Author Topic: Alyn Foundry Sphinx  (Read 1815 times)

Online Jasonb

  • Full Member
  • *****
  • Posts: 6351
  • 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: 393
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

Online Jasonb

  • Full Member
  • *****
  • Posts: 6351
  • 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: 393
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: 393
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: 393
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