Author Topic: Alyn Foundry Sphinx  (Read 1916 times)

Offline RayW

  • Full Member
  • ****
  • Posts: 396
Alyn Foundry Sphinx
« on: April 15, 2019, 08:19:04 PM »
Just returned a couple of days ago from a very enjoyable short break in Wales and a visit to Graham to collect a set of Sphinx castings. Graham and his son made my wife and I very welcome and ran a couple of their little CHUK flame ignition engines for us to see.

Most of the castings were made by a small one man concern and are of rougher external texture than Graham's normal ones, but where they have been cut, they appear to be of good quality with no evidence of flaws. A bit of fettling with a sanding disc should soon smooth them out a bit. Graham managed to find an older barrel casting for me as well as a Robinson piston and these are of much smoother finish.

First task will be to mill the bottom of the main casting, then the mating face onto which the barrel locates. Next job will be to bore the 1.75" hole in the mating face, through which the cylinder protrudes. This presents something of a problem as my milling machine is not tall enough to take the casting in a vertical position and I really do not relish the idea of swinging a 10 inch long, 9.7 kg lump of cast iron in the lathe. I can probably use my drill press, but how to hold the very heavy and irregular casting in an appropriate position will need a bit of thought.
Ray

Offline Jo

  • Administrator
  • Full Member
  • *****
  • Posts: 12255
  • Hampshire, england.
Re: Alyn Foundry Sphinx
« Reply #1 on: April 15, 2019, 08:29:18 PM »
Another Sphinx, nice one Ray  8)

Have you thought of clamping the base casting to your cross slide and holding a boring head in the spindle of the lathe?

Jo
Usus est optimum magister

Offline Jasonb

  • Full Member
  • *****
  • Posts: 6361
  • Surrey, UK
Re: Alyn Foundry Sphinx
« Reply #2 on: April 15, 2019, 08:36:21 PM »
As Jo says mount it on the cross slide, depending on what height you have above the surface you may just be able to mount on packing or if not enough then use angle plates, I have done several engines this way though I prefer a between centres boring bar. You can flycut the back face of teh casting for the cylinder flange at the same setting so it is true.





You can then swing it round to do the main bearings so they are at the same height.


Offline RayW

  • Full Member
  • ****
  • Posts: 396
Re: Alyn Foundry Sphinx
« Reply #3 on: April 15, 2019, 08:50:40 PM »
Thanks Jo and Jason,

That would be the ideal solution, but unfortunately my lathe has no facilities for mounting anything on the cross slide.
Ray

Offline Jo

  • Administrator
  • Full Member
  • *****
  • Posts: 12255
  • Hampshire, england.
Re: Alyn Foundry Sphinx
« Reply #4 on: April 15, 2019, 08:55:14 PM »
Have you considered taking off the Lathe tool post and using its mounting studs to mount an angle plate onto which the base casting could be clamped?

Jo
Usus est optimum magister

Offline RayW

  • Full Member
  • ****
  • Posts: 396
Re: Alyn Foundry Sphinx
« Reply #5 on: April 15, 2019, 08:58:44 PM »
Thanks Jo. I will have a look to see if that would be possible.
Ray

Offline Jasonb

  • Full Member
  • *****
  • Posts: 6361
  • Surrey, UK
Re: Alyn Foundry Sphinx
« Reply #6 on: April 16, 2019, 07:23:00 AM »
I'll need to go and look at my casting but it may be possible to bore the bole with the bearings uppermost and pass the head down between them which would mean you need less head room, if the mounting face were machined first with the casting sitting flat on the mill table you could them use this surface to clamp it down which should get the bore square to the hole.

The other thought is how tight a fit does the liner really need to be, could be that you could just mount it on end to mill the face and drill the holes ( drill bit in MT collet if needed) then file or otherwise bring the hole to a size that the liner will fit through. I have done a couple of engines where the cylinder is just supported on two sides and not in a hole.



Final thought, you don't need to use a boring head which takes up head room. A simple piece of bar to fit your largest MT collet with a reduced shank if needed (or a small flycutter) drilled for a HSS tool can be used with the tool being manually advanced. Even if the hole were +/- 0.010" it would not be a problem provided the liner were made to fit.

Offline Jasonb

  • Full Member
  • *****
  • Posts: 6361
  • Surrey, UK
Re: Alyn Foundry Sphinx
« Reply #7 on: April 16, 2019, 09:23:52 AM »
Had a quick play with my casting and tooling. Pics to illustrate my post above.

1. Boring with 2" head between the bearings, also if you let the foot of the casting overhang the table that will gain you another 2" or so in height.



2. Using a holder with HSS tool or small flycutter to plunge down tool will be advanced manually.



3. If you don't go with an accurate hole the four mounting holes can be drilled with minimal height and the surface can be milled at same setting



The far eastern machines may be quite small but they do generally have reasonable Z height for their size, as you can see my X3 has plenty to spare. :)


Offline Alyn Foundry

  • Full Member
  • ****
  • Posts: 758
  • North Wales, Great Britain.
Re: Alyn Foundry Sphinx
« Reply #8 on: April 16, 2019, 02:53:00 PM »
Hi Ray.

It was great to meet you both again and I'm glad to read you enjoyed your stay near Rhyg Capel.

The Sphinx was only my second engine design, a bit of a greenhorn! Conceived late 1983. I made it very " chunky " as cast Iron wasn't very expensive back then. It's at this point I have a confession to make....
I didn't ever machine the bed casting once myself.... I made several Sphinxes over the years for customers but always used the services of AWR for the very same reason as you're finding now. However at that time my entire workshop consisted of a bench pillar drill and a tiny Tyzak 3" lathe. I hope I can be forgiven?

The main reason for a " gearless " 2:1 reduction was, A. Zero gear cutting knowledge/equipment and B. Geoff Challinor had recently sent me photocopies of Robinson's 1890 patent Oblique engine, I was amazed at its simplicity.

At this time Vincent Salter who'd already made the patterns for my first design, the " Penultimate gas engine " was well underway with his " Retlas " and I thought " well if he can make patterns then so can I " !!   As work progressed the bed pattern shape reminded me of the famous Egyptian statue, the engine got its name.

Several months later Vincent's Retlas debuted at the very first 1000 engine rally held at Tatton park in June 1985. This 1000 engine rally shouldn't be confused with the two previous rallies that had been tried in 1979 and 1981 by the founder and editor of " The stationary engine " magazine, David Edgington. I'm proud to say that I attended the second event with my massive 1919 Lister type " P " who's magneto died almost immediately after its first start on the Saturday morning.

The Sphinx was coming together slowly but wouldn't be seen running until September. We three, Vincent, Martin ( The Great Lorenzo ) and myself actually finished number 103 on the Rally Field at the Malpas event held at Gredington park Hanmer using a Crossley powered generator set that Vincent had " cobbled together " for electric power tools.

It was mid afternoon on the Sunday that she finally sputtered into life amidst applause from both exhibitors and public alike. I felt so many emotions, 'twas amazing.

Being such a novice I had decided to use as many readily available parts as possible, the crankshaft came from a J.A.P. 1A petrol engine and the piston from a Honda C90. The parts that couldn't be machined on a lathe were all hand filed. I really overdid the fasteners, I mean 5/16" BSW for the valve chest, c'mon Graham, what were you thinking?? I'd suggest downsizing a little here Ray.

Three decades plus later the video attached shows number 103 with all the knowledge gained and applied, plus a little adaptation that stopped the occasional breaking of the ratchet pawl !! By extending the exhaust valve stem to be closer to the ratchet wheel centreline it stops the pushrod getting caught underneath if the engine should backfire and run backwards.

I hope you enjoyed my ramble down " memory lane " as much as I did. The Sphinx wasn't very popular probably less than 40 kits produced in as many years!!

Cheers Graham.


Offline RayW

  • Full Member
  • ****
  • Posts: 396
Re: Alyn Foundry Sphinx
« Reply #9 on: April 16, 2019, 04:31:31 PM »
Thanks Jason and Graham for your helpful suggestions and comments.
As Jason suggests, machining the front face first then mounting the casting bearings upwards on the milling machine is certainly a possibility.
I made a start on machining the underside of the base today but think I need to invest in some carbide tools as my HSS cutters were blunting pretty rapidly, even once I got under the outer skin. This is only my second experience of working with cast iron (the Robinson X type being my first), and this casting seems a lot harder than the Robinson ones.

P.S. Thoroughly enjoyed the "ramblings" Graham.
P.P.S. I always start machining with the bottom of the main casting. It gives me a chance to get a feel for how the material cuts, and is also a great place to hide any blunders!!


Ray

Offline Alyn Foundry

  • Full Member
  • ****
  • Posts: 758
  • North Wales, Great Britain.
Re: Alyn Foundry Sphinx
« Reply #10 on: April 16, 2019, 06:56:35 PM »
Continued....

As my workshop grew I managed to afford my first milling machine, a beast of a thing, a Denbigh Universal weighing in at a touch under two tons!! I still use it occasionally as it makes short work of keyways in horizontal mode. However, the vertical head is capable of pushing a 6" diameter Carbide tipped face mill that I used for the very job you're having a spot of bother with at this moment.

As Jason has pointed out the cylinder liner needs to be able to slide through the hole to allow for expansion. With hindsight it might be prudent to have an " O " ring inserted to stop the water from escaping into the bed way.

Another modification came later with regards to the cylinder head/liner flange/outer jacket assembly. A " canny " customer came up with an alteration that hides the cylinder liner flange. This makes it appear that the cylinder head fits directly to the water jacket casting. By reducing the liner flange diameter a little and counterboring the cylinder head the flange disappears. Because of this your head casting is deeper now as I modified the pattern many years ago.

Attached is a video of one of the few Penultimate's that were sold fitted with the Starwheel running flawlessly....


Offline Jasonb

  • Full Member
  • *****
  • Posts: 6361
  • Surrey, UK
Re: Alyn Foundry Sphinx
« Reply #11 on: April 16, 2019, 07:19:01 PM »
Thanks for the insight into how the Sphinx came about Graham.

The drawings I have do show an O ring seal though I may do mine a little differently when I get round to doing this engine. Will also look into hiding the flange now that you have mentioned it.

Offline Roger B

  • Global Moderator
  • Full Member
  • *****
  • Posts: 3820
  • Switzerland
Re: Alyn Foundry Sphinx
« Reply #12 on: April 16, 2019, 07:35:04 PM »
Interesting stuff  :ThumbsUp:  :ThumbsUp:  :) Those serrated clamping wedges seem to support your casting nicely Jason  :)  :wine1:
Best regards

Roger

Offline RayW

  • Full Member
  • ****
  • Posts: 396
Re: Alyn Foundry Sphinx
« Reply #13 on: April 17, 2019, 11:53:08 AM »
Hi Graham,

As regards water leakage, as Jason has mentioned, the plans already show an o-ring in the brass sealing ring at the flange end of the water jacket but just a face to face seal between the other end of the jacket and the cylinder flange. I was intending to build as per plan, but to use Loctite as an additional seal at each end to prevent any possibility of leakage.
Incidentally, the earlier jacket casting that you found for me is actually only 4 1/16" long (unmachined) as against the finished length shown on the plans of 4 7/16". Do you think that I will need to shorten the cylinder by a corresponding amount to avoid the con rod fouling it?
I like the idea of recessing the head casting to hide the cylinder flange and will probably adopt that idea.
Ray

Offline Jasonb

  • Full Member
  • *****
  • Posts: 6361
  • Surrey, UK
Re: Alyn Foundry Sphinx
« Reply #14 on: April 17, 2019, 12:59:28 PM »
I don't think I will make my ring from brass as I can't really see much point in it, iron or even steel would do and the rest of the engine is going to rust if in contact with water so why bother with a non ferrous ring. I will probably put a lip on it so the tightening force is metal to metal rather than risk the locctite bond failing and that means it can also be made thinner.

Depending on what room there is at the head end I'd also like to see if I can get a small section O ring in there to seal as the only contact is the end of the jacket and under the lip of the liner., it only touches the inside of the jacket where the four small lugs are.

Looks like my head will easily accommodate a 1/4" recess to take the lip on the liner and may try for a bit more to keep compression ratio down as it looks like my jacket will only give 4 3/16 after a clean up maybe 4 1/4

Rough sketch of my thoughts

Offline Alyn Foundry

  • Full Member
  • ****
  • Posts: 758
  • North Wales, Great Britain.
Re: Alyn Foundry Sphinx
« Reply #15 on: April 17, 2019, 01:24:19 PM »
Hi Ray.

Hmmm, must be getting old.... I'd completely forgotten about the Brass ring and seal assembly!

I wouldn't Loctite the open end as the liner will expand as the engine warms up. And as a footnote I've always preferred to use Acetate cure clear Silicon for all gaskets on my engines. If your mating faces are good a light smear and a tightened bolt will seal even exhaust fittings.

Regarding your PM, sadly I don't have a replacement " Starwheel " casting. May I suggest making one from some mild Steel round bar?

Cheers Graham.

Offline Alyn Foundry

  • Full Member
  • ****
  • Posts: 758
  • North Wales, Great Britain.
Re: Alyn Foundry Sphinx
« Reply #16 on: April 17, 2019, 01:41:15 PM »
Damn.

The gas bottle man arrived just as I was finishing.... Totally missed the jacket question.

Having just measured that rough new one and another from 30 years ago they both are 4 and 5/16" long so it seems Ray you're the first to point out that the drawing is in error!! I think it should read 4 and 1/16" long as machined.

The cylinder liner casting is a MK 2 version and was made a little longer than the original so that it protrudes through the base a little more than previously.

Jason.

I chose Brass for a reason. Theoretically it shouldn't corrode onto the Iron liner making disassembly impossible in the future.

However, a thick bead of Acetate cure Silicon to fill the gap is a very cheap but suitable alternative and these days I'd probably just do that! As I'm getting lazy.... The thin " O " ring at the front is a good idea.

Cheers Graham.

Offline RayW

  • Full Member
  • ****
  • Posts: 396
Re: Alyn Foundry Sphinx
« Reply #17 on: April 17, 2019, 01:52:04 PM »
Thanks again Graham and Jason for your thoughts. One thought I had is to machine a recess for a ring at the end of the jacket where the four lugs are and Loctite that in. The lugs are plenty long enough to allow this.This would provide a larger surface area for the cylinder flange to seal against - particularly necessary if reducing the diameter of the flange to recess in the cylinder head.
As regards the open end, as far as I can see, the o-ring seal as shown on the plans would only work if the cylinder was a snug fit into the hole in the front of the main body casting, otherwise the o-ring would tend to deform and be squeezed into any gap when the barrel retaining bolts were tightened.
Perhaps an o-ring groove on the inner face of the brass ring would provide a better seal?
Ray

Offline Jasonb

  • Full Member
  • *****
  • Posts: 6361
  • Surrey, UK
Re: Alyn Foundry Sphinx
« Reply #18 on: April 17, 2019, 02:47:53 PM »
Ray, if you need to file up a new star wheel this drawing has the radii and ctrs of the arcs that I think will give the right sort of shape. I think I would cut the flat faces with a thin slitting saw then rough hack saw the curves before filing to shape.

I'm not sure if I can use my casting but it would give me an excuse to play with the CNC. I think a 4mm cutter would be as small as I would want to go so the corners would need clearing up but may give it a go.


Offline RayW

  • Full Member
  • ****
  • Posts: 396
Re: Alyn Foundry Sphinx
« Reply #19 on: April 17, 2019, 06:48:14 PM »
Many thanks Jason, that will be very helpful. I did 3D model the wheel in Fusion 360 and created the radii by eye. I am going to see if the casting is usable, but looks as if I may need to make one manually.
« Last Edit: April 18, 2019, 07:45:42 AM by RayW »
Ray

Offline crueby

  • Full Member
  • *****
  • Posts: 8358
  • Rochester NY
Re: Alyn Foundry Sphinx
« Reply #20 on: April 17, 2019, 09:29:00 PM »
Thats a very interesting shape on the star wheel - if I follow the video correctly it holds the arm up away from pushing the rod every other time around. Clever stuff!

 :popcorn:

Offline Jasonb

  • Full Member
  • *****
  • Posts: 6361
  • Surrey, UK
Re: Alyn Foundry Sphinx
« Reply #21 on: April 18, 2019, 06:43:56 PM »
I decided to CNC a Star wheel from scratch just to get some more practice with the KX-3, more details in the "going over to the dark side thread"

http://www.modelenginemaker.com/index.php/topic,8882.msg199296.html#msg199296



« Last Edit: April 18, 2019, 06:50:03 PM by Jasonb »

Offline RayW

  • Full Member
  • ****
  • Posts: 396
Re: Alyn Foundry Sphinx
« Reply #22 on: April 18, 2019, 06:57:43 PM »
That looks really good Jason.A perfect demonstration of the benefits of CNC. Just one observation.- I think the central recess should be on the other side so that the teeth are facing to the right.
Would you be willing to make a star wheel for me please? I would, of course, be happy to pay you for your trouble.
Regards
Ray

Offline Jasonb

  • Full Member
  • *****
  • Posts: 6361
  • Surrey, UK
Re: Alyn Foundry Sphinx
« Reply #23 on: April 18, 2019, 07:25:09 PM »
Yes that is the back of the wheel, I photographed it that way as all the machining shots were from the same side. Buy cutting it that way up I could get the nut lower down which meant less of the 4mm dia cutter sticking out of the collet to avoid crashes.

Offline Alyn Foundry

  • Full Member
  • ****
  • Posts: 758
  • North Wales, Great Britain.
Re: Alyn Foundry Sphinx
« Reply #24 on: April 19, 2019, 12:23:38 PM »
Hi Both.

The recess in the back of the Starwheel is to accommodate a " double flat Grover washer " more commonly known as a spring washer these days.

The idea is to reduce the possibility of the wheel being dragged as the pawl retracts. I noticed on the picture that Jo posted earlier the builder had fitted a neat vertical flat spring to keep the Starwheel from going backwards.

Cheers Graham.

Offline RayW

  • Full Member
  • ****
  • Posts: 396
Re: Alyn Foundry Sphinx
« Reply #25 on: April 19, 2019, 02:18:15 PM »
Oops!
My apologies to Jason for thinking that he had put the recess on the wrong side of the wheel! I had mistakenly thought from the drawing that the spring washer was located between the bolt and the wheel, not between the wheel and the main body. It was only when I looked at the exploded view that I realised my error.
Ray

Offline Jasonb

  • Full Member
  • *****
  • Posts: 6361
  • Surrey, UK
Re: Alyn Foundry Sphinx
« Reply #26 on: April 19, 2019, 05:03:20 PM »
Don't worry Ray, I have a second one cut this afternoon which has the recess on the outside that may suit your way of thinking :Doh:

I got distracted while doing some alterations to the CAM and forgot to flip the part over, never mind I'll make use of this one as I had been thinking of putting a recess on the visible face that could be painted to look like a casting so you won't have any filing to do on yours.

Offline RayW

  • Full Member
  • ****
  • Posts: 396
Re: Alyn Foundry Sphinx
« Reply #27 on: April 19, 2019, 05:27:48 PM »
Thanks Jason. I have just realised that, by putting the spring washer between the head of the bolt and the wheel, I will need to put a short spacer between the wheel and the engine body to stop it rubbing, which would not be a problem with the washer on the inside. I'm sure either will work fine.
Ray

Offline Alyn Foundry

  • Full Member
  • ****
  • Posts: 758
  • North Wales, Great Britain.
Re: Alyn Foundry Sphinx
« Reply #28 on: April 19, 2019, 06:06:16 PM »
Thanks Jason. I have just realised that, by putting the spring washer between the head of the bolt and the wheel, I will need to put a short spacer between the wheel and the engine body to stop it rubbing, which would not be a problem with the washer on the inside. I'm sure either will work fine.

Hi Ray.

Just make sure it's made of Brass !  ;)

Cheers Graham.

Offline Jasonb

  • Full Member
  • *****
  • Posts: 6361
  • Surrey, UK
Re: Alyn Foundry Sphinx
« Reply #29 on: April 19, 2019, 07:51:20 PM »
The modified cutting sequence included some 2.0mm holes at the root of each internal corner that made it easier to file out the waste that the 6mm milling cutter could not get to. I have also enlarged the incorrect recess on mine with a round nose tool and will paint the recess.






Offline RayW

  • Full Member
  • ****
  • Posts: 396
Re: Alyn Foundry Sphinx
« Reply #30 on: April 23, 2019, 03:30:37 PM »
I have been working on the cylinder and jacket today, and pondering how it is possible to recess the cylinder flange into the head if you stick to the dimensions as drawn for both items.
The head and the flange are both 2 1/2" diameter. The four 3/16" studs are on a 2 1/16" PCD, giving an outside dimension across the studs of 2 1/4". To leave at least 1/16" of metal around the outside diameter, the minimum diameter that the flange could be reduced to is 2 3/8".
To recess that size of flange into the head would only leave a mere 1/16" of metal around the outside of the head. I just wonder how others have resolved this - possibly by reducing the PCD of the studs perhaps?

Personally, I quite like the look of the engine with the flange showing, as per number 103, so will probably go with that anyway.


Ray

Offline Jasonb

  • Full Member
  • *****
  • Posts: 6361
  • Surrey, UK
Re: Alyn Foundry Sphinx
« Reply #31 on: April 23, 2019, 06:19:02 PM »
I don't think there is a need for the flange to be larger than the outside dimension across the studs, I have made many engines where the flange is only 1/16" all round bigger than the OD of the liner which puts it completely withing the studs. However that was with the liner making contact all the way around it's side at the end of the jacket, here we only have contact against the four lugs unless the top of the cylinder is bored out for say 1//4" deep and a solid ring inserted and loctited into place.

If the depth of the recess were left a few thou shallower than the projection of the liner flange then all would be pulled up tight when the head was bolted on.

J

Offline Alyn Foundry

  • Full Member
  • ****
  • Posts: 758
  • North Wales, Great Britain.
Re: Alyn Foundry Sphinx
« Reply #32 on: April 23, 2019, 06:59:22 PM »
Hi All.

Let's not get into a " tizzy " 'Twas just an observation, each to their own....

You could, however pre drill the holes on the correct PCD in both the cylinder head and liner, then machine the flange OD halfway through the holes. When ready the head could be then counterbored with the opposite halves of the holes to match.

I've just located the Sphinx " Daybook " it would seem that you, Ray have got engine number 129, Jo 130 and Jason 131.

Cheers Graham.

Offline Jasonb

  • Full Member
  • *****
  • Posts: 6361
  • Surrey, UK
Re: Alyn Foundry Sphinx
« Reply #33 on: April 23, 2019, 07:21:17 PM »
I've just has a bit of a measure up of my castings and this is what I think I will do and is along similar lines to the sketch I posted earlier. I have shown O rings at each end but that would be optional and a smear of liquid silicon gasket would do the job and that is what I tend to use on all flat face to face joints anyway.

Head end of cylinder bored out to 2.25" for a depth of 1/4". Into this recess a ring 1/4" thick and 1.75" ID will be retained with Loctite. Once set the four stud holes can be drilled and tapped, holes are shown at full 3/16" dia see first image which includes a nominal 1/16" o ring sitting in a 1/16" x 1/16" recess.

The liner will be made with the flange at 2.25" OD, I have gained 1/16" on the cylinder length now 4.125" long so reduced flange thickness to 3/16" which retains same overall length and means the recess in the head only need be say 0.190"  2nd image. Four 5mm dia clearance holes in flange.

Last image shows a section through the parts together with a similar ring at the opposite end.

Offline RayW

  • Full Member
  • ****
  • Posts: 396
Re: Alyn Foundry Sphinx
« Reply #34 on: April 23, 2019, 08:19:32 PM »
That looks like a neat solution. I had already considered recessing a ring into the head end of the jacket to give a bigger mating surface with the cylinder flange,  but not thought about screwing the studs into that instead of the cylinder flange. It seems far more logical to bolt the head to the jacket rather than to the liner.
For a total belt and braces job , you could always put a couple of small screws through the jacket wall into the recessed ring to stop any possibility of it pulling out.
Ray

Offline Jasonb

  • Full Member
  • *****
  • Posts: 6361
  • Surrey, UK
Re: Alyn Foundry Sphinx
« Reply #35 on: April 23, 2019, 08:31:06 PM »
Ray, I think it was always Grahams intention that the head studs pass through the liner's flange and hold into the jacket, the 4 "lugs" inside the end of the jacket give some meat around the stud holes. This is how I read the original drawing before mention was made of recessing the head which will pull all three parts together once the nuts are done up, second image is as it would be with the ring added.

As the thread cuts across the joint that would stop any risk of teh ring pulling out even if you did not carry the threaded holes down into the lugs.

Offline Alyn Foundry

  • Full Member
  • ****
  • Posts: 758
  • North Wales, Great Britain.
Re: Alyn Foundry Sphinx
« Reply #36 on: April 24, 2019, 03:10:43 PM »
Indeed it was Jason!

However, the cylinder liner and head patterns were modified ( lengthened and deepened ) to accept the reverse of what you've drawn.
Rather than recess the water jacket you allow the liner flange to sit flat and recess the head instead.

Cheers Graham.


Offline Jasonb

  • Full Member
  • *****
  • Posts: 6361
  • Surrey, UK
Re: Alyn Foundry Sphinx
« Reply #37 on: April 24, 2019, 03:31:01 PM »
Graham, intent is to still have the liner flange in the same position as you did but sit it on a recessed ring for increased sealing area. Liner flange is then reduced to 2.25" dia so that the head can slip over the top of it with 1/8" wall to the recess.

I'll draw the head up later and post pic of the assembly.

j

PS Ray star wheel has made it as far as a jiffy bag, hope to post tomorrow

Offline RayW

  • Full Member
  • ****
  • Posts: 396
Re: Alyn Foundry Sphinx
« Reply #38 on: April 24, 2019, 03:43:20 PM »
Yes, what Jason says!! I was literally just typing a similar reply when his popped up.

Jason, many thanks again for the star wheel. Do please let me know if I owe you anything.
Ray

Offline RayW

  • Full Member
  • ****
  • Posts: 396
Re: Alyn Foundry Sphinx
« Reply #39 on: April 25, 2019, 11:50:38 AM »
Made some more progress on the water jacket and cylinder today. Bored out the head end of the jacket to accept a brass ring as has recently been discussed, and temporarily fitted the ring to ensure that the cylinder lined up with the brass O-ring retaining ring at the other end.
The head end ring still needs a final skim to bring it flush with the end of the jacket, but I will not do that until it has been Loctited in position, I will then also drill and tap the holes for the cylinder head studs. The cylinder still needs boring and the flange reducing in diameter so that it can be recessed in the head. The O-ring was made from some material that I already had to hand.I am not sure yet if I have made the groove in the brass ring deep enough. I will only be able to tell once I bolt the jacket to the main body and see how much the o-ring compresses.

Graham,
As you know, the water jacket casing I have is one of the older style ones with the inlet and outlets at opposite ends. On the plan, there is a note that the inlet underneat the jacket was move to the middle. What was the reason for that?
Ray

Offline Alyn Foundry

  • Full Member
  • ****
  • Posts: 758
  • North Wales, Great Britain.
Re: Alyn Foundry Sphinx
« Reply #40 on: April 25, 2019, 12:05:05 PM »
Good morning Ray.

You have quite a " pace " on! Progressing nicely.

The original position was to ensure a full flow of coolant across the entire length of the cylinder liner. The rearmost boss being close to the bed way made coupling a pipe fitting difficult but not insurmountable.

I decided to move the boss to make life easier for the constructor.

Cheers Graham.

Offline Jasonb

  • Full Member
  • *****
  • Posts: 6361
  • Surrey, UK
Re: Alyn Foundry Sphinx
« Reply #41 on: April 25, 2019, 12:36:20 PM »
Looks good Ray, I got a rough head drawn and assembled. I see that the flat face where the valve fits is 1 3/16" front ctr line which means it will be 1/16" at the narrowest when hollowed out. may be worth moving the face out to 1.25" and adjusting the valve block or eccentric etc to take that into account.

Regarding the pipe connections would there be anything to stop you having it the other way up? Which would put the bottom inlet near the head and top outlet nearer the engine body. There is one on Station Road that has the newer casting but with the inlet at the head end in a similar way.

https://www.stationroadsteam.com/sphinx-star-wheel-engine-stock-code-3793/

Star wheel is is posties hands now.


Offline RayW

  • Full Member
  • ****
  • Posts: 396
Re: Alyn Foundry Sphinx
« Reply #42 on: April 25, 2019, 04:46:24 PM »
Thanks Graham and Jason for your thoughts. Turning the jacket the other way up seems quite a neat solution, rather than moving the boss. Keeping the bosses at opposite ends should help circulation as Graham says.
Thanks for the tip off about the face dimension for the valve block Jason. Given that there is now a solid mating face between the cylinder flange and the inset brass barrel ring would you see any problem in reducing the flange diameter even further, say to 2.125", which would still give a reasonable mating area and leave more meat on the cylinder head?
Ray

Offline Jasonb

  • Full Member
  • *****
  • Posts: 6361
  • Surrey, UK
Re: Alyn Foundry Sphinx
« Reply #43 on: April 25, 2019, 05:04:26 PM »
I can't see a problem with that.

Offline RayW

  • Full Member
  • ****
  • Posts: 396
Re: Alyn Foundry Sphinx
« Reply #44 on: May 01, 2019, 08:06:42 PM »
Completed work on the cylinder head today. Totally forgot about Graham's suggestion about reducing the size of the studs for attaching the manifold, so have drilled and tapped to 5/16" Whitworth as shown on the plans. It would not be a problem to make up some stepped studs to reduce from 5/16 BSW at one end to 2BA at the other.
I ended up reducing the dimensions of the cylinder flange to 2"diameter x 1/4"thick, which still leaves plenty of sealing surface with the brass ring in the water jacket.
I have shown the cylinder assembled with the cylinder head, but you will notice that I have not yet drilled the cylinder flange to fit around the studs.
The cylinder itself has been bored to within a few thou of finished size and will be brought to final size with a brake cylinder honing tool, which will also be used to remove a slight taper from one end to the other.
Ray

Offline Jasonb

  • Full Member
  • *****
  • Posts: 6361
  • Surrey, UK
Re: Alyn Foundry Sphinx
« Reply #45 on: May 01, 2019, 08:40:47 PM »
Ray, did you put the inlet stud holes in at the drawn 13/32" or at 21/32" (13/32 + Recess depth) ? ditto the inlet hole at 1/2" or 3/4"

Offline RayW

  • Full Member
  • ****
  • Posts: 396
Re: Alyn Foundry Sphinx
« Reply #46 on: May 01, 2019, 09:37:23 PM »
Hi Jason,
I stuck to the dimensions as per the drawing and it looks ok. The cylinder flange just shows in the inlet port, so I may just round off that part with a Dremel to provide a smooth gas flow in and out.
Have you noticed, by the way, that there are no dimensions for the central cylinder head bore? Also, the holes for the manifold studs intersect two of the four vertical holes





Ray

Offline Jasonb

  • Full Member
  • *****
  • Posts: 6361
  • Surrey, UK
Re: Alyn Foundry Sphinx
« Reply #47 on: May 02, 2019, 07:18:46 AM »
Hi Jason,
I stuck to the dimensions as per the drawing and it looks ok. The cylinder flange just shows in the inlet port, so I may just round off that part with a Dremel to provide a smooth gas flow in and out.
Have you noticed, by the way, that there are no dimensions for the central cylinder head bore? Also, the holes for the manifold studs intersect two of the four vertical holes

I expect it will run fine with those dimensions but you may need to shorten something in the exhaust valve/eccentric as the valve block will be closer to the crankshaft by 1/4"

Yes even at 2BA they still clash so could be drilled shallower as the studs won't go in past the head bolts. The shallower depth won't be such an issue with the smaller diameter as you will get more than one diameter depth thread engagement.

I took the recess as 5/8"




Offline RayW

  • Full Member
  • ****
  • Posts: 396
Re: Alyn Foundry Sphinx
« Reply #48 on: May 02, 2019, 10:06:45 AM »
Yes, I had already thought of that. Shouldn't be a problem to shorten the pushrod to compensate. I made the central bore 9/16".
« Last Edit: May 03, 2019, 04:22:10 PM by RayW »
Ray

Offline RayW

  • Full Member
  • ****
  • Posts: 396
Re: Alyn Foundry Sphinx
« Reply #49 on: May 02, 2019, 10:40:26 AM »
This is my cylinder head on Fusion 360, with dimensions as per drawing, ie. no adjustment to compensate for the 1/4" recess.


Ray

Offline RayW

  • Full Member
  • ****
  • Posts: 396
Re: Alyn Foundry Sphinx
« Reply #50 on: May 07, 2019, 04:53:34 PM »
Finished honing the cylinder. After I had bored out the casting, there were about 8 or 10 blow holes, ranging from pinprick size up to about 2 or 3mm. Fortunately, none of the larger ones were at what I would call the business end of the cylinder. Filled them all with JB Weld before final honing, and have ended up with a really nice finish to the bore. With the cylinder held vertically against a flat surface, a heavy brass plug slides down quite slowly, and, if pushed down, there is quite good compression.
Ray