Author Topic: The Alyn Foundry IF Allman engine.  (Read 4073 times)

Offline Jasonb

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Re: The Alyn Foundry IF Allman engine.
« Reply #60 on: September 30, 2018, 07:11:27 PM »
I have made a start on the piston, not easy to get it to a constant diameter as the rim around the Hemi end was very chilled which tended to push the tool off that part leaving a larger diameter than the rest of the casting  ;), enough to put people off castings. I had to resort to external honing to get a parallel piston which has taken some of the shine off the hard areas.



I also did a bit of work on the exhaust and governor linkages starting at the bottom I decided to ass some "cast" bosses to mount the pivot blocks on rather than onto a spot faced bit of the casting so JB welded on some scraps of brass which were then milled to size. They will need a bit more cosmetic filler to get the fillets but the 1/4" ball nosed cutter has made a start on that from the squished out JBWeld and oversize bits of brass. Also knocked up the pivots which are held by CSK screws from below.

The Patent drawings show the cross bar at two different heights as well as running right through the A frame so a bit of artistic licence is needed.



« Last Edit: September 30, 2018, 07:15:05 PM by Jasonb »

Offline Jo

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Re: The Alyn Foundry IF Allman engine.
« Reply #61 on: September 30, 2018, 07:14:59 PM »
I have made a start on the piston, not easy to get it to a constant diameter as the rim around the Hemi end was very chilled which tended to push the tool off that part

Sounds like substandard machine/tooling Mr Silky has happily turn Industrial hardened tooling with his Sumitomo tipped tools  ::)

Jo
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Offline Jasonb

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Re: The Alyn Foundry IF Allman engine.
« Reply #62 on: September 30, 2018, 07:27:16 PM »
It was no problem cutting it and had it been chilled right through that would not have been a problem it is the fact the tool goes from hard to soft so you get a different depth of cut as there is far less resistance on the soft iron to the glass hard edge. Difference shows better on the cylinder head where the shiny stuff throws sparks off with blue ribbons of swarf and the dark is just like regular iron, and that is nowhere near as soft as a bit of cast iron bar. You will see what I mean when you try cutting yours, in the mean time get the Elephant man to run a file over the edge so he can give his verdict.




« Last Edit: September 30, 2018, 07:36:43 PM by Jasonb »

Offline Jasonb

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Re: The Alyn Foundry IF Allman engine.
« Reply #63 on: October 07, 2018, 05:19:39 PM »
A bit more progress.

The larger stock gear came with a 12mm bore which was too big so after cutting in half and facing off it was stuck onto a bit of bar with Loctite 638 and then the bar was turned down to take the eccentric and also bored and reamed to fit on a pivot post.



The eccentric was held in an ER collet as I find this easier so set running true when the hole is near the edge and you get the added bonus of not distorting the hole when the chuck is released.



I've made it so the eccentric is held with a grub screw so the position is fully adjustable.



Next up was the inlet valve block. This section shows what I was aiming for starting at the top is a 17mm dia hole tapped part way M18x1. On the left is a 7/32" air inlet (I have since added a couple of 8BA studs to take a flanged elbow thatcan be seen on the Patent drawing. At the bottom is the valve guide with a spotface to seat the spring. On the left is a 1/4 x 40ME threaded hole that has a 1/32" passage into the valve seating, this will hopefully allow the valve to shut off the gas and only open as the valve lifts on the intake stroke.



All the concentric holes and valve seat being done at one sitting in the 4-jaw



The 1/32" required an extended drill so I popped a hole in the end of some 1/8" rod and loctited the drill bit in place.



Hole in the valve seat



And it came out almost spot on centre




Offline Jasonb

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Re: The Alyn Foundry IF Allman engine.
« Reply #64 on: October 07, 2018, 05:28:50 PM »
I also cut some water passages between the various cast in pockets using the boring head. In this photo you an also see my bottom water connection coming in.



This view from above shows the three passages, there is not one at the front as the liner needs to seal around the primary exhaust port.



Sitting at the bottom of the liner in that photo is the piston that has now had the cavity milled out, cross drilled for the pin and tapped for a screw to retain the pin. I also cut the three ring grooves = two for iron and one for an O ring.

Offline Alyn Foundry

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Re: The Alyn Foundry IF Allman engine.
« Reply #65 on: October 07, 2018, 05:41:06 PM »
Hi Jason.

Wonderful progress.

I'm perhaps a little late in mentioning that I made a " core " style cutter for the inlet valve chest. As can be seen in your drawing there's not much to guide the valve stem left. By using the core cutter it gave a longer guide for the stem.

I guess it'll be a case of " suck it and see " to start with. Fitting a separate guide won't be much of an issue if it becomes necessary.

Cheers Graham.

Offline Jasonb

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Re: The Alyn Foundry IF Allman engine.
« Reply #66 on: November 30, 2018, 08:30:40 PM »
A bit more of the type of progress I'm more interested in.

I had been in two minds as to whether I would use the cast bearings and once in my hand decided that I would go my own way. A quick doodle in Alibre and this is what I came up with, well actually not shown are two counterbored M4 clearance holes that will let me fix the lower half permanently to the tops of the A frames and not have them move out of line any time the top caps are undone.



I kept the overall size to what could be got out of the original castings for those that may still want to use them but cut 4 pieces of aluminium, milled to O/A size and then drilled the vertical holes. Next holding side upwards the bearing holes were drilled and finish bored. Over to the lathe the pairs were tightened onto a bit of 5/8" bar to bore the recesses each side.

Then the two caps where held onto the bar and the arched top roughed out before filing to blend the facets.



Add a couple of threaded bosses for the oilers and drill and tap the A frames for the studs and cap head screws. I still need to knock off the corners and rough them up a bit to get the cast look but all rotates nicely. Bearing flange shave been left a little over length until I have finished playing with the gear and eccentric  layout



J


Offline Chipmaster

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Re: The Alyn Foundry IF Allman engine.
« Reply #67 on: November 30, 2018, 09:01:02 PM »
Looks good Jason

May your timing gears run smooth and quiet  :LittleAngel:

Andy

Offline Alyn Foundry

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Re: The Alyn Foundry IF Allman engine.
« Reply #68 on: December 01, 2018, 03:38:45 PM »
Echoing Andy's comments, they look really nice Jason.

I'm rather embarrassed to remark that the Gunmetal castings weren't fit for purpose, for that I apologise.

Cheers Graham.

Offline Jasonb

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Re: The Alyn Foundry IF Allman engine.
« Reply #69 on: December 01, 2018, 08:38:29 PM »
Spent my workshop time today trimming off the excess iron at the top of the A frames, cutting some clearance for the eccentric and making up teh pivot parts for same

Gears seem nice and quiet and are set at the correct 31.5mm ctrs


Offline Gas_mantle

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Re: The Alyn Foundry IF Allman engine.
« Reply #70 on: December 01, 2018, 08:44:47 PM »
Looks to be coming along great  :)

It's going to have some considerable momentum with that huge flywheel purring along

Offline Jasonb

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Re: The Alyn Foundry IF Allman engine.
« Reply #71 on: December 02, 2018, 05:51:56 PM »
I got the bearings drilled for oil holes and pinned them so they won't rotate and knocked off the corners of the new bearing blocks. Also did a bit of grinding around the tops of the columns so they flowed in to the shape of the blocks



Also knocked up the small intake elbow that can be seen on the patent drawings, still needs a bit more of a clean up but it fits OK and I can get the bottom nut on.


Offline Jasonb

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Re: The Alyn Foundry IF Allman engine.
« Reply #72 on: December 09, 2018, 04:45:09 PM »
Now that the crankshaft is in place I could measure what length I needed the conrod to be and come up with something suitable. I was not keen on the one shown in the Patent so went more along the lines of the engravings of actual engines which show something more like a typical marine bigend as found on steam engines.



Main Bearing studs are also made, inlet and exhaust x 2  passages drilled through jacket & liner and the piston rim notched to suit.

Spent the  rest of the time watching bits go up and down as others went round and round all nice and smoothly and even without the rings fitted compression is reasonable.

Offline crueby

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Re: The Alyn Foundry IF Allman engine.
« Reply #73 on: December 09, 2018, 05:38:41 PM »
Thats a very graceful conrod!  Is the center section of the big end one piece of bronze? The narrower section in the middle of the sides sets it off very well.

Offline Jasonb

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Re: The Alyn Foundry IF Allman engine.
« Reply #74 on: December 09, 2018, 05:47:40 PM »
Big end is a two piece split bearing, unless they need to come apart for assembly I tend to leave then soldered together during construction as it makes it quicker when you are taking things apart and putting back together several times. You might just see the joint on the radiused side.