Author Topic: 1st I.C. build "Tiny"  (Read 51359 times)

Offline 90LX_Notch

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Re: 1st I.C. build "Tiny"
« Reply #30 on: March 16, 2017, 07:53:50 PM »
Thanks for folowing along Rudy.

Thanks Carl. The picture is a little distorted and shows a radius that does not exist at the transition from the valve pocket diameter to the 45 degree angle. 



Head continued:

To locate the ports a .136 pin was inserted in the valve pocket.  The pin was then pickedup with the edge finder and the center of the pocket was zeroed.  From there the mill was stepped of to the hole location.  This was straight forward for the intake because it is located off of the flat on the head.  The exhaust was a bit more difficult.  It is at an unspecified angle which I determined to be 45 degrees.  The little sine bar was used.  It is wider then the head so I used a trick that I picked up from Joe Pie's YouTube channel.  Two parallels were set with a spring inbetween them and a "bridge" was made from a third.  The "bridge is what applies the clamping force to part.

There was a lot going on for the setup as the pictures show: sine bar, vise stop, parallels, spring and the "bridge".

-Bob
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Offline b.lindsey

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Re: 1st I.C. build "Tiny"
« Reply #31 on: March 16, 2017, 08:22:37 PM »
Guess I need to get to work on my head, you guys are giving me some useful ideas though.

Bill

Offline crueby

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Re: 1st I.C. build "Tiny"
« Reply #32 on: March 16, 2017, 08:53:08 PM »
You guys need to get together when the engines are done, get some couplers made to tie the cranks together in a line, and make a multi-cylinder Tiny!

Awesome stuff, all you guys!

 :popcorn:

Offline 90LX_Notch

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Re: 1st I.C. build "Tiny"
« Reply #33 on: March 18, 2017, 02:20:47 AM »
Bill the head isn't as bad as it seems.

That would be neat Chris.


Valves:

The valves were turned and cross drilled.  To make drilling small rods/shafts easier I setup scrap aluminum and mill it flat.  Then I drill and tap a hole for a hold down clamp.  Next I make a V groove using a center drill as a cutter.  The part is then layed in the groove and clamped securely, this guarantees alignment.  Then the hole is located and drilled.  I use scraps of plastic gift cards as packing.  That is what the green object is in the picture..

The valves were lightly lapped in the head.  The dark ring on the valve shows a good pattern and location.

A test fixture was made out of 1" aluminumn bar.  An adapter was also made that screws into the head.  It allows vaccuum or compressed air to be used for testing the head.

-Bob
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Offline steamer

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Re: 1st I.C. build "Tiny"
« Reply #34 on: March 18, 2017, 11:25:42 AM »
I really like the fact that your testing that!.....Hmmmmmm   

And to Bob's point, no the head isn't as bad as it seems.   The valves themselves were more challenging I thought.

Dave
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Offline 90LX_Notch

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Re: 1st I.C. build "Tiny"
« Reply #35 on: March 20, 2017, 01:25:20 PM »
Thanks Dave.  It's the only way that I can verify if I am even close.


Springs and Keepers:

The springs were wound using .014 wire.  I played around with different mandrels and pitches.  In the end I  believe that I am close.  My spring works. It opens the valve at less than 10 in/mg.  However, thanks to George's post in Dave's thread, I am going to get thinner wire and make a lighter intake spring.
 
The keepers are basic turning.  The pins are .029 music wire by .125 long.  To get the .125 length, the pins are held in a pinvise and gently sanded down.

-Bob
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Offline b.lindsey

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Re: 1st I.C. build "Tiny"
« Reply #36 on: March 20, 2017, 02:23:09 PM »
Bob, the springs look really good, but you may be right, the intake may be a bit stiff. I also like the chamfer you put on the top of the keepers, that looks nice!!

Bill

Offline Don1966

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Re: 1st I.C. build "Tiny"
« Reply #37 on: March 20, 2017, 03:44:01 PM »
Geeez Bob, I been behind following everyone buddy but just caught up on your's. Some nice work bud and will try to stay up now.

Don

Offline gbritnell

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Re: 1st I.C. build "Tiny"
« Reply #38 on: March 20, 2017, 04:17:37 PM »
Bob, the problem with the same size springs is first of all say they were light enough for the vacuum in the cylinder to open the intake, well then it would also open the exhaust. I don't really know if there's any kind of ratio but I always make the intake spring just heavy enough to close the valve efficiently.
gbritnell
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Offline 90LX_Notch

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Re: 1st I.C. build "Tiny"
« Reply #39 on: March 20, 2017, 04:53:19 PM »
Thanks Bill.  The keeper actually has a radius, not a chamfer.  I thought it would make for a nice detail.

Great to have you along Don.

George, you correct and thank you for your input.  However, the springs are not the same.  I played with different mandrels and pitches that resulted with different rate springs.  This was the big reason that I made the test fixture.  I made sure that the exhaust spring did not open when vaccuum was applied through the spark plug hole.  That being said, I do need to get my hands on some .009 wire and make a lighter spring.

-Bob
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Offline 90LX_Notch

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Re: 1st I.C. build "Tiny"
« Reply #40 on: March 20, 2017, 05:09:36 PM »
Follower:

I took a different approach in making the follower.  I decided to carve it out of a piece of 1" round stock.  The stock was offset in the lathe and the .156 hole was drilled and reamed.  The .015 step was also turned at that time.

Next the stock was placed in a Vblock and setup on the rotary table.  The .156 hole was indicated and the first side was milled followed by the second side. 

The part calls for a .062 radius so a D-Bit was was made.  I did sink a pilot hole with a .040 center drill just to play it safe.  The cutter in the end did work.  I did shoot a video with my IPad and posted it to YouTube of the cutter working.  Unfortunately, the IPad is unable to zoom in tight.


-Bob
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My Engine Videos on YouTube-
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Offline b.lindsey

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Re: 1st I.C. build "Tiny"
« Reply #41 on: March 20, 2017, 05:22:05 PM »
That follower looks fantastic Bob. You are moving right along and its nice to see different ways of getting to the same end result.

Bill

Offline 90LX_Notch

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Re: 1st I.C. build "Tiny"
« Reply #42 on: March 20, 2017, 11:50:29 PM »
Thanks Bill.  Not really moving along, just getting all the pictures into the thread.  Soon I will be caught up and then my snail's pace will become evident.


Follower Bolt:

Nothing really special involved with the bolt so I only have a picture of the finished part.


-Bob
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My Engine Videos on YouTube-
http://www.youtube.com/user/Notch90usa/videos

Offline Dave Otto

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Re: 1st I.C. build "Tiny"
« Reply #43 on: March 21, 2017, 12:07:57 AM »
Nicely done Bob!
The follower turned out great.

I'm enjoying following along with all three of the Tiny builds.


Dave

Offline Tennessee Whiskey

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Re: 1st I.C. build "Tiny"
« Reply #44 on: March 21, 2017, 12:13:53 AM »
I was thinking just what Dave said. Really nice Bob. Is that a piece of step tread from a doll house the bolt is laying on? :Jester:

Eric