Author Topic: Rockerblock I.C.--Something a little different-  (Read 3598 times)

Online Brian Rupnow

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Re: Rockerblock I.C.--Something a little different-
« Reply #45 on: April 15, 2017, 04:27:36 PM »
I just got a price to waterjet cut 2 curved spoke flywheels.---$69.50 each. So----I called the guy up and whined at him. The price dropped to $49.50 each. That's 2 1/2 hours setting at my computer designing something for a customer. If I tried to machine them myself I might be 80 years old before I got them finished. I said "Go ahead and make them!!" This should be very interesting.

Offline cfellows

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Re: Rockerblock I.C.--Something a little different-
« Reply #46 on: April 15, 2017, 04:47:48 PM »
I like the idea of using propane instead of liquid fuel.  The gas tank always seems to present a problem for me as well.  There's just no convenient place to put it and it always adds a lot of bulk.  I really like the looks of this little engine.  I'm surprised there aren't more full sized examples of this engine from the past.

Chuck
So many projects, so little time...

Online Brian Rupnow

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Re: Rockerblock I.C.--Something a little different-
« Reply #47 on: April 15, 2017, 05:25:56 PM »
Thanks Chuck--Glad to have you on board. As I was 3/4 of the way thru the design of this engine, I began to realize it is basically half a Comer engine like the dual opposed piston engine I built a few years ago.

Online Brian Rupnow

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Re: Rockerblock I.C.--Something a little different-
« Reply #48 on: April 15, 2017, 11:16:35 PM »
Don't ask!! This is about one of those "Having your cake and eating it too" things.

Online Brian Rupnow

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Re: Rockerblock I.C.--Something a little different-
« Reply #49 on: April 16, 2017, 11:35:33 PM »
So, here we go again, making it up as I go along. What are you looking at?--Well, I don't have any 5/16" plate, but I do have some 2" x 3/8" steel flatbar. First job was to mill a length of it long enough to make 2 crankshaft webs down to 5/16" thick. Next step was to lay out the profile on one end of the milled down section. Then cut that end off, clamp it tightly to the remaining piece, and run a bead of weld on both sides about half an inch long. This ensures two things. Most importantly, that any holes thru part #1 are going to be dead nuts in line with any holes in part #2. A secondary benefit is that I only have to drill and ream any holes one time. I don't do this in my mill vice, because I don't trust it not to "cock up" a little bit when I tighten the vice. This results in very bad juju on crankshaft webs. I will put a sacrificial piece of plate between this bar and my milling machine bed, and clamp it to the bed for all the drilling and reaming. I will then saw and mill away everything that doesn't look like a crankshaft web, leaving the two welded areas until the very last step before I separate the two pieces. They will be match marked with a center punch so that I don't reverse one or the other when assembling the crankshaft. Crankshafts are one of the things where "Close really does count".

Online Brian Rupnow

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Re: Rockerblock I.C.--Something a little different-
« Reply #50 on: April 19, 2017, 02:29:30 PM »
The crankshaft webs have been drilled and reamed, then trimmed from the parent stock with the bandsaw. They are still welded together in two places. Next step is back to the mill to square up any "straight-line" surfaces, then mount them on a stub mandrel and turn them to finished diameter in the lathe. I will probably put a bolt and nut through at least one of the "lightening" holes and cinch it up tight so that when the welds get machined away the two pieces of plate won't try and slip and get out of alignment. This wouldn't affect the geometry of the plates in any way, its just that generally bad things happen whenever something tries to "slip" from where you intended it to be when you are machining it.

Online Brian Rupnow

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Re: Rockerblock I.C.--Something a little different-
« Reply #51 on: April 20, 2017, 02:02:54 AM »
My "Gas demand valve" plans from Jerry Howell came today, along with some very small Tecumseh engine carburetor needle and seats parts and a diaphragm. The detail drawing of the parts I have to make seem to be well done, but it's pretty damned sparse on assembly drawings. In fact, there are no "assembly drawings" as such, just printed instructions that eventually make sense after you have read them and taken all the tiny parts out of the bags and studied on them to see how this thing works. Apparently I now have to buy a propane regulator to use with this thing, and I have no idea what that will cost, but will try to find out tomorrow. I had an email today from the waterjet cutter saying I could pick up my curved spoke flywheels tomorrow, so I'm fair excited about that. I am going nuts right now with design work, to the point where I can't get time to do my own "hobby" stuff.

Online Brian Rupnow

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Re: Rockerblock I.C.--Something a little different-
« Reply #52 on: April 20, 2017, 01:15:48 PM »
Here is a link someone sent me, with some very good information about the "demand gas valve" that I just purchased.---Brian
http://www.floridaame.org/HowTo2.htm

Online Brian Rupnow

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Re: Rockerblock I.C.--Something a little different-
« Reply #53 on: April 20, 2017, 08:57:38 PM »
Today we are talking "beautiful things". I went this morning and picked up my waterjet cut flywheels. Man, are they ever nice. These are 3/4" thick mild steel, and the finish on the inside of the cutouts is very, very nice. The man who cut them said he can cut up to 6" mild steel. I will be machining the outside diameter, the 3/8" bore thru the center, and will take a 3/16" deep "face" cut on both sides in the spoke area. I may paint the parts of the flywheel I don't machine. These flywheels are 4 7/8" diameter and have about 1 1/8" diameter inside the cutouts in what will become the hub area. These are the first parts I have had waterjet cut, and although they are pretty, they are not for the faint of wallet. I paid $90 for these two. Fortunately, I got a $100 bonus last week for finishing a "panic" design job ahead of schedule.--that worked out well!!! Laying on my old blue steel handbook you can see my two finished crankshaft webs. If anybody wants the dxf file for these flywheels, email me at brupnow@rogers.com and I will send it to you. I have to give credit to Philip Duclos for the pretty shape of the spokes/cut-out areas. I didn't copy his numbers, but his "How to" article in "The Shop Wisdom of Philip Duclos" was certainly a big help to get me started in the right direction.---Brian

Online Brian Rupnow

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Re: Rockerblock I.C.--Something a little different-
« Reply #54 on: April 20, 2017, 10:15:44 PM »
I'm going to get bold here, and do something I haven't done before. Since my crankshaft is built up from individual components pressed, Loctited, and possibly pinned together, I'm going to make up a one piece con-rod and assemble it with the crankshaft. If it works, then great, I'm way ahead of the game. If it doesn't, all I've wasted is a bit of time. Since this is a "demonstration" engine and is not going to see long hard hours of use, I'm not going to run any bearings on the con rod. Aluminum rod running on steel crankshaft lasts a long time if it is kept well lubricated.

Online Brian Rupnow

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Re: Rockerblock I.C.--Something a little different-
« Reply #55 on: April 21, 2017, 12:54:58 AM »
I'm not blazing thru this build like I have some others, but I did manage to get some machining time in today. The con-rod still has to have the center relieved, but at least I did something. I can't assemble the crankshaft until I have the con-rod finished so I thought this had better be a priority.

Offline Flyboy Jim

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Re: Rockerblock I.C.--Something a little different-
« Reply #56 on: April 21, 2017, 03:13:31 AM »
Today we are talking "beautiful things". I went this morning and picked up my waterjet cut flywheels. Man, are they ever nice. These are 3/4" thick mild steel, and the finish on the inside of the cutouts is very, very nice. The man who cut them said he can cut up to 6" mild steel. I will be machining the outside diameter, the 3/8" bore thru the center, and will take a 3/16" deep "face" cut on both sides in the spoke area. I may paint the parts of the flywheel I don't machine. These flywheels are 4 7/8" diameter and have about 1 1/8" diameter inside the cutouts in what will become the hub area. These are the first parts I have had waterjet cut, and although they are pretty, they are not for the faint of wallet. I paid $90 for these two. Fortunately, I got a $100 bonus last week for finishing a "panic" design job ahead of schedule.--that worked out well!!! Laying on my old blue steel handbook you can see my two finished crankshaft webs. If anybody wants the dxf file for these flywheels, email me at brupnow@rogers.com and I will send it to you. I have to give credit to Philip Duclos for the pretty shape of the spokes/cut-out areas. I didn't copy his numbers, but his "How to" article in "The Shop Wisdom of Philip Duclos" was certainly a big help to get me started in the right direction.---Brian


Still not bad Brian. Two 5" cast flywheels from Martin Model & Pattern would of cost $60 (US): http://www.martinmodel.com/MMPflywheelslist.html

Jim
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Sherline 5400 Mill

Online Brian Rupnow

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Re: Rockerblock I.C.--Something a little different-
« Reply #57 on: April 21, 2017, 01:01:44 PM »
Yes Jim, and when you factor the difference in our dollars USA vs Canadian, and the shipping, and the tax I pay when it comes into Ontario, they probably are more than I paid.

Online Brian Rupnow

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Re: Rockerblock I.C.--Something a little different-
« Reply #58 on: April 21, 2017, 07:13:26 PM »
I got so tired of bodging up temporary fixtures to relieve the center portion of connecting rods that today I actually took an hour and built a dedicated fixture for it. I will post a clearer picture of it when I get the other side of the rod finished. It works like a charm.

Online Brian Rupnow

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Re: Rockerblock I.C.--Something a little different-
« Reply #59 on: April 21, 2017, 08:05:53 PM »
This is the finished con-rod, along with a shot of the fixture I made for relieving the section of rod between the two end bosses. The round rod in the center is turned to 3/8" x about 0.290" long. The remainder of the round rod is 9/16" diameter and passes thru a 9/16" reamed hole in the flatbar, and is welded a coupe of places on the side which fits into the chuck. The other bolt passes thru the far end of the con-rod and holds it snug against the flatbar, with the help of a flatwasher. The piece of flatbar which sticks out on the other side of center gives the fixture balance and can be tapped anywhere to accept a different length con rod.