Heat Riser Spring

[athawk11]

Okay, now I'm confused.

I have two heat riser springs.  I heat one of them and it contracts.  I heat the other and it expands.  

The one that contracts was on this Willys when I got it.  The spring that expands was purchased on Ebay with the rest of the heat riser set up and was a take off part.  

The one that expands when heated seems to function right but is smaller (less coils) and does not lift the riser all the way when warm.

My old one could be installed, but the tab that contacts the catch is in the wrong place.  

Questions: Suppose to expand or contract?
                Without breaking the spring, can I bend it to put the catch in the right spot?

Tim

[Bob W]

Check out this video

http://www.youtube.com/watch?v=c5a4AjyGcDg

[Kendog]

Also:

http://www.thecj2apage.com/forums/heat-riser_topic12389.html

[athawk11]

Thanks guys.  
I had spotted the Utube video a while back when I was trying to understand how the heat riser works. That's how I tested mine, (with a torch) once I put it together.

The 2A site discussion makes reference to the springs expanding....and contracting....and I am lucking enough to have both style springs.  

My issue still exists.  I've installed them both and when heating them with a torch, they both expand enough to open the riser all the way.  

Neither spring allows a full open riser when the Willys is warmed up and the supplier of the heat.  It has generally been cold when testing, but I don't know if that makes a difference.

Do I have 2 bad springs?  

Tim

[Carls_jeep]

The exhaust from the engine will blow the flap open even when the engine is cold. The spring only helps to hold it open when it has heated up. From past experience with heat risers I decided to wire mine in the open position so it would never be an issue.

If your a purist about everything being exact to stock and show room correct then use it as is because that's factory correct. In the hot summer time it may stay more open but it still won't hurt anything if it's not wide open.

[aboyandhisdog]

Tim,  don't know if you've seen this but it might give you some insight:

  http://www.1944gpw.com/c-83-G503_WWII_Jeep_Exhaust_Heat_Control_Valve_detailed.aspx

My 2 cents...either there is something blocking the free travel of your flapper (unlikely) or you happened to get 2 bad springs that aren't working properly.  Note step #18 in this link...the spring is supposed to contract according to the author.

[Carls_jeep]

Yes, it will contract and it will never see as much heat as that torch blowing directly on the bi-metal coil. Don't expect it to open the flapper as much with heat from the exhaust manifold as it does with a torch directly on the coil. It just won't happen.

[athawk11]

Looks like Army Jeep Parts has new Bimetal springs.  On another site, some folks said their risers worked perfectly after getting the replacement spring.  They are only charging $5.00 for the spring.  I think I'll get one and see if the riser function improves.  If not, I'll tie it up as Carl suggests.  

Thank you for all the thoughts and suggestions.  I would like to meet all of you at some point.  I hear the Fall Colors Tour held in Colorado is a really nice time.  2A Site sponsors it.  Maybe some of you easterners could make the trek??

Tim  

[F Bill]

Looks like Army Jeep Parts has new Bimetal springs. �On another site, some folks said their risers worked perfectly after getting the replacement spring. �They are only charging $5.00 for the spring. �I think I'll get one and see if the riser function improves. �If not, I'll tie it up as Carl suggests. �

Thank you for all the thoughts and suggestions. �I would like to meet all of you at some point. �I hear the Fall Colors Tour held in Colorado is a really nice time. �2A Site sponsors it. �Maybe some of you easterners could make the trek??

Tim �

There is actually a spring trail ride as well usually. The 2A site only is a place for information on the trips, they are "sponsored " my M38 Mike and Bruce W.....and are definitely well worth attending.  Calvin put out an invite to the AZ UT area as well.....and that looked like fun too.

On the spring issue, I picked up a canning jar full of bimetal springs at a yard sale last year. some might even work in a jeep. They were all unused and came from a guy who worked for the phone or power company.. I have no idea what they were originally for,but they looked very similar to the jeep part.

[athawk11]

Update:  

I did get a new heat riser spring from Army Jeep Parts.  It did work.  The new spring holds the riser all the way open once the Willys has warmed up.  The replacement spring was larger than my old springs.  The bimetal reaction on the larger spring, coils more.  I guess it just needed more spring.

Tim

[Ryan_M]

I just installed a new heat riser. It took a fair amount of forum surfing to figure out the correct placement of everything. I posted a video here of it assembled without the intake manifold installed. Assuming I've done it correctly, I thought this might help others see how the flapper moves in relation to the spring and counter-weight.  If anyone sees a glaring error I'd appreciate input before I bolt the entire thing back onto the engine.

http://www.youtube.com/watch?v=EuwoZNlNxvM&feature=youtu.be

[athawk11]

Hey Ryan,
Nice video. �Your set up looks right to me. Heck, if it functions as designed, it must be right. �

It's hard to tell in your video, but the orientation of the counter weight, per most drawings and discussions, is set at about 4:00 when cold, and about 2:00 when warm. �Yours looks like around 3:00 and 1:00. �Could just be the angle of the video you shot. � If your flapper is already welded to the shaft, then I wouldn't mess with the angles. �Bottom line, yours works. � �

I did the same torch test to mine, prior to reassembly. �It worked while out of the Jeep. �In real time driving, the spring wasn't strong enough to lift the weight. �As Carl mentions above, the manifold wasn't heating my worn out spring as much as a flame from a torch.

Tim

[Ryan_M]

Thanks for the feedback. The way the counter weight setting was a little bit off. The camera angle makes it look worse than it really was but I did adjust it slightly after this video. It is now in the more correct 5:00 and 2:00.