raym/rupinow vert hit & miss

[el gringo]

I was looking at the "weight" drawing and it is difficult for me to discern the actual lines of the part from the dimensional lines... is it possible to ask the computer to define the lines of one or the other on the drawing ?
Ray M

 

[Brian Rupnow]

Ray--Maybe this will help.---Brian

 

[el gringo]

Thanks!
Ray M

 

[el gringo]

Hi Brian,

There is a .063 hole in the cyl head and a matching one in the upper bracket, what are they for?
RAy M

 

[Brian Rupnow]

They were in there mainly for set-up. I put an 0.063" pin in there to hold everything in correct alignment before I drilled the holes in the bracket and cylinder. The hole really doesn't have anything to do with the function of the engine.--Brian

 

[el gringo]

They were in there mainly for set-up. I put an 0.063" pin in there to hold everything in correct alignment before I drilled the holes in the bracket and cylinder. The hole really doesn't have anything to do with the function of the engine.--Brian

good idea!! I'll do that when I get there.
Ray M

 

[el gringo]

upper bracket... kind of a tetchy part for me to make.

in a vise on the mill

in the vise on the mill... the vise turned 30degrees on the mill bed to pick up the angles

in the rotary table on the mill

please holler if any questions
Ray M

 

[Brian Rupnow]

Good looking parts Ray. That bracket is a good example of something made for "pretty". It could have been a lot simpler, but it wouldn't have looked nearly as nice.---Brian

 

[el gringo]

Good looking parts Ray. That bracket is a good example of something made for "pretty". It could have been a lot simpler, but it wouldn't have looked nearly as nice.---Brian

yes, truly a case where form doesn't follow function. I suppose the question of form and /or function must have come up often for a design engineer due to possible cost
implications.
One of my favorite examples of a 'form and function' design is my old Southbend 9 inch model 'a' lathe.
Ray M

 

[el gringo]

cylinder head

parting off a valve cage

an old photo showing how I used VSR to grind in the valves to the cage...
Ray M

 

[Johno1958]

Your making some good progress Ray. I also when I get to it am going to have a go at making the rings which I have never done .
I have been saving a little bit of cast iron I have left over from another job that I got from Germany for making some rings as it seems
a better quality than what I have sourced locally of ebay.
Cheers
John

 

[el gringo]

I think I will make rings next... will try to Make a somewhat detailed show and tell as to the way I make them... I use some of these instructions as a help.
http://jerry-howell.com/PistonRings.html

I usually slice off more'n I need "allow for breakage"

Ray M

 

[Johno1958]

Good stuff. I'll be watching
John

 

[el gringo]

Looks like I have ~ 4.72:1 Compression Ratio with >.032 gaskets @ top and bottom of cyl. Am wondering how that compares with the original?
Looks like I can increase to ~5.5:1 by using .010 and .016 thick gaskets top and bottom...Also wondering what would be minimum CR for this engine to run properly?

Ray M

 

[Brian Rupnow]

Ray--I used .031" thick gasket under the cylinder and under the cylinder head. Engine ran just fine with that. I am not sure what you mean by minimum CR. I don't know what CR is.---Brian

 

[el gringo]

Sorry Brian, here is a definition...
https://en.wikipedia.org/wiki/Compression_ratio

Do you have a feel for what the compression ratio is on your engine, possibly in your design notes?, or by checking the distance from top of piston @ TDC to cylinder deck with your computer aided design criteria or direct measurement?
Can anyone suggest a low end Compression Ratio on this type of engine?
I am wondering if I have made a mistake in dimensions and should possibly re-make some parts before continuing... looks like I can increase the CR to ~5.5:1 by decreasing gasket thickness to .o12 if need be.
Thanks
Ray M

 

[Brian Rupnow]

Ray--For this type of engine compression ratio only needs to be 3.5:1 up to 5:1 The higher the compression ratio is, the less chance the engine will have of restarting after a series of misses. I believe the compression ratio of my engine is 4.5:1.--Brian

 

[el gringo]

Thank you Brian... looks like my 4.7:1 is in line with yours, I didn't need to create a cavity in the head because of the type of spark plug used. I might use a .010 gasket on top cyl in order to increase the CR to 5:1.
Raym

 

[el gringo]

RINGS

the blank finished to ID&OD of rings

making spares

breaking for the gap

loaded on the heat treating fixture

to be continued...

 

[el gringo]

RINGS... continued


heating with acetylene torch without direct flame contact with the rings

'bout the color of a robins breast

cleaning up the rough edges prior to final fit in the cyl (.003" gap)

after de-burr and cleanup

installed on piston

cyl wall after thirty minute test run-in using external motor power

Ray M