Simon.
Title: Re: Compressed Air V8 Engine
Post by: Hagar on January 02, 2015, 09:17:28 PM
Thank you, Chuck.
Interesting pdf.

Of course, if i lead this project to the end, your name will appear.
Very nice of you to let us use your ideas.