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Author Topic: Inline-four crankshaft  (Read 215192 times)

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Offline fordboy628

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Re: Inline-four crankshaft
« Reply #225 on: July 28, 2015, 01:32:56 PM »
my insistence on fitting it all under a M/T rocker cover caused many headaches!

Waaay cool Jack!!!!!!!

 :cheers: :cheers: :cheers:
Fordboy
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Online Peter Jack

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Re: Inline-four crankshaft
« Reply #226 on: July 28, 2015, 05:05:16 PM »
Jack, that's an awesome looking piece!!!  :-D :-D 8-)

Pete

Offline Jack Gifford

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Re: Inline-four crankshaft
« Reply #227 on: August 11, 2015, 12:46:17 AM »
I now have the CNC-milled magnesium segments- very precise work.
Attachment of two of them completed; six to go, but very time-consuming on a manual mill.
I purposely co-located the heads of each pair of Allen head 1/4-28 screws, to reduce "disturbances" of the O.D. During final assembly, aluminum plugs will be inserted above the heads of all 29-degree-canted screw heads, then plunge-milled to accept the heads of the radial (15-degree) screws- thus minimizing disruptions of the smooth O.D.
« Last Edit: August 11, 2015, 12:49:45 AM by Jack Gifford »
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Offline tauruck

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Re: Inline-four crankshaft
« Reply #228 on: August 11, 2015, 03:04:51 AM »
Jack, I wish I had you over here.
That is some serious engineering. :cheers: :cheers: :cheers: :cheers:

Offline Jack Gifford

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Re: Inline-four crankshaft
« Reply #229 on: August 21, 2015, 12:24:48 AM »
Finally- a view of a full-round crankshaft!
Next, I take a break from that job, while awaiting Tagnite surface treatment of the magnesium segments (to prevent corrosion).
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Offline Rex Schimmer

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Re: Inline-four crankshaft
« Reply #230 on: August 21, 2015, 07:40:28 PM »
Jack,
Great work, I really like the multi direction retainer bolts, reminds me of the way ship builders used to dowel the wooden blanking on to the ship ribs with dowels at various angles. Stress from any direction would cause at least one of the dowels to be in shear and not be pulled out.

Balancing should be interesting, I know you will keep us abreast of your continuing development.

Rex
Rex

Not much matters and the rest doesn't matter at all.

Offline Jack Gifford

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Re: Inline-four crankshaft
« Reply #231 on: October 13, 2015, 12:27:13 AM »
As usual... many delays were encountered (TAG lost my phone number, etc.). TAG suggested also applying an epoxy they've developed to better resist any acidity in the crankcase. It actually is absorbed into the pores of the Tagnited magnesium, adding less than .001" to any dimension. I finally received them a few days ago and assembled everything- Loctited all fasteners and torqued them to 52% greater than I had used for the spin-test sample. The only remaining machining on the crank will be to bore/ream the snout for a round key, after I finish the cam-drive sprocket hub and blower-drive hub.
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Offline tauruck

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Re: Inline-four crankshaft
« Reply #232 on: October 13, 2015, 12:41:08 AM »
That's beautiful Jack.

You've been at it a long time and it turned out great. :cheers:

Online Peter Jack

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Re: Inline-four crankshaft
« Reply #233 on: October 13, 2015, 03:59:28 AM »
Nice work Jack. You're a more patient man than me.  :cheers: :cheers: :cheers:

Pete

Offline wobblywalrus

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Re: Inline-four crankshaft
« Reply #234 on: October 13, 2015, 10:51:07 PM »
That crank looks nice.  It reminds me of old style motorcycle crankshafts from twins and fours that were pressed together and had roller and ball bearings instead of shells and journals.   

Offline Jack Gifford

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Re: Inline-four crankshaft
« Reply #235 on: October 14, 2015, 01:16:30 AM »
I'm mainly relieved to tear down the crank setup and free up my mill for other stuff. I used a "leftover" 15" pulley from the spin-testing to create a REAL degree wheel- one degree is about 1/8" at the rim! After turning the rim true, I used an index fixture to mill lines every one-degree, with the 5 & 10-degree points slightly deeper (lousy photo resolution doesn't even show them). I've got taper-lock pulley hubs for both the 1.125" cam snouts and the 1.375" crank snout.
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Offline tauruck

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Re: Inline-four crankshaft
« Reply #236 on: October 14, 2015, 06:51:07 AM »
Absolute work of art. :cheers:

Offline Jack Gifford

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Re: Inline-four crankshaft
« Reply #237 on: October 26, 2015, 12:07:30 AM »
A milestone of sorts: accomplished the first spin-test of my DOHC design today and no parts escaped! Using belt/pulley reduction from a one HP motor, I ran the exhaust cam and valvetrain for a number of minutes. Only about 700 RPM (would be 1,400 engine RPM), but I'll do some parts-inspection before spinning it faster. Oiling of cams and followers looks good- I may decide to restrict the volume somewhat. Oil supply for now is a variable-speed drill driving an old oil pump, and uses the top-end scavenge cavity as a temporary wet-sump (1 1/2 qt.). Once I'm satisfied with the exhaust side, I'll need to do the intake side also, since the follower geometry differs (can't run intake and exhaust simultaneously until the synchronous belt drive is finished, or valves would collide).

Prior to this test, I finished incoming-inspection of the cams that Crane built (measured lift every one degree!). They agree 100% with the print and the lobe profiles are exactly what I specified- including the limit I placed on maximum negative acceleration [2x10^(-4) inches/cam degree-squared].
« Last Edit: October 26, 2015, 12:25:53 AM by Jack Gifford »
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Offline Jack Gifford

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Re: Inline-four crankshaft
« Reply #238 on: October 27, 2015, 01:11:00 AM »
Swapped V-belt pulleys and ran the exhaust train for awhile today at 1,300 RPM. All is looking good. Now adapting some pulleys to see whether the one-HP electric motor will spin the valvetrain to 4,500 RPM (engine speed of 9,000 RPM).
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Offline wobblywalrus

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Re: Inline-four crankshaft
« Reply #239 on: October 27, 2015, 10:06:19 PM »
Jack, are you making your engine rather than modifying one?