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Heat Riser

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samcj2a View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote samcj2a Quote  Post ReplyReply Direct Link To This Post Posted: 10 Sep. 2009 at 1:16am
Originally posted by westforkboyd westforkboyd wrote:

. . . . As the engine warmes the bi-metal spring unwinds driving the counterweight up and closes the flap. Now the intake is not getting direct exhaust heat. . . .
Allen, I think that the only thing that you have wrong is saying that as the engine warms, the spring unwinds.   I believe that as it warms, the spring winds tighter, thus raising the counterweight.   If you are looking at the end of the shaft from the front of the Jeep, the shaft must turn counter-clockwise to raise the counterweight.  That means the spring is getting tighter - not unwinding.

With my '46, the slot in the shaft is parallel to the arm of the counterweight as the G drawing shows it and as yours is positioned in your photo.  Also, when the engine is cold and the counterweight is down, there is no tension in the spring.   If I raise the counterweight by hand the least bit, the spring is lifted off the stop.

Does all this make sense to you?
Sam

1946 CJ2A   15292 ACM    6678

1947 CJ2A 122031 ACM 111989

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Post Options Post Options   Thanks (0) Thanks(0)   Quote westforkboyd Quote  Post ReplyReply Direct Link To This Post Posted: 10 Sep. 2009 at 1:49am
Sam
 
We'll have to talk this out over a few bottles of wine or something in a couple weeks. My thinking is if the spring contracts or winds tighter the coil would get smaller and pull away more from the stop completly not moving the counter weight at all. It has to expand when hot and in effect unwind making the coil larger, pushing against the stop therfore driving the counterweight up. Now the effect of the bimetal coil is in there too. It was interesting when cleaning up that coil a bit I could see the mating line of the two metals. They are both very thin and plyable. Its cool how in the old days they incorporated very basic physics into their designs using simple materials. Now days its all computers and electronics. Now how this plays out wind or unwind will have to be debated.
 
There now........ we have something to disagree on...... Finally.
 
Allen
'48 CJ-2A #184135 Lefty
'49 CJ-2A #219719 Mule
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Post Options Post Options   Thanks (0) Thanks(0)   Quote samcj2a Quote  Post ReplyReply Direct Link To This Post Posted: 10 Sep. 2009 at 1:58am
Originally posted by westforkboyd westforkboyd wrote:

Sam  . . . . 
 
There now........ we have something to disagree on...... Finally . . . .
Allen
  LOLLOLLOL

I like the wine idea!

Think about it this way.  When the engine is cold and you lift the counterweight as the spring would lift it, the spring lifts off of the stop.  If the spring were doing the lifting, the spring would still be in contact with the stop and would have to have been wound clockwise or tighter to do so.
Sam

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Post Options Post Options   Thanks (0) Thanks(0)   Quote lowenuf Quote  Post ReplyReply Direct Link To This Post Posted: 10 Sep. 2009 at 2:15am
Sam, your above summation is correct :)  
 
with the shaft "slit" is this position ---> "\", the weight is indexed in the closed position (down position).....
 
with the shaft "slit" in this position ---> "--", the weight is indexed open, with the weight in the up position...
 
i just checked on my open manifold.....
 
so, if you can visualize looking at the cross section from the front end of the shaft, the interior plate is closed with the plate at 2 (upper end) and 7 o'clock (lower end), or thereabouts...and open the plate is reoughl;y noon (upper end) and 6 o'clock (lower end), maybe even 11 and 5...
 
 
45 #10012
45 #10033 ACM #47
45 #10163 ACM #188
57 CJ5    Dauntless V6, T-18 4-speed, D-44 rear/D-30 front, D-20 twin stick



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Post Options Post Options   Thanks (0) Thanks(0)   Quote woodshopguy Quote  Post ReplyReply Direct Link To This Post Posted: 10 Sep. 2009 at 2:25am
Has anyone thought about assembling it one way, putting a little propane heat to it to see what happens? I'd do it, but I just got my bolted back on with the carb and linkage . . . . next time I have it apart I'll try it and take some video . . .

-Doug.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote samcj2a Quote  Post ReplyReply Direct Link To This Post Posted: 10 Sep. 2009 at 2:36am
It's easier to just warm up the engine.  Wink
Sam

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Post Options Post Options   Thanks (0) Thanks(0)   Quote westforkboyd Quote  Post ReplyReply Direct Link To This Post Posted: 10 Sep. 2009 at 2:49am
Geesh how could this be? But after looking at the photos and reading yours and Lows explanation it does have to be winding tighter to move the flap to the closed position. I don't understand how heat contracts something though. There must be something with the bimetals response to heat that causes this seeming incongruity. Duhhhhh I tawt I thaw a puddy tat.
 
Do I have that together correcty? I might put the torch to it tomorrow and watch. I have it all together but know the orientation of the flap in relation to the weight. Ya think all I need to do is change the wording in the caption? Maybe Sean (he always has the answer) or any other member can splain what's happening with the bimetal to cause it to wind rather than unwind.
 
I think in that link Rod posted to the G the poster says unwind also. But Sam I now think you are correct it must wind....If I have it together right that is.
 
Allen
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Post Options Post Options   Thanks (0) Thanks(0)   Quote samcj2a Quote  Post ReplyReply Direct Link To This Post Posted: 10 Sep. 2009 at 3:02am
Allen,

The bimetallic spring is made of two [duh] layers of different metals.   One metal expands and contracts with changes in temperature at a greater rate than the other.  If the one that expands quicker is on the outside of the curved spring, the spring will get tighter as it warms up because the arc will assume a slightly smaller radius as the metals warm up.

Edit: Conversely, if the metal that expands at a more rapid rate is on the inside of the coiled spring, then the spring would unwind as it is heated because the inside layer would tend to straighten out the curve or arcs of the spring.


Edited by samcj2a - 10 Sep. 2009 at 3:14am
Sam

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Post Options Post Options   Thanks (0) Thanks(0)   Quote samcj2a Quote  Post ReplyReply Direct Link To This Post Posted: 10 Sep. 2009 at 3:07am
Allen,

I looked at that thread on the G again.  One of the posters asks if warming the spring will wind or unwind the spring.  Tony Norton responded that warming the spring would cause the spring to wind tighter so I think that thread on the G is correct in both the drawing and the explanation.
Sam

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Post Options Post Options   Thanks (0) Thanks(0)   Quote sean Quote  Post ReplyReply Direct Link To This Post Posted: 10 Sep. 2009 at 3:26am
Allen, your assembly & photos are correct.

NOS:






Edited by sean - 10 Sep. 2009 at 3:49am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote tony Quote  Post ReplyReply Direct Link To This Post Posted: 10 Sep. 2009 at 3:31am
Way to go Allen......ClapClapClap  i didnt think you would give in Approve
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Post Options Post Options   Thanks (0) Thanks(0)   Quote samcj2a Quote  Post ReplyReply Direct Link To This Post Posted: 10 Sep. 2009 at 3:36am
Sean,

Are you agreeing with his original post that the spring unwinds when it warms up?   That's the only part we were thrashing about.
Sam

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Post Options Post Options   Thanks (0) Thanks(0)   Quote sean Quote  Post ReplyReply Direct Link To This Post Posted: 10 Sep. 2009 at 3:48am
Sam:

No, I'm saying his assembly instructions & part orientations are correct.  There was dispute about the assembly too.  If assembled as shown, it works.

The spring winds up, as you rightly pointed out.

I'll edit the post for clarity Big smile
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Solar Quote  Post ReplyReply Direct Link To This Post Posted: 10 Sep. 2009 at 7:20am
I have a new spring from my kit that I put into the oven, then after it was hot, I slid it into a pan of ice water to watch the reaction.

The spring TIGHTENS COUNTER-CLOCKWISE when heated with the spring end  facing to the right, looking towards the back of the jeep and the spring winding COUNTER-CLOCKWISE.

If it is flipped upside down, so the winding is CLOCKWISE, then the Spring winds CLOCKWISE when heated.

That means the spring end should be positioned UNDER the stop?

Reading an earlier post, it appears not though. I think I see how it being on the top would work.

This is my understanding. Comments?




Edited by Solar - 10 Sep. 2009 at 7:36am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Solar Quote  Post ReplyReply Direct Link To This Post Posted: 10 Sep. 2009 at 11:26am
Ok, I am agreeing with the notion that only the winding versus unwinding issue was wrong with the initial post. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote samcj2a Quote  Post ReplyReply Direct Link To This Post Posted: 10 Sep. 2009 at 1:21pm
Originally posted by Solar Solar wrote:

. . . .  the spring end should be positioned UNDER the stop?

Reading an earlier post, it appears not though. I think I see how it being on the top would work.

This is my understanding. Comments?


The spring should rest on top of the stop.  If it were under the stop, the spring would simply be wound tighter as it warmed, but it would not lift the counterweight.  

(It was not clear to me whether or not you were still looking for comments.  I'm mainly motivated to see that the information in the thread is as clear as possible to future readers.)
Sam

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Solar Quote  Post ReplyReply Direct Link To This Post Posted: 10 Sep. 2009 at 1:31pm
I was originally looking for comments, but then realized what the earlier threads were saying regarding operation. I went into the project thinking that the spring unwound and having the stop on top made no sense to me. Just trying to clear things up. Thanks for the info and correcting the post.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote russnj Quote  Post ReplyReply Direct Link To This Post Posted: 10 Sep. 2009 at 2:19pm
check this post again!

http://www.g503.com/forums/viewtopic.php?p=433014#p433014


Edited by russnj - 10 Sep. 2009 at 2:20pm

43 MB, 48 CJ2A, 50 CJ3A, 55 M38A1, 56 CJ5, 79 M151A2, M100 ,65 M416
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