Author Topic: Myrick Eclipse one-third scale model part two  (Read 8244 times)

Offline fidlstyks

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Re: Myrick Eclipse one-third scale model part two
« Reply #15 on: December 15, 2017, 01:25:53 PM »
Than you for sharing. I always enjoy some one else's genius and creativity.

Offline Myrickman

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Re: Myrick Eclipse one-third scale model part two
« Reply #16 on: December 28, 2017, 01:16:15 AM »
Continuing work on the cylinder head. The  head is mounted to an aluminum block first gasket surface down to spot the head bolt bosses and the spot where the intake goes.  The head bolt holes are also drilled. The head is flipped over and the gasket surface faced flat. Head is then flipped and spot drill/tapped to the plate. The main bore for the intake and exhaust chest is reamed to 5/8" and a 90 degree countersink forms the exhaust valve seat. Head is then tipped up on a 55 degree angle to drill/ mill out the passage between the intake/exhaust chest and the combustion chamber. Since this my second rodeo, the passage cutting went way quicker...for that matter the whole head. Still have to counterbore the underside of the head for the exhaust valve guide and drill/tap for the exhaust. Since this is a ported engine, the port takes most of the hot gas load and the exhaust valve merely seals off the combustion chamber for the intake stroke. Did I mention, this is also a hit and miss engine?

Online Dave Otto

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Re: Myrick Eclipse one-third scale model part two
« Reply #17 on: December 29, 2017, 12:48:33 AM »
Hi Paul

Great progress on the new engine, I have been following along since the beginning but had forgot to post a comment on your work.


Dave

Online Jo

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Re: Myrick Eclipse one-third scale model part two
« Reply #18 on: December 29, 2017, 09:20:10 AM »
Nice castings and proress :)

Did I mention, this is also a hit and miss engine?

Don't say that too loud around JasonB he likes making Hit and Miss engines especially out of castings  ;)

Jo
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Offline Jasonb

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Re: Myrick Eclipse one-third scale model part two
« Reply #19 on: December 29, 2017, 10:10:59 AM »
Flywheels are too big on this one for me to be able to machine :(

Online Jo

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Re: Myrick Eclipse one-third scale model part two
« Reply #20 on: December 29, 2017, 11:35:43 AM »
Flywheels are too big on this one for me to be able to machine :(

 :ShakeHead: Feeble excuse. It will be good practise for when you do the winding drum for the Superba  :naughty:

Jo
Enjoyment is more important than achievement.

Offline Myrickman

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Re: Myrick Eclipse one-third scale model part two
« Reply #21 on: December 29, 2017, 12:47:42 PM »
Thanks all for the encouraging comments. I'll be on the flywheels soon and I must say they tax the size capability of my Boxford 280. I purchased the lathe at an auction of a school shops contents being sold off. There were three of them at the auction and sadly, one of them went to a guy who left it in an unheated shed where it rusted badly.
I'm partial to the larger sic models as they can be run slowly and can be made to work on a hot tube.

Offline Myrickman

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Re: Myrick Eclipse one-third scale model part two
« Reply #22 on: December 29, 2017, 01:04:25 PM »
Finishing the head up here. The casting is mounted to the aluminum chucking block and the combustion chamber is finished machined on the rotary table. I was pleased with the passage between the valve chest and combustion chamber. The exhaust stub is machined also on the rotary table by flipping the whole affair vertically. This setup maxed out the height capability of the Index 747 mill. Had to use a collet and mini chuck to get the pilot hole started. Luckily the drill size for a 1/4 NPT is 7/16...so a collet worked here also to get it to fit. All there is to go is two 10-32 tapped holes for the exhaust valve guide. I'll be working on the guide later today.

Offline Jasonb

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Re: Myrick Eclipse one-third scale model part two
« Reply #23 on: December 29, 2017, 01:20:16 PM »
I thought the flywheels were about 12" if you can fit them on your Boxford 280 they may fit my Warco 280

Offline Myrickman

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Re: Myrick Eclipse one-third scale model part two
« Reply #24 on: December 30, 2017, 04:55:10 PM »
Jason, flywheels are about 10.5" finished...made of heavium aka cast iron with thick cross sections. Paul

Offline Myrickman

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Re: Myrick Eclipse one-third scale model part two
« Reply #25 on: December 31, 2017, 09:13:38 PM »
Some last of the vacation progress on the build.... With the head completed, next step is to align it with the engine frame to drill the mating holes in the cylinder. Here a piece of 5/8 drill rod orients the center of the valve chest with the main bearing as the thru hole in the head is also reamed 5/8. The head is stuck to the cylinder with double sided tape in the correct position and  a transfer punch is used to spot the female threaded hole locations.
The exhaust valve guide is then machined from the casting. The large round end is turned to fit into the bottom of the valve chest on the head. From there, the turned end is held in a 5C collet in the lathe and the sides of the guide are cleaned up until parallel. The center cutout is made on the mill with the top end filed square for the exhaust valve spring. The valve is a piece of cast iron round stock silver soldered onto 3/16 drill rod.  Happy new year...all the best in 2018. Paul

Offline Myrickman

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Re: Myrick Eclipse one-third scale model part two
« Reply #26 on: March 13, 2018, 10:39:36 PM »
Was away from this in early Feb. The fuel mixer gets a thimble cap to cover the intake valve spring so here is the copy based on the factory blueprint. It is about 1-1/8 on the base diameter and about 1-1/2" long

Offline Myrickman

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Re: Myrick Eclipse one-third scale model part two
« Reply #27 on: March 13, 2018, 10:55:41 PM »
The governer uses a "lollipop" which pivots under centrifugal force a bit and drives a dog on the inboard side which in turn, rotates a brass sleeve. The brass sleeve rides on a pin in a 45 degree slot in the sleeve rim. As the sleeve rotates, it moves in and out to actuate the governer latch arm. First step is to put a pin in the inboard flywheel hub for the sleeve. It was tight drilling and tapping the 6-32 hole. I need to clean up my slot in the sleeve a bit and make the pin a tad larger to get the most movement.

Offline Myrickman

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Re: Myrick Eclipse one-third scale model part two
« Reply #28 on: March 13, 2018, 11:03:18 PM »
Cam and governer arm pivot assembly. The center threaded portion is offset about 50 thou  from the larger shaft to allow the gear lash to be adjusted. The pivot on the left was hogged from a piece of round stock.

Offline Myrickman

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Re: Myrick Eclipse one-third scale model part two
« Reply #29 on: March 13, 2018, 11:24:57 PM »
To pour the bearings, I made a tee-shaped rig to align the bore perpendicular to the axis of the crankshaft. The saddles are spot drilled to hold the Babbitt and shims inserted under the caps and everything smoked with a candle. A sleeve the ID/OD of the saddle and shaft is inserted in the side opposite the pour to assure alignment. My old school Johnson forge melts the bearing alloy. I preheat the pour area to about 250F; spit sizzle or hand held IR pyrometer... The whole affair is repeated on the other side but using the poured bearing in place of the sleeve. Finished results are shown sans oil swipes and holes.

 

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