90 degree V-twin engine

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gbritnell

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I have just finished the drawings for my winter project. It will be a 90 degree V-twin engine with a 1.00 bore and 1/25 stroke. It will have a pressure oil system with a Hall effect ignition trigger. The timing will be controlled by a slotted disc which will fire both plugs at the same time. I have a twin fire coil just waiting for this project. The cover side that you see in the picture will have the crank gear driving an intermediate gear which in turn will drive the cams. This will keep the cams on the centerline of the cylinders. It will be a scratch built engine as per my latest engines. Most of the components will be aluminum but the cylinders will be iron. I thought about putting dual carbs on it but didn't need the aggravation of trying to get them both running equally. Heaven knows it's hard enough to get one to run well.
gbritnell
VTWINENGINE238-1.jpg


 
That's a nice looking engine! I look forward to seeing the progress on this project.

Will the plans be available to us in the future? ;)

Regards,

Anthony
 
Looks good, I'll be watching with great intrest.

Philly
 
Having seen your work and shop methods here, I'd imagine this is going to be a stunner!

Dean
 
Have got to follow this one !

Ian (Seagar)

th_wwp
 
Well the drawings are finished except for the things I will catch as I start building this thing. I'm starting with the crankcase. I milled the blocks to size, put in the perimeter holes and reamed a pilot hole on the mill. I then moved them to the lathe where I indicated the reamed hole and started boring out the internals.
gbritnell

VTWINA.jpg


VTWINB.jpg
 
looking like a very interesting build.............will be watching this one step by step 8)

chuck
 
That's a very interesting project George. It amazes me that not only will you machine all those complex pieces, but that you also did the design work.

I look forward to seeing your progress and posts. :)

-MB
 
I got a little time in on the lathe today so I bored out the inside cavities. The large bore is for the crankshaft, the next bore is for the ball bearing and the last bore is clearance for the crankshaft. I then turned the one crankcase piece around and turned off the excess stock. Next up is to make a fixture to hold these pieces for all the profile work.
gbritnell
VTWINC.jpg

VTWIND.jpg

VTWINE.jpg
 
Here's the progress for today. I milled out the oil sump area on both halves. I roughed it out with a .50 endmill and then went around the bottom edge with a .187 ball mill to put a fillet in it. On the one half I cut some of the bolt boss away so that the oil will drain back from the front side to the rear. I drilled and tapped the cover holes on the left crankcase half and also cut the crankcase vent opening. I have the fixture made up to hold the halves for the profiling. I'll start roughing them out tomorrow.
gbritnell
VTWINF.jpg

VTWING.jpg

VTWINH.jpg

VTWINJ.jpg


 
I have no idea what happened to all the pictures. I went to my Photobucket account and my bandwith is fine. Maybe the moderators can help.
gbritnell
 
Mine are all gone too, George. I use a paid server, and all my pictures show up on my own web site. Looks like a problem with the forum picking them up from the various servers.

Dean
 
Well, now that the pictures are back, I can see!
They look great so far, George. Such a neat project.

Dean
 
George, just seen this. That's a really nice engine design. I will be watching with interest :bow:

Nick
 
I mounted the crankcase half on my locating and set up fixture plate and layed it out. The next step was to start milling to my lines leaving stock in the corners for my fillets. The block was square to begin with so all of the surfaces are being set up off of the bottom surface of the crankcase. One shot is the cylinder surface being cut and the other picture is the fillets being machined out. The last two show the crankcase half to this point. When I get the other half machined to this point I will tear down my vise and put up my rotary table to spin the crankcase radius. The bolt bosses will be cut down so they are .25 long from the split face. The motor mount pad will be .50 long from the split face.
gbritnell

VTWINK.jpg

VTWINL.jpg

VTWINM.jpg

VTWINN.jpg

VTWINO.jpg

VTWINP.jpg





 
Hi George;

In the two shots of the piece where you show it being milled, there is a shaft in the crankshaft bore. What is its purpose? Does it fill the inner cavity of the crankcase for some work holding purpose?
It appears to be the same piece as in your surface plate jig, but it's got me a little puzzled.

I figure if it's there, you put it there for a reason. Just curious.

Thanks.

Dean
 
Hi Dean, it's a setup plug. I find it easier to indicate over a small diameter than trying to pick it up from the inside of the bore for layout purposes. I also use it to bump up against with my edge finder when I'm setting up on the mill. I also put a very small center drill dimple in it to use as a point for my dividers to layout the radius of the crankcase.
gbritnell
 
George
You can bet I'll be paying close attention to this build.

Steve
 

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