5 Cylinder radial (winter's project)

[coopertje]

Hi George,

I am quietly following along, its becoming a piece of true art (as usual). I really enjoy your progress, hoping one day I can make an engine half as beautiful as this one (they claim that patience comes with time, I am impatiently waiting for that moment).

Regards Jeroen

 

[Lesmo]

Hi George
I am increasingly astonished at the level of engineering expertise shown on this forum and this build has opened up yet another new dimension to me, as I would not have thought it possible to create the complicated shapes that you have achieved without casting. I can see now why Marve made the comment about breaking his mill down for scrap.

It’s just an illustration of how incredibly high the bar is set, that few of us, least of all me will ever achieve that level of expertise. I will have to be content to look on and pick up whatever I can from people like yourself who take the time and trouble to share their talent.

Regards Les :bow: :bow: :bow:

 

[gbritnell]

The machining of the heads is finished. All that remains is to press in the seats and valve guides. I used a tiny 3/32 burr with a conical shape to blend in the flat and angular surface. I then used my riffler files to smooth out the radius. Every operation along the way I kept thinking "maybe I should have made and extra head just in case". I guess luck was on my side. With so many steps in the machining process one wrong turn and I would have been quite depressed, especially getting near the end.
These three pictures will be the last for the heads.
I just received and invoice from Stock Drive Products telling me that my internal gear would be shipping. Now I can start on the cam ring.
George

 

[jpeter]

George, you work fast. Gonna be running in time for NAMES?

 

[gbritnell]

I hope to have it ready for NAMES but time seems to fly when you're having fun.
George

 

[gbritnell]

This is going to be a small tutorial on how I make valves, at least for this engine.

The valves are made from 303 stainless steel. They are .783 long with a .093 stem and .231 head. The groove for the retaining ring is .02 wide and deep.

For the job I used a piece of .312 dia. stainless held in my 5c collet chuck. When the piece is extended out a little over 1.00 the collets give more support than the 3 jaw chuck. This is the same reason I used .312 as opposed to .25, it's just a little more rigid.

I first cut a short length of the stem diameter to .094 to keep the stem from flexing when I cut the groove for the retaining ring. I know I have .093 above and now I'm saying .094. Well the truth is I leave a small amount for filing. If I could cut the whole stem at one time I would go with the finished diameter but it's easier to match up and adjust the dimension by filing and polishing.

The first picture show the stem diameter being cut. Next is touching off the necking tool and setting my -0-. I then go back .057 and cut in to depth.

 

[gbritnell]

I now make my next cuts to about .400 back from the end working down to .094 diameter. After this I go to the full length minus the fillet at the head. This is .700 back from the end.
Finally for this series I put in my radiusing tool and cut the fillet at the head to .734 from the end.

 

[gbritnell]

While I have the radiusing tool mounted I cut the head diameter to .231. Now comes the cutoff tool. I touch off the end of the stem and go back .794, this leaves .01 for cleanup and gives me a visual for cutting the seat angle. I only cut in deep enough to see where I'm at. Now the turning tool goes back in to cut the seat angle. The compound has been set to 45* right from the start.
This is where a QCTP saves the day.
Now the cutoff tool goes back in and the piece is parted off.
From here the piece is chucked up in my small lathe and the length is qualified to .784, leaving about .010-.014 of true head diameter.

 

[gbritnell]

And here you have some finished valves. The diameters are about .0932 so with the guides at .09375 I will have about .0005 clearance.
George

 

[vcutajar]

George

Thanks for the tutorial. Good thing I still haven't done my valves.

Vince

 

[krv3000]

HI this is a wonderful billed

 

[steamer]

Man you fly George! :bow:

Dave

 

[b.lindsey]

I'm with steamer George. I am beginning to think you are in some other space/time continuum or something!! :big: Its still looking amazing though and beautifully documented as always. Looking forward to each new post !!

Bill

 

[petertha]

So when folks talk about matching the 45 deg valve angle to the valve seat 'using the same setup on the lathe' ... I've never really been clear on this. You are obviously switching toolpost setups as you machine valves & including the 45 deg angling. And likely will have similar sequence turning the cage/seat. Is there a trick I'm missing like you somehow register the lathe compound to some repeatable known 45 deg reference so it stays as close as possible? I thought maybe all the valves would be turned with a blank/square face & then the 45 deg operation would be carried out on the batch in sequence, but then the setup has changed by re-chucking the stem.

Wonderful pics & progress BTW, just awesome! Im learning a lot just following along.

 

[Till]

The valves are made from 303 stainless steel.

I use to make IC valves from stainless steel screws. They are a good source of suitable valve material and it's easy to machine...

 

[gbritnell]

Hi Pete,
The seats will be made somewhere down the road. As far a matching the angles, I don't worry about it. Lets say that you cut the valve at 45* by the marks on your compound. Even if they're not exactly 45* I'm using this as a reference. Now I make up a tool to cut the seats like I normally do and cut it using the same register mark on my compound and let's say I was .5* off. Usually I cut my seats about .02 wide but even if you went .03 wide the difference in the 2 angles would only be .0003 in that distance. So you see it's not that big of a deal. With a magnifying glass I'm sure I could get the marks within say 1/4 of a degree, or closer so the mismatch would be negligible.
I'm sure for the fellows with small lathes the spacing on the degrees register marks would be finer but like I said you're just lining up lines for each operation, it doesn't matter if they're not exactly 45* but that they're both the same.
If a fellow wanted to get really critical he could put a bar in the chuck and do the trigonometry method by using the compound feed. I would think that most compounds would have at least 1.00 of travel so to set for 45*one would just calculate for the side opposite in a 1.00 distance and take a reading.
George

 

[gbritnell]

It's been awhile since I updated the group but I have been working feverishly on this engine. I got the valve seats and valve guides made and pressed them into the heads. The seats are steel with a .002 press fit with Loctite. The guides are bronze. The seat were pressed in and then a cutter was made to cut the seats in place. This provides a more accurate lineup with the guides.
The valve, spring and cap are held in place with a .018 ring made from music wire. I wound a section of wire onto a mandrel and then cut individual rings from it.

 

[gbritnell]

The valves had all been lapped and matched to their respective locations so it was time to start assembly. The first one got a bit dicey trying to hold everything compressed with a fingernail while trying to slip the ring over the top so I reverted back to full sized practice and made a small ring compressor. What a difference when using a tool to do something. While trying to assemble the first head my fingernail slipped a couple of times and sent spring and retainer the the farthest reaches of my shop somewhere. It was at this point that the tool got made. The retainers have a 30* chamfer cut into the top to compress and hold the split ring in place. The rings had to be expanded to get them over the valve stem but once in place I could squeeze them down with needle nosed pliers and then the chamfer took over. A very good setup unless you have to take them back apart, then getting the ring off is going to be a bear.

 

[gbritnell]

With the tool doing it's job it didn't take long to get them all assembled. Everything needs to be in place and tested because the next step will be to screw the cylinder and head together tightly so that they can be fixtured up to drill the base holes. That's not to say that they can't come apart but it's much easier to put the valves in now.
Here's a couple of shots of the assembled heads.
gbritnell

 

[petertha]

Maaaan George, you sure make nice parts... and quickly!

I'm guessing you wont be using any kind of ring gasket between the aluminum head & steel cylinder (like copper shim stock)? The two just get screwed together & seal/mate each other like your assembly thus far?

I couldnt quite tell on the picture of your neat combustion chamber profile cutting tool, but is it shaped like a half-circle dome that gets 'submerged' X amount into the head?

What is the target compression ratio on this engine?

Maybe you will talk about valve seat seal testing later on, I'm all ears.