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Author Topic: Milwaukee Midget  (Read 1985949 times)

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Offline forker

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Re: Milwaukee Midget
« Reply #6780 on: February 08, 2018, 09:19:32 AM »
For the nub-end of that; JLR. The Rover company as-was is now Chinese. I'm in Powertrain certification.

Offline jacksoni

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Re: Milwaukee Midget
« Reply #6781 on: February 08, 2018, 09:25:50 AM »
The rod small end in post 6749 is blue.  Something bad is happening there.

There might be some distinct advantages to using a steel or ti H-beam rod where the troughs between the flanges direct lube up to oil holes for the pin that are at the upper ends of troughs, at 4:30 and 7:30 clock positions.  Like Carrillo does. 
H beam strength vs I beam strength produces nearly as much argument as rod ratio. Seems both have advantages and disadvantages depending on various factors. Carrillo certainly makes good rods, have used them too. My current are Crower I beams and have been happily been going to 10200 going on 10 years now with no stress seen. I don't know about the trough of the beam directing oil as WW suggests. Have seen the oiling holes as he also notes and but have never seen any discussion about how that may be preferable to the perhaps more common top of the small end location as with the ones under discussion here. That I haven't seen it means nothing of course and would be happy to see some discussion pro or con of that design.
Jack Iliff
 G/BGS-250.235 1987
 G/GC- 176.245  2018
 G/GMS-182.144 2019

Offline WOODY@DDLLC

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Re: Milwaukee Midget
« Reply #6782 on: February 08, 2018, 09:30:14 AM »
All models are wrong, but some are useful! G.E. Box (1967) www.designdreams.biz

Offline Milwaukee Midget

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Re: Milwaukee Midget
« Reply #6783 on: February 08, 2018, 09:35:05 AM »
For the nub-end of that; JLR. The Rover company as-was is now Chinese. I'm in Powertrain certification.

Welcome aboard!  :cheers:

If you see us doing something way out of line or non-conforming, please don't inform the authorities in Changshu . . . or Brussels.  :wink:
"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 forker

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Re: Milwaukee Midget
« Reply #6784 on: February 08, 2018, 09:36:36 AM »
hehe. Thanks!

Brussels might not be an issue in a few months, though....

F

Offline jacksoni

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Re: Milwaukee Midget
« Reply #6785 on: February 08, 2018, 09:52:35 AM »
Great article Woody. Thanks. Does talk a bit about the I beam/H beam debate, oil slinging as WW mentioned and also about rod bolts and stretch etc that was a subject of discussion here a while back.
Jack Iliff
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Offline fordboy628

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Re: Milwaukee Midget
« Reply #6786 on: February 09, 2018, 01:33:44 PM »
As the Connecting Rod Turns,  episode 2 . . . . . . .






The 3mm hole shown in the left view is, in fact, the oil hole at the top of the rod.  The two small curves at the bottom of the rod cap in the front view are apparently just an indication of a curved surface there.  The alleged centering hole appears nowhere else in the drawing.  If the 74.8 mm dimension is indeed intended to indicate a cylindrical feature, it is not properly so presented.  Also, that area in the isometric view is shown as a flat along the split line.
Saenz may know what they’re doing, but that is not what the print says.




Shows 74.8 across the flats big end, into a 75mm bore!!?? Like IO says.
 


After haranguing others about  "properly" interpreting graphical information, I am also guilty of the same crime . . . . . . .

Mea culpa, mea culpa, mea maxima culpa . . . . .


I've scanned and posted the print, as a jpeg photo above.    And, as IO, jacksoni, and others have pointed out, the "print" does not depict what is required.

My error in quickly reviewing the drawing, (problematic in itself), was "assuming" the print's views were conventionally placed.    Even though it is clearly labeled "left view", and should be on the left, it has been placed on the right hand side of the top, front, and section views, which are properly centered and aligned.     As such, there is no "center hole" for turning the big end to 74.8mm radial diameter.    And even if this process is intended, it is NOT called out on the drawing, as others have noted.     The hole shown, is actually the pin end oiling hole, as IO correctly points out.     I should have been more thorough in my inspection of the drawing, for instance, cross checking the isometric view, as IO did.

Now it might be convention and common practice to radially machine the big ends of con rods intended for small bore sizes, say less than 3-1/4" diameter bore size.     But since it not on the drawing, it is unclear as to whether this will be done.   And, there are other issues, bolt dimensions, locating sleeve dimensions, etc, pointed out by others.

It would be prudent for all of the issues to be cleared up, before approval of the "print".     And there is good reason to do so.

The convention in industry is that if a client approves or supplies a print, then the following conditions apply:

A/     If the part does not match the print, then the manufacturer is responsible.

2/     If the part matches the print, but doesn't work, the client is responsible.

If nothing else, being particular about the print, shows the manufacturer that the client is serious about the manufacturing and fitting process.

Again, JMHO . . . . .

 :dhorse:  :dhorse:  :dhorse:
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Offline fordboy628

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Re: Milwaukee Midget
« Reply #6787 on: February 09, 2018, 01:41:59 PM »

The rod small end in post 6749 is blue.  Something bad is happening there.

There might be some distinct advantages to using a steel or ti H-beam rod where the troughs between the flanges direct lube up to oil holes for the pin that are at the upper ends of troughs, at 4:30 and 7:30 clock positions.  Like Carrillo does. 
 

Bo,

I'm impressed by how observant you are.    But no, nothing bad is going on there.    It is a con rod where the piston pin is press fit into the rod.    To ease the fitment process, the pin end of the rod is heated "blue", to expand the pin eye to a "slip fit".    When the rod cools, the requisite press fit is obtained, with no installation stress imposed on the piston.

 :cheers:
F/b
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 #6788 on: February 09, 2018, 02:11:18 PM »

H beam strength vs I beam strength produces nearly as much argument as rod ratio. Seems both have advantages and disadvantages depending on various factors. Carrillo certainly makes good rods, have used them too. My current are Crower I beams and have been happily been going to 10200 going on 10 years now with no stress seen. I don't know about the trough of the beam directing oil as WW suggests. Have seen the oiling holes as he also notes and but have never seen any discussion about how that may be preferable to the perhaps more common top of the small end location as with the ones under discussion here. That I haven't seen it means nothing of course and would be happy to see some discussion pro or con of that design.
 

I've used both I beam & H beam rods, and they both work.    When a forged rod is the choice, you have to go I beam, as that is what is manufacturing friendly.     The H beam design might be somewhat less weight for the same center to center length.    I usually choose based on the rpm range the engine will see.    Lower rpm means a heavier rod is less of a penalty.     And it is the reciprocating weight I'm most concerned about.

Similar deal on pin oiling holes, single top Vs twin bottom, both seem to be effective.    I think ANY oil hole works better than none.     IMO placement is less important than the size of the hole, especially when you realize that the piston pins rotate in the pistons and the rods, spreading the lubricant around.

As far as the trough of the rod "directing" oil somewhere specific, I'm uncertain that happens.    Many moons ago, I was involved in some V8 oil pan research, both wet and dry sump.    The pans were modified for a Lexan "window", so observations could be made.    What was "observed" was a freakin' "typhoon" of oil on the wet sump.     The dry sump, (an early, undersized one), merely had a "tornado" of oil . . . . . .     The parts that were lubed and cooled by "splash" lubrication, did not seem to be in any danger, in either case.      Late style, high vacuum dry sumps, on the other hand, are a different story.     Without additional oiling, directed where needed, some parts will not survive a "distance" event.

 :cheers:
F/b
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 #6789 on: February 09, 2018, 04:56:01 PM »
The Chronicles of Pistonia . . . . . . I've lost track of what episode this is . . . . .

Combustion Chamber Mold Porn! ! ! !

So you wanna make a hard mold of your combustion chamber?    Starting with a liquid epoxy?     Here are the photos of what I went through . . . . .


I used a Starrett 6" Machinist's Level, cause that's what was available.
And, yes, things need to be level for the "plug" to be even on the deck surface.




It required some "creativity" for the bolt up.












level in both planes












And yes, it took a bit of dicking about to get things "leveled out"




The finished product, intake side



exhaust side




Lateral view







This sucked up pretty much the whole morning on Wednesday.     Had it packed up for UPS pickup Wed afternoon, but the driver did not stop.    By the time I got to the local UPS agent, their daily pickup had already taken place.     So it went out on the Thursday truck.      UPS tracking info shows that severe weather has delayed delivery, but it is in Wyoming, Michigan, so hopefully it will be delivered on Monday.

That's all for today.

 :dhorse:  :dhorse:  :dhorse:
Epoxiedoutboy
« Last Edit: February 09, 2018, 04:58:39 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 #6790 on: February 09, 2018, 05:43:02 PM »
How did you "unscrew" that threaded plug hole? What mold release did you use?

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

Offline Interested Observer

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Re: Milwaukee Midget
« Reply #6791 on: February 09, 2018, 06:20:02 PM »
Regarding rod design---

Probably not an issue, but has anyone checked for rod-to-cylinder liner skirt clearance?

Also, how is it that ARP L19 bolt material got specified?  Having gone to a pretty beefy 3/8” bolt, is there really a need for this quite high-strength and less ductile material which has a propensity for suffering from hydrogen embrittlement?  Seems like one of the lower grades would be perfectly adequate and less worrisome from that aspect.  Also presumably less expensive.

For that matter, given the hardnesses quoted for the rod material, and if the print is being revised, it might be good to get a detail of the bolt head seating area and have generous radii there.  (Granted, this thing isn’t going to Le Mans).

Are they going to be shot peened?

Personal thought on oil holes.  To me, the dual underneath holes just provide great exhaust passages for the oil at the highest loaded location.

Offline Milwaukee Midget

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Re: Milwaukee Midget
« Reply #6792 on: February 09, 2018, 07:00:48 PM »

Also, how is it that ARP L19 bolt material got specified? 

Saenz's "default" bolt. 

I could downgrade it, but I've worked with them before, and I have already made the mistakes - I did overstretch the first set on the Grenade and was oblivious to the handling issues.

But now I've got latex gloves, patience and experience, and they'll be fine.  I don't know that the potential savings of a 2000 ARP over the L19 is worth changing up the order.

If I do it right this time, I should only have to handle them once.
"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 wobblywalrus

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Re: Milwaukee Midget
« Reply #6793 on: February 09, 2018, 10:55:38 PM »
The B/S ratio and photos indicate the cylinders provide a confined area for oil mist access to a hole on the top of the rod for small end lubrication.  What about drilling two holes from the troughs on the sided of the rod up to the small end bearing?  It would be similar to what Carillo does on the front and the back but on the sides.

The concern is the oil slung off of the crank webs will not get up into those narrow cylinders in enough quantity to do the job.  Oil crawling up the rod might be a big help.

Offline fordboy628

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Re: Milwaukee Midget
« Reply #6794 on: February 10, 2018, 04:52:35 AM »

How did you "unscrew" that threaded plug hole? What mold release did you use?

Regards, Neil  Tucson, AZ


Hi Neil,

I did not unscrew the plug threads.    The instructions recommend de-molding after 30 minutes of curing.    The epoxy is still somewhat "flexible" at this point, and can be gently pulled free, set aside and left to harden fully.   It seemed to harden with little distortion from the original shape.

For mold release I used:   Pol-ease 2300 mold release in a spray can     Silicone based and formulated for polyurethane rubber, plastic and epoxy.    The casting released pretty well, even though there were some "complicated areas" of the chamber.

https://www.polytek.com/products/pol-ease-2300-release-agent

 :cheers:
F/b
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