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Author Topic: Milwaukee Midget  (Read 2259217 times)

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Offline TheBaron

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Re: Milwaukee Midget
« Reply #5730 on: March 18, 2016, 11:30:08 AM »
What alloy of aluminum do you like for casting cylinder heads,,, or billet alloy for C&C machining heads ???

Thinking I might try casting some heads for a small 175cc motorcycle..

Robert
Baron Race Team

Offline fordboy628

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Re: Milwaukee Midget
« Reply #5731 on: March 18, 2016, 12:30:40 PM »
What alloy of aluminum do you like for casting cylinder heads,,, or billet alloy for C&C machining heads ???

Thinking I might try casting some heads for a small 175cc motorcycle..

Robert
Baron Race Team

For casting:  A356, heat treated to T6 prior to machining.    British/English equivalent:  LM25, also heat treat to T6.

For billet:  2024 or 7075, both heat treated and normalized before machining.   You might also try 2038, a newer and more expensive alloy.

Depending on complexity of the part, billet might be the way to go.    CNC places do not like any of the "hard" aluminum alloys.    Lots of tool wear from the silicon, even with carbide tooling.

Hope you have a friend with a CNC machining center . . . . . .

 :cheers:
Fordboy
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"Only two things are infinite, the universe and human stupidity, and I'm not sure about the former."     Albert Einstein

Offline fordboy628

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Re: Milwaukee Midget
« Reply #5732 on: March 18, 2016, 05:54:49 PM »
midget,

Just poured the cast of the combustion chamber.    6 hour cure time for the mold.   Photos later.

 :cheers:
Fordboy

midget,

As promised:

Chamber coated with release agent and surrounded by 'clay' to contain molding compound.



Silicone rubber compound, mixed 1 to 1 by volume.    What a lovely mess . . . . . .



Sorry, no pics of the pour process, not enough hands . . . . . . .   :cry:


A slow, drizzle pour removes most of the air bubbles.    The compound is quite liquid, but I poured from the low spot, allowing the liquid to fill all the nooks and crannies while depleting more of the trapped air bubbles.



Five minutes in, the bubbles are starting to ease up.



8 hours later, the completed cast.


Intake side view.


Exhaust side view.



The casting quality is excellent and the part appears to be hard enough to digitize.   The mold released well, but there was a little sticking on the head surface where the release agent was a bit thin.    You MUST use a release agent with this material.    I suspect it might be a great "bonding agent" without the mold release liquid.

Since the standard dome volume of the Wossner piston for the application does not provide enough compression ratio, it is necessary to provide either a print of what we want or this type of combustion chamber mold so Wossner can determine if they can bump the dome volume up to what we require.  They can "overlay" this digitized mold onto their digital dome model, and then the rest is just design and math.

If I get ambitious (?) I might mold a Cosworth BDD chamber just to show the detail differences.   This early Rover design has more surface area than needed, especially compared to Cosworth "style" designs.   The "ends" are very vertical due to the valve centerline spacing, trapping extra volume and lowering the compression ratio.

Oh, wait.     I guess the "crappy" Rover design could be better than the BMC . . . . . . . .    :roll:

This casting was made with OOMOO 30 Tin-Cure Silicone Rubber from Smooth-On Products.   The 2.8 pound sample size is large enough for several castings.

 :cheers:
Fordboy
« Last Edit: March 18, 2016, 06:01:50 PM by fordboy628 »
Science, NOT Magic . . . .

I used to be a people person.  But people changed that relationship.

"There is nothing permanent except change."    Heraclitus

"Only two things are infinite, the universe and human stupidity, and I'm not sure about the former."     Albert Einstein

Offline manta22

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Re: Milwaukee Midget
« Reply #5733 on: March 18, 2016, 05:58:10 PM »
Nice detail in that casting.

Regards, Neil  Tucson, AZ
Regards, Neil  Tucson, AZ

Offline RichFox

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Re: Milwaukee Midget
« Reply #5734 on: March 18, 2016, 06:48:52 PM »
i used Cerrobend 156 to cast my combustion chamber. About $25 worth was more than enough. Melts at 156 degrees. It's as hard as lead at least. And you can melt it again and use it over if you want. If you need your pattern to give a litttle to remove it, I don't think Cerrobend would be a good choice.

Offline Crackerman

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Re: Milwaukee Midget
« Reply #5735 on: March 18, 2016, 10:49:56 PM »
could you fill the vertical ends with weld to fill the chambers a bit, without shrouding valves excessively?

Offline Milwaukee Midget

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Re: Milwaukee Midget
« Reply #5736 on: March 19, 2016, 02:02:04 AM »
Wow - really nice cast, Mark!  :cheers:

could you fill the vertical ends with weld to fill the chambers a bit, without shrouding valves excessively?

Probably, but if we can achieve ~ 14:1 CR without resorting to welding on a head that's tough to come by in the States, I'd prefer to go that route.

In other news, despite the Michigan State Charlatans (beaten twice by Iowa during the regular season), and the Purdue Boilermakers (the greatest non-credited bartending school in the Midwest) dropping games to a pair of Southern community junior colleges, my brackets are in remarkable shape!

I actually picked Yale and S. F. Austin, and in the first round, came away with 25 winners.  I've never had a first round go that well.

The one that really hurt, though, was the Arizona loss.  

I miss Lute Olson, but I'm cheering for North Carolina.
"Problems are almost always a sign of progress."  Harold Bettes
Well, I guess we're making a LOT of progress . . .  :roll:

We are NOT rebuilding . . . We are reloading.

GOD SAVE MG - The Queen can take care of herself!

Offline fordboy628

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Re: Milwaukee Midget
« Reply #5737 on: March 19, 2016, 05:26:21 AM »
could you fill the vertical ends with weld to fill the chambers a bit, without shrouding valves excessively?

Probably, but if we can achieve ~ 14:1 CR without resorting to welding on a head that's tough to come by in the States, I'd prefer to go that route.


These head castings are so thin, AND, the cam bearing races are integrated into the top of the head, so I'm afraid that any welding will precipitate a "cascading nightmare" of re-machining.

Now it isn't like I haven't welded any alloy heads before, because I have.    I've repaired dozens of Cosworth and Lotus TwinCam heads over the decades.    Heavy welding, like combustion chamber filling, usually distorts the head to some degree, requiring re-machining of some areas.    Cosworth BDs, with their separate cam carrier are easier to re-machine.    Lotus heads on the other hand, with cams running in the head, typically require cam bore align-boring, a real pain in the a**.      This Rover piece of cheese promises to bring new meaning to the phrase: pain in the a**.    I'd prefer to not become aware of any of these "Secrets of the Welded Cylinder Head Rover Racing Engine", especially if the compression ratio can be achieved with a bigger dome on what will be a custom piston anyway.   That process is just more efficient.

What I might do though, is add bondo or clay to the ends of the combustion chamber and run another flow test.    That will answer the question about the flow.

 :cheers:
Fordboy
Science, NOT Magic . . . .

I used to be a people person.  But people changed that relationship.

"There is nothing permanent except change."    Heraclitus

"Only two things are infinite, the universe and human stupidity, and I'm not sure about the former."     Albert Einstein

Offline fordboy628

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Re: Milwaukee Midget
« Reply #5738 on: March 19, 2016, 05:30:22 AM »

Wow - really nice cast, Mark!  :cheers:


Thanks!     I consulted with the "Banger Sisters" about what product to use to get the "best details" . . . . . . .    :-o

 :cheers:
FormerRocknRollboy
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I used to be a people person.  But people changed that relationship.

"There is nothing permanent except change."    Heraclitus

"Only two things are infinite, the universe and human stupidity, and I'm not sure about the former."     Albert Einstein

Offline fordboy628

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Re: Milwaukee Midget
« Reply #5739 on: March 19, 2016, 05:38:32 AM »
In other news, despite the Michigan State Charlatans (beaten twice by Iowa during the regular season), and the Purdue Boilermakers (the greatest non-credited bartending school in the Midwest) dropping games to a pair of Southern community junior colleges, my brackets are in remarkable shape!

I actually picked Yale and S. F. Austin, and in the first round, came away with 25 winners.  I've never had a first round go that well.

The one that really hurt, though, was the Arizona loss.  

I miss Lute Olson, but I'm cheering for North Carolina.

College basketball?    Brackets?    BORING!!!

In other news, the Australian Gran Prix starts the 2016 F1 season tonight.   Check your cable/whatever listings.

 :cheers:
F1fanboy
« Last Edit: March 19, 2016, 05:43:50 AM by fordboy628 »
Science, NOT Magic . . . .

I used to be a people person.  But people changed that relationship.

"There is nothing permanent except change."    Heraclitus

"Only two things are infinite, the universe and human stupidity, and I'm not sure about the former."     Albert Einstein

Offline Stainless1

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Re: Milwaukee Midget
« Reply #5740 on: March 19, 2016, 09:07:24 AM »
Midget, I coulda told you to pick Wichita State over Arizona.... but then it mighta gone the other way...
SFA busted more brackets than any other game  :cheers:
Stainless
Red Hat 228.039, 2001, 65ci, MSA Bockscar Lakester with a little N20 
MSA Bockscar Lakester #1000 my fastest mile 245 and change, 84 ci turbobusa motor... but Corey's 233 MPH H/BFL record is still 3MPH faster than mine.

Offline Elmo Rodge

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Re: Milwaukee Midget
« Reply #5741 on: March 19, 2016, 09:09:51 AM »
Fordboy, I thought the Vanwalls would do better.  :-P  :cheers: Wayno

Offline Milwaukee Midget

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Re: Milwaukee Midget
« Reply #5742 on: March 19, 2016, 10:01:37 AM »

In other news, the Australian Gran Prix starts the 2016 F1 season tonight.   Check your cable/whatever listings.

 :cheers:
F1fanboy

If I want to watch a professional sporting event run by mobsters, I'll tune in soccer . . .
"Problems are almost always a sign of progress."  Harold Bettes
Well, I guess we're making a LOT of progress . . .  :roll:

We are NOT rebuilding . . . We are reloading.

GOD SAVE MG - The Queen can take care of herself!

Offline Elmo Rodge

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Re: Milwaukee Midget
« Reply #5743 on: March 19, 2016, 11:11:40 AM »

In other news, the Australian Gran Prix starts the 2016 F1 season tonight.   Check your cable/whatever listings.

 :cheers:
F1fanboy

If I want to watch a professional sporting event run by mobsters, I'll tune in soccer . . .
That's 'cause they almost never score so as to distract you from the beer.  :-D  :cheers: Wayno

Offline fordboy628

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Re: Milwaukee Midget
« Reply #5744 on: March 21, 2016, 08:09:25 AM »
midget,

When do you want to send the chamber casting to Wossner?

I'm thinking I make at least one additional cast to section & keep for reference.

Your thoughts?

 :cheers:
Fordboy
Science, NOT Magic . . . .

I used to be a people person.  But people changed that relationship.

"There is nothing permanent except change."    Heraclitus

"Only two things are infinite, the universe and human stupidity, and I'm not sure about the former."     Albert Einstein