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Your Own Design / Re: Building a twin cylinder inline i.c. engine
« Last post by Laurentic on Today at 10:35:02 PM »
Mike R - you make a number of really valid points.

Chris
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Your Own Design / Re: Kearsarge Windlass Engines
« Last post by Kim on Today at 10:27:42 PM »
Nice work on the base, Chris!  :ThumbsUp: :popcorn: :popcorn:

... Lots to go on this part!
Lots to go, yes.  But you've done a LOT already!  This is a labor intensive part!

Kim
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Vehicles & Models / Re: Pennsylvania A3 Switcher (Kozo)
« Last post by Kim on Today at 10:16:50 PM »
Chapter 31.5 – Blower Valve Parts

The next item to focus on is the Blower Valve.  This is a valve that allows you to send some seam directly up the smokestack to help increase the air drawn through the firebox.  From a big-picture view, the valve will take steam from one of the bushings on the backhead of the boiler and send it through a little tube to another bush on the backhead which is plumbed straight through the boiler to the front, where the blower is positioned under the smokestack.  Most of this pathway already exists, but the control valve and a bit of plumbing to get the steam to the blower bush on the backhead remain to be done.

The first thing I’ll be making is a round handle for the blower valve stem.  I’d originally specified in my BOM to use 3/32” brass sheet for this. But on some reflection, I chose to make it from a slice of 9/16” diameter brass rod.  I think this worked out much easier than the sheet route.

Starting with the rod, I faced it and started to part off a 3/32” wide disk, but didn’t finish that job.  I wanted the disk to still be connected to the parent stock for a while as it’s easier to hold this way.  With the disk defined on the end of the rod, I rounded the edge with a file and drilled a 3/32” center hole in it.


Then I moved the rod over to the mill and mounted it in the spin indexer.  Using a 3/32” ball nose mill I cut 12 notches around the perimeter – every 30o.  The spin indexer made this a cinch!


Back to the lathe, I trepanned a little out of the middle using a 3/8” end mill, then finished parting it off.


Now, back to the mill where I found the center of the valve wheel using a gauge pin, then proceeded to drill four holes to open up between the spokes.


I considered leaving it like that – with the holes.  But Kozo’s drawing shows more pie-wedge shaped openings between the spokes.  So I used a tiny diamond needle file to open them up some.   Looking at the results, I probably should have stopped while I was ahead, with the round holes.


I may try to even things up a little more tomorrow when I’m feeling a little fresher. Or I may just leave it so it doesn’t get worse!  I’ll sleep on it for a bit.

I’m just not that good at freehanding things, you know?  :-\

Thanks for checking in on me!
Kim
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Your Own Design / Re: Building a twin cylinder inline i.c. engine
« Last post by Mike R on Today at 08:59:45 PM »
Laurentic--Yes the compression ratio was changed. Was it changed enough to keep the engine from running? I doubt it very much. I didn't do an actual calculation on it.---Brian



Brian,


What was the thickness of the spacer under the cylinders? To me it looks like its about 1/8" (3.175mm)?  That is going to have a significant impact on the compression ratio of the engine. 


The following are assumptions as we don't have all the details, but I think it gives a good idea as to what may still be wrong with the internal combustion process (induction, compression, ignition, expansion and exhaust). 
Assuming that you designed it initially with the a 6:1 compression ratio (as a copy of Malcom Strides Bobcat), using your modified 25.4mm x 22mm bore and stroke we can reverse engineer a few things:
total displacement = 11.15cc with compression ratio 6:1 results in a design intent of 1.86cc combustion chamber volume


adding the volume the spacer adds (assuming 3.175mm) = 1.61cc  plus the original chamber volume of 1.86cc = 3.47cc combustion chamber volume as built.
working that out 11.15 to 3.47 is roughly a 3.2:1 compression ratio - likely too low IMHO.


Brian, you have been asked a few times about how the engine behaves with a bump test - its not a pointless exercise - it will help validate if there is compression, and how much is there.  We don't need a psi # to know if there is no compression, just spin the engine by hand - is there resistance to compression once per rev and if so does it feel good (snap over TDC) or is it "soft"? Take a video as you do it, and share,  if you really want some help from those on this forum. 




Suggestions for anyone else looking for help on why their engine will not run:


1.  provide all possible info:
   Is it built to an existing design or is it a new or modified design?
      If modified - what did you change?  details matter when things aren't working.
                    In this case Brian has changed a fair amount I understand:
   Cam tower height,
   valve length
   valve spring
   Cylinders spaced up (i.e. reduced compression ratio)
   induction (twin carb)
   bore and stroke,
        o-ring piston ring
   crankcase size,
   etc. , etc. to the point that I think it is effectively a new design (along with all the possible errors that come with a new design).


2.  Can you provide a video?  If so it should show if possible:
   a.  slowly turning the engine over - is there compression resistance as its turned over? For multi cylinder is there resistance as each cylinder comes to its compression stroke?  Does the engine "snap" over TDC, or is it "soft" when turning over.
   b.  If spark ignition, does it spark when turned over (assuming coil ignition or CDI, not magneto) and spark approximately when it should (just before TDC on compression stroke)?
   c.  slowly turning the engine over, show direction of rotation, and if possible the valve actuation (for each cylinder if multi cylinder)




Regards,


Mike

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Chatterbox / Re: Is Facebook as bad as I have read, or is it OK?
« Last post by gipetto on Today at 08:08:49 PM »
a friend of mine finds non running atv and motorbikes on facebook marketplace all the time, repairs and resells them. he makes quite a lot of money at it. in ireland there's more of that stuff on facebook at a low price than on any classified website. He often shows me pics of stuff for sale on it.
as for the site though,  i had an account and made an ass of myself talking to people that i remembered from years back. do not recommend, and I have since deleted it. internet friends are not real friends, you can't make a connection over it and since your every communication is monitored and monetized, it will actively impair your social skills by warping what you want out of friendship.
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Your Own Design / Re: Building a twin cylinder inline i.c. engine
« Last post by Brian Rupnow on Today at 08:01:27 PM »
Jason---the ones I made are setting in a jar and will be used in a future engine.---Brian
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Your Own Design / Re: Kearsarge Windlass Engines
« Last post by crueby on Today at 07:39:49 PM »
More done on the engine bed, got the side cuts on the first side done. The top ends of the vertical flanges will be cut back, so they are full width at the bottom and taper in to meet the side of the base at the top.


Then got to work on the other side. This is a bit more complex because of the extensions sticking out from the crank web openings. The solid block just left of center in this picture needs to be undercut - that block is there to form the angled holder for a frame post.

So, here is the engine bed so far, mounted back on the base without the plywood spacer. Next steps will be to lay out and cut the bearing block openings, and drill all the holes in the top faces for the frames and bearing caps. Lots to go on this part!
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Your Own Design / Re: Kearsarge Windlass Engines
« Last post by cnr6400 on Today at 07:24:10 PM »
 :ThumbsUp: :ThumbsUp: :ThumbsUp: :popcorn: :popcorn: :popcorn:
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Your Own Design / Re: Kearsarge Windlass Engines
« Last post by crueby on Today at 06:49:21 PM »
Just out of idle curiosity, did you Count the Number of Cranks it took to bring the top down to finished height?  That was some mighty fine CNCing.
The bar was 1" thick to start, finished height was 0.9", so two cranks vertically. Horizontally? Thats a LOT!  Back and forth and back and forth...
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From Plans / Re: 30ft 1890's navy steam launch 1/6th scale
« Last post by tghs on Today at 06:21:08 PM »
learning the joys of turning copper!!! :wallbang: but got the parts done.. upper section of header pipe soldered up.. had to temporally mount the vacuum gauge I purchased a while back (also have its match in a pressure gauge) no complaints out of Slim (for now) :cheers:
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